CKDBWR.TXT          "Beware File" for C-Kermit Version 7.0        -*- text -*-

			       AOS/VS VERSION

Applies to C-Kermit 7.0.195 Beta.11
Last update: Sun Dec  5 14:31:19 1999

Authors: Frank da Cruz, Christine M. Gianone, Columbia University.

  Copyright (C) 1985, 1999,
    Trustees of Columbia University in the City of New York.
    All rights reserved.  See the C-Kermit COPYING.TXT file or the
    copyright text in the ckcmai.c module for disclaimer and permissions.

Report problems, suggestions, fixes, etc, by e-mail to:

  kermit@columbia.edu

The Kermit Project
Columbia University
612 West 115th Street
New York NY  10025-7799
USA
http://www.columbia.edu/kermit/

AOS/VS C-Kermit system requirements and installation instructions are in the
file CKDINS.TXT.  Please be sure you have read that file before concluding
that C-Kermit isn't working correctly on AOS/VS.


DOCUMENTATION

Frank da Cruz and Christine M. Gianone, "Using C-Kermit", Second Edition,
1997, Digital Press / Butterworth-Heinemann, Woburn, MA, ISBN 1-55558-164-1
US single-copy price: $44.95; quantity discounts available.  Available in
computer bookstores or directly from Columbia University:

  http://www.columbia.edu/kermit/manuals.html

Features added after version 6.0 was released are documented in the text file,
ckermit2.txt.


RESTRICTIONS

Accessing AOS/VS from outside:

 . When making Telnet connections *to* AOS/VS from C-Kermit 7.0 or later,
   or K95 1.1.18 or later, it might take several minutes for negotiations
   to complete; this is because the AOS/VS Telnet server does not reply to
   messages for which replies are mandatory (thus violating the Telnet
   protocol specification).  To speed up your connections, tell the C-Kermit
   or K95 Telnet client to "set telnet wait off".

Commands:

 . Sliding windows don't work very well, or at all, at least not over TCP/IP
   connections, so if you have trouble transferring files, "set window 1".
   (If anybody can get select() working, this will be fixed.)

 . During file transfer, be careful about unprefixing control characters when
   sending files to the AOS/VS system; in general it best to "set prefixing
   all".

 . Incoming TCP/IP connections are not supported.

 . Local C-Kermit commands such as WHO, DIR, etc, that are implemented through
   CLI calls cannot be interrupted except by entering BREAK (CMD-BRK on DG
   terminals) followed by ^C^A.

 . The server end of the MAIL command has not been implemented.

 . The server end of the BYE command has not been implemented.  The BYE
   command in Kermit is NOT the same as the BYE command in AOS/VS.

 . The WHO command does not accept arguments.

 . It is not possible to suspend AOS/VS C-Kermit sessions.

Installation:

 . If you obtain the AOS/VS C-Kermit binary from Columbia or elsewhere,
   be sure to transfer it in binary mode, or else it will be corrupted and
   will not be usable.

 . If you transfer the binary using certain utilities (such as CEO-BLAST),
   it might wind up with an inappropriate type, such as UDF, in which case
   AOS/VS reports "Error: Illegal File Type" when you try to "x" it.
   In this case you need to change the type to UNX or PRV.  Example:

   ) x kermit
   Error: Illegal file type
   x,kermit.pr
   ) create/type=prv x.pr
   ) copy/a x.pr kermit.pr
   ) delete kermit.pr
   )nrename x.pr kermit.pr
   ) x kermit
   C-Kermit> ...

   If you have C-Kermit on a tar tape, you should be able to read it
   with TAR_VS.  Just type "tar_vs" at the CLI prompt for a summary of
   options.

Communications:

 . The AOS/VS serial communication device driver requires the RS-232 Carrier
   Detect (CD) signal to be on before it can communicate.  For dialout
   connections, therefore, the modem must be configured to force Carrier Detect
   to be on at all times.  Direct connections should feed another active
   signal, such as DTR, into the VS system's serial port CD circuit.

 . Incoming characters are very likely to be lost if they come in spurts
   longer than (some number, perhaps as low as 128), especially on serial
   ports, where the IAC ring buffer size is the limiting factor.  For file
   transfer, incoming packet-length x window size might need to be reduced to
   fit this size.  Devices can be re-gen'd to use larger buffers.  When
   sending files, AOS/VS Kermit can (usually) use arbitrarily large packet
   and window sizes.

 . AOS/VS Kermit cannot determine the status of modem signals on a line.

 . Hardware flow control (char/on/hifc/hofc) on the controlling terminal
   doesn't seem to work.  Xon/Xoff (char/on/ifc/ofc) seems to fare better.

 . When a locally-established connection to a remote system has been broken,
   the local AOS/VS C-Kermit will write "Communications disconnect" to the
   screen, but will not finish the rest of the line until there is input from
   the keyboard.

 . Domain Name Service (DNS) might not work.  In that case, you must use
   numeric IP addresses in your SET HOST and TELNET commands.  Reportedly,
   this problem is fixed in AOS/VS II 3.00 / TCP/IP 1.30, but in order to
   get the improved functionality in C-Kermit, C-Kermit must be compiled and
   linked on a system of this level (the current development system is still
   running an older release).

File Transfer:

 . The fullscreen file transfer display is not supported.

 . When AOS/VS C-Kermit is running in server mode, and receives a BYE command,
   AOS/VS C-Kermit terminates but its parent process does not.  Thus you must
   still CONNECT back to the AOS/VS system and log out.

 . When AOS/VS C-Kermit is receiving a file, and the file collision action is
   set to "update" (meaning that the incoming file should overwrite the
   existing file only if its "creation" date is more recent), and the incoming
   file is in fact newer, the modification date on the resulting file will
   actually be the date/time of the transfer (the real last modification
   date/time).  This can cause succeeding "update" operations on this file
   to fail.

 . One user reports that in order for AOS/VS C-Kermit to receive 8-bit binary
   files, the CLI command CHAR/ON/8BT must be given before starting C-Kermit.


KNOWN PROBLEMS

Abnormal terminations (stack dumps) may occasionally occur on expiration of
certain timers (when, for instance, the local Kermit gets no response from the
remote Kermit).  Apparently this happens only in local mode, i.e. when
C-Kermit was used to initiate a connection to another computer by DIALing.
Cause: Unknown.  Cure: Unknown.  Possible workarounds:  (a) Tell C-Kermit to
SET SEND TIMEOUT 0; (b) Make your connection without using the DIAL command.
(These workarounds are untested.)

(End of CKDBWR.TXT)