Internet Info 1994 March/Internet Info CD-ROM (Walnut Creek) (March 1994).iso/networking/terms/kermit/b/ckvker.bwr

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CKVKER.BWR          "Beware File" for C-Kermit Version 5A        -*- text -*-

            (Open)VMS VERSION FOR DEC VAX AND AXP

Applies to 5A(189)
Last update: Tue Jul  6 11:14:18 1993

Authors: Frank da Cruz, Christine M. Gianone (Columbia University, NYC);
         Terry Kennedy (Saint Peters College, Jersey City, NJ).

  Copyright (C) 1985, 1993, Trustees of Columbia University in the City of New
  York.  The C-Kermit software may not be, in whole or in part, licensed or
  sold for profit as a software product itself, nor may it be included in or
  distributed with commercial products or otherwise distributed by commercial
  concerns to their clients or customers without written permission of the
  Office of Kermit Development and Distribution, Columbia University.  This
  copyright notice must not be removed, altered, or obscured.

Report problems, suggestions, fixes, etc, to:

  Frank da Cruz
  Columbia University
  Academic Information Systems (AcIS)
  612 West 115th Street
  New York, NY  10025  USA

  Internet:         [e-mail]
  BITNET/EARN/CREN: FDCCU@CUVMA
  Fax:              [phone]

VMS C-Kermit installation instructions are in the file CKVKER.INS.  Please
be sure you have read that file before concluding that C-Kermit isn't working
right on VMS.

Note: "VMS" as used in this document refers to both VMS and OpenVMS on both
VAX and AXP (Alpha) processors.  Most of the words in the previous sentence
are trademarks (TM) of Digital Equipment Corporation.


DOCUMENTATION

C-Kermit 5A is documented in the book "Using C-Kermit" by Frank da Cruz
and Christine M. Gianone, Digital Press, Burlington, MA, USA.  Digital
Press ISBN: 1-55558-108-0; Prentice-Hall ISBN: 0-13-037490-3.  Price: US
$34.95.  In USA, call DECdirect at 1-800-344-4825, refer to order number
EY-J896E-DP.  Available: January 1993.


COMMAND PARSER

VMS-style command-line editing (arrow keys, etc) is not supported.  Kermit
does not use the VMS F$PARSE facility -- it has its own command parser that
lacks certain features of F$PARSE (arrow-key editing, command recall, etc) but
has many other features that F$PARSE lacks: "?"-help, keyword and filename
completion, filename menus, variables, macros, etc.

Contrary to expectations of VMS users, the MSEND command does NOT use
commas to separate file specifications.  E.g. say this:

  C-Kermit>msend ckc*.% cku*.% ckv*.%

not this:

  C-Kermit>msend ckc*.%, cku*.%, ckv*.%

CD (Change Directory) to a DECnet node does not work in VMS C-Kermit.

OPEN !WRITE does not work in VMS C-Kermit.

APPEND operations (such as OPEN APPEND and SET FILE COLLISION APPEND) do
not work in VMS; they always create a new version of the file rather than
appending to the most recent version.

VMS C-Kermit does NOT provide program status codes in the normal VMS manner.
Rather, it returns the codes described on pp. 323-324 of "Using C-Kermit", by
assigning them to the symbol CKERMIT_STATUS.  For example, if a RECEIVE
operation failed:

  $ show symbol ckermit_status
    CKERMIT_STATUS == "4"
  $

Arguments supplied to the EXIT (or QUIT) commands take precedence:

  C-Kermit>exit 1234
  $ show symbol ckermit_status
    CKERMIT_STATUS == "1234"
  $

If C-Kermit encounters no execution errors, and EXIT (QUIT) is given without
an operand, then:

  C-Kermit>exit
  $ show symbol ckermit_status
    CKERMIT_STATUS == "0"
  $

You can use the CKERMIT_STATUS symbol as in this DCL example:

  $ kermit -s oofa.txt
  $ if ckermit_status .eq. 0 then goto ok


GENERAL FAILURES

...can occur for many reasons beyond Kermit's control, many of them related to
VMS system parameters or limits on the user or process: disk quotas, user
pagefile quotas (AUTHORIZE parameter PGFLQUO), system pagefile space filling
up, etc.  See CKVINS.DOC (installation instructions) for details.

To increase a user's pagefile quota, tell AUTHORIZE to MODIFY
username/PGFLQUO=number.  If the system itself is running out of pagefile
space (which would cause the system to grind to a halt and eventually crash).
You can check the system pagefiles with SHOW MEMORY/FILE: add up the "Free"
numbers for the [*]*PAGEFILE.SYS files and see if the total is big enough
(there should normally be at least 100K free pages on an active system).  If
not, the system manager would use the procedure @SYS$UPDATE:SWAPFILES to
resize the files.


FILE TRANSFER

File transfer modes (TEXT vs BINARY) are set automatically for each when
sending.  The SET FILE TYPE BINARY and SET FILE TYPE TEXT commands are ignored
when sending files.

Incoming files are rejected if the available space on the disk device is less
than the size of the file.  However, the user's disk quota is not checked.
Quota checking could erroneously report that a user couldn't store a file for
a number of reasons: for example, the user has the EXQUOTA privilege, C-Kermit
is installed with EXQUOTA privilege (not recommended!), overdraft, etc.
Because of the large potential for denying a transfer that would fit, the file
is accepted regardless of the disk quota.  This is consistent with the way
other VMS utilities work.

The file size shown in the file transfer display when sending a file might
be incorrect under certain conditions (but the file is still transferred
correctly).

Incoming files, if accepted, are always stored as a new file with the next
highest version number, even when FILE COLLISION is set to OVERWRITE or
or RENAME.

Transfer of VFC (Variable with Fixed Control) files, such as those created
by DCL, is problematic, since the meaning of the control bytes is defined by
the application.

ZIP files: If you have trouble transferring ZIP files into or out of VMS
using BINARY mode, use IMAGE mode instead (SET FILE TYPE IMAGE).  The same
applies to binary files created by VMS UNZIP.

When transferring files in LABELED mode, the file transfer display will show
the name the file was sent as, not the "true" name within the labeled file.
Also, note that a transfer may fail with an obscure error (can't create output
file) if there is something incorrect with the label information (for example,
if you specified that the file should be restored to the original directory
and you don't have privilege to write to that directory on this system).

DEC PATHWORKS file services normally create files in stream mode,  but
this can be overridden when the file service is created:

  $ ADMIN/PCSA
  PCSA> SET FILE_SERVER SERVICE service-name/ATTRIBUTES=SEQUENTIAL_FIXED

The normal stream files will be treated as TEXT by Kermit.  To transfer
PATHWORKS files that are really binary, such as executables, use IMAGE mode.

Reportedly, when transferring files TO a VMS system over a LAT connection (for
example, from a PC equipped with PATHWORKS and MS-DOS Kermit), packet sizes
greater than 255 (some reports say 70!) cannot be used, irrespective of the
VMS SYSGEN parameters regarding MAXBUF, etc.  The problem seems to lay in the
LAT protocol itself, or DEC's implementation of it, whereby applications are
not informed of -- and cannot find out -- limits on transmission.


SERIAL COMMUNICATIONS

If your terminal is set to /ESCAPE (validate escape sequences), C-Kermit gives
an error message, "contti.iosb invalid escape sequence", because it is doing
byte-by-byte output and VMS wants to see the whole sequence in one gulp.  The
workaround is to set the terminal to /NOESCAPE before starting C-Kermit.  The
fix is to add /NOESCAPE to the list of modes saved/restored for communication.
(NOTE: This was done in edit 189).

If you CONNECT to a modem or other device, and see a neverending stream of
messages, the terminal device probably has the /LOCAL_ECHO characteristic.
As of edit 189, C-Kermit attempts to turn off this characteristic, but since
it is a /PERMANENT characteristic, some degree of privilege might be required,
and this operation might fail for nonprivileged users.

The SET CARRIER and SET FLOW RTS/CTS commands are not supported in the
VMS version of C-Kermit.

Certain operations driven by RS-232 modem signal do not work on VAXstations or
other DEC platforms whose serial interfaces use MMP connectors (DEC version of
RJ45 telephone jack with with offset tab).  These connectors convey only the
DSR and DTR modem signals, but not carrier (CD), RTS, CTS, or RI.

When used on a serial communication device, the HANGUP command (as well as
the CONNECT-mode escape command, H, and the HANGUP done by the DIAL command
when DIAL HANGUP is ON) takes at least 3 seconds.  This is a FEATURE of VMS.

During terminal connection (SET LINE) and file transfer over a serial device,
buffer-overrun or BYTLM-quota-exceeded messages might appear.  It is essential
that any VMS system that needs to use Kermit or any other program to transfer
files over serial devices, especially when long packets or sliding windows are
to be used, be SYSGEN'd with large typehead buffers, and that user accounts
be given large BYTLM quotas.  See CKVINS.DOC.

  Note that LATmaster software (optional as of VMS V5.4-1, mandatory as of
  VMS V5.5) requires a minimum alt-typeahead buffer of 2064 bytes. Thus, you
  may already have increased the size.  Kermit needs packet-size times window-
  size plus a small amount of overhead.

To get around problems on systems where users have small BYTLM quotas, the
txbufr() routine in CKVTIO.C has been limited to reading 512-byte chunks at
a time from the communication device.  This does not appear to have an adverse
affect on performance, but time will tell.  If it does, a quick fix is to
recompile CKVTIO.C, defining CKV_IO_SIZE to be something bigger, e.g.

  /define=("CKV_IO_SIZE=8192")

or whatever.  A better fix might be to have txbufr() check the user's
remaining BYTLM quota before doing each read.  But that might be more expense
(overhead) than it is worth.

It is possible to SET LINE to an LTA (LAT) device, but correct operation
is reportedly dependent on the version of DECserver code and the VMS
version, and which patches have been applied.  Correct operation has been
verified for DECserver 200 software V3.1-37 and VMS V5.4-3, unpatched.

If you use C-Kermit to SET LINE to an LTA device and receive a hangup message
immediately:

  contti: ttiosb.status: %SYSTEM-F-HANGUP, data set hang-up

then:

 . Make sure you've created an LTA port on your VMS system which is
   mapped to the DECserver port that the modem is connected to.

 . Can you use the VMS SET HOST/DTE command to connect to that line? If you
   get the same error (which you should) there's a configuration problem in
   the DECserver setup for that port.

 . Are you trying to use that modem for both dial-in and dial-out
   configurations?  Try configuring different ports for dial-in and dial-out.

 . In order for VMS to connect to the dial-out modem, it needs to see the
   carrier detect signal asserted.  If that signal isn't asserted, the server
   will return a "hangup" error on the first character sent to the port.
   C-Kermit's SET CARRIER command has no effect in VMS.

 . Additionally, some modems want to see various settings on RTS/CTS and
   DSR/DTR before they will accept input.  If you have a breakout box and
   someone who is skilled at using it, you can usually resolve these problems.

Reportedly, if you have CONNECTed out through a LAT device, the CONNECT-mode
escape command to hang up (<esc-char>H) does not work.  Reason: unknown.
Cure: unknown (The LAT programming interface is very poorly documented).
Workaround: SET LINE <cr> to close the SET LINE device.


NETWORK COMMUNICATIONS

There is (as yet) no support for initiating connections over DECnet, nor for
VAX/PSI.  Certain types of TCP/IP are supported (including DEC TCP/IP (UCX),
TGV MultiNet, and Wollongong WIN/TCP), other types: not yet (Fusion, CMU/Tek).

If you enter the VAX from elsewhere through a TELNET connection, and the VAX
is running CMU/Tek, Fusion, or DEC TCP/IP (UCX), you might notice that file
transfers into the VAX fail almost immediately.  If this happens, it is most
likely the result of small VMS typeahead buffers.  See CKVINS.DOC for how to
increase typeahead buffer sizes, or work around the problem by telling VMS
C-Kermit to ask for smaller packets, for example:

  C-Kermit>set receive packet-length 65  ; (Use the longest length that works)

Reportedly, when building C-Kermit with WIN/TCP support with older versions
(5.1 and earlier?) of WIN/TCP, the symbol WIN$PERROR is undefined at link
time and the build fails.  Workaround: change the one reference to
win$perror(), which occurs in the contti() function in CKVTIO.C, to be
simply perror().

Although VMS C-Kermit can be built on the Alpha with TGV Multinet support,
TCP/IP connections cannot be made.  The problem has not yet been isolated, but
probably has to do with Alpha's underlying architecture -- word/byte
configuration vs Internet addresses, or somesuch.  In the meantime, it is
possible to run the Alpha AXP UCX version on a MultiNet system -- it works
automatically in "UCX compatibility mode".  You can also use the non-network
version of C-Kermit on a MultiNet system to make TCP/IP connections as
follows:

$ telnet/create foo.bar.baz.com
Trying...
TELNET session now connected to _NTY5:
%DCL-I-ALLOC, _$4$NTY5: allocated

$ kermit
C-Kermit 5A(189), 30 June 93, OpenVMS AXP
Type ? or HELP for help
C-Kermit>set line telnet_nty
C-Kermit>connect
etc...

MISCELLANEOUS

When C-Kermit is run "in a mailbox" (i.e. has been spawned by another
program), it can't transfer files because it doesn't think the controlling
terminal is a terminal.  Workaround: before attempting to transfer files, tell
C-Kermit to "SET LINE SYS$OUTPUT".


(End of CKVKER.BWR)