Columbia Kermit/kermit.zip/gould2/gm2kermdoc.txt

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Kermit-MPX

Program:       L. Tate, Simulation Associates Inc.
               Derived from CYBER-170 version 1.0,
               Jim Knutson, University of Texas.
Language:      Gould Fortran 77 4.2, with some assembler routines
Version:       2.3
Date:          May 1986
Documentation: L. Tate, Simulation Associates Inc.,
               Mike Niswonger, Computer Science and Applications

Kermit-MPX Capabilities at a glance:

    Local operation                    Yes; MPX 3.2B or later
    Remote operation                   Yes
    Transfers text files               Yes
    Transfers binary files             No
    Wildcard send                      No
    ^X/^Y interruption                 No
    Filename collision avoidance       No
    Can time out                       Yes
    8th-bit prefixing                  No
    Repeat count prefixing             No
    Alternate block checks             No
    Terminal emulation                 No
    Communication settings             No
    Transmit Break                     Yes
    IBM communication                  Yes
    Transaction logging                No
    Session logging                    Yes
    Raw upload                         No
    Act as server                      Yes
    Talk to server                     Yes
    Advanced commands for servers      No
    Local file management              No
    Handle file attributes             No
    Command/init files                 Yes
    Printer control                    No

14.1 Kermit-MPX Description

Kermit-MPX runs on Gould's Concept and Series computers running MPX 2.X or  MPX
3.X  operating  systems.   MPX 3.2B and later versions allow true  full  duplex
terminal  operations  so  these installations may use the Kermit program  in  a
local mode although the response is very poor.

This  Kermit  requires the use of an eight line asynchronous  (8LAS)  interface
(sorry  ALIM  and  ADS users) on an IOP.   This interface  buffers  the  input,
performing  some  rudimentary translations like lower to upper case  and  block
reads and writes.   Unfortunately, it's efficiency is very poor for single byte
reads  and writes,  thus the connect mode's effective throughput is only  about
300  baud.   To make matters worse  when the type-ahead buffer is full  (40-128
characters)  then  the  buffer empties and a program  interruption  (break)  is
generated. Also a break can be generated by recognition by the 8LAS of a 'wake-
up' character.   Convenient for the terminal processor, but really bad for file
transfer if the wake-up character is a '?' or any other printable character.

This  Kermit has a timeout that functions at random intervals.  If the  timeout
doesn't work then sending a break should wake it up.

The initialization file KERMIT.INI may be used to initialize Kermit.   The file
must  be in the current directory when starting Kermit up.    Any valid Kermit-
MPX command may be included.

14.2 Kermit-MPX Commands

Kermit-MPX uses the DECSYSTEM-20 keyword style command language.   Each keyword
may be abbreviated to its minimum length.  "?" may be type to request a menu of
the available options for the current field at any point in a command.

Kermit-MPX prompts with 'Kermit-' with the machine type concatenated on to  it.
For example on a Concept 32/27 machine, the prompt will be 'Kermit-27>'.

BYE
         Sends  a message to the remote server to log out the remote Kermit and
         exits local Kermit to system level. Since Kermit-MPX cannot log itself
         off, it just exits the task.

CONNECT
         Enter  terminal  emulation  mode.   Presents  the  illusion  of  being
         directly  connected as a terminal to the remote system.   When  escape
         character is typed, interprets next character as follows:

                   0               (zero) transmits a null
                   B               transmits a BREAK
                   C               close a connection, return to
                                   local Kermit
                   Q               quit logging (if being done)
                   R               resume logging
                   ?               show available arguments
                   escape character
                                   transmits the escape character

         Invalid arguments are beeped and reenters connect mode.

EXIT
         Exit from local Kermit.

FINISH
         Sends a message to the remote server to shut itself down,  leaving the
         local Kermit at command level, and the remote at system level.

GET  remote-filename
         Tells a remote Kermit to send a file.

HELP  topic
         Typing  HELP alone prints a brief summary of Kermit and its  commands.
         You can also type

            HELP command

         for  any  Kermit command,  e.g.  "HELP SEND",  to  get  more  detailed
         information about a specific command.  Type

            HELP ?

         to  see  a  list of all the available help commands,  or  consult  the
         Kermit Users Guide.

QUIT
         Exit from local Kermit.

RECEIVE
         Expects one or more files to arrive.

SEND local-filename
         Sends a file to remote Kermit.

SERVER
         Act  as a server for another Kermit.   Take all further commands  from
         the  other Kermit.   After issuing this command,  escape back to  your
         local system and issue SEND, GET, BYE or other server-oriented command
         from there.  If your local Kermit does not have a BYE command, it does
         not  have  the full ability to communicate with a  Kermit  server  (in
         which case you can only use the send command).

SET
         Establish  system-dependent parameters.   You can examine their values
         with  the  SHOW  command.    Numeric  values  may  be  decimal,  octal
         (postfixed with an O or B), or hexadecimal (postfixed with an H).  The
         following may be SET:

         DEBUG options
            Show packet traffic explicitly.  Options are:
            ALL      Set all debug options.
            LOG-FILE local-filename
                     Log states and packets to the specified file.
                     The default log-file is file L.KERMLOG
            OFF      Don't display debugging information. (this is
                     the default).  If debugging was in effect, turn
                     it off and close any log file.
            PACKETS  Display each incoming and outgoing packet
                     (lengthy)
            STATES   Show Kermit state transitions and packet numbers
                     (brief).

         LOG options
            Log all inputs from remote port during connection.
            Options are:
            LOG-FILE local-filename
                     Log inputs to specified file.  The default
                     log-file is file L.SESSION
            OFF      Turn off the session logging
            ON       Turn on the session logging

         PORT terminal-address
            Sets the communication port;  to which connect,  send,  receive and
            server  interact  with.   Any  MPX terminal address  may  be  used.
            Examples: TY7EC0, U17CC4, or UT.
            Default is UT.

          ESCAPE number
            Control character used to escape from connect mode.
            Default is 29, (^])

          ECHO on/off
            Turns on or off the echo by Kermit during connect mode.
            Echo is normally off.

          DELAY number
            How  many seconds to wait before sending the  first  packet.   This
            gives you time to "escape" back and issue a RECEIVE command.  Delay
            defaults to 5 seconds.

          INIT-RETRY number
            Set   the  maximum  number  of  retries  allowed  for  the  initial
            connection before giving up.
            Default is 20.

          RETRY number
            Set the maximum number of retries allowed for sending a  particular
            packet.
            Defaults to 5.

          SEND parameter
            Parameters for outgoing packets as follows:

            EOLCHR  number
              The  octal  value  of the ASCII character to be used  as  a  line
              terminator  for packets,  if one is required by the other system.
              Carriage return (0DH) by default.

            PACKLEN number
              Maximum packet length to send, decimal number, between 20 and 94.
              94 by default.

            PADCHR number
              Character to use for padding.  Default is NUL.

            PADLEN number
              How much padding to send before a packet.
              Default is no padding.

            QUOTECHR number
              What   printable  character  to  use  for  quoting   of   control
              characters.  The default is '#' (23H).  There should be no reason
              to change this.

            SYNCCHR number
              The  control character that marks the beginning of  the  packet.
              Normally SOH (Control-A,  ASCII 1).  There should be no reason to
              change this.

            TIMEOUT number
              How  many  seconds the other Kermit wants before being asked  for
              retransmission.  Default is 10 seconds.

          RECEIVE parameter
            Parameters to request or expect for incoming packets, as follows:

            EOLCHR  number
              The  octal  value  of the ASCII character to be used  as  a  line
              terminator for packets, if one is required by the other  system.
              Carriage return (0DH) by default.

            PACKLEN number
              Maximum packet length to send, decimal number, between 20 and 94.
              94 by default.

            PADCHR number
              Character to use for padding.  Default is NUL.

            PADLEN number
              How much padding to send before a packet.
              Default is no padding.

            QUOTECHR number
              What   printable   character  to  use  for  quoting  of   control
              characters.  The default is '#' (23H).  There should be no reason
              to change this.

            SYNCCHR number
              The  control  character that marks the beginning of  the  packet
              Normally SOH (Control-A,  ASCII 1).  There should be no reason to
              change this.

            TIMEOUT number
              How  many seconds the other Kermit wants before being  asked  for
              retransmission.  Default is 10 seconds.

SHOW
         Display current SET parameters, version of Kermit, and other info.

STATUS
         Give statistics about the most recent file transfer.

TAKE local-filename
         Read and execute Kermit commands from a local file.

X
         Exit from Kermit.


14.3 Software Installation

MPX-3.2B  and  later operating systems support true full duplex TSM  terminals.
With these operating system versions set the LOCALON flag .TRUE. in the include
file KVER.INS.  This allows the local commands to be used; BYE, CONNECT, FINISH
and GET.  Otherwise, Kermit-MPX is good as a remote server (which is it's prime
function anyway).

The source is a series of files;

          KVER.INS                  version include file
          KDEF.INS                  Kermit definitions
          KPROT.COM                 protocol common
          KPACK.COM                 communication parameters of Kermits
          KFILE.COM                 I/O package common data
          KTIME.COM                 Timing of connect mode
          KDBUG.COM                 Debug output control
          KMSG.COM                  Prompt and version message

          GM2KERM.INS               Consolidated include file
                                     (has all above files in it)
          GM2KERM.F77               main Kermit code
          GM2KERM.ASM               assembler routines for I/O system
          GM2KERM.BAT               batch deck to compile, assemble
                                    and catalog task image

The  small COM and INS files are found in the larger GM2KERM.INS file.   Use  a
text editor to split out the smaller files for the Fortran compiler to  access.
When creating the task, edit the batch deck for appropriate directory names and
file names.

14.4 Hardware Requirements

The front end of a Gould can be quite trouble-some, requiring some expertise to
overcome some of the 8LAS shortcomings.

The  wakeup  character  on many system is the '?'.   This  is  a  valid  Kermit
character,  but  every time it is sent,  it breaks the terminal thus ending the
packet.   To  avoid  this we change the wakeup character to a non-valid  Kermit
character such as control-E (05H).

The  connect  mode is rather slow,  having an aggregate rate of  300  baud,  if
system  load is low.   However,  we usually like to transfer at 9600  or  19.2k
baud.  In one installation,  we set the baud rate to maximum.  Since the remote
system is sending characters back at the same high rate,  it outpaces the local
Kermit  and we lose the buffer (remember the break) in connect mode.  Note that
this  does  not affect the server mode where transfers occur  at  full  channel
speed.   Logging  in  and  activating the server does not require  much  system
interaction  and dropped characters can be tolerated for the short duration  of
the  connect  mode required.   This limitation of connect mode  emphasizes  the
primary  use  of Kermit-MPX as a file server,  not as  an  interactive  connect
terminal program.

The other solution is to dynamically change the baud rate from 300 to 9600  and
back.  This requires a program to change the baud rate dynamically and a direct
linkage between computers. The procedure is to log on to the remote's terminal,
change the baud rate to desired rate,  close your local connection,  change the
baud rate of connect port, then reopen connection.

A  port  characteristic changing program was not built into Kermit  because  of
it's system dependence.   All that's needed is a program to translate the  port
characteristics to a 3 byte ACE code used 8LAS.   This may be sent to the  port
using  the  M.WRITE macro,  with the data format inhibit (DFI) bit set and  the
transmit  ACE  parameter  bit set.   See MPX reference  manual,  volume  I  for
details. A good future enhancement.


14.5 Future Work

     Install a port setting capability to Kermit.

     Improve CONNECT speed.  Suggested alternatives could be;
         Block reads with 1 sec timeouts and special character detect.

         Total interrupt driven.   This requires assembler routine,  and use of
         M.CALL to IOCS since M.WRITE/M.READ does not perform well in interrupt
         driven environment.

         Activate Kermit to get higher priority.  This sounds cheap.

     Added server commands for file management, particularly;
         cd       change directory
         copy     copy file
         rename   rename file
         delete   delete file
         list     list file
         dir      directory listing,

     These commands are most needed since it's difficult to use volume  manager
     at 9600 baud connected.

     Correct  error  reporting.   Error packets are not displayed and for  some
     reason, sent error packets are not displayed by other Kermits.

14.5 Kermit-MPX Revision List

      2.3  Added to SERVER the ability to recognize the I packet.   This packet
           is  used  by  advanced Kermits (at least MS-Kermit 2.27 and  up)  to
           initialize  the  server.   Changed  the method by  which  nowait  is
           established so that if ECHO was off before Kermit operation, then it
           will remain so afterwards.   Good for network operation.   Corrected
           the error reporting code such that the error messages are  produced.
           However,  they  can  be very cryptic.   What is needed is a  general
           method  of handling text,  like help and error messages,  such  that
           memory is not filled but ready access is available.
            L. Tate, SAI, May 1986.

      2.2  Improved  receive/get reliability by moving the  terminal  reporting
           before  the ACK/NAK is sent.   The problem seems to have been during
           the reporting time, the sending flooded the 8-line buffer and caused
           a break,  losing data.  Also corrected error in printl routine which
           wrote to stdout instead of the parameter fd.
            L. Tate, SAI, Mar. 1986.

      2.1  Correct bug in SUDT.  When use the SVC 1,X'27' which set full duplex
           on a terminal it previously used a trashed file control block.  This
           had  caused  unpredictable results in a lot of the I/O  including  2
           reads  pending at once.  Correcting this problem allowed removal  of
           HIOALL  routine.  Files to be read are opened with OPENMODE='R'  and
           files  to be written are opened with OPENMODE='U'.   Also added  the
           TAKE command.
            L. Tate, SAI, Mar. 1986.

      2.0  Added  the  CONNECT,  GET,  FINISH,  BYE  commands.   This  required
           significant  changes to the io interface.   The local on/off  option
           was also part of this.
            L. Tate, SAI, Nov. 1985.

      1.0  This  Kermit was the direct implementation of the Cyber-170 version,
           University of Texas.
            L. Tate, SAI, Sept. 1985.