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C-Kermit 8.0 VMS Hints and Tips
[ [1]Contents ] [ [2]C-Kermit ] [ [3]Kermit Home ]
As of C-Kermit version: 8.0.201, 8 Feb 2002
This file last updated: Mon Feb 11 17:55:47 2002 (New York City
time)
IF YOU ARE READING A PLAIN-TEXT version of this document, note that
this file is a plain-text dump of a Web page. You can visit the
original (and possibly more up-to-date) Web page here:
[4]http://www.columbia.edu/kermit/ckvbwr.html
Authors:
F. da Cruz, C. Gianone, Columbia University, New York, NY.
Terry Kennedy, Saint Peters College, Jersey City, NJ.
________________________________________________________________________
CONTENTS
1. [5]INTRODUCTION
2. [6]THE C-KERMIT COMMAND PARSER
3. [7]COMMUNICATIONS
4. [8]GENERAL FAILURES
5. [9]LOCAL FILE OPERATIONS
6. [10]FILE TRANSFER
7. [11]OTHER TOPICS
________________________________________________________________________
1. INTRODUCTION [ [12]Top ] [ [13]Contents ] [ [14]Next ]
SECTION CONTENTS:
1.1. [15]Terminology
1.2. [16]Documentation
1.3. [17]Technical Support
1.4. [18]Other Sources of Information
This is what used to be called the "beware file" for VMS C-Kermit,
formerly known as CKVBWR.TXT (and before that CKVKER.BWR). This
edition is current as of C-Kermit 8.0. It contains hints and tips
specific to the VMS version of C-Kermit not necessarily found in the
manual, or which developed since the manual was published ([19]Section
1.1). The General C-Kermit Hints and Tips document:
[20]http://www.columbia.edu/kermit/ckcbwr.html
formerly known as CKCBWR.TXT (and before that CKCKER.BWR), contains
similar material that applies to all C-Kermit versions: Unix, VMS,
VOS, etc.
VMS C-Kermit installation instructions are in a separate document:
[21]http://www.columbia.edu/kermit/ckvins.html
(formerly known as CKVINS.TXT. Please be sure you have read that file
before concluding that C-Kermit isn't working right on VMS.
[ [22]C-Kermit ] [ [23]Kermit Home ]
________________________________________________________________________
1.1. Terminology
[ [24]Top ] [ [25]Contents ] [ [26]Section Contents ] [ [27]Next ]
"VMS" as used in this document refers to both VMS and OpenVMS on VAX
processors and OpenVMS on Alpha (formerly known as AXP) processors,
and presumably any other architectures that VMS will be adapted to,
such as IA64, PowerPC, or PA-RISC. Most of the words in the first part
of the previous sentence are or were trademarks (TM) of Digital
Equipment Corporation and/or Compaq Computer Corporation.
"DEC" is the way most people refer to Digital Equipment Corporation.
Digital Equipment Corporation was acquired in 1998 by Compaq Computer
Corporation, and thus references to Digital Equipment Corporation or
DEC should be interpreted accordingly in light of the evolving
integration, transfer of copyrights and licenses, product renaming,
etc. In this document we stick with the traditional and familiar
nomenclature. Compaq, in turn, is on its way into the stomach of an
even bigger fish, most likely Hewlett Packard.
There might be contradictory bits of advice in this file, since much
of the information was culled from different sources at different
times. Comments, reports, suggestions, contributions are always
welcome.
[ [28]C-Kermit ] [ [29]Kermit Home ]
________________________________________________________________________
1.2. Documentation
[ [30]Top ] [ [31]Contents ] [ [32]Section Contents ] [ [33]Next ] [
[34]Previous ]
1. Frank da Cruz and Christine M. Gianone, [35]Using C-Kermit, Second
Edition, Digital Press / Butterworth-Heinemann, Woburn, MA, 1997,
622 pages, ISBN 1-55558-164-1. This is a printed book. It covers
C-Kermit 6.0.
2. The C-Kermit 7.0 Supplement:
[36]http://www.columbia.edu/kermit/ckermit2.html
3. The C-Kermit 8.0 Supplement:
[37]http://www.columbia.edu/kermit/ckermit3.html
The C-Kermit home page is here:
[38]http://www.columbia.edu/kermit/ckermit.html
[ [39]C-Kermit ] [ [40]Kermit Home ]
________________________________________________________________________
1.3. Technical Support
[ [41]Top ] [ [42]Contents ] [ [43]Section Contents ] [ [44]Next ] [
[45]Previous ]
Email: [46]kermit-support@columbia.edu
News: [47]comp.protocols.kermit.announce
[48]comp.protocols.kermit.misc
<-- Announcements, moderated
<-- Discussion, unmoderated
Web: [49]http://www.columbia.edu/kermit/
[50]http://www.kermit-project.org/
[51]http://www.columbia.edu/kermit/faq.html <-- Kermit Project Home
Page
<-- Alternative Web address
<-- Frequently Asked Questions
Post: The Kermit Project
Columbia University
612 West 115th Street
New York NY 10025-7799
USA
Fax: +1 (212) 663-8202
+1 (212) 662-6442
[ [52]C-Kermit ] [ [53]Kermit Home ]
________________________________________________________________________
1.4. Other Sources of Information
[ [54]Top ] [ [55]Contents ] [ [56]Section Contents ] [ [57]Previous ]
The OpenVMS Frequently Asked Questions (FAQ) document is available at
various sites on the Internet, including (checked Nov 2001):
[58]ftp://ftp.digital.com/pub/Digital/dec-faq/vms
[59]ftp://rtfm.mit.edu/pub/usenet/news.answers/dec-faq/vms
[60]http://www.openvms.digital.com/wizard/openvms_faq.txt
The following newsgroup is dedicated to discussion of VMS-related
topics:
[61]comp.os.vms
And this one to more general DEC-related topics:
[62]comp.sys.dec
[ [63]C-Kermit ] [ [64]Kermit Home ]
________________________________________________________________________
2. THE C-KERMIT COMMAND PARSER
[ [65]Top ] [ [66]Contents ] [ [67]Next ] [ [68]Previous ]
SECTION CONTENTS:
2.1. [69]Running C-Kermit in DCL Command Procedures
2.2. [70]Running C-Kermit from ALL-IN-1
2.3. [71]Running C-Kermit under DECIntact
When you start C-Kermit at your terminal, everything should work as
expected. You get the prompt, you can type commands, your keystrokes
echo (once, not zero or two times), ? gives help, Ctrl-C interrupts a
command in execution and returns to the prompt. However, VMS offers a
wide variety of "other" environments (Batch, Spawn'd, DCL command
procedures, pipes, mailboxes, ...) in which programs can execute, and
Kermit tries to recognize and adapt itself to them automatically, but
this might not always work. Therefore, two command-line options are
provided so you can force the required adaptations:
-z
Force foreground. If Kermit thinks it's in the background, i.e.
that it does not have a connection to a command terminal (your
keyboard), it is likely to (a) not issue a prompt; (b) not echo
your keystrokes; (c) not respond to "?", Esc, etc. Use the -z
option to force it to treat SYS$INPUT as a real terminal, even
if it doesn't seem to be one.
"-B"
Force Background (the doublequotes are necessary to prevent DCL
from lowercasing the B). This is for the opposite situation: If
Kermit thinks SYS$INPUT is a real terminal, but it's not, then
Kermit command procedures might fail immediately with "?Can't
initialize" or somesuch. Use the "-B" option to tell Kermit it
doesn't really have a terminal.
VMS-style command-line editing (arrow keys, etc) is not supported (you
can, however, use up and down arrow keys for command recall in
C-Kermit 8.0.201 and later). 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, etc) but has many other features that
F$PARSE lacks: context-sensitive "?"-help and file lists, keyword and
filename completion, filename menus, variables, macros, etc. C-Kermit
does, however, support command recall via Ctrl-B (or Ctrl-P, same
thing) and Ctrl-N.
If you write a DCL command file that starts Kermit with a command-file
name as its first command-line argument, e.g.:
$ kermit oofa.ksc
and then SUBMIT this DCL command file as a batch job, be aware that
the batch job is executed out of your login directory, so if the
command file (OOFA.KSC in this case) is not in your login directory,
you must either SET DEFAULT to the directory it is in, or else give a
fully qualified filename:
$ set default [mydir.mysubdir]
$ kermit oofa.ksc
or:
$ kermit [mydir.mysubdir]oofa.ksc
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.
The VMS 6.1 and 6.2 C Run Time Libraries (CRTL) have bugs in them that
prevent the CD command from working totally right when given no
argument, which is supposed to put you back in your login directory,
when SYS$LOGIN indicates a search list and/or hidden directories.
C-Kermit tries to work around this bug (technical explanation: use
CRTL chdir(), which is supposed to do all the right things; if it
fails then use the VMS sys$setddir() system service, which works in
cases where VMS 6.1/6.2 CRTL doesn't, but which applies to your whole
job rather than to Kermit's process tree only, and then when Kermit
exits, it tries to use sys$setddir() again to restore your startup
directory -- but if C-Kermit is interrupted or terminated abnormally
this won't work, etc etc.) If you have trouble with all this, then CD
to the desired device:directory explicitly or define a macro to do
this. (The problem, if it occurs, is in the library that C-Kermit was
linked with, not the one on your VMS system, so installing ECOs, etc,
would not help.)
OPEN !WRITE does not work in VMS C-Kermit.
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
[ [72]C-Kermit ] [ [73]Kermit Home ]
________________________________________________________________________
2.1. Running C-Kermit in DCL Command Procedures
[ [74]Top ] [ [75]Contents ] [ [76]Section Contents ] [ [77]Next ]
It is often desirable to wrap C-Kermit in a DCL command procedure.
Such a procedure, for example OOFA.COM, can be run either directly on
your job's controlling terminal by:
$ @OOFA [ parameters ]
or as a batch job via:
$ SUBMIT OOFA [ switches ]
When you are writing a DCL command procedure that runs C-Kermit, you
must make a choice:
1. If you want to be able to include Kermit commands in the DCL
procedure as "image data" (i.e. lines that don't start with $),
then you can not include any Kermit commands that would require
access to the real console terminal's keyboard and screen, such as
CONNECT. That is, the person who runs the DCL procedure can not
interact directly with a remote computer. This type of DCL command
procedure can be run either on a terminal via @, or as a batch job
via SUBMIT.
2. If you want the user to be able to interact directly with the
remote computer through Kermit's CONNECT command, then:
a. The DCL procedure can be run only with @, not with SUBMIT.
That is, it cannot be a batch job; it must have access to the
console terminal.
b. You must include the following DCL command in the DCL
procedure immediately before starting Kermit:
$ DEFINE /USER SYS$INPUT SYS$COMMAND
c. You can not include Kermit commands as "image data" in the
DCL command procedure. Instead, you must create a separate
Kermit command file, and use command-line arguments to
instruct Kermit to execute it; for example:
$ define /user/nolog sys$input sys$command
$! Execute oofa.ksc instead of normal initialization file.
$ kermit -y oofa.ksc
or:
$ define /user sys$input sys$command
$! Execute oofa.ksc after executing normal initialization file.
$ kermit "-C" "take oofa.ksc"
Here is a sample DCL command procedure of the first type, which can be
run either on the controlling terminal or as a batch procedure, and
requires no interaction from the user. Lines beginning with dollar
sign ($) are DCL commands, other lines are fed to the application
program (Kermit).
1. $ write sys$output "Hello from DCL"
2. $ set default [myuserid.mysubdirectory]
3. $ kermit
4. set background off
5. echo Hello from C-Kermit
6. @ write sys$output "Hello from DCL from inside C-Kermit"
7. take oofa.ksc
8. exit
9. $ write sys$output "All done."
(The numbers are not part of the file.) Lines 1-3 are DCL commands.
Line 3 starts C-Kermit. Lines 4-8 are C-Kermit commands.
Line 4 causes Kermit prompts and commands read as image data from the
remainder of the .COM file to be echoed to the batch log. Normally
this is not done, and the only material that goes into the batch log
is output from Kermit commands like ECHO (next item). The SET
BACKGROUND OFF command tells Kermit that even though it is running in
batch, it should issue its prompt and echo its commands. You can
accomplish the same thing by starting Kermit the "-z" command-line
option (line 3 would be "$ kermit -z").
Line 5 shows how to enter messages in the batch log. Line 6 shows how
to run DCL commands from within Kermit (you can use @ (at-sign), !
(exclamation mark), or the word RUN -- all of them are synonyms,
followed by a DCL command). Line 8 exits from C-Kermit back to DCL.
In line 7, C-Kermit is told to execute a script program from another
file, OOFA.KSC. Script programs to be run during the batch session are
best kept in separate C-Kermit command files because certain commands,
notably GOTO, FOR, WHILE, and IF, do not work when entered in the
interactive command stream. Here is a sample command file:
set take echo on ; Make Kermit commands appear in the batch log
set take error on ; This stops execution automatically upon error
set input echo on ; This makes INPUT material appear in the batch log
set host blah ; Make a network connection to host "blah"
set file brief serial ; Use SERIAL or NONE for the batch log, not FULL or CRT
input 5 login: ; Wait for a login prompt
output myuserid\13 ; Send my user ID and a carriage return
input 5 Password: ; Wait for password prompt
output \$(P1)\13 ; Send my password (see below) and a carriage return
input 20 \13\10$\32 ; Wait for system prompt
output kermit\13 ; Start Kermit on host "blah"
input 5 Kermit> ; Wait for Kermit> prompt
output server\13 ; Put remote Kermit in server mode
in 5 READY TO SERVE...; Wait for READY message
get oofa.txt ; Get a file from the remote server
bye ; Terminate the remote session
end ; Return to local C-Kermit prompt
Note that the commands from a TAKE file are not echoed to the batch
log unless you include SET TAKE ECHO ON.
VERY IMPORTANT: Batched login scripts are inherently insecure because
the passwords are visible in plaintext, either in a file or else in
the batch queue entry. VMS presently offers no secure way that we know
of to enter a password into a batch job.
Two very insecure methods can be used:
1. Put the password in the Kermit script file. The risk here is that
anybody who gains access to the file, or to the system backup
tapes, can learn your password on the remote system.
2. Give the password as a parameter to the SUBMIT command when
starting the batch job, for example:
$ SUBMIT OOFA /NOTIFY /PARAM=("mypassword")
(This sets the DCL parameter P1 to your password on the remote
host (for further information, give the DCL command "help submit
/param"). Quotation marks are necessary to preserve lowercase
letters (important when logging in to UNIX hosts). DCL parameters
may be referenced in Kermit commands as \$(P1), \$(P2), etc.) The
disadvantage here is that the VMS SHOW ENTRY/FULL command displays
the parameters from your SUBMIT command, making the password
visible to (at least) the system operator, and (most likely) also
to other users, such as members of your group (batch queues are,
by default, read-accessible by all members of their group).
Both methods can be made somewhat safer by adjusting the protections
on the files and/or batch queues that will contain sensitive
information, but there can be no guarantees. Therefore: EXERCISE
EXTREME CAUTION with passwords in login scripts and batch jobs.
And please note further that passwords passed in plain text -- as they
still must be in most cases, particularly those involving dialup
access -- are subject to discovery by various other means, including,
but not limited to, wire tapping, Ethernet packet tracing, etc.
[ [78]C-Kermit ] [ [79]Kermit Home ]
________________________________________________________________________
2.2. Running C-Kermit from ALL-IN-1
[ [80]Top ] [ [81]Contents ] [ [82]Section Contents ] [ [83]Next ] [
[84]Previous ]
Contibuted by: Dr. David Kelly, Australian Environmental Protection
Authority, [85]kellyd@airmoon.epa.nsw.gov.au
ALL-IN-1 uses mailboxes (MBX) devices, rather than terminals. TT: is
reassigned from the user's controlling terminal to a mailbox device.
C-Kermit uses TT: as its default line device and so doesn't work
straight off under ALL-IN-1. SYS$INPUT is reassigned to something else
again. SYS$OUTPUT remains assigned to the user's original terminal
line so it can be used to specify the line device for C-Kermit when
called from within ALL-IN-1. Below is a script which can be run from
ALL-IN-1 which calls C-Kermit to receive a file. SYS$OUTPUT is
temporarily redefined to stop some guff showing on the screen.
$! RECEIVE_FROM_PC.COM
$!
$! Transfer file from PC into ALL-IN-1 using KERMIT
$! Invoked by TRANSFER_PC_TO_A1.SCP, which is in turn called by the RF
$! option on DT menu.
$!
$ set noon
$ on control_y then goto exit
$
$ tt1=f$trnlnm("sys$output")
$ kermit :== $epa__system:Ckermit
$ define/user sys$input sys$command
$ define sys$output sys$login:del.txt
$ kermit -l 'tt1' -b 9600 -r -a a1file.a1f -q -i
$ deassign sys$output
$ del sys$login:del.txt;
$exit:
$ exit
Similarly a file can be sent :
$! SEND_TO_PC.COM
$! Transfer document from ALL-IN-1 to the PC
$! invoked by TRANSFER_A1_TO_PC.SCP which is, in turn, called by the
$! SF option on the DT menu
$!
$ set noon
$ on control_y then goto exit
$!
$ write oamailbox "OA GET #CURDOC_FILENAM"
$ @dclmailbox:
$ a1file = "''result'"
$ vmsfile = "A1FILE.A1F"
$ copy/nolog/noconfirm 'a1file' 'vmsfile'
$ kermit :== $epa__system:Ckermit
$ define/user sys$input sys$command
$ tt1=f$trnlnm("sys$output")
$ define sys$output sys$login:del.txt
$ kermit -l 'tt1' -b 9600 -s A1FILE.A1F -q -i
$ deassign sys$output
$ del sys$login:del.txt;
$ if $severity .le. 1 then goto exit
$! if an error occurs, tell ALL-IN-1
$ write oamailbox "OA GET $PC_KERMIT_STATUS=0"
$ @dclmailbox:
$exit:
$ deletex/nolog a1file.a1f;*
$ exit
[ [86]C-Kermit ] [ [87]Kermit Home ]
________________________________________________________________________
2.3. Running C-Kermit under DECintact
[ [88]Top ] [ [89]Contents ] [ [90]Section Contents ] [ [91]Previous ]
To use C-Kermit in remote mode under DECIntact, you must:
a. Have C-Kermit 7.0 or later, and:
b. Tell it to "set line /share tt:".
This might also work with ALL-IN-1 ([92]Section 2.2).
[ [93]C-Kermit ] [ [94]Kermit Home ]
________________________________________________________________________
3. COMMUNICATIONS
[ [95]Top ] [ [96]Contents ] [ [97]Next ] [ [98]Previous ]
SECTION CONTENTS:
3.1. [99]Serial and LAT Communications
3.2. [100]Network Communications
Also see:
* [101]Section 6 of the [102]Installation Instructions: Using Modems
by Richard B. Gilbert.
* [103]http://www.tmesis.com/modem/.
3.1. Serial and LAT Communications
[ [104]Top ] [ [105]Contents ] [ [106]Section Contents ] [ [107]Next ]
SUBSECTION CONTENTS:
3.1.1. [108]Dialing
3.1.2. [109]Speed
3.1.3. [110]Echoing
3.1.4. [111]Modem Signals
3.1.5. [112]Buffering and Flow Control
3.1.6. [113]LAT
If you are experiencing very poor performance on serial connections,
use the VMS command SHOW TERMINAL to make sure that the terminal
device has the DMA (Direct Memory Access) characteristic. If it does
not, try setting it (or get your system manager to, in case privilege
is required):
$ SET TERMINAL device_name /PERMANENT/DMA
On some slower VAX models with built-in serial ports, such as the
VAXstation 3100 or MicroVAX-II, receiving files on serial ports at
(say) 19200 bps results in high CPU utilization, slowing down the
system for other processes. This is because on certain systems, such
as the VS3100, serial ports interrupt the CPU every time a character
arrives. Most VMS systems nowadays, however, support either DMA for
serial port i/o, or have their users coming in through terminal
servers.
3.1.1. Dialing
If dialing out a serial port does not work at all -- modem ignores
commands sent to it, etc -- make sure the terminal port has the /MODEM
characteristic, e.g.:
$ SET TERMINAL TTA0 /MODEM /PERM
Dialing is possible only on LAT devices and on serial ports that have
that have the /MODEM attribute (e.g. "set term tta0 /modem /altypahd
/perm"). The modem must be configured for "DSR tracks CD" -- that is,
it must not turn on its DSR signal before the connection is made;
otherwise VMS will hang up on it during the dialing process. C-Kermit
7.0 and later include "&S1" in the initialization string for modems
that use the AT command set. If you are modifying init strings or
defining your own modem type, be sure to include this command or the
equivalent.
If a DIAL or SET SPEED command gives the error:
?ttbin: sys$qiow: %SYSTEM-F-NOLOG_IO, operation requires LOG_IO privilege
then either the user must be given LOG_IO privilege or else the device
must be given the SET_SPEED attribute. However, note that under
certain versions of VMS the TT2$M_SETSPEED bit in TTY_DEFCHAR2 is not
properly propogated to LAT devices. It is best to issue the command
SET TERM/PERM/SET_SPEED LTA31: at startup when the LTA31 device is
initially created (which, of course, would be done by a sufficiently
privileged account).
"How do I dial with C-Kermit and then exit, leaving the connection
open so I can use it from another application?" Prior to starting
Kermit, tell VMS to set the device to /NOMODEM. Another possibility is
to allocate the line BEFORE you run C-Kermit. Ownership is defined as
either having a channel assigned to the device or having allocated the
device. All the channels get closed when the image exits, but
allocation persists.
3.1.2. Speed
Prior to C-Kermit 6.0, there was no way to select a serial
communications speed higher than 38400 bps. In version 6.0, it is
possible to SET SPEED 57600, 76800, and 115200, since these speeds are
supported in VMS 6.x and later. However, the fact that you can set a
particular speed doesn't mean this will work. The device might not
support it. In some cases, the device will actually use the low-order
bits of the speed value, because its speed register is smaller than
the codes used for the new higher speeds.
3.1.3. Echoing
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 automatically as part of the SET LINE procedure.
3.1.4. Modem Signals
SUBSECTION CONTENTS:
3.1.4.1. [114]The SET CARRIER-WATCH Command
3.1.4.2. [115]The SHOW COMMUNICATIONS Command
3.1.4.3. [116]The WAIT Command
3.1.4.4. [117]The HANGUP Command
A VMS serial communication device has either the /MODEM or else the
/NOMODEM characteristic. You can view a device's configuration with
the VMS SHOW TERMINAL command, for example:
$ SHOW TERMINAL TTA0:
and you can change it with SET TERMINAL, e.g.:
$ SET TERMINAL TTA0: /MODEM
When a /MODEM device is opened (e.g. with C-Kermit's SET LINE
command), VMS asserts the DTR signal (assuming the interface and cable
support modem signals), and allows I/O with the device even if the
device is not asserting the CD signal. However, once the device does
assert CD (or, perhaps more accurately, whenever the phone is "off
hook"), VMS requires CD to stay up for further I/O; if the CD signal
goes off, VMS returns a hangup (SS$_HANGUP) indication.
When a /NOMODEM device is opened, VMS does not assert any modem
signals, including DTR, and does not require or test for any modem
signals from the device. Thus the /NOMODEM is of little use with any
kind of data communication equipment (e.g. modems, terminal servers,
multiplexers) that require DTR (some modems can be configured to
ignore DTR, e.g. with AT&D0).
On the other hand, /NOMODEM is probably necessary for VMS serial ports
that do not support modem signaling (such as the one on the VAXstation
3100), or cables that do not contain all the needed wires (such as
DEC's MMJ connector; looks like an RJ45 modular jack, but with an
offset tab). If you use a /NOMODEM port, the device it is connected to
must be configured to operate without seeing DTR, and in any case
C-Kermit will not be able to detect connection loss.
Setting /MODEM or /NOMODEM on a LAT device has no effect on the LAT
port itself, nor, evidently, on VMS -- reportedly, SS$_HANGUP is still
reported when the LAT device hangs up, even when set to /NOMODEM.
Although it is within the power of an application such as C-Kermit to
switch the device between /MODEM and /NOMODEM, it is not practical
because doing so hangs up the device. Thus C-Kermit lets the VMS
terminal driver control the modem signals, and interprets and reacts
to indications about modem signals from VMS as best it can, according
to your preferences.
3.1.4.1. The SET CARRIER-WATCH Command
When CARRIER-WATCH is ON or AUTO, C-Kermit checks for carrier at the
beginning of any communications-related command (CONNECT, SEND, GET,
FINISH, INPUT, OUTPUT, etc), and each of these commands fails at any
time during its execution if VMS reports a "data set hangup"
(SS$_HANGUP). Thus, it is not possible to CONNECT to a modem and type
AT commands before the modem has made a connection if CARRIER-WATCH is
ON or AUTO.
When CARRIER-WATCH is OFF, the aforementioned checks are not made, and
any SS$_HANGUP errors that occur are ignored.
If the device is set to /NOMODEM, all checks for carrier will fail,
and the device will be unusable unless CARRIER-WATCH is OFF.
On LAT devices, the initial checks are never made since LAT devices do
not reveal their modem signals to VMS. SS$_HANGUP errors, however, are
treated as they are for real serial ports.
3.1.4.2. The SHOW COMMUNICATIONS Command
As of C-Kermit 7.0, SHOW COMMUNICATIONS should display modem signals
on both VAX and Alpha when the SET LINE device is a local serial-port
device. Modem signals are not displayed for LAT devices.
3.1.4.3. The WAIT Command
As of C-Kermit 7.0, the WAIT command (which waits a specified amount
of time for a given set of modem signals to appear on the current SET
LINE device) should work on both VAX and Alpha serial port devices. It
does not work on LAT devices.
3.1.4.4. The HANGUP Command
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 (three) seconds;
perhaps as many as six. This is a feature of VMS.
If you use the HANGUP command on a /NOMODEM device that is,
nevertheless, connected to a modem, be sure that Kermit has been told
to:
SET MODEM HANGUP-METHOD MODEM-COMMAND
3.1.5. Buffering and Flow Control
Hardware flow control (RTS/CTS) is not supported by VMS, despite
rumors to the contrary. From "[118]Ask the Wizard #0153" (July 1998):
Setting the port to hardware flow control at the console will not
have any meaning to VMS. It does not see or make use of that
information. Also VMS does not officially support hardware flow
control for serial lines. For output when using modem lines the
system will honor CTS. But we will not lower RTS when the type-
ahead buffer is almost full. In V7.1 there is an attribute to
enable RTS for input flow control on modem lines. But this support
is not documented and there is no way from DCL to enable it.
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
typeahead buffers, and that user accounts be given large BYTLM quotas.
See the [119]Installation Instructions.
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.
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. 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 the overhead in
doing this might cancel out the advantage of doing it.
The SET FLOW RTS/CTS command is not supported in the VMS version of
C-Kermit. VMS versions prior to 7.0 do not support RTS/CTS (hardware)
flow control. However, RTS/CTS flow control can still be used on LAT
ports that support it.
VMS flow control is governed by two SET TERMINAL parameters: /TTSYNC
and /HOSTSYNC. TTSYNC lets the terminal control the flow of data from
the host and HOSTSYNC lets the host control the flow of data from the
terminal. In general, these are implemented as Xon/Xoff flow control
in each direction, but on LAT and TCP/IP connections, they can also
affect the internal networking protocol, and they can be implemented
on the LAT server's serial interface with any flow control method at
all - Xon/Xoff, RTS/CTS, etc.
In VMS C-Kermit, SET FLOW XON/XOFF is equivalent to $ SET TERM
/HOSTSYNC /TTSYNC. There should never be a reason to SET FLOW NONE in
VMS -- in fact, it is almost always a bad idea (see [120]File Transfer
section).
When C-Kermit is in "remote mode", i.e. it is on the far end of a
connection, and is not establishing a connection itself, it uses your
current VMS SET TERMINAL parameters for flow control during command
processing. During packet mode, however, it obeys your C-Kermit SET
FLOW-CONTROL setting to ensure the chances of lost data are minimal.
When C-Kermit is in "local mode", i.e. it is being used to establish a
connection with SET LINE or TELNET, there are two components to your
connection: the part between your terminal and C-Kermit (call this
"Part A"), and the part between C-Kermit and the remote computer or
service that you have connected to ("Part B"). At all times, the flow
control used on Part A is governed by your VMS SET TERMINAL
parameters, and the flow control used on Part B is always governed by
C-Kermit's SET FLOW-CONTROL command.
If you are using C-Kermit in local mode to access a remote host to use
the EMACS editor, you might find that the Ctrl-S (Search) and Ctrl-Q
(Quote) commands don't work -- your screen and keyboard "freeze" when
you type Ctrl-S, and Ctrl-Q seems to have no effect (except unfreezing
your session after Ctrl-S). This means that your VMS command terminal
has the /TTSYNC characteristic; Ctrl-S and Ctrl-Q are being used for
flow control between your terminal and the VMS system -- the remote
system and EMACS never see them. There are two ways around this
problem:
1. Tell VMS to SET TERM /NOTTSYNC before starting C-Kermit. In this
case, you are in danger of losing data on the connection,
particularly if your connection to VMS is through a LAT device.
2. Leave the /TTSYNC characteristic in force and use the long forms
for the EMACS commands: ESC-X Search-Forward and ESC-X
Quoted-Insert. Or assign these functions to other EMACS keys in
your EMACS initialization file.
3.1.6. LAT
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, and of course
the way the whole setup is configured. More about LAT configuration in
the [121]Installation Instructions.
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:
* Perhaps the line is already being used on another system that is
connected to the same terminal server (in this case SET HOST /DTE
will fail the same way). Unfortunately LAT has no way to signal
this condition.
* 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, or the
devices protection, or your privileges or quotas, or somesuch.
* 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.
C-Kermit puts LAT terminal servers into PASSTHRU mode, which disables
their forward/backward session switch characters.
Reportedly, if you have CONNECTed out through a LAT device, the
CONNECT-mode escape command to hang up (<esc-char>U) does not work.
Reason: unknown. Cure: unknown (The LAT programming interface is very
poorly documented). Workaround: SET LINE <cr> or CLOSE <cr> to close
the SET LINE device.
Reportedly, although Kermit can SET LINE to a LAT device and work OK,
the same can't be said for a "LAT group" (whatever that is). The user
who submitted this report said that this problem could be worked
around by telling VMS to SET TERM <blah> /NOALTYPEAHD before starting
Kermit (take this one with a grain of salt).
Reportedly, to use C-Kermit with a LAT device under LATmaster, the
associated terminal device must be set /NOREADSYNC.
Reportedly, when transferring files TO a VMS system over a LAT
connection (for example, from a PC equipped with PATHWORKS or SuperLAT
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 the particular implementation of it, whereby applications
are not informed of -- and cannot find out -- limits on transmission.
(And yet, others say they have no problems with file transfers over
LAT connections, even with packet sizes greater than 1000.)
[ [122]C-Kermit ] [ [123]Kermit Home ]
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3.2. Network Communications
[ [124]Top ] [ [125]Contents ] [ [126]Section Contents ] [
[127]Previous ]
SECTION CONTENTS:
3.2.1. [128]X.25
3.2.2. [129]TCP/IP
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), CMU-OpenVMS/IP ("CMU/Tek"), TGV MultiNet, Wollongong
WIN/TCP or PathWay, Process Software TCPware); other types: not yet
(e.g. Fusion).
3.2.1. X.25
Poor performance has been observed when C-Kermit is receiving files on
a VAX/PSI (X.25) system, attached to a certain X.25 network (Autonet),
but not others, attached via a DSW42 interface: huge numbers of I/O
requests drive the load way up. Reportedly, "this is due to a VAX PSI
feature called Synchronized Echo Protocol (SEP), which is supposed to
coordinate echo by the X.25 PAD, e.g. when typing ahead. When
disabling this feature, the file transfers proceed fast and efficient.
This feature is a network-specific X.25 1"facility" negotiated at
call-setup time, not an X.3 parameter (standard or otherwise) --
Facility Number 66 (decimal, or 42 hex). It could not even be set or
viewed by the user or the VAX administrator. It had to be disabled by
the network provider. I think that most X.25 networks do not even
implement this feature and thus is it not common issue. In any case,
in our situation, I asked the X.25 network provider to disable this
feature, and now C-Kermit is performing efficiently, but now, of
course, echoing (e.g. of material that is typed ahead) is no longer
synchronized."
3.2.2. TCP/IP
Reportedly CMU/IP support in C-Kermit 7.0 and later does not work at
all. Cause and cure unknown.
The TCPware version works correctly with TCPware versions 4.1-2 or
later; earlier versions, such 3.1-3, have a bug that can result in
failure of C-Kermit to make network connections, with a message like:
?contti: network sys$qio: %SYSTEM-F-IVCHAN, invalid I/O channel
Process Software recommends upgrading to the current TCPware release.
DEC TCP/IP (UCX) 2.0C and earlier, which runs only on VAXes, has a bug
that prevents TCP port lookup by name from working as expected, so if
you tell C-Kermit to "telnet blah" or "set host blah", you'll get a
"Connection refused" error. If you don't specify a port, Kermit
substitutes the service name "telnet" and then asks UCX to look it up;
UCX finds it but erroneously returns a port number with its bytes
swapped (e.g. 5888 instead of 23), and then Kermit tries to connect to
port 5888 on the host; most hosts will refuse the connection; if they
don't, you probably didn't reach a Telnet port anyway. The workaround
is to include a port number (not name) in your command. Any of the
following will work:
set host blah:23
set host blah 23
telnet blah:23
telnet blah 23
A patch was issued after C-Kermit 6.0.192 was released, adding the
following command to VMS C-Kermit versions built on VAXes with UCX:
SET TCP UCX-PORT-BUG { ON, OFF }
If you have UCX 2.0C or earlier, and C-Kermit won't make Telnet
connections, tell it to:
SET TCP UCX-PORT-BUG ON
In case your version of C-Kermit 6.0 does not have this patch, then
use the workaround of specifying a port number.
The previous hint also applies when running UCX versions of C-Kermit
under Wollongong or other TCP/IP products that have a UCX
compatibility mode. If you get "connection refused", then include the
port number in the TELNET or SET HOST command.
The UCX version of Kermit works on MultiNet systems too, because
MultiNet automatically goes into "UCX compatibility mode" when a UCX
application is run.
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 8.0.200, OpenVMS AXP
Type ? or HELP for help
C-Kermit>set line telnet_nty
C-Kermit>connect
etc...
If you enter the VAX from elsewhere through a TELNET connection, and
the VAX is running CMU-OpenVMS/IP, Fusion, or an early version of 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 the [130]Installation Instructions
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)
When using the CMU-OpenVMS/IP TCP/IP transport, assign the system
logical INET$SERVICE_TELNET_TCP to the telnet port as follows:
$ DEFINE /SYSTEM INET$SERVICE_TELNET_TCP 23
This is only required if the -j option is used without specifying a
port to use (e.g. -j host). If this logical assignment is not made
using `-j host' option will fail with the error:
%CKERMIT-E-FATAL, can't open host connection
The default port, hardcoded in C-Kermit, is 23. Another port may be
specified using the -j option as `-j host:port'.
SET INPUT ECHO OFF seems to have no effect when given to VMS C-Kermit
and the INPUT command is reading from the console terminal.
[ [131]C-Kermit ] [ [132]Kermit Home ]
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4. GENERAL FAILURES
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General failures can sometimes occur for reasons beyond Kermit's
control, many of them related to VMS system parameters or limits on
the user or process: disk quotas, user pagefile quotas (AUTHORIZE
parameter PGFLQUO), system pagefile space filling up, etc. See the
[137]Installation Instructions for details.
To increase a user's pagefile quota, tell AUTHORIZE to MODIFY
username/PGFLQUO=number. The system itself might be running out of
pagefile space, which would cause the system to grind to a halt and
eventually crash. You can check the system pagefiles with SHOW
MEMORY/FILE: add up the "Free" numbers for the [*]*PAGEFILE.SYS files
and see if the total is big enough (there should normally be at least
100K free pages on an active system). If not, the system manager would
use the procedure @SYS$UPDATE:SWAPFILES to resize the files.
VMS C-Kermit can hang or crash with an "access violation" under
certain conditions when trying to hang up a modem-controlled device
that is already hung up; investigation shows that the hang or crash
happens in VMS kernel space, not in Kermit.
Reportedly, on certain VMS configurations (but not others), the
following sequence can cause C-Kermit to crash:
set host somewhere
connect
(escape back)
receive
Ctrl-C
connect
The problem appears to be in the VMS C library's implementation of
signal handling and longjumps.
"Zombie" process can be left behind under certain conditions when a
VMS Kermit server has been sent a BYE command, particularly over a
TCP/IP connection (connection disappears before VMS has a chance to
print its "logged out" message, and now there is nothing to print it
on).
One user reported "massive failures" when transferring files with VMS
C-Kermit through a particular kind of terminal server. She had
followed all the directions in the manual, the CKVINS.TXT file, and
the CKVBWR.TXT files (as it was before this item was added). The
terminal server, an Equinox ELG48, uses TELNET protocol to a
DECstation 3000 Model 600 running VMS 6.1 and TGV MultiNet 3.3. Later,
she reported: "It turned out that upgrading the software on our
terminal server has fixed the problem. It's so odd that the problem
only occured after we upgraded from VMS V5.5-2 to V6.1, since the
terminal server worked fine before the upgrade. It's also weird that
this terminal server has always worked fine for our Suns, also. Here's
the details of the terminal server if you want to keep these details
on file: Equinox PBX 20 with ELG 48 board. The ELG 48 rev was 2.30.
After upgrading it to V2.33, everything works fine."
[ [138]C-Kermit ] [ [139]Kermit Home ]
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5. LOCAL FILE OPERATIONS
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As of edit 190, VMS C-Kermit supports append operations: the various
logs (packet, debug, transaction, etc) can be opened in append mode by
including the APPEND keyword after the filename, e.g.:
LOG TRANSACTIONS TRANSACT.LOG APPEND
An arbitrary file can be opened for output in append mode:
OPEN APPEND OOFA.TXT
and the SET FILE COLLISION APPEND option now works during file
transfer.
When using append operations:
* Be careful not to append files of different types together, such
as a text file to an indexed file, or a fixed-record binary file
to a text file, etc. The result will generally be unusable.
* SET FILE COLLISION APPEND does not work when the FILE TYPE is
LABELED. This is deliberate: labeled transfers are designed to
give you an exact copy of the file, including attributes.
C-Kermit 7.0 (Jan-Feb 2000) added a new stdio-based FILE command
allowing opening, closing, reading, writing of local files. Since
C-Kermit is a C program, this works best with stream files. In
particular FOPEN /APPEND works only with stream (Stream_LF) files. If
you try to use FOPEN /APPEND on a non-Stream_LF file, the appended
portion is in Stream_LF format but the original portion remains in
whatever format it was in before.
There is no facility in C-Kermit to distinguish between "overwriting"
and "versioning". SET FILE COLLISION OVERWRITE always creates a new
version in VMS.
BUG: As of this writing, APPEND operations do not use the RMS "first
free byte", and so start on a new block boundary.
[ [144]C-Kermit ] [ [145]Kermit Home ]
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6. FILE TRANSFER
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SECTION CONTENTS:
6.1. [150]Automatic Transfer Mode
6.2. [151]Oddball File Formats
6.3. [152]Disk Quotas
6.4. [153]Control-Character (Un)Prefixing
6.5. [154]External Protocols
6.6. [155]Miscellaneous
Remember that VMS file formats are substantially different from those
on UNIX, DOS, Windows, etc. Be sure to consult the VMS Appendix of
"Using C-Kermit" on this topic, and to find out the special commands
and procedures that apply to VMS.
C-Kermit 7.0 has the following problems, which we hope can be resolved
before the final release:
* LABELED mode lacks relative pathname option; directory-tree
transfers don't work between two VMS systems because they go into
LABELED mode automatically (this one should be fixed in C-Kermit
7.0).
* Confusion about SET TRANSFER MODE { AUTOMATIC, MANUAL } vs FILE
TYPE IMAGE (should AUTOMATIC unset IMAGE? Should IMAGE set MANUAL?
...)
* Need better error message for failure to receive a file in text
mode that has lines longer than 32K, or else a way to recover when
this happens, e.g. by breaking the long line.
C-Kermit 7.0 also enables proper transfer of fixed-length-record files
with odd record lengths, and fixes problems with overstrike records in
Fortran Carriage Control files. These fixes should go a long way
towards eradicating the complaints about files that Kermit-32 could
transfer correctly, but C-Kermit could not.
[ [156]C-Kermit ] [ [157]Kermit Home ]
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6.1. Automatic Transfer Mode
[ [158]Top ] [ [159]Contents ] [ [160]Section Contents ] [ [161]Next ]
File transfer modes (TEXT vs BINARY) are set automatically for each
file when sending. The SET FILE TYPE BINARY and SET FILE TYPE TEXT
commands are ignored when sending files. So (in C-Kermit 7.0) are
filename patterns (SET FILE PATTERNS). To force binary-mode
transmission, use SET FILE TYPE IMAGE. See the VMS appendix of
[162]Using C-Kermit.
One notable consequence of this fact is that if you send a file from
VMS C-Kermit in IMAGE mode (because it would not be transferred in
binary mode without this setting), then any attempt to RESEND or REGET
it must also be done with VMS C-Kermit in IMAGE mode.
The other aspect of automatic transfer mode is that VMS-to-VMS
transfers shift automatically into LABELED mode (again, see the
[163]manual). One consequence of this is that any "as-name" that you
give for the file is ignored. To defeat this, use "set transfer mode
manual".
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.
[ [164]C-Kermit ] [ [165]Kermit Home ]
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6.2. Oddball File Formats
[ [166]Top ] [ [167]Contents ] [ [168]Section Contents ] [ [169]Next ]
[ [170]Previous ]
When sending binary files that have an odd record length, please note
that these files are actually stored with an even record length on
disk. For example, suppose DIR/FULL X.VDM says "fixed-length records,
record length 17". On disk, the file really has 18-byte records; each
17-byte record is padded with a NUL (0) byte to make its length even;
this is revealed by DUMP. Prior to version 7.0, C-Kermit sent the raw
records, INCLUDING THE PADDING. In 7.0 and later, odd-length records
are sent without padding.
If a text file is accidentally sent to VMS C-Kermit in binary mode,
you can fix it afterwards (in recent VMS versions) with a DCL command
like:
$ SET FILE/ATTRIBUTES=(RFM:STM,LRL:0,MRS:0) filename
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.
VMS MAIL messages: If you want to download mail messages to a PC (or
other non-VMS system), select the message of interest using the SELECT
and DIRECTORY commands within VMS MAIL, then EXTRACT/ALL to extract
all the selected messages to a normal text file, then use Kermit to
SEND this file. Don't even think about trying to transfer your mail
file as-is to a non-VMS system; it is a complicated indexed file,
possibly containing pointers to other files, etc.
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.
[ [171]C-Kermit ] [ [172]Kermit Home ]
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6.3. Disk Quotas
[ [173]Top ] [ [174]Contents ] [ [175]Section Contents ] [ [176]Next ]
[ [177]Previous ]
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.
[ [178]C-Kermit ] [ [179]Kermit Home ]
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6.4. Control-Character (Un)Prefixing
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[ [184]Previous ]
Exercise caution when sending files to VMS when C-Kermit is in remote
mode. Aside from all the buffering limitations of LAT and VMS, please
note the following:
* On most VMS systems, the controlling terminal MUST have the
/TTSYNC and /HOSTSYNC characteristics, even on Telnet connections,
or else massive amounts of data can be lost.
* There are evidently certain control characters that can not be
safely unprefixed when sending to VMS, no matter how far C-Kermit
goes to put the job's controlling terminal in "passthrough" mode.
These include:
Ctrl-Q XOFF 17
Ctrl-S XON 19
Ctrl-C ETX 3
Ctrl-N SO 14
Ctrl-O SI 15
Ctrl-X CAN 24
Ctrl-Y EM 25
As well as 141, 145, 147 (CR, XOFF, XON with their high bits set). If
you find file transfers into VMS stalling, it is very likely because
one or more of the these characters is unprefixed.
On a related note, Carriage Return (13) and IAC (255) must be prefixed
on Telnet connections, and Kermit's start-of-packet character
(normally SOH, ASCII 1) should also be prefixed. NUL (0) should be
prefixed too.
[ [185]C-Kermit ] [ [186]Kermit Home ]
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6.5. External Protocols
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[ [191]Previous ]
You can use the ZMODEM SZ and RZ commands as "external protocols" over
a connection you have established with C-Kermit, to a host or service
that does not support Kermit protocol. Start the file transfer on the
remote end, escape back to C-Kermit, give the SPAWN command, and then
(for example):
$ define tt xxx:
$ rz
where xxx is the designation of the terminal device (TT or LTA) that
you have dialed out on. When the transfer is complete, LOGOUT from the
SPAWN'd subprocess and you'll be back at the C-Kermit prompt.
[ [192]C-Kermit ] [ [193]Kermit Home ]
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6.6. Miscellaneous
[ [194]Top ] [ [195]Contents ] [ [196]Section Contents ] [
[197]Previous ]
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 RENAME.
When you send a BYE command to a VMS C-Kermit server, it does not
guarantee that the VMS job will be logged out. If C-Kermit was SPAWN'd
from another process, only C-Kermit itself disappears in this case.
Even if the whole VMS session ends, if the user came in through a LAT
terminal server, they will be back at the "Local>" prompt and the
phone line won't be disconnected.
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).
Reportedly, when VMS C-Kermit is in local mode and transferring a file
(file transfer display is showing) over a MultiNet TCP/IP connection
and a broadcast from a completing batch job (SUBMIT/NOTIFY) arrives,
it crashes C-Kermit with %SYSTEM-F-ACCVIO, access violation. The stack
dump shows this occurs in the netinc() routine while reading a packet
(rpack).
[ [198]C-Kermit ] [ [199]Kermit Home ]
________________________________________________________________________
7. OTHER TOPICS
[ [200]Top ] [ [201]Contents ] [ [202]Previous ]
(So far just one...)
7.1. Non-DEC Terminal Types
Non-DEC terminal types are not well supported under VMS. While it
might be possible to install a definition for a non-DEC terminal (such
as the IBM 3151) in the SMG database, very few applications actually
use this information. Also, although C-Kermit 5x and 6.x used SMG,
C-Kermit 7.0 bypasses it entirely due to problems discovered during
the development cycle.
[ [203]Top ] [ [204]Contents ] [ [205]C-Kermit Home ] [ [206]Kermit
Home ]
_________________________________________________________________
C-Kermit 8.0 VMS Hints and Tips / The Kermit Project / Columbia
University / 12 Dec 2001
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