CMS Kermit 4.0 "Beware File" - Known Bugs, Problems, Limitations. As of: 5:21pm Friday, 1987 October 23 Kermit-CMS uses ASCII/EBCDIC translation tables which conform to the ones given in the IBM System/370 Reference Summary. If your site's translation tables do not conform to the one Kermit uses, then enter the appropriate SET ATOE/ETOA/TATOE/TETOA commands in the SYSTEM KERMINI file. Your system's ASCII/EBCDIC translation tables need not be mutual inverses, but if either table is not invertible at all, then Kermit will not and cannot work unless you change your system's table. See the Kermit-CMS chapter in the User's Guide for more information. When CMS Kermit is to be used with a 7171, make sure the 7171 is set up with its "keyboard lock delay" set to 0. Otherwise, the "terminal" will hang whenever CMS Kermit clears the screen. This happens consistently when the parameter is set to 10, and not at all when set to 0. For numbers in between, the higher the number, the more it happens. ------------------------------ No updates have been received since Kermit-CMS 4.0 was originally released. Any updates created later than your source should be applied before you make the executable module. In general, updates received at Columbia will not be applied to the source files in the CMS Kermit distribution until and unless "major" bugs are uncovered, and then all accumulated updates will be applied at once. The description of each problem and a pointer to its solution will always be included in IKCKER.BWR (the present file), but the updates themselves are to be found in IKCKER.UPD. The procedure to update your copy of CMS Kermit is as follows: 1. Obtain the latest version of IKCKER.UPD, which contains all the updates, each preceded by a separator beginning ":READ" and giving the update's name. 2. Determine the date of your sources. If you received them from a secondary supplier, you will need to examine the source code to determine the most recent update applied. Just sort the combined source by columns 67-71, e.g., using :1 SORT * A 67 71 in XEDIT; the last line will be labelled with the last-applied update. 3. Discard all updates up to and including that date as well as the corresponding lines in the AUX file. Note that updates are listed in reverse order in the AUX file. To discard one of the update files, simply delete the lines from the corresponding :READ up to (but not including) the next :READ. 4. Separate the updates into individual files either by using an editor to split the file at each :READ card (which should not be included in the output files) or by punching the entire file and copying it back to disk using READCARD. In either case, the resulting update files should be RECFM F and LRECL 80. 5. Apply the updates to your composite source via the command: UPDATE KERMIT (CTL The resulting file, $KERMIT ASSEMBLE A, can replace the old one when it has been assembled and tested. It will be identical to the current composite source at Columbia (including updates). You must remember that assembling this test source will produce an object file called $KERMIT TEXT, which should be renamed KERMIT TEXT for testing. Alternatively, you can keep your original composite source as a base file and apply the updates only when you assemble it; just follow steps 1-4 above, and use the command, VMFASM KERMIT KERMIT, instead of the usual assemble command. The resulting object will be called KERMIT TEXT as usual. ------------------------------ Date: Mon, 31 Aug 87 11:09:50 CST From: Mike Sorsen Subject: 7171 Causes CMS Kermit Problems When Flow Control Used There is a bug in the 7171 that causes CMS Kermit file transfers to abort in the middle of a SEND after a large number of retries when XON/XOFF flow control is used by the receiver or when XON/XOFF flow control is used by hardware in between the 7171 and the receiver. The symptom of this failure is that CMS Kermit attempts to retransmit a packet before other Kermit has responded. This bug was observed using CMS KERMIT 3.1 running under VM/SP 3.1 (PUT 8409 SLU 311) through a 7171 at EC A31864 to MS-DOS Kermit version 2.29b. The sequence of events is this: CMS Kermit sends a packet using transparent write/read. The receiver (or other hardware in between the 7171 and the receiver) sends a pacing stop (XOFF) and then a pacing start (XON) to the 7171 while the packet is being sent by the 7171. The 7171 performs the pacing, but then ends the transparent read prematurely, returning X'93' (XOFF) to CMS as the reply to the packet sent out. CMS Kermit rejects this and retransmits the packet. The SEND then breaks down because the recieving Kermit usually starts transmitting an ACK to CMS while the packet is being retransmitted. Circumvention: Set the 7171 flags so that XOFF is not a valid termination of a transparent read. See page 4-20 of 'IBM 7171 Reference Manual and Programming Guide', IBM publication number GA27-0021. This has been tested at our site and found to circumvent the bug even though the XOFFs are being transmitted during the transparent write part of the transparent write/read order and this flag concerns the transparent read part of the order. ------------------------------ Date: 02 July 87 10:31 EDT From: JOWY@CORNELLC Subject: Using KERMIT with an IBM 3708 and VCNA I thought you might be interested in knowing that we finally got KERMIT working on our system (without any change in the KERMIT program). Using protocol enveloping mode on the 3708, you must go through 7 separate steps to get things working. Briefly, they are as follows: 1) Apply IBM APAR DY30352 to bypass VCNA translation tables. 2) Apply IBM APAR II01192 to increase the length of a 'line' for a TWX- type terminal to 80 bytes instead of 72 bytes. 3) Set the packet length on both sides of KERMIT to 80 bytes. 4) Change DTIPDODR source code for VCNA to skip the addition of a 'CRLF' on the front of any line beginning with 02 (CNTRL B). 5) Require that both sides of the link use 02 (CNTRL B) as the start- of-packet character. This is because the 3708 interprets the normal start-of-packet character (CNTRL A) as an attention signal. Use the alternate translate table provided on the 3708, which allows for more accurate transmission of some control characters. I don't know if anyone else will ever need to use KERMIT on this type of system, but if they do, this info should help. Also, if anyone has any questions on this, they are welcome to contact me: Linda Poppleton, JOWY@CORNELLC. My phone number is 607-255-7925. ------------------------------