














                    IBM SYSTEM/370 CMS KERMIT USER'S GUIDE


                                  VERSION 4.3


                                 John Chandler

                  Harvard/Smithsonian Center for Astrophysics

                              September 30, 1993



                            Copyright (C) 1981,1993
            Trustees of Columbia University in the City of New York

     Permission is granted to any individual or institution to use, copy,
    or redistribute this document so long as it is not sold for profit, and
                  provided this copyright notice is retained.
                               Table of Contents

1. IBM 370 KERMIT                                                             1

   1.1. Translation Tables                                                    1
   1.2. File Attributes                                                       2
   1.3. Program Operation                                                     2
   1.4. Kermit-370 Subcommands                                                3
   1.5. Before Connecting to the Mainframe                                    9
   1.6. Trouble-shooting Protocol Converters                                  9
   1.7. After Returning from Kermit-370                                      10
   1.8. What's New                                                           10
   1.9. What's Missing                                                       11
   1.10. Further Reading                                                     11

2. IBM CMS KERMIT                                                            12

   2.1. The CMS File System                                                  12
   2.2. Program Operation                                                    12
   2.3. Kermit-CMS Subcommands                                               13
   2.4. How to build an executable Kermit-CMS                                15
   2.5. What's New                                                           15
   2.6. What's Missing                                                       15

Index                                                                        16
                                List of Tables

   Table 1-1:   Allowed character set combinations in Kermit-370              1
   Table 1-2:   EBCDIC (hexadecimal) code points for LATIN1                   2
   Table 1-3:   Character graphics for EBCDIC codes                           2
   Table 1-4:   Error messages and codes for Kermit-370                      11
1. IBM 370 KERMIT

Program:       John  Chandler  (Harvard/Smithsonian  Center  for Astrophysics);
               contributions from Vace Kundakci and Daphne Tzoar (Columbia  U),
               Bob  Shields  (U.  Maryland),  Greg  Small  (UC Berkeley), Clark
               Frazier (Harvard Bus. Sch.), Bob  Bolch  and  Steve  Blankinship
               (Triangle),  Ron  Rusnak  (U.  Chicago),  Roger  Fajman and Dale
               Wright (NIH), Andre Pirard (U. Liege),  Pierre  Goyette  (McGill
               U.)
Language:      IBM 370 Assembler
Documentation: John Chandler (CfA)
Version:       4.3
Date:          1993 September

Kermit-370  is  a  family  of  programs  implementing  the KERMIT file transfer
protocol for IBM 370-series mainframes (System/370,  303x,  43xx,  308x,  3090,
etc.)  under  a  variety  of  operating  systems.    Kermit-370  operates  over
asynchronous ASCII communication lines attached to a 3705-style or protocol en-
veloping  3708  front  end  ("TTY" or line-mode devices), to a Series/1 or 4994
running the Yale ASCII Terminal Communication System  or  the  IBM  7171  ASCII
Device  Control Unit or a 9370 with ASCII subsystem ("SERIES1" devices), to the
IBM 3174 protocol converter at level B2.0 or  higher  ("AEA"  devices),  or  to
front-ends with graphics pass-through mode, such as the Datastream/Leedata 8010
and PCI 1076 ("GRAPHICS" devices).  As of this writing, the  pending  implemen-
tation  of  full(er)  7171 compatibility in the program product SIM3278 has not
been completed.    The  non-line-mode  devices  are  often  called  full-screen
devices.  For more details on front ends, see the section SET CONTROLLER.

The  source is coded in IBM 370 assembly language and is compatible with the F,
VS, and H assemblers.  The code is divided into sections, some generic and some
specific  to  an individual operating system.  While the details of file-system
and supervisor interaction vary widely among  the  systems  available  for  IBM
370's, the basic features are essentially the same.  This chapter describes the
features common to all variants of Kermit-370, and a separate chapter will deal
with the system-specific details for each variant.

IBM  370 systems have some peculiarities that users should be aware of.  First,
these systems are essentially half-duplex; the communication  line  must  "turn
around"  before  any  data  can  be  sent.    The  "TTY"  devices  are strictly
half-duplex, and even the "SERIES1", "GRAPHICS", and  "AEA"  devices,  although
they  maintain  full-duplex  communication  with  the terminal, must transmit a
block at a time to the mainframe.  The fact that a  packet  has  been  received
from the IBM system through a "TTY" device is no guarantee that it is ready for
a reply; generally, the true indicator of  readiness  is  the  line  turnaround
character  (XON), which the operating system sends immediately before issuing a
read request.  On some systems, however, it is possible for Kermit to  do  away
with  the  system-supplied  turnaround  and  schedule read requests immediately
after the corresponding writes.  It is up to the user to tell the other  Kermit
how it must conform to the requirements of the IBM mainframe.

A  second distinction is that disk files are encoded using the EBCDIC character
set.  Consequently, there are three layers of character translation on  packets
exchanged  on  a  "TTY"  device.    For  an incoming packet, the outer layer is
provided by the operating system, which translates all characters from ASCII to
EBCDIC.    Kermit-370 must then translate the packets back to ASCII (the middle
layer) in order to calculate and verify the checksum.  Data arriving through  a
"SERIES1",  "GRAPHICS", or "AEA" device are still in ASCII and therefore bypass
the two outer layers.  In any case, Kermit-370 translates  text  files  finally
into  EBCDIC (the inner layer) before storing on disk.  When Kermit-370 sends a
file, the opposite translations occur.  The middle-layer tables used by  Kermit
must  be  the  inverses  of the corresponding outer-layer ones used by the host
operating system if file transfers are to work at all.  If necessary, the  sys-
tem  programmer  should  add the appropriate SET TATOE/TETOA/TTABLE subcommands
(q.v.)  to the global INIT file.  Indeed, it is usually  a  good  idea  to  set
TTABLE  ON  in  the  global INIT file to force using different built-in sets of
tables for the inner and middle layers whenever the system has  "TTY"  devices.
The standard 7-bit ASCII-to-EBCDIC translations can be found in the Appendix or
the IBM System/370 Reference Card.  See the section  "Translation  Tables"  for
more details.

Another  distinction  of  IBM  370's  is  that they store and retrieve files as
records rather than byte streams.  Records may be either fixed-length with some
sort of padding (as needed) or varying-length with some sort of (generally hid-
den) delimiters.  Thus, Kermit-370 must assemble  incoming  data  packets  into
records  by  stripping  off carriage return-linefeed pairs (CRLF's) and padding
with blanks or truncating as needed and must strip trailing blanks  and  append
CRLF's to outgoing records.  (See the SET FILE TYPE subcommand.)  Further, disk
files typically have the records combined into blocks for efficiency.  One con-
sequence  of  this form of storage is that files have attributes describing the
component records: maximum record length (LRECL), record  format  (RECFM),  and
sometimes block size (BLKSIZE).

As  mentioned before, Kermit-370 is a family of programs.  At present, only the
CMS, TSO, MUSIC, ROSCOE, and CICS variants are operational.  Variants for DOS-4
and MTS have at least reached the "drawing board," but no others have even been
started as of this writing.  Volunteers are always welcome to  port  Kermit-370
to  other operating systems or add new features to the existing family.  Anyone
interested should first get in touch with the Center for  Computing  Activities
at  Columbia  University  to find out what projects of a similar nature are al-
ready pending (and thereby prevent unnecessary duplication of effort).    There
are  supplemental  files in the Kermit distribution with explanations of how to
go about porting Kermit-370 and how to add support for new terminal  controller
types.    For  details, refer to the installation guide for the variant of your
choice.


1.1. Translation Tables

Traditionally, IBM mainframe Kermits have translated 7-bit ASCII characters  to
8-bit   EBCDIC  characters  and  ignored  the  "parity"  bit  in  the  process.
Similarly, the 8-bit EBCDIC characters  have  been  mapped  onto  7-bit  ASCII,
thereby  producing  many  ambiguities  in  translating  the ASCII files back to
EBCDIC.  These ambiguities fall into  two  categories:  EBCDIC  characters  not
representable  in ASCII have been rendered as ASCII nulls, and alternate EBCDIC
representations of characters such as the  ASCII  backslash  have  been  mapped
together,  but  at  least no two 7-bit ASCII characters are translated into the
same EBCDIC character.  The ambiguities were tolerable  in  environments  where
the  traditionally  non-printable  characters never occurred in text files, but
text processing has increasingly tended to include such  characters  for  math-
ematical  formulas or for languages other than English.  Ultimately, the trans-
lation tables must become completely invertible, lest information  be  lost  in
the  transfer.    There  has long been an option to replace parts of the trans-
lation tables via commands from the user (or imbedded in the INIT  files),  but
such  replacements were always supported locally and were, therefore, basically
non-standard.

The concept of standard translations is currently in a state of flux because of
the  proliferation  of 8-bit code pages and the countervailing efforts at stan-
dardization among groups such as the ISO and Kermit developers.  In particular,
Kermit-370  now  supports  a set of EBCDIC and "extended ASCII" code pages with
built-in translation tables and automatic identification of the "ASCII"  trans-
fer  character  set via Attribute packets.  This facility supports files stored
using numerous IBM Country Extended Code  Pages  and  permits  transfers  using
character  sets  ASCII,  ARABIC,  CYRILLIC, GREEK, HEBREW, JAPAN-EUC, KATAKANA,
LATIN1, LATIN2, LATIN3, and THAI.  See Table 1-1 for a display of  the  allowed
combinations  of  character  sets.   See also file ISOK7.TXT in the Kermit dis-
tribution for a somewhat  outdated  description  of  the  protocol  extensions.
Kermit-370   currently   supports   text  files  in  the  following  languages:
Afrikaans, Albanian, Arabic, Bulgarian, Byelorussian, Catalan, Czech, Croatian,
Danish, Dutch, English, Esperanto, Faeroese, Finnish, French, Gaelic, Galician,
German, Greek, Hebrew, Hungarian, Icelandic, Italian,  Japanese  (Katakana  and
Kanji),  Lao,  Latin,  Macedonian, Maltese, Norwegian, Polish, Portuguese, Que-
chua, Romanian, Russian, Serbian, Slovak, Slovene, Spanish,  Swahili,  Swedish,
Thai,  Turkish,  Ukrainian, and Volapuk.  Visual representations of the charac-
ters sets may be found in the ISO register (for transfer) and  in  various  IBM
documents, such as S544-3156 "About Type" (for files).

Kermit itself normally operates in English, but there are versions with the in-
teractive messages translated into other languages.   The  currently  available
languages  are  Czech,  Dutch,  Finnish,  French, German, Italian, Polish, Por-
tuguese, Russian, and Spanish.  Special thanks to  Petr  Adelsberger,  Mauricio
Alvarenga,  Lorenzo  Beltrame,  Janusz  Bien,  Jose  Eduardo  de Lucca, Richard
Gatersleben, Kauko Haumalainen, Jaroslaw Kurowski, Roberto Magana, Alberto Rio,
Christian  Robert,  Gisbert  Selke,  Karel  Smuk,  Rob  van der Wal, Konstantin
Vinogradov, and Joachim Wlodarz for preparing these translations.  See the  in-
stallation  guide for details on the alternate-language versions.  There are no
translations yet of the help files, nor of this document.

-------------------------------------------------------------------------------

                              Transfer character set

  Local  ASCII ARAB. CYR. GREEK HEB. JAPAN KATAK.  L1 L2 L3 THAI

 CP037     *                                       **
 CP273                                             **
 CP275                                             **
 CP277                                             **
 CP278                                             **
 CP280                                             **
 CP281                                 *           **
 CP282                                             **
 CP284                                             **
 CP285                                             **
 CP290                                 *     **
 CP297                                             **
 CP420           **
 CP424                           **
 CP500     *                           *           **
 CP838                                                       **
 CP870                                                **
 CP871                                             **
 CP875                      **
 CP880     *          **
 CP905                                                   **
 CZECH                                                 *
 DKOI      *          ***
 EBCDIC    *      *                               ***
 H-EBCD                                *      *
 KANJI                                 *

         Table 1-1:  Allowed character set combinations in Kermit-370

All  allowed  combinations  are  marked  with  asterisks,  and  the   preferred
combination in each row or column is the one with the most asterisks.  Whenever
a character set is specified, either directly or through an  Attribute  packet,
the other category of character set is checked to see if it makes up an allowed
combination.  If not, it is forced to the preferred character set.

-------------------------------------------------------------------------------

As nearly as possible, the tables in Kermit-370 are invertible, but all of  the
character  sets  reserve many (typically 65) code points for control characters
and leave them officially undefined and unprintable.  This applies both to  IBM
code  pages and ISO standard 8-bit character sets.  Although 33 of the controls
have widely accepted mappings, the others do not, and Kermit-370 currently uses
those  given  in an appendix of IBM's VS/Fortran Reference Manual.  Needless to
say, such translations are arbitrary and may be invalidated by future decisions
at  IBM or ISO.  Still, most of the translations are likely to be stable in the
long run.  Table 1-2 shows the current translation from LATIN1 to EBCDIC, which
is likely to be the most often used.  Other translations, including the reverse
ones, may be displayed using the TDUMP subcommand of Kermit-370.

-------------------------------------------------------------------------------

      -0 -1 -2 -3 -4 -5 -6 -7 -8 -9 -A -B -C -D -E -F

  0-  00 01 02 03 37 2D 2E 2F 16 05 25 0B 0C 0D 0E 0F
  1-  10 11 12 13 3C 3D 32 26 18 19 3F 27 1C 1D 1E 1F
  2-  40 5A 7F 7B 5B 6C 50 7D 4D 5D 5C 4E 6B 60 4B 61
  3-  F0 F1 F2 F3 F4 F5 F6 F7 F8 F9 7A 5E 4C 7E 6E 6F
  4-  7C C1 C2 C3 C4 C5 C6 C7 C8 C9 D1 D2 D3 D4 D5 D6
  5-  D7 D8 D9 E2 E3 E4 E5 E6 E7 E8 E9 AD E0 BD 5F 6D
  6-  79 81 82 83 84 85 86 87 88 89 91 92 93 94 95 96
  7-  97 98 99 A2 A3 A4 A5 A6 A7 A8 A9 C0 4F D0 A1 07
  8-  20 21 22 23 24 15 06 17 28 29 2A 2B 2C 09 0A 1B
  9-  30 31 1A 33 34 35 36 08 38 39 3A 3B 04 14 3E FF
  A-  41 AA 4A B1 9F B2 6A B5 BB B4 9A 8A B0 CA AF BC
  B-  90 8F EA FA BE A0 B6 B3 9D DA 9B 8B B7 B8 B9 AB
  C-  64 65 62 66 63 67 9E 68 74 71 72 73 78 75 76 77
  D-  AC 69 ED EE EB EF EC BF 80 FD FE FB FC BA AE 59
  E-  44 45 42 46 43 47 9C 48 54 51 52 53 58 55 56 57
  F-  8C 49 CD CE CB CF CC E1 70 DD DE DB DC 8D 8E DF


            Table 1-2:  EBCDIC (hexadecimal) code points for LATIN1

This table shows the values of the EBCDIC equivalents for the  code  points  in
the  LATIN1  character  set.    The  values  are  arranged  in LATIN1 collating
sequence, and the rows and columns  are  labeled  with  the  first  and  second
digits,  respectively,  of the LATIN1 code points.  For example, LATIN1 code 41
(hex) is upper-case "A", and the intersection of row "4-" and column  "-1"  has
the  value  C1 (hex), which is the EBCDIC code for "A".  Rows "0-", "1-", "8-",
and "9-" are officially undefined in ISO 8859-1 and so, in principle, could  be
changed  at  some  future time, especially "8-" and "9-".  Note that this table
uses a format close to that of the TDUMP subcommand  and  of  the  Kermit  code
itself,  but character-set tables are often displayed with the rows and columns
interchanged.

-------------------------------------------------------------------------------

Besides converting files for transmission, Kermit-370 must also  compensate for
the  EBCDIC/ASCII translation performed by some front ends and must, therefore,
be able to apply the exact reverse translations on both input and output.  This
is the "middle layer" of translation described earlier for "TTY" devices.  Con-
sider the fate of a Left Square Bracket character in an  inbound  packet  on  a
"TTY"  line.    It  begins  as ASCII code x'5B' (91 decimal), but the front end
translates it to EBCDIC before presenting it to Kermit-370.  In  this  example,
suppose it becomes EBCDIC code x'4A' (74 decimal) instead of the standard x'AD'
(173 decimal).  Then, Kermit must be primed with a SET TETOA  74  91  so  that,
when  reconstructing  the  original  ASCII  packet, the character becomes x'5B'
again.  Otherwise, the packet checksum will appear invalid.  Kermit comes  with
a  pair  of  default tables, but it may be necessary to customize them, as this
example shows.  The following procedure will reveal any changes  needed.    The
procedure  has  two  stages:  the first is for any line-mode front end, and the
second only for front ends capable of full 8-bit data transfer.  Note that, al-
though  the discussion refers to hexadecimal values, the Kermit-370 SET subcom-
mands require decimal numeric arguments.  Also, note that  this  procedure  as-
sumes  you  will  run  Kermit  with  TTABLE  set  on;  hence, the references to
Kermit-370 tables are to TATOE and TETOA.  If you  choose  to  define  Kermit's
file  translation  to  match that of the front end, you should leave TTABLE set
off and remove the T's from the SET subcommands described  below.    This  will
also  turn  off  the automatic switching of translation tables according to the
Attribute packets received from the other Kermit.  Under CMS, you must issue  a
CMS SET INPUT and a CMS SET OUTPUT before starting this procedure.

   1. Create  a file containing all the non-control EBCDIC characters (hex
      codes 40-FF) and display the file on any  available  ASCII  terminal
      hooked up to the line-mode front end in question.

   2. If any printable ASCII character is missing from the display, Kermit
      cannot work through this front end (unless you modify the tables  in
      the front end itself).

   3. If any ASCII character appears twice, there is no cause for alarm.

   4. If any ASCII character does not appear where it should, according to
      Table 1-3, a SET TATOE must be added to the system INIT file.    For
      example, if EBCDIC code 5F (Not Sign, according to the Appendix) ap-
      pears as an ASCII Tilde (7E), but EBCDIC A1 (Tilde) does not, a  SET
      TATOE  126  95 is required.  Warning: characters considered unprint-
      able by the front end are likely to be filtered  out  entirely  when
      you display the file; do not expect the display to line up just like
      Table 1-3.

   5. Create a file on the mainframe using an ASCII  terminal  for  input,
      and  enter  all 95 printable ASCII characters in collating sequence.
      You  can  presumably  save  time  by  skipping  the  52  upper-  and
      lower-case letters and the 10 digits.

   6. Display  the file from the previous step in hexadecimal or other bi-
      nary form.

   7. If any duplicates appear among the 95 characters (or 33, if you have
      taken the short cut), Kermit cannot work through this front end (un-
      less you modify the tables in the front end).

   8. Compare the hexadecimal codes with rows 2-7 of Table 1-2.  If a dis-
      crepancy appears, a SET TETOA must be added to the system INIT file.
      For example, if ASCII Left Bracket (5B) appears as EBCDIC 4A, a  SET
      TETOA 74 91 is needed.  At this point, the first stage is complete.

   9. If 8-bit line-mode file transfer is desired, you must now verify the
      extended character set.  Display the file  of  EBCDIC  codes  again,
      this  time  using a terminal with extended character set display, or
      capture the session with a micro Kermit and  display  the  resulting
      file  in  hexadecimal.   If any code in the range A0-FE does not ap-
      pear, the front end will not  allow  8-bit  Kermit  data  transfers.
      Generate  SET TATOE entries for the entire range, as needed, just as
      in the example given for 7-bit codes.  If  the  front  end's  trans-
      lation  tables  are  documented,  it  may be easier to work from the
      manual, but you must be sure that you have tables  for  all  of  the
      translations that occur on the data path.

  10. Create  a file of the 95 extended ASCII codes A0-FE, if possible, by
      using a terminal capable of transmitting those codes or transmitting
      a  pre-made  file "raw".  If necessary, use the appropriate table(s)
      in the manual(s) instead.

  11. Again, if any duplicates appear, this  front  end  is  incapable  of
      8-bit  file transfers.  Otherwise, generate SET TETOA entries as be-
      fore.

-------------------------------------------------------------------------------

       0  1  2  3  4  5  6  7  8  9  A  B  C  D  E  F

  4-                                    .  <  (  +  |
  5-   &                             !  $  *  )  ;  ^
  6-   -  /                             ,  %  _  >  ?
  7-                              `  :  #  @  '  =  "
  8-      a  b  c  d  e  f  g  h  i
  9-      j  k  l  m  n  o  p  q  r
  A-      ~  s  t  u  v  w  x  y  z           [
  B-                                          ]
  C-   {  A  B  C  D  E  F  G  H  I
  D-   }  J  K  L  M  N  O  P  Q  R
  E-   \     S  T  U  V  W  X  Y  Z
  F-   0  1  2  3  4  5  6  7  8  9


                Table 1-3:  Character graphics for EBCDIC codes

This table shows the representations of the EBCDIC  codes  arranged  in  EBCDIC
collating  sequence,  row  by  row.    Codes  that do not correspond to ISO 646
characters (7-bit ASCII), have been left blank.  One special case is the EBCDIC
code 5F, which represents a Not Sign in IBM's CP037, but which is traditionally
mapped to the ASCII Circumflex, as shown here.  WARNING: this manual  may  have
been  printed  on  a  device  that  maps  characters  differently.  Consult the
Appendix to verify.

-------------------------------------------------------------------------------


1.2. File Attributes

Kermit-370 attempts to send and receive file attributes along  with  the  files
themselves.    Before  Kermit receives a file, it compares the Length attribute
(if available) with the amount of disk space available (if known) so  that  the
file can be rejected if it will not fit.  In addition, the Type, Access, Encod-
ing, Disposition, and Format attributes, if any, are interpreted  in  order  to
match  the  received file to the original as nearly as possible.  All other at-
tributes (including Date) are simply ignored.  For Type, Kermit recognizes text
and binary specifications; for Access, it recognizes append, normal, and super-
sede; for Encoding, it recognizes ASCII, extended, and EBCDIC (which it  treats
as  binary);  for Disposition, it recognizes mail, print, and job; and for For-
mat, it recognizes text, D-binary, V-binary, binary,  and  LRECL.    Any  other
values are rejected.

On  sending a file, if the other Kermit is willing to accept Attribute packets,
Kermit-370 sends the Type, Encoding, Format, Date, and Length  attributes  (un-
less  some  or  all of them have been disabled -- see the SET ATTRIBUTE subcom-
mand).

Unfortunately, the set of file attributes defined in the Kermit protocol is not
well  matched  to  the  needs  of  IBM  370  file  systems, so that much of the
machinery for creating and interpreting of Attribute packets is useless.    For
example, the "Format" attribute, which should logically specify the record for-
mat of the received file, gives only the format of the file in transmission and
cannot  distinguish  between  fixed-length  and varying-length records for text
files.  This limitation is partly due to the fact that  other  Kermits  do  not
generally  support the same attributes.  In short, even if the protocol made it
possible, some of the important attributes would  never  be  specified  anyway.
Nonetheless,  efforts  are  being  made  to extend the protocol to be more com-
prehensive.


1.3. Program Operation

Kermit-370 can be invoked directly or from a  command  procedure.    In  either
case,  it  reads  and executes subcommands sequentially until directed to quit,
and then returns.   A  subcommand  consists  of  one  or  more  fields  (words)
separated by spaces or commas.

Upon  startup,  the  program looks for two (optional) initialization files, one
system-wide and a second specific to the user.  Both filespecs are, of  course,
system-dependent.    The  purpose  of these files is to allow Kermit to be cus-
tomized for a particular system and for  a  user's  specific  settings  without
changing  the source code.  The system-wide file, which is maintained by a sys-
tems programmer, should contain Kermit subcommands that all users would need to
issue  in  order for Kermit to run on the system, such as subcommands to modify
the ASCII/EBCDIC tables used by Kermit-370.  The user-specific  file,  if  any,
should  contain subcommands that the user generally issues every time Kermit is
run.  Kermit-370 executes any subcommands found in these files as  though  they
were typed at the terminal.  Here is a sample INIT file:

    * Asterisk in column one is a comment.
    set transfer character-set latin1
    set file collision rename
    set block 3

During  interactive  execution,  you  may  use  the built-in help feature while
typing Kermit-370 subcommands.  A question mark ("?") typed at almost any point
in a subcommand, followed by a carriage return, produces a brief description of
what is expected or possible at that point.  Moreover, mistyping  a  subcommand
will generally produce a helpful error message or a list of possible options at
the  point  of  error.    Keywords  in  such  lists  are  displayed  with   the
minimum-length  abbreviation  in upper case and the remainder, if any, in lower
case.  In entering Kermit subcommands, any keyword may be shortened to any sub-
string that contains the minimum abbreviation.

Besides  knowing  the mechanics of entering Kermit subcommands and interpreting
responses, the user must understand  which  subcommands  are  necessary.    The
default  values for Kermit-370 options have, in some cases, been constrained by
a desire for continuity, so that some of the  default  behavior  is  distinctly
"suboptimal."    An  example of this is the traditional 80-byte default RECEIVE
packet size, which generally gives much slower transmission than a size of 1000
or  more.    Such options are flagged in this chapter with a notation that they
perhaps ought to be set in the INIT files.  Note, however, that  the  interplay
of Kermit protocol sometimes provides a performance upgrade with no special ac-
tion required from the Kermit-370 user.    An  example  of  this  is  the  SEND
packet-size, which is always under the control of the other Kermit.  Kermit-370
always sends packets as long as the other Kermit allows, unless  the  frequency
of  transmission  errors indicates that shorter packets would be more efficient
(see the subcommand SET SPEED).

Kermit-370 also attempts to produce optimal results by adapting to the file at-
tributes sent by the other Kermit along with the files, such as TYPE and LRECL.
Such attributes, when sent by the other Kermit, temporarily override  the  cur-
rent  settings  in  Kermit-370  during  the  reception  of the associated file.
Potentially even more  importantly,  Kermit-370  automatically  recognizes  the
character  set  used  for  the  file transfer and chooses, if necessary, a com-
patible character set for file storage.  Table 1-1  shows  the  currently  sup-
ported  list  of  character  sets.    As with any automatic operation, Kermit's
honoring of the transmitted attributes may need to be suppressed in part or al-
together, and the SET ATTRIBUTE subcommand provides this capability.

Another  attribute  that  Kermit-370 supports is file disposition, which allows
files to be received and immediately retransmitted as electronic mail, sent  to
a  printer,  or  submitted  as  a  batch  job.   These three options are highly
site-specific and are implemented as a set of three host commands with  similar
calling  sequences.  In each case, the command is invoked in two different ways
in the process of processing the file.  It is called without  any  filespec  or
other  options  as  soon  as  the  corresponding  attribute  is  recognized  by
Kermit-370.  If the command is not implemented or for  some  reason  returns  a
non-zero  completion code (such a code should be negative, if at all possible),
Kermit-370 rejects the file using  the  normal  attribute  exchange  mechanism.
Otherwise,  the  file is received as usual, and the command is invoked again at
the end-of-file.  The second time,  the  command  is  given  the  name  of  the
received  file  and  the  options received from the sending Kermit (such as the
list of recipients for electronic mail).  The command is then  responsible  for
disposing  of  the file (and deleting it, if desired).  If, for any reason, the
file cannot be sent as required, the command should return a  negative  comple-
tion  code  (or  non-zero, at any rate), and Kermit-370 will send back an error
message to the sending Kermit.  The command itself should refrain from  issuing
any  messages  of  its own or permitting commands that it invokes to issue mes-
sages.  See the beginning of the chapter  on  the  system-specific  variant  of
Kermit-370  for  the exact command syntax.  Some sample implementations of such
commands  may  be  available  in  the  Kermit  distribution  --  refer  to  the
system-specific installation guide for a list of samples.


1.4. Kermit-370 Subcommands

The  following is a summary of Kermit subcommands.  The starred subcommands can
be issued as remote Kermit commands to Kermit-370 when it is  in  server  mode.
System-specific subcommands are omitted from this list.
          BYE      logs out other Kermit server.
          CWD*     establishes a new working directory.
    DIRECTORY      displays all or part of the disk directory.
         ECHO      a line back to the user.
         EXIT      from Kermit-370.
       FINISH      other Kermit server.
          GET      file(s) from a Kermit server.
         GIVE*     creates a TAKE file snapshot of a table.
         HELP      about Kermit-370.
         HOST*     executes a system command.
       KERMIT*     executes a Kermit subcommand.
         QUIT      from Kermit-370.
      RECEIVE      file(s) from other Kermit.
         SEND      file(s) to other Kermit.
       SERVER      mode of remote operation.
          SET*     various parameters.
         SHOW*     various parameters.
        SPACE*     displays disk storage allocation.
       STATUS*     inquiry.
         STOP      easy escape from protocol mode.
         TAKE*     subcommands from file.
        TDUMP*     dumps the contents of a table.
         TYPE*     a file.
      VERSION*     of Kermit-370.
        XECHO      echoes a line (transparently).
        XTYPE      displays a file (transparently).

Although Kermit-370 is generally a remote Kermit, it has the capability of com-
municating with another  Kermit  in  server  mode.    In  that  situation,  the
subcommand prefixes REMOTE and LOCAL refer to the Kermit server and Kermit-370,
respectively, even when Kermit-370 is, strictly speaking,  the  remote  Kermit.
To  help  avoid  confusion,  this  chapter will often use the term "foreign" to
apply to the Kermit at the other end from Kermit-370.  All  the  above  subcom-
mands may be preceded by the LOCAL prefix, but only certain ones are valid with
REMOTE, including some not shown here.  See the description of the SERVER  sub-
command  for details.  Any text replies Kermit-370 gets from the foreign Kermit
server  are  added  to  a  disk   file   (whose   filespec   is,   of   course,
system-dependent).    Such a transaction can be carried out, for example, under
control of a TAKE file if Kermit-370 is not operating locally.   If  the  local
Kermit  has  a "magic" character sequence that switches it from terminal emula-
tion to server mode, then an  entire  session  could  be  controlled  from  the
mainframe,  possibly  in  response  to a single command issued by a naive user.
For example,

    .grab

         Kermit-370 is invoked and executes the following TAKE file

    ECHO Serve Me!        the local Kermit switches to server mode
    GET file.a            the server uploads file.a
    FINISH                the server switches back to terminal mode

The remainder of this section describes subcommands with special meaning or use
in  Kermit-370, except the highly system-dependent ones.  For the latter, refer
to the appropriate chapter.  Subcommands are listed in alphabetical order.


                        THE ECHO AND XECHO SUBCOMMANDS

Syntax: [X]ECHO line

These subcommands type the line back at the user.  The line may contain control
characters  or  any desired text, including upper or lower case.  These subcom-
mands may be used, for example, to test the ASCII/EBCDIC translate tables or to
issue coded commands to the user's terminal.  XECHO differs from ECHO primarily
in that it sends the text as a raw transmission according to the  current  CON-
TROLLER setting.  Thus, XECHO will, if necessary, break the text into pieces no
larger than the current SEND PACKET-SIZE and will use transparent mode if  CON-
TROLLER  is  SERIES1,  GRAPHICS  or  AEA.    It  also  offers  its own brand of
control-character quoting, using the "^" character to indicate  that  only  the
five  low-order  bits of the ASCII codes are to be used.  Thus, "^a", "^A", and
"^!" are all translated to SOH (CTRL-A), while  "^["  becomes  ESC.    However,
there  must  be one exception for "^" itself: "^>" and "^~" are both translated
to RS (CTRL-^), but "^^" becomes just "^".  XECHO also decodes 8th-bit quoting,
just as in Kermit protocol, and this feature can be disabled by setting 8th-bit
quoting off.  For example, if the 8th-bit quote character is "&", entering  the
subcommand  "XECHO &A" will transmit a code x'C1', but the same subcommand with
quoting off will transmit two bytes: x'2641'.


                              THE GET SUBCOMMAND

Syntax: GET [foreign-filespec [filespec]]

The GET subcommand tells Kermit to request a file or file group from the  other
system,  which  must  have a Kermit running in server mode.  Provided the other
Kermit complies, the effect is the same as if SEND  foreign-filespec  had  been
issued  directly  to the other Kermit and RECEIVE [filespec] to Kermit-370.  If
this subcommand is issued without any arguments,  Kermit-370  will  prompt  the
user  for  both  foreign  and  native filespecs (and will insist on getting the
former, but will do without the latter).  See the respective SEND  and  RECEIVE
subcommands for a description of the each filespec.


                              THE GIVE SUBCOMMAND

Syntax: GIVE table-name filespec

This compares the named translation or selection table with its current default
values and saves the differences in the form of a TAKE file consisting  of  SET
subcommands that would convert the default into the current arrangement.  ATOE,
ETOA, TATOE, and TETOA are the available translation tables,  and  CONTROL-CHAR
is  the selection table.  The details of the filespec are system-dependent, but
those details will, in general, be the same as for the TAKE subcommand  (q.v.).
In  the  case of tables ATOE and ETOA, the current defaults are the values from
the most recent character-set definition, if any, but the  defaults  for  TATOE
and  TETOA always remain at the initial values.  See the SET FILE CHARACTER-SET
and SET TRANSFER CHARACTER-SET subcommands for more details.


                             THE HINTS SUBCOMMAND

Syntax: HINTS

This subcommand produces a screenful of suggestions for Kermit  operation,  in-
cluding warnings about any current settings that may be undesirable.
                              THE HOST SUBCOMMAND

Syntax: HOST text of command

This  issues  a  command  to the host operating system from Kermit-370.  When a
command returns a  non-zero  completion  code,  the  code  will  be  displayed.
Generally,  the  name of the system (e.g., CMS) is treated as a synonym for the
HOST subcommand.

When Kermit-370 is in (non-local) server mode, you must avoid  sending  it  any
HOST  commands  that  trigger full-screen terminal I/O, since the server-client
interface  does  not  provide  any  full-screen  terminal  emulation,  nor   is
Kermit-370 usually able to intercept such I/O in any case.


                             THE KERMIT SUBCOMMAND

Syntax: KERMIT text of subcommand

This  is  provided  for  redundancy  as the counterpart of the HOST subcommand.
Kermit-370 executes the specified text as a Kermit subcommand just  as  if  the
LOCAL prefix had been entered.  Note, however, that the specified text must not
begin with a second KERMIT prefix.


                            THE RECEIVE SUBCOMMAND

Syntax: RECEIVE [filespec]

The RECEIVE subcommand tells Kermit-370 to accept a file or file  group.    The
user  must  issue  the corresponding SEND subcommand to the other Kermit.  When
files are received, their names are recorded in a transaction log in memory and
may be viewed later via the TDUMP NAMES subcommand.  The log contains the names
along with the file sizes and any relevant error messages.  Another form of log
may  be provided through an accounting exit routine, which is called at the end
of every RECEIVE session.  Such an accounting log may contain elapsed time  and
numbers of bytes sent, received, and transferred to/from disk.  If an error oc-
curs during the file transfer, as much of the file as was received is saved  on
disk.    If,  however,  the  sending  of a file is cancelled by the user of the
foreign system, Kermit-370 will discard whatever had arrived, unless FILE  COL-
LISION is APPEND or INCOMPLETE is KEEP.

Kermit-370  has a context-dependent maximum record length, and received records
longer than that will be folded or truncated to the proper  length;  when  this
happens,  Kermit  may  or  may  not  stop,  depending  on the FILE subparameter
LONGLINE.  If truncation does occur, Kermit will later note the fact as an  er-
ror (unless something more serious happens in the meantime).  In addition, when
a fixed record length is specified, received records are padded to the  correct
length.   The padding character is a blank for text files and a null for binary
files.  Received binary (but not V-binary or D-binary)  files  are  treated  as
byte streams and broken up into records all of the logical record length, i.e.,
folded.  For more details on the RECEIVE subcommand syntax and  operation,  see
the  chapter  on  the  desired system-specific variant of Kermit-370 under both
RECEIVE and SET FILE.  See also (in this chapter) the SET FILE LONGLINE subcom-
mand for details on record truncation and folding.


                              THE SEND SUBCOMMAND

Syntax: SEND [filespec[<options>] [foreign-filespec]][, ...]

The  SEND subcommand tells Kermit-370 to send a file or file group to the other
(foreign) Kermit.  If no such file exists, Kermit-370 simply displays an  error
message  and issues another prompt.  Like RECEIVE, SEND keeps a transaction log
of all files transferred in a group and calls the accounting  exit  routine  at
the  end  of  the session.  If this subcommand is issued without any arguments,
Kermit-370 will prompt the user for both native and foreign filespecs (and will
insist  on getting the former, but will do without the latter).  Either with or
without prompting, SEND allows specifying a list of up to  13  files  (or  file
groups)  separated  by  commas.    (By  ending  the  command line or subsequent
response with a comma, the user ensures further prompting.)   In  this  syntax,
the  options  enclosed  in angle brackets may be regarded as part of the native
filespec.  There must be no intervening blanks.  At present, the only supported
option  is a range of line numbers within the file to be sent.  The range takes
the form [n][-[m]], where n is the number of the first line to  send  (counting
from  1),  and m is the last.  Omitting either number implies the corresponding
limit is the physical beginning or end of the file.  This  same  option  syntax
may  be  used  in some commands issued to the foreign Kermit, namely, those in-
volving filespecs in 370 form.  In particular, GET and REMOTE TYPE can use this
syntax.    Note  that  a  trailing  ">"  is used by some other Kermits, such as
MS-Kermit, to indicate redirection of the output from REMOTE commands to  disk.
In order to transmit the ">" and also prevent the redirection to disk, it would
be necessary to add an explicit redirection to the terminal, as in

    REM TYPE filespec<n-m> > CON

Although file transfers cannot be cancelled from the 370  side,  Kermit-370  is
capable of responding to "cancel file" or "cancel batch" signals from the local
Kermit; these are typically entered by typing CTRL-X or CTRL-Z, respectively.

When Kermit-370 sends files using long packets (longer than 94), the throughput
is  especially  sensitive to the level of noise on the line because retries are
so time-consuming.  Therefore, Kermit-370  imposes  an  extra,  heuristic  size
limit  on  packets  when  retries  have been found necessary.  When that is the
case, after every 15 packets, Kermit  computes  the  packet  size  for  maximum
throughput   assuming   that  the  transmission  errors  were  due  to  sparse,
Poisson-distributed noise bursts.  The result of this calculation is then  used
as  another  limit on the size of outgoing packets besides the one specified by
the other Kermit.  If no retries are required, then Kermit-370 assumes the line
to  be  noiseless  and sends packets of the maximum length the other Kermit al-
lows.  The algorithm is explained in Kermit News V. 3 #1.  For more details  on
the  SEND  subcommand  syntax  and  operation,  see  the chapter on the desired
system-specific variant of Kermit-370.


                             THE SERVER SUBCOMMAND

Kermit-370 is capable of acting as a server.  In server  mode,  Kermit-370  can
send and receive files, execute host commands, execute a restricted set of Ker-
mit subcommands, and perform a variety of generic Kermit functions.   The  fol-
lowing list shows the typical local Kermit commands along with the server func-
tions they elicit.  When Kermit-370 is talking to  another  Kermit  running  in
server mode, these same subcommands may be used in the other direction.
BYE                 log out the Kermit server.
FINISH              server mode.
GET                 a file or files from the server.
REMOTE
  COPY              a file or files.
  CWD               set new working directory.
  DELETE            a file or files.
  DIRECTORY         display file attributes.
  HELP              display a command summary, such as this.
  HOST              execute a system command.
  KERMIT            execute a Kermit-370 subcommand.
  PRINT             send a file to be printed by the server.
  RENAME            a file or files.
  SPACE             display disk space.
  TYPE              a file.
SEND                a file or files to the server.

If  your  local Kermit does not support the REMOTE KERMIT command, you may need
to issue SET subcommands to select various options  before  typing  the  SERVER
subcommand.    Once  in server mode, Kermit-370 will await all further instruc-
tions from the client Kermit on the other end of the connection until a  FINISH
or BYE command is given.

Command  execution  in  server  mode  is different in some respects from normal
operation.  First of all, some Kermit subcommands are not allowed (see the list
at  the  beginning of this section).  Moreover, command errors always terminate
any active TAKE file.  Also, all commands will be run in the  special  environ-
ment that Kermit sets up during protocol transfers.  Among other things, Kermit
intercepts all terminal I/O (if possible)  in  this  environment  in  order  to
transmit the data to the local Kermit as text packets.

Note  that  some operations can be requested by several different commands.  If
for example, the IBM 370 system has a command "PRT" for displaying  a  file,  a
user  interacting  with a Kermit-370 server can choose to display a file by is-
suing any of the commands: REMOTE TYPE, REMOTE HOST PRT,  REMOTE  KERMIT  TYPE,
REMOTE  KERMIT HOST PRT, or (if SYSCMD has been set ON) REMOTE KERMIT PRT.  The
first form simply transfers the requested file as text, but the  others  invoke
the  "PRT"  command  with any specified options, intercept the terminal output,
and return the results to the local Kermit.  The first  form  is  also  distin-
guished  by the fact that the line range may be specified in the same manner as
in the SEND subcommand.  The syntax of the others is system-dependent.


                              THE SET SUBCOMMAND

Syntax: SET parameter [value]

The SET subcommand establishes or modifies various parameters controlling  file
transfers.    The  values  can,  in turn, be examined with the SHOW subcommand.
Some parameters have two levels.  In particular, there are two  matching  lists
of  SEND  and  RECEIVE  sub-parameters corresponding to the values exchanged by
Kermits in the Send-Init/ACK sequence.  For each of  these  SEND/RECEIVE  pairs
one  element is encoded in outgoing parameter packets, and the other is decoded
from incoming ones.  Setting the latter by hand may be needed to establish con-
tact  and also has the effect of redefining the default value for decoding from
subsequent parameter packets.  Generally,  the  distinction  between  SEND  and
RECEIVE  parameters  is  unambiguous,  the only exception being TIMEOUT (q.v.).
The following SET subcommands are available in Kermit-370:
ATOE                Modify the Kermit-370 ASCII-to-EBCDIC table.
ATTRIBUTE           Determine A-packet generation.
BLOCK-CHECK         Level of error checking for file transfer.
CONTROLLER          Indicate type of terminal connection.
CONTROL-CHAR        Set prefixing state.
DEBUG               Log packet traffic during file transfer.
DELAY               Length of pause before a SEND subcommand.
EOF                 Text file truncation at CTRL-Z.
ETOA                Modify the Kermit-370 EBCDIC-to-ASCII table.
FILE                Attributes for incoming or outgoing files...
  CHARACTER-SET     ... for 370 storage.
  COLLISION         ... treatment for duplicate names.
  LONGLINE          ... treatment of too-long records.
  OVERWRITE         ... treatment of attributes.
  TYPE              ... text or binary.
  other             ... system-specific attributes.
FOREIGN             Strings added to outgoing filespec...
  PREFIX
  SUFFIX
INCOMPLETE          Determine the action on an aborted file transfer.
LINE                Specify alternate communication line.
MARGIN              for sending files...
  LEFT
  RIGHT
PROMPT              For Kermit-370 subcommands.
RETRY               Maximum retry count...
  INIT              ... for initial packet exchange.
  PACKET            ... per packet for ongoing transfer.
SERVER-TIMEOUT      Spacing between server NAK's.
SPEED               Line speed for packet-size calculations.
SYSCMD              Try apparently invalid Kermit subcommands on host system.
TABS-EXPAND         Determine tab-to-space conversion on reception.
TAKE
  ECHO              Echo subcommands read from TAKE files.
  ERROR-ACTION      Exit from TAKE file on command error.
TEST                Facilitate testing of Kermit.
TATOE               Modify the Kermit-370 ASCII-to-EBCDIC table.
TETOA               Modify the Kermit-370 EBCDIC-to-ASCII table.
TRANSFER            Options for transmission...
  CHARACTER-SET     ... of text files.
  LOCKING-SHIFT     ... protocol extension.
TTABLE              Determine which tables undo the terminal translation.
8-BIT-QUOTE         Determine state of 8th-bit prefixing.
SEND or RECEIVE
  END-OF-LINE       Packet terminator.
  PACKET-SIZE       Maximum packet size.
  PAD-CHAR          Character to insert before each packet.
  PADDING           Number of pad characters to insert.
  PARITY            Indicate if 7-bit or 8-bit data.
  QUOTE             Use to quote control characters in packets.
  START-OF-PACKET   Packet beginning marker.
  TIMEOUT           Time limit for response.


SET ATOE etc.

Syntax: SET table [num1 num2]

This modifies one of the ASCII/EBCDIC translation  tables  used  by  Kermit-370
(for  example,  to  conform  to  your system).  The valid table names are ATOE,
ETOA, TATOE, and TETOA.  The arguments are, respectively, the offset within the
named  table  and the new value for that offset.  If the arguments are omitted,
the table is restored to its initial arrangement.  Both num1 and num2 should be
in the range 0-255 (decimal).  For example, in ATOE or TATOE, the offset is the
ASCII character code, and the new value is the new EBCDIC  result  code.    In-
itially,  ATOE  and  TATOE each contain two identical copies of the 7-bit ASCII
character table.  Helpful hint: if you have files that  make  use  of  extended
(8-bit)  ASCII  codes and wish to upload them via Kermit-370, be sure to define
unique EBCDIC equivalents of all the needed 8-bit ASCII  codes  or  else  treat
such  files  as binary data.  Any time you use the SET ATOE or SET ETOA subcom-
mands, that has a side effect equivalent to SET ATTRIBUTE ENCODING OFF  (q.v.).
If the extended ASCII character set is one of those supported for file transfer
in Kermit-370, you need only issue a SET TRANSFER CHARACTER-SET (q.v.).

Note: the meaning of the tables depends on the TTABLE setting -- if  TTABLE  is
OFF, the TATOE and TETOA tables are not used.


SET ATTRIBUTE

Syntax: SET ATTRIBUTE [attribute] ON or OFF

The  individual  attributes  are  LENGTH,  TYPE,  DATE, CREATOR, ACCOUNT, AREA,
PASSWORD, BLOCKSIZE, ACCESS, ENCODING, DISPOSITION,  PROTECT,  ORIGIN,  FORMAT,
SYS-INFO,  and  BYTE-LENGTH.  Kermit-370 distinguishes between the two forms of
this subcommand by counting "words".  In order to see the list of supported at-
tributes, you must enter "SET ATTR ? ?"; if you enter just "SET ATTR ?", Kermit
will list just the alternatives ON and OFF.

ON      The specified attribute is to be processed, or  attribute  packets  are
        generated  for  all outgoing files, provided the other Kermit indicates
        the ability to accept them.  (Default).

OFF     The specified attribute is to be ignored  and  not  generated,  or  at-
        tribute packets are never generated.


SET BLOCK-CHECK

Syntax: SET BLOCK-CHECK type

This determines the type of block check used during file transfer, provided the
other Kermit agrees.  Valid options for type are:  1-byte (for a  one-character
checksum), 2-byte (for a two-character checksum), 3-byte (for a three-character
CRC), and Blank-free-2 (for a shifted two-character checksum that avoids  using
blanks.    This  is  one  of  only  two Send-Init parameters that cannot be SET
separately for SEND and RECEIVE.


SET CONTROLLER

Syntax: SET CONTROLLER type

The type may be TTY, SERIES1, GRAPHICS,  AEA,  FULLSCREEN,  VTAMTTY,  or  NONE.
Kermit-370  automatically  determines  whether you are connected via a Series/1
(or similar) emulation controller or a TTY line.  In some  circumstances,  such
as when the connection is through a non-graphics-capable 3174 port, Kermit will
set CONTROLLER to NONE, which has the effect of disabling file transfers.  This
subcommand is provided, though, to allow the automatic choice to be superseded,
and because Kermit may not be able to  distinguish  between  Series/1-type  and
other  3270-emulation  controllers.   In particular, there is no way to distin-
guish between FULLSCREEN and GRAPHICS from within Kermit.  When  CONTROLLER  is
set  to SERIES1, GRAPHICS, or AEA, Kermit disables the 3270 protocol conversion
function by putting the terminal controller into "transparent mode", which  al-
lows Kermit packets to pass through intact.  Note: an incorrect CONTROLLER set-
ting may lock up or wipe out your session when you try to transfer files.

Kermit operation is possible through an IBM 3708  front  end,  but  only  in  a
rather  specific configuration.  See the installation guide for your variant of
Kermit-370 for the details of that and other hardware-related restrictions  and
configurations.


SET CONTROL-CHAR

Syntax: SET CONTROL-CHAR mode [number]

The mode may be PREFIXED (normal Kermit protocol for control characters) or UN-
PREFIXED.  In the latter case, the specified  control  character  (given  as  a
decimal  number  in  the range 0-31 or 128-159) is transmitted "as is".  If the
number is omitted, then all control characters are set accordingly.  Kermit-370
automatically  overrides  the  user's  settings for certain characters used for
Kermit protocol: the start-of-packet,  the  end-of-packet,  the  handshake  (if
set),  and  XOFF (not really used, but too dangerous to send).  Sending control
characters without prefixes can speed up transfers of binary files.

The status of prefixing is initially "PREFIXED" for all control characters.  It
can  be  displayed  by  the TDUMP CONTROL subcommand, or saved in the form of a
TAKE file by the GIVE CONTROL subcommand (q.v.).


SET DEBUG

Syntax: SET DEBUG OFF or ON [RAW] [I/O] [SAVE] [LONG] [TIME]

Note: any combination, in any order, of RAW, I/O, SAVE, and TIME may follow  or
replace ON.  Each of the three implies ON.

ON      Keep  a journal of all packets sent and received in a log file on disk.
        If the file already exists, it is erased and overwritten.  The filespec
        of  the log is, of course, system-dependent.  All packets are logged in
        EBCDIC  for  legibility,  even  when  CONTROLLER  is  set  to  SERIES1,
        GRAPHICS, or AEA.

RAW     The same as ON, but packets are logged in the form that is passed to or
        from the operating system, i.e., EBCDIC for TTY or  VTAMTTY  terminals,
        and  ASCII  for  SERIES1,  GRAPHICS, and AEA terminals.  This option is
        generally not recommended; I/O is preferable.

I/O     The same as ON, but the log includes additional transmission status in-
        formation, such as the AID returned by a full-screen device.  See below
        for a summary of the log formats.

SAVE    The same as ON, but the log file is closed after each entry  is  added,
        so  that, if the session is abnormally terminated, the log file will be
        complete and readable.

LONG    The same as I/O, but the additional information is not truncated to  36
        bytes.

TIME    Used  only  with I/O or LONG.  The lines of hexadecimal dump are tagged
        with the time of day from the  CPU  clock,  truncated  to  the  nearest
        second.

OFF     Stop logging packets and close the the log file.  (Default.)

Often,  problems  with  Kermit  file transfers or server-mode operations can be
diagnosed by setting DEBUG on in one or both Kermits, regardless of  where  the
problems  actually  lie.  For Kermit-370, the maximum amount of information can
generally be obtained by setting DEBUG to I/O or LONG, but the  format  of  the
log  depends  somewhat  on which variant of Kermit-370 is involved.  Before ex-
amining the log, you should set DEBUG OFF either explicitly or by exiting  from
Kermit-370.

There  is  an  optional feature for logging dumps of storage blocks at selected
points in the execution.  By default, this feature  is  disabled  (at  assembly
time) by having the variable symbol &KTRACE set to NO and also by virtue of the
fact that no calls to the dump routine are present in  the  distribution  code.
Further, the dumps are suppressed unless both DEBUG and TEST (q.v.) are set on.
To select when and what blocks to dump, it is  necessary  to  insert  calls  to
KHDMP  at  appropriate  points in the source before assembling.  Each such call
generates a dump each time it is executed, provided that  DEBUG  and  TEST  are
set,  and  the contents of all registers are preserved.  The call specifies the
starting address, the length, and a short title for  the  block.    Only  eight
characters of the title will be used.  Some examples:

            KHDMP ATOE+128,128,'ATOEhigh'
                          Dump the 2nd half of the ATOE table.

            KHDMP KHDSAV,20,'R14 - R2'
                          Dump registers 14-2.

            KHDMP 32(,13),40,'**R3-R12'
                          Dump registers 3-12.

            KHDMP (3),(0),'**QBLOCK'
                          Dump  block  addressed by R3 with length specified in
                          R0.

There is another debugging facility that is  enabled  by  the  variable  symbol
&KTRACE  along  with  the  dump option, namely, an execution trace.  There is a
circular buffer of trace elements in Kermit's working storage, and a  new  ele-
ment  is  written each time a Kermit subroutine is called or returns.  The ele-
ments contain the subroutine name plus (on entry) a  sequence  number  and  the
contents  of  registers 0 and 1 or (on exit) the character ">" and the contents
of registers 15 and 1.  There is also a mechanism for tracing extra  events  by
inserting KTRACE calls into the source.  For example,

            KTRACE 0(5),REGS=5
                          Trace eight bytes pointed to by R5 and R5 itself.

            KTRACE FOOBAR Trace eight bytes at label FOOBAR.

            KTRACE 'Found it',REGS=(1,7)
                          Trace "Found it", R1, and R7.

The  trace  table is simply updated in storage, eating its own tail.  It can be
found in a memory dump by locating the "eye-catcher" that says "KTRACE:", which
precedes the start, current, and end pointers for the table.  The table is also
accessible interactively via the TDUMP subcommand (q.v.).

Each line in the debug log begins with a one-letter tag and a  colon  and  con-
tains information according to the tag.  The following tags are defined.

S:  The text of a packet sent.  Normally, it will be encoded in EBCDIC for con-
    venience, but if DEBUG is set to RAW, the packet  will  appear  exactly  as
    passed  to or from the system, i.e., in EBCDIC for TTY or VTAMTTY lines and
    in ASCII for full-screen lines.

R:  The text of a packet received.  The same encoding applies.

A:  The AID and buffer address returned by a full-screen device  along  with  a
    read  operation (three characters in all).  The values should all be print-
    able EBCDIC.  This obsolete tag was used by TSO and MUSIC Kermits  and  ap-
    peared only when DEBUG was set to I/O.

*:  Data dumped by the optional KHDMP routine.

The  following  tags  appear only when DEBUG is set to I/O or LONG.  All values
are in hexadecimal.  The meanings differ slightly according  to  the  operating
system.   For CMS, the I/O parameter list is a channel command; for TSO or ROS-
COE, the SVC 93  (TPUT/TGET)  parameters;  for  CICS,  an  intermediate  string
similar  to channel commands.  Similarly, the status data consist of the stored
CSW plus an attention interrupt indicator for CMS, but the return code from the
I/O operation for TSO, ROSCOE, CICS, and MUSIC.

a:  Channel and device status after an unexpected attention interrupt.

b:  I/O parameter list for recovering from a CP break-in on screen.

c:  I/O parameter list for resuming normal screen operation.

d:  Data transferred on the previously indicated I/O operation.

e:  Status data after an I/O command has completed with an error.

g:  I/O parameter list for reading from the screen buffer.

i:  Status data after an I/O command has completed normally.

m:  I/O parameter list for displaying text on the screen.

o:  I/O parameter list for initializing the screen for transfers.

r:  I/O parameter list for reading from the terminal.

w:  I/O parameter list for a transparent write.

?:  I/O parameter list for some other operation, such as clearing the screen.


SET DELAY

Syntax: SET DELAY number

Normally, Kermit-370 waits 10 seconds after the SEND subcommand before starting
the transfer, but this delay may be set to any non-negative value.   Two  DELAY
values have special meaning.  When DELAY is 1, the usual two-line greeting dis-
played during protocol mode is abbreviated to a short message (the default Ker-
mit prompt with three dots...), and when DELAY is 0, the greeting is suppressed
entirely, along with the extra one-second pause for subcommands  like  RECEIVE,
SERVER, REMOTE, and the like.


SET EOF

Syntax: SET EOF ON or OFF

ON      Scan each incoming TEXT file for the first occurrence of CTRL-Z and ig-
        nore the remainder of the file (but continue decoding up to the  actual
        end of the file).  BINARY files are not affected.

OFF     Accept incoming files in their entirety.  (Default.)


SET FILE CHARACTER-SET

Syntax: SET FILE CHARACTER-SET name

Specifies  the  name  of  the character set used in files stored on disk.  This
setting may be superseded by an Attribute packet of an  incoming  file.    Cur-
rently,  the  available  names  are  CP037,  CP273, CP275, CP277, CP278, CP280,
CP281, CP282, CP284, CP285, CP290, CP297, CP420, CP424,  CP500,  CP838,  CP870,
CP871,  CP875,  CP880,  CP905,  CP1047, CZECH, DKOI, EBCDIC, H-EBCDIK-DASH, and
KANJI (or FUJITSU-KANJI, HITACHI-KANJI, or IBM-KANJI).    The  names  beginning
with  CP  refer  to  IBM  code  pages, while DKOI is the Cyrillic standard GOST
19768-87 used in the USSR, CZECH is a character set sometimes used in  Czechos-
lovakia,  and  EBCDIC (the default) is the traditional de facto standard EBCDIC
character set.  A character set other than the default may be required by local
conventions  and,  if so, should be specified in the system or user INIT files.
See Table 1-1 for the allowed combinations of transfer and file character sets.
Explicitly  setting this option has a side effect equivalent to issuing SET AT-
TRIBUTE ENCODING ON (q.v.).

The name KANJI is actually just an alias for the  local  preferred  proprietary
Kanji  code  (Fujitsu, Hitachi, or IBM).  The various Kanji character sets have
two-byte codes (DBCS), but are used with one-byte code pages  (SBCS)  as  well.
It is normally necessary to issue two SET FILE CHARACTER-SET SUBCOMMANDS in or-
der to set up for a DBCS: first, selecting  a  compatible  SBCS,  and,  second,
selecting  the  DBCS  itself.    If  the  current SBCS is incompatible with the
selected DBCS, a default will be chosen.  This default, along with  the  choice
of the particular proprietary character set associated with the alias KANJI, is
chosen by the installer.


SET FILE COLLISION

Syntax: SET FILE COLLISION action

Specifies the action to take when an incoming file has the same name as an  ex-
isting  one.    Two of the options involve choosing an alternative, unique name
similar  to  the  one  in  conflict,  but   the   details   of   choosing   are
system-specific.   Typically, the method involves adding digits to the existing
name.

APPEND       The new file is appended to the old one.  This option has the  the
             same effect as the old subcommand SET APPEND ON.

BACKUP       The  existing  file  is  renamed,  and  the  new file is given the
             desired name as if no conflict had occurred.

DISCARD      The incoming file is rejected by returning a "cancel file" indica-
             tion on any Data packets.

OVERWRITE    The  existing file is overwritten with the incoming file.  This is
             the default for the CMS, TSO, ROSCOE, and MUSIC variants.   Chang-
             ing  this  default  is a good candidate for INIT files.  When COL-
             LISION is set to OVERWRITE, the attributes of  the  new  file  are
             determined by the current setting of FILE OVERWRITE (q.v.).

RENAME       The  incoming file is renamed so as not to destroy (overwrite) the
             pre-existing one, and the new name is returned to the sending Ker-
             mit for information purposes.  This has the same effect as the old
             subcommand SET WARNING ON.  This  is  the  default  for  the  CICS
             variant.


SET FILE LONGLINE

Syntax: SET FILE LONGLINE FOLD or TRUNCATE or HALT

This  specifies the action to take when a received line is longer than the cur-
rent maximum record length.  That length is determined  by  the  context  in  a
system-specific way.  Refer to the description of the RECEIVE subcommand in the
appropriate chapter for details.

FOLD        Specifies that long lines are to be split into two or more  records
            as  needed,  all but the last being of the maximum length.  No null
            records are created when the received line is an exact multiple  of
            the  record length.  BINARY files are always considered, by defini-
            tion, as a single line and, therefore, are always  folded,  regard-
            less  of  the  setting  of  this  parameter.  V-BINARY and D-BINARY
            files, on the other hand, are reconstructed by  folding  at  points
            determined  by  the context within the received file, and cannot be
            folded further to fit the current maximum length.  Any such records
            that are too long will be truncated.

TRUNCATE    Specifies  that  long  lines  are  to  be  truncated at the maximum
            length.  (Default.)  Kermit-370 takes note of the  number  of  such
            truncations  performed  on a file and reports it in the STATUS mes-
            sage and also treats the fact of truncation as an  error  when  the
            file  transfer  is  complete.  The file will have been transferred,
            but obviously not quite intact.  However, this option can be useful
            for  some  tasks,  such  as  stripping  sequence  numbers from card
            images.  The process is similar to that provided by the SET  MARGIN
            RIGHT subcommand for sending files.

HALT        Specifies that a file transfer is to halt immediately if a received
            line is too long.  Kermit-370 then issues an error packet and stops
            the transfer.


SET FILE OVERWRITE

Syntax: SET FILE OVERWRITE DEFAULT or PRESERVE

DEFAULT    Specifies  that  the  current file attribute settings are to be used
           for the new file.  The result is roughly the  same  as  if  the  old
           file,  if  any,  were  completely  erased  before  the  new  file is
           received.  (Default.)

PRESERVE   Specifies that the attributes of the file being overwritten  are  to
           be  retained  and  used for the new file.  The result is roughly the
           same as if the old files contents were deleted,  and  the  new  file
           were appended to the empty stub.
SET FILE TYPE

Syntax: SET FILE TYPE type

Specifies  the type of data comprising files to be sent or received.  This set-
ting may be temporarily superseded by the Attribute packets for  a  file  being
received.

TEXT       Specifies  ordinary text.  ASCII-to-EBCDIC or EBCDIC-to-ASCII trans-
           lation is performed on the data.  Trailing blanks are  removed,  and
           CRLF's  are  appended to outgoing records. CRLF's are used, in turn,
           to determine the end of incoming  records,  which  are  padded  with
           blanks  if  necessary  to  fill buffers.  (Default.)  Note: trailing
           blanks are removed from outgoing,  varying-length  records  only  if
           they  consist  of a single blank each, or if there is a right margin
           specified (q.v.).  Further  note:  a  given  file  is  intrinsically
           categorized  as fixed-length or varying-length (or undefined-length)
           by the file system and cannot be changed simply by setting the  FILE
           RECFM  parameter  in  Kermit.    Conversion  between  formats  is  a
           system-specific function; see the system  documentation  or  consult
           your local support staff for details on conversion techniques.

BINARY     Specifies  bit-stream  data.  No translation is performed, no CRLF's
           are added to outgoing records, and  blanks  are  neither  added  nor
           removed.    Incoming  bytes  are  added  successively to the current
           record buffer, which is  written  out  when  the  current  LRECL  is
           reached.  Padding, if necessary, is done with nulls.

V-BINARY   Specifies  varying-length-record binary data.  This type is like BI-
           NARY, except that a two-byte binary prefix is added to each outgoing
           record giving the number of data bytes, and incoming records are set
           off by (and stripped of) their prefixes on receipt.

D-BINARY   Is like V-BINARY except  that  the  length  prefixes  are  five-byte
           ASCII-encoded decimal (right-justified with leading zeroes).


SET FOREIGN

Syntax: SET FOREIGN PREFIX string

This  defines a prefix string to be added to the outgoing filespec generated by
the SEND subcommand.  For example, the string might be set to "B:"  to  specify
output to the B disk drive on the other Kermit's system.  The default is a null
string.  There is also a FOREIGN SUFFIX handled in the same manner.


SET HANDSHAKE

Syntax: SET HANDSHAKE number

This defines the character, if any, that Kermit-370 should send (or cause to be
sent)  immediately  before  reading each packet.  The character is given as the
decimal of an ASCII control character, or as zero if  no  handshake  is  to  be
sent.    The default is 17 (XON), and any value in the range 0-31 is valid, but
13 (CR) should not be used because it is generally the end-of-packet character.
When  Kermit-370  is  running  through  a  full-duplex  connection  (such  as a
"SERIES1"), the traditional IBM handshaking is  not  necessary,  and  HANDSHAKE
should be set to 0 (as long as the other Kermit can be instructed not to expect
a handshake).  Note the distinction between SET HANDSHAKE in Kermit-370  (where
it  defines a character to be sent) and in many micro Kermits (where it defines
a character to be expected).


SET INCOMPLETE

Syntax: SET INCOMPLETE DISCARD or KEEP

DISCARD   Specifies that incomplete files (that is, files partially received in
          a  transfer cancelled by the other Kermit) are to be erased.  This is
          the default.  Note that when FILE  COLLISION  is  APPEND,  incomplete
          files are never erased, lest pre-existing data be lost.

KEEP      Specifies that incomplete files are to be kept.


SET LINE

Syntax: SET LINE [name]

This specifies an alternate communication line for file transfers.  If the name
is omitted, the default line (the user's terminal) is used.  The format of name
is, of course, system-dependent, and some variants of Kermit-370 do not support
any alternate lines.  No variant currently allows Kermit-370 to CONNECT over an
alternate line.


SET MARGIN

Syntax: SET MARGIN side column

When  Kermit-370  sends  a text file, each line may be truncated on the left or
right (or both) at fixed column numbers.  Only the text from the left margin to
the right margin (inclusive) will be sent, and any trailing blanks in the trun-
cated lines will be stripped.  A value of zero for either margin disables trun-
cation on that side.


SET PROMPT

Syntax: SET PROMPT [string]

This  defines  the  character string that Kermit-370 displays when asking for a
subcommand.  The prompt may be any string of up to 20 characters.  The  default
is  the  name  of  the  system-specific variant of Kermit-370 followed by a ">"
sign, e.g., Kermit-CMS>.  If the string is  omitted,  normal  system  prompting
will occur.


SET RETRY

Syntax: SET RETRY INITIAL or PACKETS number

Kermit-370  resends its last packet after receiving a NAK or bad packet, but it
eventually gives up after repeated failures on the same packet.  The  limit  on
retries  can  be  set  separately for the initial packet exchange (Send-Init or
server-mode command) and for ordinary packets.  The default for INITIAL  is  16
and for PACKETS, 5.  Either limit can be set to any positive value.


SET SERVER-TIMEOUT

Syntax: SET SERVER-TIMEOUT time

This defines the time in seconds that Kermit-370 in server mode should wait for
a command before sending a NAK packet.  The default is 120.  A value of 0 means
that  Kermit  should wait indefinitely, not only in the server loop, but in all
transfers, regardless of the timeout value specified by the other Kermit.  Some
variants  are  unable  to  time  out  in  any case.  Also, timeouts are not im-
plemented for any of the full-screen terminal controllers.


SET SPEED

Syntax: SET SPEED number

This determines the communication line speed assumed by Kermit-370 in calculat-
ing  the optimum packet size.  If the value is zero, such calculations are sup-
pressed.  This option is purely informative and has no effect  on  actual  line
speed.  (Default 1200.)


SET SYSCMD

Syntax: SET SYSCMD ON or OFF

ON      If the user enters a command string which is not a valid Kermit subcom-
        mand, Kermit-370 will pass the string along to the host operating  sys-
        tem  for  execution.   If the string is rejected by the system as well,
        Kermit will report it as an invalid Kermit subcommand.  Otherwise, Ker-
        mit  will  assume  the  string  was intended as a host command and will
        simply report the completion code if non-zero.

OFF     Invalid Kermit subcommands are simply rejected as such.    System  com-
        mands  may  be  executed, of course, but only by specifying the generic
        prefix "HOST" or the appropriate system-specific prefix, such as CMS or
        TSO.  (Default.)


SET TABS-EXPAND

Syntax: SET TABS-EXPAND ON [list] or OFF

ON      Tab  characters  in  incoming  TEXT  files  are replaced by one or more
        blanks to bring the record size up to the next higher multiple of eight
        for  each  tab.   If tab settings other than columns 1, 9, 17, etc. are
        desired, they may be specified  explicitly  in  a  list  following  the
        keyword  "ON".   Items in the list may be separated by spaces or commas
        and must be in strictly increasing order.

OFF     Incoming tabs are retained.  (Default.)


SET TAKE ECHO

Syntax: SET TAKE ECHO ON or OFF

ON      Subcommands are echoed to the terminal as they are executed from a TAKE
        file.

OFF     Subcommands from a TAKE file are executed "silently."  (Default.)


SET TAKE ERROR-ACTION

Syntax: SET TAKE ERROR-ACTION CONTINUE or HALT

CONTINUE   Execution  continues  in a TAKE file regardless of illegal commands,
           except in server mode.  (This is the default.)

HALT       A command error in a TAKE file causes immediate exit to Kermit  sub-
           command level.


SET TEST

Syntax: SET TEST ON or OFF

ON      Allow  setting  the START-OF-PACKET and other special characters to any
        value, and suppress type 1 checksum testing on received packets.

OFF     Normal operation.  (Default.)


SET TRANSFER CHARACTER-SET

Syntax: SET TRANSFER CHARACTER-SET name

Specifies the name of the character set used in  sending  or  receiving  files.
This  setting  may  be  superseded  by an Attribute packet of an incoming file.
Currently, the available names  are  ASCII  (the  default),  ARABIC,  CYRILLIC,
GREEK,  HEBREW,  JAPAN-EUC,  KATAKANA, LATIN1, LATIN2, LATIN3, THAI, and TRANS-
PARENT.  There are also special aliases L1, L2, and L3 for  the  LATINx  names.
All  but  JAPAN-EUC, TRANSPARENT, and ASCII represent 8-bit codes composed of a
pair of 94- or 96-character sets from the ISO  registry  combined  with  normal
definitions  for  the  so-called C0 and C1 characters.  JAPAN-EUC is a DBCS for
encoding Kanji characters, plus Roman, Greek,  and  Cyrillic.    ASCII  is  the
traditional character set supported by Kermit, but one of the newer, 8-bit sets
would be preferable for most users.  This option is,  therefore,  a  good  can-
didate  for  inclusion  in the system INIT file.  See Table 1-1 for the allowed
combinations of transfer and file character sets.  Explicitly setting this  op-
tion  has a side effect equivalent to issuing SET ATTRIBUTE ENCODING ON (q.v.).
There is one exception,  namely,  TRANSPARENT,  which  sets  ENCODING  OFF  and
replaces  both  translation tables with null operations, regardless of the cur-
rent nominal file character set.

The biggest drawback of the built-in tables for the various character  sets  is
that  neither  the  ISO  registry  nor  IBM  defines any mapping between the C1
characters (hex 80-9F in ISO arrangements) and the characters  of  EBCDIC  code
pages.  Thus, the mappings in Kermit-370 tables are somewhat arbitrary, and fu-
ture pronouncements may suddenly invalidate some or all of those 32 mappings.


SET TRANSFER LOCKING-SHIFT

Syntax: SET TRANSFER LOCKING-SHIFT ON or OFF or FORCED

ON       The Kermit locking-shift protocol is to be used  in  transfers  to  or
         from cooperating partners, provided that 8th-bit quoting is enabled.

OFF      The Kermit locking-shift protocol is not to be used.

FORCED   The  Kermit  locking-shift  protocol  is to be used, regardless of the
         cooperation of the other Kermit.  The encoding uses only  the  locking
         shifts, to the exclusion of 8th-bit quoting.


SET TTABLE

Syntax: SET TTABLE ON or OFF or KP

ON      The translation that undoes the terminal controller's ASCII/EBCDIC con-
        version comes from the TATOE and TETOA tables, rather than the ATOE and
        ETOA tables (which are used only for translating disk files).  This op-
        tion has no effect when there is no translation  built  into  the  con-
        troller, i.e., with SERIES1, GRAPHICS, and AEA connections.

OFF     The  ATOE  and ETOA tables are used for all translations by Kermit-370.
        (Default.)

KP      Same as ON, but also establishes values in the TATOE and  TETOA  tables
        based  on  IBM's  corporate standard ASCII/EBCDIC translation (distinct
        from the internationally accepted de facto standard).


SET 8-BIT-QUOTE

Syntax: SET 8-BIT-QUOTE char or ON or OFF

This controls whether eighth-bit prefixing is done and can be used  to  specify
the  character  to  be used.  This is one of only two Send-Init parameters that
cannot be SET separately for SEND and RECEIVE.

char    Eighth-bit prefixing will be done using char, provided the other Kermit
        agrees.  The default value is an ampersand.

ON      Eighth-bit prefixing will be done, provided the other Kermit explicitly
        requests it (and specifies the character).

OFF     Eighth-bit prefixing will not be done.


SET SEND/RECEIVE

The following parameters can be set either as SEND or RECEIVE options.    As  a
rule,  in  each  pair,  one  is the operational value, and the other is used to
change the default for Send-Init packets received from the other Kermit and  to
set  up  parameter values as if the other Kermit had specified them on the pre-
vious exchange.  When both values are described, the operational  one  will  be
first.  For all parameters besides QUOTE, the operational value is the RECEIVE.
After a transfer, the operational values will be unchanged, but the others  (as
displayed  by  SHOW) will reflect the parameters specified by the other Kermit.
The underlying defaults established by previous SET subcommands will  still  be
in effect.  In the syntax descriptions, mode is SEND or RECEIVE.


END-OF-LINE

Syntax: SET mode END-OF-LINE number

RECEIVE should not be changed.

SEND  may be needed to establish contact.  If the other system needs packets to
be terminated by anything other than carriage return, specify the decimal value
of  the  desired  ASCII character.  number must be in the range 0-31 (decimal).
The default is 13 (CR).


PACKET-SIZE

Syntax: SET mode PACKET-SIZE number

RECEIVE defines number as the maximum length for incoming packets.   The  valid
range  is  26-9024,  but 94 is the limit for normal short-packet protocol.  The
default is 80.  Specifying a value greater than 94 is necessary and  sufficient
to  enable  the  long-packet protocol for transfers to Kermit-370 (provided the
other Kermit is willing).  Kermit-370 will actually accept long packets in  any
case,  but  the  protocol  requires  that the other Kermit not send them unless
Kermit-370 asks.  Raising this value from the default is a good  candidate  for
inclusion  in  INIT  files.    In  practice,  the packet size may be limited by
hardware and programming considerations.  See the system-specific chapters  for
details.

SEND  might  be  needed  for  sending  files  to  a minimal Kermit that neither
specifies a buffer size in the Send-Init sequence nor can  accept  the  default
(80).   It may also be used to specify the packet size for a "raw" download via
the XTYPE subcommand.  This parameter has no other function and  is  completely
irrelevant  to  long  packets.    If  the  other  Kermit asks for long packets,
Kermit-370 will always comply.


PAD-CHAR

Syntax: SET mode PAD-CHAR number

RECEIVE defines number as the character to be used by the other Kermit for pad-
ding  packets.   The character must be an ASCII control character (in the range
0-31).  The default is 0 (NULL).  This option is seldom useful.

SEND may be needed to establish contact if the other Kermit (or  the  transmis-
sion line) needs padded packets.


PADDING

Syntax: SET mode PADDING number

RECEIVE  defines  the  number  of pad characters to be used for padding packets
from the other Kermit.  This number may be anywhere from 0 to 94.  The  default
is 0.  This option is seldom useful.

SEND  may  be needed to establish contact if the other Kermit (or the transmis-
sion line) needs padded packets.


PARITY

Syntax: SET mode PARITY MARK or NONE

RECEIVE specifies the  parity  expected  in  the  transparent-mode  ASCII  data
received  by the mainframe from a full-screen device.  Such data will typically
have either all Mark parity (seven data bits with the eighth  bit  set)  or  no
parity (eight data bits).  This is typically not the same as the parity used in
communications between the protocol convertor and  the  terminal.    Kermit-370
must  know  which  kind  of  parity  to  expect in order to calculate checksums
properly.  Since Kermit-370 does not actually verify parity, the other possible
variants  (ODD,  EVEN,  and SPACE) are lumped together with MARK parity for the
purpose of this subcommand, which merely chooses between 7-bit and  8-bit  data
transfer.  The default is MARK.

SEND  is  also  an  operational value, specifying the parity to be used in con-
structing outgoing data packets on full-screen devices.  NONE  is  the  default
and  is  generally  preferable, in that it permits binary transfers without the
need for eighth-bit prefixing, but MARK may be required in some configurations.


QUOTE

Syntax: SET mode QUOTE char

SEND indicates a printable character for prefixing (quoting) control characters
and other prefix characters.  The only good reason to change this would be  for
sending a file that contains many "#" characters (the normal control prefix) as
data.  It must  be  a  single  character  with  ASCII  value  33-62  or  96-126
(decimal).

RECEIVE  would  be  needed  only  for  talking to a crippled Kermit that uses a
non-standard quoting character, but does not admit it.


START-OF-PACKET

Syntax: SET mode START-OF-PACKET number

RECEIVE defines number as the character to be expected to  mark  the  start  of
packets  from the other Kermit.  The character must be an ASCII control charac-
ter (in the range 0-31).  The default is 1 (SOH).  This may need to be  changed
to establish contact.

SEND  may  also  need to be changed to establish contact.  It defines number as
the character to be used to mark outgoing packets.


TIMEOUT

Syntax: SET mode TIMEOUT time

RECEIVE defines the time in seconds the other Kermit is to wait for a  response
from  Kermit-370  before  resending  a packet.  The default is 5.  A value of 0
means the other Kermit should wait indefinitely.

SEND may be needed to define the time in seconds Kermit-370 is to  wait  for  a
response  from  the  other  Kermit in the initial packet exchange, although the
default value 0 (indefinite wait) is probably  satisfactory,  especially  since
Kermit-370  in  many cases cannot time out anyway.  Specifying a non-zero value
will prevent the other Kermit from ever  requesting  infinite  "patience"  from
Kermit-370.


                              THE SHOW SUBCOMMAND

Syntax: SHOW [option]

The  SHOW  subcommand displays the values of all parameters that can be changed
with the SET subcommand, except CONTROL-CHAR, ATOE, ETOA, TATOE, and TETOA (for
those,  see  the  TDUMP  subcommand).  If specified, option can be a particular
parameter or the keyword "ALL" (the default).  Groups of  parameters,  such  as
SEND,   can   be   displayed  by  requesting  the  group  name,  or  individual
sub-parameters can be displayed by specifying the complete name.  For example,

    SHOW RECEIVE EOL

will display the decimal value of the packet terminator  that  Kermit-370  cur-
rently expects, i.e., 13.  Similarly,

    SHOW FOREIGN

will  display  the  character strings currently in use for prefix and suffix on
each outgoing filespec.  When "ALL" is specified  or  implied,  all  parameters
other than the attribute switches are displayed.


                             THE STATUS SUBCOMMAND

Syntax: STATUS

This  subcommand displays information about the previously executed subcommand.
The response will include either the appropriate error message or  the  message
"No  errors".    The  initial status is "No file transfers yet".  If the status
reflects an error condition, the name of the last  file  used  (excluding  TAKE
files)  will be displayed as well.  If the error was detected by the other Ker-
mit, the message will be "Micro aborted" followed by the text  from  the  Error
packet.    Conversely, if Kermit-370 detected the error, the text of the status
message will have constituted the error packet sent out.  In any case,  if  the
last  file transfer was cancelled (by virtue of an attribute mismatch or manual
intervention), the reason for cancellation is displayed.  Also,  if  the  error
occurred in disk I/O, any available explanatory information is displayed.  Nor-
mally, the error status is altered only when a  transfer-initiating  subcommand
(SEND or RECEIVE) is executed, but there are several exceptions.  If an invalid
subcommand is entered, the status becomes "Kermit command error", and the  next
subcommand  entered  will reset the status.  Also, in server mode every subcom-
mand is received through a transfer from the other Kermit and  may  affect  the
status (except the STATUS subcommand itself, of course).

Other  information  is also included.  When Kermit-370 has been forced to trun-
cate one or more records in the last RECEIVE operation (because of the  current
maximum  record  length),  the  number  of  records truncated is reported.  The
status display also includes throughput statistics for the last transfer:  num-
ber of files sent, duration, number of packets, number of retries, and averages
of bytes/packet and bytes/second.  These last  two  quantities  are  calculated
separately  for  bytes  sent  and received on the communication line (including
padding, if any), and the last quantity is also calculated on the basis of  the
number  of bytes read from or written to disk.  Further, if retries were neces-
sary, Kermit-370 computes the optimum packet size assuming the retries to  have
been  due  to  sparse,  Poisson-distributed  bursts of noise.  This is the same
heuristic  optimum  that  Kermit-370  computes  and  uses  as  an   alternative
packet-size  limit  when  sending long packets.  If TEST is set on, Kermit also
reports the maximum size attained by its storage stack since execution began.


                              THE STOP SUBCOMMAND

Syntax: STOP

This is not a subcommand in the usual sense.  Instead, it is a  command  string
that  can  be entered on the communication line while Kermit-370 is in protocol
mode and will cause protocol mode to cease immediately.  This may be useful  if
the  other  Kermit has crashed.  The word "stop" may be entered in either upper
or lower case, but it must be the only character  string  in  the  "packet"  in
question.    If  you are using a full-screen terminal, and if other information
appears on the screen, you must clear that other text from  the  screen  (using
CLEAR EOF) before pressing ENTER.


                              THE TAKE SUBCOMMAND

Syntax: TAKE filespec

Execute Kermit subcommands from the specified file, usually called a TAKE file.
The TAKE file may in turn include TAKE subcommands, and the  nesting  may  con-
tinue  to  a  depth  of  ten.    If a TAKE file includes the subcommand SERVER,
however, the nesting count is saved and starts over again  in  server  mode  in
case  the client Kermit should transmit a REMOTE KERMIT TAKE command.  The user
has the option of seeing the subcommands echoed from the TAKE file as they  are
executed  and  also the option of automatically exiting from a TAKE file on er-
ror.  See the subcommand SET TAKE for details.


                             THE TDUMP SUBCOMMAND

Syntax: TDUMP table-name or NAMES or TRACE

This displays the contents of table-name.  The same table can be modified using
the  SET  subcommand.   The ATOE, ETOA, TATOE, and TETOA translation tables and
the CONTROL-CHAR prefixing selection  table  can  presently  be  displayed  and
changed.    The  NAMES table is the transaction log for the last transfer, con-
sisting of the filespec of each file sent or received, along with the size  (in
Kbytes)  and  any error messages.  If the Kermit TRACE facility is enabled, the
TRACE table may be displayed (and destroyed in the process).  This  table  con-
tains  entries  for  subroutine calls and returns during program execution, but
Kermit normally does not have the facility enabled.  See  SET  DEBUG  for  more
details on execution tracing.


                        THE TYPE AND XTYPE SUBCOMMANDS

Syntax: [X]TYPE filespec

These  subcommands  display  the named file.  TYPE is effectively a synonym for
(and allows the same options as) the host system command for  displaying  files
at  the  terminal,  but  XTYPE performs a raw file transfer on the current com-
munication line (which need not be the terminal) according to the current  CON-
TROLLER  setting.   Thus, XTYPE uses transparent mode if CONTROLLER is SERIES1,
GRAPHICS, or AEA.  Also, it sends the data in bursts no larger than the current
SEND  PACKET-SIZE.    Since XTYPE is basically a modified SEND, the options al-
lowed on the filespec for SEND are also allowed for XTYPE.


                            THE VERSION SUBCOMMAND

Syntax: VERSION

This subcommand displays the program version number and date.


1.5. Before Connecting to the Mainframe

Several options must be set in the micro Kermit before connecting to an IBM 370
system  as  a  line-mode  device.  You should set LOCAL-ECHO to ON (to indicate
half-duplex).  This is the norm but not true in absolutely every case; if  each
character  appears  twice  on  your  terminal  screen,  set  LOCAL-ECHO to OFF.
FLOW-CONTROL should be set to NONE, and on some systems HANDSHAKE should be set
to XON.  The parity should be set according to the system's specifications.  On
some micro Kermits, all of the above is done in one step using the DO IBM macro
(or SET IBM ON).  Set the baud rate to correspond to the line speed.

Connecting  through  a full-screen device also requires that certain options be
set in the micro Kermit.   You  should  set  LOCAL-ECHO  to  OFF  (to  indicate
full-duplex).   FLOW-CONTROL should be set to XON/XOFF, and HANDSHAKE should be
set to OFF.  For many systems, the PARITY should be set to EVEN.  Set the  baud
rate to correspond to the line speed.

One  exception  to these rules is the case where the micro Kermit is attempting
automated  file  transfer,  e.g.,  downloading  several  separate  files   from
Kermit-370  running  in server mode.  In fact, under those circumstances, hand-
shaking is necessary even with "SERIES1" connections, and the two Kermits  must
be  instructed to adopt a common handshake character (e.g., by SET HANDSHAKE 10
to Kermit-370 and SET HANDSHAKE LF to the micro).

In any case, you should make sure that either the micro  Kermit  or  Kermit-370
will  provide  timeouts  during file transfers (if not both).  Some variants of
Kermit-370 (notably CMS) cannot provide timeouts, and you may need to  set  the
TIMER to ON in the micro.

When  you are connecting through a protocol convertor, it is useful to know the
key sequence that causes the screen image to be repainted from the controller's
memory.  In many cases, it is CTRL-V, although CTRL-G and CTRL-C are also some-
times used.  In general, this sequence should be typed whenever reconnecting to
Kermit-370  after being in Kermit protocol mode (and sometimes after merely es-
caping to the local Kermit), since the  local  Kermit  may  have  modified  the
screen.


1.6. Trouble-shooting Protocol Converters

Many,  but not all, protocol converters have transparent modes that permit Ker-
mit file transfers.  The welter of competing and often incompatible  communica-
tions  devices  would  cause  a major headache, except for three circumstances.
First, Kermit-370 has routines for automatically detecting which kind of  front
end  is  controlling  the  current session; second, the Kermit installer is en-
couraged to tailor Kermit to force the correct choice  of  CONTROLLER  whenever
those  routines  don't  work  properly; and, third, Kermit offers a last-resort
mode of operation that will work with almost any protocol converter.    Because
of  the  limitations  in  the  catch-all mode (known as FULLSCREEN mode), it is
still best to take advantage of the transparency, if any, in the protocol  con-
verter,  and the automatic detection routines still play an important role.  It
will be instructive to outline what those routines actually do and how they can
go wrong.
Recognizing a Series/1

Although  protocol  converters are advertised as simulating the behavior of IBM
3270-type terminals, there generally are differences which  could  be  used  to
distinguish  each  type  of device from the others and from real 3270-type ter-
minals.  However, all that really matters to Kermit-370 is whether there  is  a
transparent  mode  available  such  that file transfers can be carried out.  To
date, only three fundamentally different transparent modes have  been  reported
to  Columbia,  and  it seems likely that no others have been (or, perhaps, ever
will be) implemented.  All are supported by Kermit.

Kermit-370 recognizes these front  ends  automatically  by  making  two  simple
tests.    The  first  takes advantage of one of the advanced features first im-
plemented in the Yale ASCII system and  subsequently  copied  in  many  of  the
devices that adopted the same transparent mode.  This feature is a special 3270
data-stream order which requests a status report from the  protocol  converter.
Kermit  sends  this  order  and then reads the "3270 screen".  If Kermit sees a
valid status report, it sets CONTROLLER to SERIES1 and stops testing.


Two catches

Obviously, the Yale status order is not implemented  in  most  other  kinds  of
hardware.  Thus, the order would be rejected by a non-Yale-type controller, and
that could have undesirable side effects on the hardware.  However, hardware is
generally  designed  to be robust -- the real drawback lies in the side effects
on certain communications software (notably VTAM/TSO), which may respond  badly
while  trying to protect the robust hardware from illegal orders.  If it proves
impossible to make the external software behave properly, the only recourse  is
to  modify  Kermit-370  to skip the first test altogether and possibly to force
the CONTROLLER setting; this modification is described in the relevant "Beware"
file in a note dated 89/2/27.

Catch  Two  is  that  the status order is not implemented in all of the devices
that support Yale-ASCII-style transparent mode.  This means that  some  devices
"fall  through  the  cracks"  in this procedure.  A site where such devices are
used may find it expedient to modify Kermit (following the same  "Beware"  pat-
tern)  to  force the procedure to set CONTROLLER to SERIES1 (assuming there are
no other protocol converters also in use that support one of the  other  trans-
parent modes).  A list of such devices can be found in a footnote in the Kermit
distribution file ik0aaa.hlp.


Recognizing a 3174

The second diagnostic test uses a hardware command (Read Partition Query)  that
is  defined  by  IBM, but is not implemented on all 3270-type equipment.  There
is, thus, the same danger as in the first test, but the danger  appears  to  be
slight.    Indeed,  both  CMS  and  TSO allow a user program to know in advance
whether a Query is permitted.  The Query  response  consists  of  one  or  more
structured fields, and the 3174 AEA ASCII Graphics system (the only device with
the AEA style of transparency) is easily identified by the appearance and  con-
tent  of  a particular type of field.  In fact, it is possible to tell from the
Query data whether the particular  3174  line  is  allowed  to  use  the  ASCII
Graphics  transparency.  Therefore, this test has three possible outcomes: Ker-
mit may detect a transparency-enabled 3174 line (and set CONTROLLER to AEA); it
may  detect  an  incapable  3174  line  (and set CONTROLLER to NONE); or it may
detect "none of the above" (and set CONTROLLER to GRAPHICS).  Thus, aside  from
the  exceptions  already noted, GRAPHICS simply means that the front end either
supports SAS-style transparency or none at all.


Fallback positions

What should you do when the automatic detection fails?   Obviously,  the  first
thing is Be Prepared.  Often, the misbehavior of VTAM can be halted by pressing
ENTER or PA1, so you should be sure to know how to generate a PA1  when  trying
out  Kermit on an unfamiliar type of protocol converter.  Also, you should know
what kind of  transparency  to  expect  for  the  front  end  and  verify  that
Kermit-370 has, in fact, set CONTROLLER appropriately.  This means checking the
list of devices in the Kermit distribution file ik0aaa.hlp.  If your configura-
tion  is  listed  as unsupported, you may be wasting your time, but the list is
not necessarily up-to-date.  If your configuration is not listed  at  all,  you
have  the opportunity to be a pioneer and report your findings back to Columbia
for inclusion in future editions of the list.  There are a few rules  of  thumb
for quickly deducing the controller type by reading the manuals for the device;
the manuals may not be specific enough, but this is clearly the easiest way  of
determining whether Kermit can support a given device and which controller type
is applicable.    The  rules  are  as  follows  (in  order  of  simplicity  and
likelihood):

   1. GRAPHICS or SERIES1 may be implied when the device has a transparent
      or graphics mode described as compatible with that  of  a  supported
      device listed in ik0aaa.hlp.

   2. SERIES1  is  implied when the device runs the "Yale ASCII Communica-
      tion System" or something with a similar name.

   3. GRAPHICS is implied if the manual mentions the SAS Institute in  the
      context of ASCII graphics.

   4. GRAPHICS  is implied when output transparent data may be preceded by
      a WCC (Write Control Character) and 70 (hex).

   5. SERIES1 is implied when transparent data must be preceded by  a  WCC
      and either 115D7F110005 (write-read) or 115D7F110000 (write-only).

   6. GRAPHICS  or  SERIES1 may be implied when some of the manufacturer's
      other products are listed in ik0aaa.hlp, and all are shown as  being
      of one type.

   7. If  none of the above rules apply, but the manuals describe a trans-
      parent mode in detail, the device may be a totally new  type.    The
      distribution  file  ik0con.hlp has hints on implementing Kermit sup-
      port for the new type.

   8. If nothing else works, you can probably use FULLSCREEN mode, as long
      as the micro Kermit supports it.

If  Kermit tries to transfer a file with the wrong CONTROLLER value, there is a
distressing possibility for the session to lock or, at least, appear  to  lock.
When  and  if  this  happens,  be  sure  to connect back to the mainframe, type
"STOP", and press ENTER several times (perhaps as  many  as  15  times)  before
taking any drastic steps like breaking the connection.  "STOP" is a special es-
cape mechanism for getting out of Kermit protocol  mode  quickly.    Kermit-370
recognizes such a request in most situations where terminal I/O is not entirely
frozen.  Sometimes, apparent lock-ups are due to something as simple as  incor-
rect  parity settings in the micro Kermit, so always check the basic communica-
tion settings and, if necessary, experiment  before  trying  a  different  CON-
TROLLER type.  Also, to avoid unnecessary confusion, check for the existence of
a Kermit initialization file (possibly created by the installer) which could be
re-setting  CONTROLLER  after  the  automatic  procedure  has finished.  Such a
re-setting is a poor idea in an initialization file, even a personal  one,  un-
less there is absolutely only one kind of communications equipment on your sys-
tem.

If file transfers do not work at first, it is best to do the  following  before
trying again:

   1. Reduce the packet size to no more than 80 at both ends.

   2. Enable 8th-bit quoting at both ends.

   3. Set SEND PARITY MARK in Kermit-370.

If  those  changes do not make transfers work, the next remedial action depends
on the symptoms of failure.

   - No packets exchanged and session locked up after reconnecting: change
     packet characters in both directions.

   - No  packets  exchanged,  but  no  lockup: change packet characters or
     parity.

   - Always multiple retries of third or fourth packet:  reduce  receiving
     packet size.

   - Multiple  retries  after random number of packets: check hardware and
     cables.

   - Multiple retries after file-dependent number of  packets:  check  for
     equipment  that intercepts one or more printable characters or reduce
     the packet size.

When all else fails, you should be ready to reset CONTROLLER by  hand  and  try
again.    The  change  most likely to be necessary is from GRAPHICS to SERIES1.
However, it is conceivable that the installer has modified Kermit-370  at  your
location  to  force  the  CONTROLLER setting from the start, in which case, you
might need to go the other way.  Normally,  Kermit's  diagnostic  procedure  at
start-up takes one or two seconds (because of programmed delays), so you should
be suspicious if the Kermit prompt appears  immediately  after  you  start  the
program.    The  only  initial CONTROLLER setting that you should not change by
hand is NONE, which means that Kermit-370 has recognized a 3174 AEA  line  that
is  not configured for file transfer (or else the Kermit installer has a warped
sense of humor).

If no amount of experimenting gets a transparent mode to work, it  is  time  to
recheck  the list of supported devices and the age of your equipment.  If yours
is very old, it may require new microcode or some other  software  or  hardware
upgrade.    In any case, if your results (whether positive or negative) are not
already shown in ik0aaa.hlp, you should report them to Columbia so that  others
may profit by your experience.


1.7. After Returning from Kermit-370

When  Kermit-370  receives a QUIT or EXIT subcommand or finishes the subcommand
or subcommands specified in the original command string  that  invoked  Kermit,
control is returned to the caller.  Before returning, Kermit-370 closes any ac-
tive TAKE files (the EXIT or QUIT subcommand may be issued from a  TAKE  file).
On  return,  the completion code is set from the current error status according
to the codes in Table 1-4.

The error codes in Table 1-4 bear no relationship to the severity  of  the  as-
sociated error conditions, aside from the assignment of code 0.  The underlying
rationale is that the only current generic system for the treatment of  comple-
tion  codes is to take a non-zero code as an indication of error.  Indeed, Ker-
mit returns a completion code of 0 when "error" condition 1 holds.


1.8. What's New

Below is a list of the changes in Version 4.3 of Kermit-370.

   1. Compatibility with the (aging) F-level assembler.

   2. Support for LATIN2, LATIN3, TRANSPARENT, CP870, CP905, and CP880, as
      well as the aliases L1, L2, and L3.  New alias CP1047 for EBCDIC.

   3. Support for IBM 3174 ASCII Graphics mode.

-------------------------------------------------------------------------------

Code  Symbol  Error Message
 0    NOE     No errors
 1    NFT     No file transfers yet
 2    TRC     Transfer cancelled
 3    USC     Invalid server command
 4    TIE     Terminal I/O error
 5    BPC     Bad packet count or chksum
 6    IPS     Invalid packet syntax
 7    IPT     Invalid packet type
 8    MIS     Lost a packet
 9    NAK     Micro sent a NAK
10    ABO     Micro aborted
11    FNE     Invalid file name
12    FNF     File not found
13    FUL     Disk or file is full
14    DIE     Disk I/O error
15    MOP     Missing operand
16    SYS     Illegal system command
17    KCE     Kermit command error
18    TIM     No packet received
19    RTR     Records truncated
20    COM     Bad communication line
21    PTY     8th-bit quote not set
22    FTS     File too short
23    SOH     Missing start-of-packet
24    OPT     Option error on filespec
25    DSP     Unable to dispose of file

              Table 1-4:  Error messages and codes for Kermit-370


-------------------------------------------------------------------------------


   4. Improved  controller  detection,  including  local customization op-
      tions.

   5. Support for new unprefixed transmission of selected control  charac-
      ters.

   6. Support for REMOTE PRINT, REMOTE MAIL, and REMOTE SUBMIT.

   7. Improved  error message for bad packet-size, new alias PACKET-LENGTH
      for PACKET-SIZE.

   8. Correct observance of FILE COLLISION for all files in a group.

   9. Ignoring  spurious  flow-control  "packets"   from   (for   example)
      MS-Kermit.

  10. Support for new locking-shift Kermit protocol.

  11. Support  for  Japanese  Kanji file transfer and support for the Thai
      and Arabic character sets.

  12. New versions of Kermit with the interactive  messages  in  languages
      other than English.

  13. New FULLSCREEN controller type.

  14. New HINTS subcommand.

  15. More graceful recovery from terminal I/O errors and exceptions.

  16. Support for SNA LU1 3770-type devices and 8-bit, no-parity devices.

  17. Optional  conversion  of  EBCDIC printer carriage control into ASCII
      control characters.

  18. Support for STOP command on "dumb" 3270 terminals and  PCI  protocol
      converters.

  19. New efficiency display in STATUS report, based on SPEED setting.

  20. New, uniform messages upon entering protocol mode, in the form "KER-
      MIT READY TO SEND..." (or RECEIVE or SERVE).

  21. 8-bit XECHO output.

  22. Control prefixing for C1 controls.

  23. New VERSION subcommand.

  24. Improved debugging facilities.


1.9. What's Missing

Work on Kermit-370 will continue.  Features that need to be improved  or  added
include:

   - Implement file archiving.

   - Implement file transfer checkpointing.

   - Add SET REPEAT subcommand.

   - Improve Kermit-370 operation as a local Kermit.

   - Implement public server mode.

   - Allow  REMOTE  KERMIT  HELP, REMOTE KERMIT DIR, and REMOTE SET from a
     micro.

   - Add new SET FILE LONGLINE DISCARD option to allow multi-file transfer
     to proceed past a truncation problem.

   - System-specific upgrades; see the respective chapters for details.

Anyone interested in working on these or other improvements should first get in
touch with the Center for Computing Activities at Columbia University  to  find
out if someone else has already begun a similar project (and, if so, who).


1.10. Further Reading

Below is a list of references for some of the material in this chapter.

   1. About  Type:  IBM's  Technical Reference for 240-Pel Digitized Type,
      S544-3156-02 (1989).  This manual contains  visual  tables  of  many
      EBCDIC  code  pages  and a comprehensive list of character names and
      acronyms.

   2. IBM System/370 Reference Summary, GX20-1850-3 (1976).   This  refer-
      ence card contains EBCDIC and ASCII character codes.

   3. IBM   VS   Fortran   Application  Programming:  Language  Reference,
      GC26-3986-1 (1982).  Appendix E contains a table of EBCDIC and ASCII
      characters with an implied full 256-byte translation table.

   4. IBM  3174  Character  Set Reference, GA27-3831-02 (1990).  Chapter 5
      contains visual tables of many EBCDIC code pages.

   5. Info-Kermit Digest Vol. 11 #1 (1989).   This  issue  contains  draft
      specifications of some Kermit protocol extensions.

   6. ISO  International  Register of Coded Character Sets to be used with
      Escape Sequences (1989).  This (very large)  document  has  complete
      and  unambiguous  descriptions of standard coded character sets.  It
      can be obtained from the ECMA.

   7. Kermit, A File Transfer Protocol by Frank  da  Cruz;  Digital  Press
      (1987).    This  book  contains a thorough description of the Kermit
      protocol and services with copious examples.

   8. Kermit distribution file ISOK7.TXT (1992).  This  preliminary  draft
      describes  the  new  transfer  protocol, including the international
      character-set support.

   9. Kermit News Vol. 3 #1, p.5, "Dynamic Packet  Size  Control"  (1988).
      This article describes an algorithm for optimizing Kermit throughput
      in the face of line noise.

  10. Kermit News #4, p.16, "International Character Sets" (1990).    This
      article discusses the new transfer protocol.

  11. ASCII  and  EBCDIC Character Set and Code Issues in Systems Applica-
      tions Architecture, SHARE white paper by Edwin Hart  (1989).    This
      document,  available as file SHARE REQUIRE from LISTSERV@JHUVM, lays
      out general considerations for character codes and translatability.

  12. Kermit distribution file LSHIFT.TXT (1991).  This file describes the
      new  protocol  extension  for  better compression of 8th-bit text on
      7-bit channels.
2. IBM CMS KERMIT

Program:       John Chandler  (Harvard/Smithsonian  Center  for  Astrophysics);
               contributions  from Vace Kundakci and Daphne Tzoar (Columbia U),
               Bob Shields (U.  Maryland),  Greg  Small  (UC  Berkeley),  Clark
               Frazier  (Harvard  Bus.  Sch.),  Bob Bolch and Steve Blankinship
               (Triangle), Ron Rusnak (U. Chicago), Andre Pirard (U. Liege)
Language:      IBM/370 Assembler
Documentation: John Chandler (CfA)
Version:       4.3.0 (93/9/30)
Date:          1993 September


Kermit-CMS Capabilities At A Glance:

  Local operation:                   Yes
  Remote operation:                  Yes
  Transfers text files:              Yes
  Transfers binary files:            Yes
  Wildcard send:                     Yes
  ^X/^Z interruption:                Yes (through micro)
  Filename collision avoidance:      Yes
  Can time out:                      No
  8th-bit prefixing:                 Yes
  Repeat count prefixing:            Yes
  Alternate block checks:            Yes
  Terminal emulation:                No
  Communication settings:            No
  Transmit BREAK:                    No
  Packet logging:                    Yes
  Transaction logging:               Yes
  Session logging:                   No
  Raw transmit:                      Yes (no prompts)
  Sliding window:                    No
  Long packets:                      Yes
  Act as server:                     Yes
  Talk to server:                    Yes
  Advanced server functions:         Yes
  Advanced commands for servers:     Yes
  Local file management:             Yes
  Handle Attribute Packets:          Yes
  Command/init files:                Yes
  Command macros:                    No


CMS Specifics of Kermit-370:

  Global INIT file:                  SYSTEM KERMINI *
  User INIT file:                    userid KERMINI *
  Debug packet log:                  KER LOG A1
  Server reply log:                  KER REPLY A1
  Mail command:                      EXEC KERMAIL filespec ( users
  Print command:                     EXEC KERMPRT filespec ( options
  Submit command:                    EXEC KERMSUB filespec ( options
  Maximum packet size:               1913 (SERIES1), 2030 (TTY)
  Maximum disk LRECL:                65535

Kermit-CMS is a member of the generic Kermit-370 family and shares most of  the
features and capabilities of the group.  As its name implies, Kermit-CMS is the
variant of Kermit-370 that runs under the CMS operating system.    The  primary
documentation  for  Kermit-CMS  is actually the chapter on Kermit-370 (entitled
IBM 370 Kermit), which describes general properties; the  present  chapter  as-
sumes  the reader is familiar with that material.  Only the details specific to
CMS operation will be discussed here, e.g., command syntax relating to the  CMS
file system or commands not offered in general by Kermit-370.


2.1. The CMS File System

The  features  of  the CMS file system of greatest interest to Kermit users are
the format of file specifications (or filespecs) and the  concept  of  records.
The latter is described in the Kermit-370 chapter.

The CMS filespec takes the form

    filename filetype filemode

(often  abbreviated  FN  FT  FM).    The filename and filetype are one to eight
characters each.  The filename is the primary identifier for the file, and  the
type  is an indicator which, by convention, tells what kind of file it is.  For
instance, TEST FORTRAN is the source of a Fortran program named TEST.    MODULE
is  the  filetype  for executable programs (as distinct from object code, which
has a filetype of  TEXT!).    Although  some  operating  systems  consider  the
filetype  optional,  CMS  requires a type for each file.  Therefore, Kermit-CMS
supplies a default type of "$" for any received file if no type is provided  by
the  remote  system.   The same default is used for a missing filename.  At the
same time, Kermit forces the FN and  FT  to  conform  to  CMS  rules  in  other
respects.   The FN and FT may contain, in any order, uppercase letters, digits,
and the special characters "$" (dollar sign), "#" (number sign), "@" (at sign),
"+" (plus), "-" (hyphen), ":" (colon), and "_" (underscore).  Any other charac-
ter, if found in the FN or FT, is replaced by an underscore  (or  converted  to
uppercase if it is a lowercase letter).  Also, both FN and FT are truncated, if
necessary, to eight characters.

The filemode, which consists of a letter and a number, is similar to  a  device
specification on microcomputer systems: FN FT FM would translate to FM:FN.FT in
CP/M or MS-DOS if the filemode number is ignored.  Indeed, the filemode  number
is  more  properly an attribute of a file than part of its name -- no two files
can co-exist with names that match in all but the filemode number.    Even  the
filemode  letter is not a fixed part of the filespec because the same mini-disk
or Shared File System (SFS) directory could be accessed under a different  mode
letter.  In some ways, the filemode letter is like a disk directory designator,
even when it refers to a mini-disk, since many such mini-disks  may  reside  on
the  same  disk  drive.    For  this reason, the Kermit concept of the "working
directory" is equated with a particular disk mode letter under Kermit-CMS.  The
current  "working directory" is, thus, the "home" filemode (normally "A", which
is the primary user  mini-disk  under  CMS),  and  file  transfers  take  place
preferentially  to and from the "home" disk.  If the filemode is omitted from a
filespec when sending, the "home" disk is normally used, but there is an option
for using a default of "*" instead.  In this case, the user's disks are scanned
according to the search order and the first occurrence of the file is  the  one
that  is  sent.  If the filemode is omitted from a filespec when receiving, the
"home" disk is used with a filemode number of "1".

To provide compatibility with other operating systems, when Kermit-CMS sends  a
file,  it  ordinarily  makes a file header with only the filename and filetype.
It also converts the intervening blank to a period.  However, extra information
may be added by way of the SET FOREIGN subcommand.

CMS  allows  a group of files to be specified in a single filespec by including
the special "wildcard" characters "*" and "%".  A "*"  matches  any  string  of
characters  (even  a  null  string) from the current position to the end of the
field; a "%" matches any single character.  Here are some examples:

  * COBOL A   All files of type COBOL (all COBOL source files) on the A disk.

  F* * *      All files whose names start with F.

  % * B       All B-disk files with one-character FN's.

CMS files, like those in other IBM 370 systems, are  record-oriented  (see  the
introduction  to the Kermit-370 chapter).  In particular, CMS files are charac-
terized by record format (RECFM), which may be fixed-length or  varying-length,
and  by  record  length  (LRECL).    The  size  of record blocks is irrelevant,
however, because CMS performs the blocking and deblocking operations  automati-
cally  and  transparently, including the spanning of records across block boun-
daries.  An important point to note is that records being written to a RECFM  V
file are not limited in length by the LRECL, but only by the CMS maximum (65535
bytes).

Another file system feature of occasional interest is the  means  of  reporting
errors.    When Kermit-CMS encounters a disk error, it records the function and
error code for inclusion in the STATUS report.  The explanations can  be  found
in  the  CMS  reference  manual under the FSREAD and FSWRITE macros (which cor-
respond to the RDBUF and WRBUF functions).


2.2. Program Operation

At startup time, Kermit-CMS looks for two initialization  files,  "SYSTEM  KER-
MINI" and "userid KERMINI" (where userid is the user's logon ID).  If either of
these files exists on more than one disk, it will be read and executed from the
first  copy in the search order.  The file "SYSTEM KERMINI" should be placed on
a publicly accessible disk by a systems programmer, preferably  the  same  disk
where  the  Kermit executable module is kept.  The file "userid KERMINI" can be
maintained by the user on any convenient disk.

One important distinction between  Kermit-CMS  and  other  Kermits  is  that  a
program running under CMS is unable to interrupt a read on its "console".  This
means that the CMS variant of Kermit cannot time out after  sending  a  packet.
The  only  way to time out is from the other side:  typing a carriage return to
the local Kermit causing it to retransmit its  last  packet,  or  an  automatic
timeout as provided by most other Kermits.

Five  CP  SET  parameters  (MSG, IMSG, WNG, ACNT, and TIMER) are set OFF during
protocol mode (and restored afterwards) to prevent CP from interrupting any I/O
in  progress,  LINEDIT  is  set  OFF  to  ensure  that all characters are taken
literally, and RUN is set ON to ensure that Kermit can recover from  accidental
attention interrupts.  Also, on a TTY line, the TERMINAL LINESIZE is set OFF to
prevent CP from inserting carriage return-linefeed pairs into packets, TERMINAL
SCROLL  is  set  to CONT to prevent CP pauses, and the CMS user terminal trans-
lation tables (established via the CMS SET INPUT and OUTPUT commands) are  tem-
porarily  suppressed for both short and long packet protocols.  The settings in
effect when Kermit starts up are saved as a sort of  "normal"  status  snapshot
(as  opposed  to the "protocol" status just described).  The protocol status is
selected whenever Kermit enters protocol mode and also after Kermit executes  a
CP  command  in  server mode.  Similarly, normal status is selected when Kermit
leaves protocol mode and before Kermit executes a CP command  in  server  mode.
Note:  if  Kermit  is interrupted in the midst of a transfer or while in server
mode, these parameters  will  be  left  with  peculiar  settings  (namely,  the
protocol status), and they may need to be restored by hand.

If, at some installation, Kermit can be run only on "TTY" lines, users will of-
ten be forced to disconnect or log off ongoing sessions  on  fullscreen  lines.
In  general, users may operate through IBM 3270-type terminals and then discon-
nect in order to reconnect to a line that supports Kermit.  In cases like this,
users should be warned that reconnecting to a session over a "TTY" line is dif-
ferent from logging on initially over such a line.  In particular, the CMS  SET
parameters AUTOREAD and BLIP and the CP TERMINAL parameter LINESIZE may need to
be reset after reconnecting.  AUTOREAD should be ON for "TTY" lines and OFF for
fullscreen  lines;  the  other two parameters are a matter of taste.  A similar
warning applies to reconnecting in the opposite direction.

CMS is different from some other IBM mainframe systems  in  that  it  allows  a
program  to  take  control  of  prompting  and  synchronization on "TTY" lines.
Kermit-CMS takes advantage of this option, and it is not, in general, necessary
to  enable  handshaking on the micro Kermit before connecting to CMS.  In other
words, handshaking should be suppressed for both "TTY"  and  "SERIES1"  devices
(the  micro  Kermit  should  have HANDSHAKE set OFF, and Kermit-CMS should have
HANDSHAKE set to 0).  Since the generic Kermit-370 default handshake  (XON)  is
retained  in  Kermit-CMS,  the subcommand "SET HANDSHAKE 0" is a good candidate
for inclusion in SYSTEM KERMINI.


Kermit under VM/XA and beyond

Recent evolution of IBM's VM operating system has been marked by sharp  discon-
tinuities  caused  by, among other things, the transition to Extended Architec-
ture (XA) mode.  As a result, there are now two CMS variants of Kermit-370, one
for  the traditional systems and one for VM/XA.  The former is now XA-cognizant
but not, in IBM's terminology, XA-tolerant.  In other words, it will  run  only
in  370  mode or under VM/SP.  The latter variant is fully bimodal and will run
in 370, XA, or ESA mode under a bimodal (5.5 or 7 or higher) CMS, but will  not
assemble or run under pre-5.5 releases of CMS.  The differences between the two
variants are essentially invisible to the user, however,  aside  from  the  an-
nouncement  of  the  release number when Kermit starts up.  Both variants care-
fully determine whether they are running under VM/XA and, if so, avoid  setting
the CP parameters ACNT and TIMER, which VM/XA SP 2 does not support.  Also, the
traditional variant halts gracefully if it finds itself running in XA mode.


Interactive Operation:

To run Kermit-CMS interactively, invoke the program from CMS by typing  KERMIT.
When you see the prompt,

    Kermit-CMS>

you may type a Kermit subcommand.  When the subcommand completes, Kermit issues
another prompt.  The cycle repeats until you exit from the program.    For  ex-
ample:

    .KERMIT

    Kermit-CMS Version 4.3.0 (93/9/30)
    Enter ? for a list of valid commands

    Kermit-CMS>send foo *

      Files with fn FOO are sent

    Kermit-CMS>receive test spss

      File is received and called TEST SPSS A1

    Kermit-CMS>exit

The  prompt  string under CMS is truly interactive.  In other words, the string
(without carriage return or linefeed) appears only when fresh input  is  needed
from  the  terminal.   If, for example, Kermit is invoked after several subcom-
mands have been stacked up, the stack is read and  executed  before  the  first
prompt appears.


Command Line Invocation:

Kermit-CMS  may  also be invoked with command line arguments from CMS.  The ar-
guments are interpreted as one or more subcommands to  be  executed  by  Kermit
after completion of the initialization.  For instance:

    .KERMIT send test fortran

or

    .KERMIT set debug on # set file type binary # server

Kermit will exit and return to CMS after completing the specified subcommand or
subcommands.  Several subcommands may be given on the command line as  long  as
they  are separated by the LINEND character, which is number sign in this case.
Note that the LINEND delimiter is a function of CP, rather than Kermit, and ap-
plies only to commands entered from the terminal and only when LINEDIT is on or
when talking to CP itself.  A command line may contain up to 130 characters.


EXEC Operation:

Like other CMS programs, Kermit-CMS may be invoked from a CMS  EXEC.    Subcom-
mands  can  be passed to Kermit using the program stack and/or command line ar-
guments.  For example, to start up Kermit-CMS and have it act as a server,  in-
clude the line:

    KERMIT server

To  pass  more  than one subcommand, they must be stacked in the order in which
they are to be executed.  To start up a Kermit-CMS server with a three  charac-
ter CRC, include:

    &STACK set block 3
    &STACK server
    KERMIT

Another  way of setting up multiple subcommands would be to collect the subcom-
mands into a TAKE file and then issue the TAKE subcommand via the command  line
or  program stack.  EXEC's may be executed from Kermit, either directly or from
a TAKE file, and Kermit subcommands, in turn, may be issued from EXEC's as long
as Kermit is active.  See the TAKE subcommand for more details.


Server mode:

Command  execution  in server mode is different in several respects from normal
operation.  First of all, some Kermit subcommands are not allowed (see the list
of  subcommands  in  the  Kermit-370 chapter).  Moreover, command errors always
terminate any active TAKE file.  Also, commands other than CP commands run in a
special  environment  with RUN ON, TIMER OFF, and so forth.  Another difference
is that Kermit intercepts all SVC instructions in order to  catch  console  I/O
and  transmit  the data to the local Kermit as text packets.  However, some CMS
system or user commands may issue console I/O directly to CP, so that some mes-
sages  never appear to the local Kermit (except, perhaps, as bad packets).  For
non-TTY terminals, such messages are stacked up in the console output queue and
appear  all at once when Kermit returns from server mode.  However, some system
configurations, especially those including VTAM, are incapable of resuming Ker-
mit  protocol  transmission  after  interruption by direct console I/O, so such
commands should generally be avoided.


2.3. Kermit-CMS Subcommands

Kermit-CMS supports all the subcommands described in  the  Kermit-370  chapter.
In  addition,  there are two more, both of which can be issued as remote Kermit
commands when Kermit-CMS is in server mode.  The first is "CMS", which is  just
a  synonym  for  the  generic  subcommand  "HOST".    The second is "CP", which
specifically issues a command to CP.  In most circumstances, the latter is  not
needed, since CMS will pass along CP commands to CP.

This  section concentrates on the subcommands that have special form or meaning
for Kermit-CMS.   These  are  ordered  alphabetically.    See  the  chapter  on
Kermit-370 for further details.


                          THE CP AND CMS SUBCOMMANDS

Syntax: CP or CMS text of command

Although  Kermit-CMS does not have a full set of its own subcommands for manag-
ing local files, it provides those services through the operating system.   You
can issue any CP or CMS command, but if Kermit-CMS has been invoked as a normal
user-area program, rather than as a high-memory "resident" program  or  nucleus
extension,  other  user-area CMS commands (such as COPYFILE) are illegal.  Even
then, you can list, type, rename or delete files, send  messages,  and  so  on.
The CMS subcommand under Kermit is synonymous with the HOST subcommand.


                              THE CWD SUBCOMMAND

Syntax: CWD letter

The  CWD  (Change  Working  Directory)  subcommand  establishes  a  new default
("home") CMS disk.  letter may be the mode letter of any accessed disk.    Sub-
sequent  file transfers take place preferentially to and from the default disk.
The initial home disk is "A".  Note: setting the home disk in Kermit has no ef-
fect on the CMS search order.


                           THE DIRECTORY SUBCOMMAND

Syntax: DIRECTORY [filespec]

Under  Kermit-CMS,  the  DIRECTORY  subcommand is identical to the CMS LISTFILE
command.


                              THE GET SUBCOMMAND

Syntax: GET [foreign-filespec [filespec]]

The GET subcommand tells Kermit to request a file or file group from the  other
system, which must have a Kermit running in server mode.  The syntax is compli-
cated by the allowance of two forms for the foreign-filespec, just  as  in  the
SEND  subcommand.    Here  the  parsing  is  based  on  the  number  of "words"
(blank-delimited strings) in the subcommand argument,  which  can  be  anything
from  one  to  five.  If the number is anything but four, the interpretation is
unambiguous, but when there are four words, the first word plays the key  role.
If it has more than eight characters or contains a "." or "/", it is assumed to
be the whole foreign-filespec; otherwise, it is assumed to be the first of  two
words that, when joined by a ".", make up the filespec on the other system.  If
this subcommand is issued without any arguments at all, Kermit-CMS will  prompt
the user for both foreign and native filespecs.


                              THE GIVE SUBCOMMAND

Syntax: GIVE table-name filespec

This  subcommand  compares  the named translation table with its default values
and saves the differences in a  TAKE  file  named  filespec.    The  format  of
filespec  is  fn  [ft  [fm]].   The default filetype is "TAKE", and the default
filemode is that of the "home" disk.  See the CWD subcommand.


                              THE HELP SUBCOMMAND

Syntax: HELP subcom

This subcommand displays the relevant part of the Kermit  help  file  when  the
latter is a partitioned data set.  Kermit verifies that the argument is a valid
Kermit subcommand (or a non-ambiguous abbreviation) and then displays the  cor-
responding  member  of  the PDS.  For the SET subcommand, individual parameters
may also be specified, as in
    HELP SET BLOCK-CHECK

If no subcommand name is included, Kermit displays the  member  that  gives  an
overview  of  Kermit  operation.   Kermit looks for a help file with a filename
matching the Kermit command itself, but will settle for one with a filename  of
KERMIT if necessary.  Thus, the response to the HELP subcommand may depend upon
which Kermit module is invoked.  The choice of whether to format the help  file
as  a  PDS  is  an option at installation time.  If the installer has chosen to
leave it as an ordinary sequential file, or if no help file has been  installed
recently,  Kermit will fall back on the old behavior of the HELP subcommand: it
will issue the CMS HELP command for Kermit and  therefore  display  the  entire
file.    Since the help file is rather long, this subcommand is not recommended
for users with line-mode terminals, unless the help file is installed as a PDS.
See the installation guide for more details about the help files.


                            THE RECEIVE SUBCOMMAND

Syntax: RECEIVE [filespec]

The  RECEIVE  subcommand  tells Kermit to receive a file or file group from the
other system.  You must issue the corresponding SEND subcommand  to  the  other
Kermit.

The format of filespec is:

    filename filetype [filemode]

If  the  optional filespec is omitted, Kermit-CMS will use the name(s) provided
by the other Kermit.  If that name is not a legal  CMS  file  name,  Kermit-CMS
will  delete  excess  characters  and  will change illegal characters to under-
scores.  A filespec in the subcommand indicates what  name  the  incoming  file
should be given.  The filespec may include a filemode to designate the destina-
tion disk.  If none is provided, the file will be saved on the "home" disk with
filemode  number  "1".    If  you  want  to  use  the same name but a different
filemode, specify "= = FM".  Wildcards may  not  be  used.    If  the  optional
filespec  is  provided,  but more than one file arrives, the first file will be
stored under the given filespec, and the remainder will be stored  under  their
own names on the "home" disk.  If, however, "= = FM" is used, all files will be
placed onto the specified disk.

For purposes of truncation  and  folding,  the  maximum  record  length  for  a
received file is 65535 if RECFM is V and "LRECL" if RECFM is F.

If  the  incoming  file has the same name as an existing file, the action taken
depends on the FILE COLLISION setting.  The possible settings and  their  mean-
ings  are  given  in  the  Kermit-370 chapter.  Two of the settings (BACKUP and
RENAME) require  that  Kermit-CMS  change  the  incoming  name  so  as  not  to
obliterate  a  pre-existing file.  It attempts to find a unique name by succes-
sively modifying the original and checking for the existence of such a file  at
each  step.   The procedure begins by truncating the filetype to six characters
if necessary and then appending "$0".  If a file by that  name  exists,  Kermit
then  replaces  the "0" with a "1".  It continues in this manner up to "9", and
if an unused name cannot be found, the transfer fails.


                              THE SEND SUBCOMMAND

Syntax: SEND [filespec[<options>] [foreign-filespec]][, ...]

The SEND subcommand causes a file or file group to be sent from CMS to the Ker-
mit on the other system.  filespec takes the form:

    filename filetype [filemode]

or

    fn.ft.[fm]

but  the  filemode  is  optional  only if the foreign-filespec is omitted.  The
"dotted" notation is interpreted by changing up to two  dots  into  spaces,  so
only  the  normal  CMS-style form is "real" as far as Kermit is concerned.  For
details on the options, see the description of SEND in the Kermit-370  chapter.
Note  that  no  blanks  may intervene between the CMS filespec and the options,
even though the filespec itself has imbedded blanks (either explicitly  or  im-
plicitly through the "dotted" notation).

The  filespec may contain the wildcard characters "*" or "%".  If it does, then
all matching files will be sent.  If, however, a file exists by the  same  name
on  more  than one disk, only the first one Kermit-CMS encounters, according to
the disk search order, is sent.  See also the CWD subcommand.

The foreign-filespec, if any, is used for the file header of the outgoing file,
replacing  the  usual  filename.filetype  copied from the CMS filespec.  It may
take one of two forms:

    filename filetype

or

    arbitrary-string

Normally, this form of the SEND subcommand is used only for  single  files  be-
cause  the  foreign-filespec  is  used only for the first file of a group (sub-
sequent files having default headers).  However, in the two-token form  of  the
foreign-filespec  either  the name or type may be an Equals sign "=" to signify
that the corresponding CMS name or type is to be retained in the  file  header.
In  that  case,  the partial renaming carries through an entire group of files.
It is the user's responsibility to prevent such partial renaming  from  sending
duplicate  file headers within a file group.  If both filespecs are omitted for
this subcommand, Kermit will prompt separately for  each,  and  the  respective
syntaxes  are  exactly as described above, except the filemode is optional even
if a foreign-filespec is to be supplied.  This  prompting  mode  is  especially
useful when more than one file (or file group) is to be sent, since the command
line is limited to 130 characters.

Trailing blanks in a text file with RECFM F  are  deemed  superfluous  and  are
stripped off when Kermit-CMS downloads the file.  In order to treat such blanks
as significant, you must convert the record format to V, for example, by  using
COPYFILE  with  the  "RECFM V" option.  Note: you must not use XEDIT for such a
conversion, since it also strips trailing blanks from files with RECFM V.


                              THE SET SUBCOMMAND

Syntax: SET parameter [value]

The SET subcommand establishes or modifies various parameters controlling  file
transfers.    The following SET parameters are available in Kermit-CMS, but not
in Kermit-370 in general:
DESTINATION         "Home" disk.
FILE
  LRECL             Logical Record length for incoming file.
  RECFM             Record format for incoming files.
SEARCH-ALL          Determine the default disk search scope.


SET DESTINATION

Syntax: SET DESTINATION letter

This subcommand is equivalent to the CWD subcommand (q.v.).


SET FILE LRECL

Syntax: SET FILE LRECL number

This sets the logical record length for incoming files to a number  from  1  to
65535  (64K-1).   This variable is used only for fixed-format and binary files.
The default is 80.


SET FILE RECFM

Syntax: SET FILE RECFM option

This sets the record format to use for  incoming  files.    Valid  options  are
"Fixed" and "Variable" (the default).  Fixed-format records are padded, folded,
or truncated, as needed, to the current LRECL.


SET PROMPT

Syntax: SET PROMPT [string]

This sets the prompt string, just as in other variants  of  Kermit-370,  except
that  the string is padded with the current HANDSHAKE character, if any, unless
the string is empty or already ends with that character.


SET SEARCH-ALL

Syntax: SET SEARCH-ALL ON or OFF

ON      If the user omits the filemode from a SEND subcommand (or a GET request
        via  the  other  Kermit), Kermit-CMS will search all accessed disks for
        the named file or files.  The search follows the usual search order.

OFF     If the filemode  is  not  specified,  only  the  "home"  disk  and  its
        read-only extensions will be searched for matching files.  (Default.)


                             THE SPACE SUBCOMMAND

Syntax: SPACE [letter]

This  subcommand displays the storage allocation on the specified CMS mini-disk
or SFS directory.  If letter is omitted, the default disk specified by the  CWD
subcommand  is displayed.  Aside from this default, the subcommand is identical
with CMS QUERY DISK.


                              THE TAKE SUBCOMMAND

Syntax: TAKE filespec

Execute Kermit subcommands from the specified file, where filespec has the for-
mat  fn [ft [fm]].  The default filetype is "TAKE", and the default filemode is
"*".

Kermit subcommands may also be executed from CMS EXEC's, so that the TAKE  sub-
command  is, in a sense, superfluous under CMS.  In CMS terminology, Kermit es-
tablishes a Kermit subcommand environment, and EXEC's written in EXEC 2 or REXX
may  invoke  subcommands  within that environment.  For example, to display the
current packet checksum type, an EXEC 2 would issue

    &SUBCOMMAND KERMIT SHOW BLOCK-CHECK

and a REXX macro would issue
    Address KERMIT 'SHOW BLOCK-CHECK'

There is one important difference between executing a TAKE file  and  an  EXEC:
the  former may issue a QUIT or EXIT subcommand, but the latter may not.  Also,
a Kermit subcommand issued from an EXEC returns a completion code according  to
the current error status (see the table under "After Returning from Kermit-370"
in the Kermit-370 chapter).  An EXEC could therefore be set  up  to  react  ap-
propriately to file transmission errors or other unpredictable events.  A third
difference is that, although an EXEC may issue a TAKE  subcommand,  the  latter
will not be executed until after the EXEC processor returns to Kermit.


2.4. How to build an executable Kermit-CMS

Before  attempting  to  build Kermit-CMS, look in the Kermit distribution under
IKCKER for an installation document, as well  as  "beware",  help,  and  update
files,  and  read  them  first.  They will probably contain information that is
more current than what you see here.  In fact, IKCKER INS contains an EXEC  for
installing Kermit nearly automatically.

Kermit-CMS  consists  at  present of a large assembly and a small optional one.
The large assembly (KERMIT ASSEMBLE) contains the Kermit program, and the small
one  (KERMBOOT  ASSEMBLE)  is  a bootstrap program for loading Kermit into high
memory and running it.  KERMBOOT can be  useful  under  CMS/SP  Release  3  and
below,  but  is  not  needed  under  Release  4 and cannot be used at all under
Release 5 and above.  Although KERMBOOT is all in one file in the  Kermit  dis-
tribution,  the  source  for  Kermit itself is in many pieces, some generic for
Kermit-370 and some specific to CMS.  All the necessary pieces are sequenced in
columns  73-80 so that the numbers form a strictly increasing sequence when the
pieces are correctly "pasted" together.    It  is  important  to  preserve  the
original  sequence  numbers  so  that  updates,  if  any, can be applied to the
source.

To create a runnable version (the hard way):

   1. Combine the following "ASM" files from the Kermit distribution  into
      a single file with "RECFM F" and "LRECL 80": IK0DOC, IK0MAC, IKCMAC,
      IK0DEF, IK0MAI, IK0COM,  IK0CMD,  (optional:  IK0KAN),  IKCUTL,  and
      IK0PRO.   The resulting file is the composite source for Kermit-CMS,
      called KERMIT ASSEMBLE.  This source must retain  the  original  se-
      quence  numbers  in  columns  73-80  (in other words, be sure not to
      resequence the source accidentally using the editor!)

   2. Copy or rename IKCBOO ASM from the Kermit distribution (if  desired)
      to a file called KERMBOOT ASSEMBLE with "RECFM F" and "LRECL 80".

   3. GLOBAL the necessary MACLIBs.  Under VM/SP and VM/XA SP 2, these are
      DMSSP, CMSLIB, TSOMAC, and OSMACRO.  Under VM/XA SP  2.1,  they  are
      DMSOM, DMSGPI, and OSMACRO.

   4. Assemble the source file(s).

   5. Load one file into memory via: "LOAD KERMIT" or "LOAD KERMBOOT".  In
      the former case, the entire Kermit program is  now  loaded;  in  the
      latter,  only  a  bootstrap program which expects to find the object
      file "KERMIT TEXT" at run time.  Under CMS/SP Release 4  and  above,
      there is a third and better option, namely, "LOAD KERMIT (RLDSAVE)".

   6. Create  the  executable called "KERMIT MODULE" via: "GENMOD KERMIT".
      Alternatively (under CMS/SP Release 3 and below), create both KERMIT
      and  KERMBOOT  modules  to  give  the  user a choice of user-area or
      high-memory execution.  Since Kermit-CMS is  serially  reusable,  it
      can  be  reinvoked  in the user area with the START command, but the
      high-memory version must be reloaded each time.  If Kermit is loaded
      using  the  RLDSAVE option (Release 4 and above), the module can, in
      fact, be run either way; the command  "NUCXLOAD  KERMIT"  will  load
      Kermit  "permanently" as a nucleus extension for invocation at need.
      Note: the nucleus extension can be removed by the command  "NUCXDROP
      KERMIT".

To  create a runnable version the easy way, extract IKCINS EXEC from IKCKER INS
and run it.  When it is finished, you may perform any desired  tests  and  then
move  the MODULE and HELP files to their permanent locations.  It is useful for
the Kermit module and help file to have the same filename  and  reside  on  the
same mini-disk.

If your site's ASCII/EBCDIC translation table for TTY lines does not conform to
the one listed in the appendix (which in turn conforms to the one given in  the
IBM   System/370   Reference   Summary),   then   enter   the  appropriate  SET
ATOE/ETOA/TATOE/TETOA subcommands in the  SYSTEM  KERMINI  file,  which  should
reside  on  the  same  disk  as  KERMIT MODULE (and KERMIT TEXT).  NOTE: If the
ASCII/EBCDIC translation is not invertible, Kermit will not and cannot work.


2.5. What's New

Below is a list of the CMS-specific features in  Version  4.3.0  of  Kermit-CMS
added since the previous major release, Version 4.2, in March of 1990.  For the
list of generic additions, see the chapter on Kermit-370.

   1. New, automated installation procedure collected as an EXEC contained
      in  the  installation  guide.  This includes selection of XA support
      and SFS support as appropriate.

   2. Help for individual Kermit subcommands from the HELP subcommand.

   3. Improved recovery from I/O errors during file transfer.

   4. Improved execution of CMS commands under Kermit with SYSCMD ON.

   5. File names no longer considered to "collide" with files existing  on
      read-only extensions.

   6. Support for disk space check in advance of receiving a file into SFS
      and more accurate space check for ordinary mini-disks.

   7. Improved SFS wildcard sending.

   8. Small bug fixes.


2.6. What's Missing

Work on Kermit-CMS will continue.  Features that need to be improved  or  added
include:

   - Allow  timeouts  so Kermit-CMS does not wait forever if a packet does
     not arrive in a timely fashion.  This is not possible  under  CMS  at
     present.

   - Implement file archiving.

   - Add a SET REPEAT subcommand.

   - Implement public server mode, allowing a disconnected virtual machine
     to provide Kermit services via CP DIAL.

   - Add a CONNECT subcommand.  This may be impossible.

   - Intercept CP messages during protocol mode,  rather  than  just  sup-
     pressing  them.    Display  the messages later or log them or send in
     packets as appropriate.

   - Define EXEC variables from Kermit by analogy with the  XEDIT  EXTRACT
     subcommand.

   - Set file date/time on received files from the information sent by the
     other Kermit.

Anyone interested in working on these or other improvements should first get in
touch  with  the Center for Computing Activities at Columbia University to find
out if someone else has already begun a similar project (and, if so, who).
Index


          3174   1, 5
          3708   5

          Alternate lines   7
          Appending   6
          Arabic   1, 8
          ASCII-to-EBCDIC   5
          Attributes.   See   File   at-
                  tributes

          Batch jobs   3
          Binary files   1, 4, 6, 7
          Blanks
             preserving trailing   7, 14
             stripping   1, 7
             trailing   1, 7
          BLKSIZE   1
          Block check   5

          Cancelling a file transfer   4
          Character sets   1, 6, 8
          CICS   6
          CMS   6, 12
          Code pages   1
               See also   Character sets
          Collision.  See  Filename col-
                  lision
          Command echoing   7, 9
          Command prefix   3, 4, 7
          Completion codes   10
               See also   Error codes
          Control characters   5, 9
          Controller   5
          CRLF   1, 7
          CSW   6
          CWD   13
          Cyrillic   1, 6, 8

          Debugging   5
          Delimiter   13
          DIRECTORY   13
          Discarding files   6, 7, 11
               See also   DELETE
          DOS-4   1
          Dumping storage   5

          EBCDIC-to-ASCII   5
          ECHO   3
               See also   Command  echo-
                  ing
          Eighth-bit prefix   8
          Electronic mail   3
          End of file   6
          Error codes   10, 12
          EXEC   14
          EXEC operation   13
          Extended ASCII   5

          File attributes   1, 5, 9
          File disposition   3
          File management   13
          File renaming   6
          File truncation   6
          Filename collision   6, 14
          Flow control   9
          Folding   4, 6, 14
          Foreign   3, 7
          Front end   1
          Full screen   4, 9

          GET   3, 13
          GIVE   3, 13
          Greek   1, 8

          Handshake   7, 9, 12
          Hebrew   1, 8
          HELP   13
          Home disk   12, 13, 14
          Host commands   4, 7

          IBM   1, 12
          Incomplete files   4, 7
          Initialization  files    1, 2,
                  3, 6, 8, 12, 13, 15

          Kanji   1, 6, 8
          Katakana   1, 8
          KERMBOOT   13, 15

          Languages   1
          Local   3
          LOCAL-ECHO   9
          Log files   12
          Long packets   4, 8, 9, 12
          LRECL   1, 7, 12

          MACLIB   15
          Mail   3
               See  also      Electronic
                  mail
          Margins   7
          MTS   1
          MUSIC   6

          Optimum packet size   4, 7
          Overwriting files   6
               See  also   Filename col-
                  lision

          Packet size   4, 8
          Parity   8, 9
          Prefix.      See      Command,
                  Eighth-bit, Foreign
          Prefixing   5
          Printing files   3
          Prompt   7

          Quote. See Prefix

          Raw transmission   3, 9
          RDBUF   12
          RECEIVE   3, 4, 14
          RECFM   1
          Reconnecting   12
          Records   1
          Remote   3
          RENAME   6
          Renaming files   6
               See also   File renaming
          ROSCOE   6

          Screen refresh   9
          Search order   12, 13, 14
          SEND   3, 4, 14
          SEND delay   6
          Series/1   1, 5, 12
          SERVER   4
          SET   4, 14
          SHOW   9
          SNA   1, 5
          SPACE   14
          STATUS   9
          STOP   9
          Stripping blanks. See Blanks
          Subcommand prefix. See Command
                  prefix
          Submitting jobs   3
               See also   Batch jobs

          Tabs   7
          TAKE   9, 14
          TDUMP   9
          TEST   7
          TGET   6
          Thai   1
          Timeout   7, 9
          TPUT   6
          Tracing execution   5, 9
          Trailing blanks. See Blanks
          Transaction log   4, 9
          Translation   1, 2, 8
          Translation tables   1, 3,  8,
                  12, 13, 15
          Transparent mode   3, 9
          Truncation   4, 6, 14
               See  also      File trun-
                  cation
          TSO   6
          TTY   1, 5, 9, 12
          Type   4

          User area   13, 15

          VM/XA   13

          Warning   6
          Wildcard   12
          Wildcards   14
          WRBUF   12

          XECHO   3
