key%marlin@Nosc.ARPA (06/11/84)
From: Gerald S. Key <key%marlin@Nosc.ARPA>
I am trying to transfer a text file from a Kaypro 4 through a
MILNET TAC (specifically, the ACCAT-TAC) to VAX-11/780 running
4.2bsd UNIX. I am using a MODEM7 variant, kmdm795, in checksum
mode on the Kaypro. I have used both xmodem and umodem on the
VAX side, in both receive-text and receive-binary mode and also
with the 7-bit mask option (with umodem). I have tried sending
both with and without "binary input start" and "binary output
start" set on the TAC. In each instance I receive the following
error message:
Sending #1 (0001H)
87H Rec'd, not ACK
Sending #1 (0001H)
87H Rec'd, not ACK
. .
. .
until the transfer dies from too many errors.
Curiously, if I turn things around and transfer a file from the
VAX to the Kaypro using the same software and the same path, all
works fine!
I have been using umodem/xmodem and kmdm795 for a long time to
transfer files without problem to/from the same VAX via a local
area network.
Any suggestions?
Gerry Key
key@nosc.arpa
...!ucbvax!sdcsvax!noscvax!key ABN.ISCAMS@Usc-Isid.ARPA (06/11/84)
Gerald, I suspect you may be having the same problem I am with going through a TAC. Downloads work fine, upload NO GO! I suspected the TAC's input buffer was to blame (heck, I can overrun that just by manual typing when the system is slow), and someone else out on the net confirmed that. They also said you can talk with your local TAC wizards about getting the buffers expanded from their usual size (I THINK 60-some bytes) to 130-some (whatever MODEM's packet length is) to overcome this problem. I talked with mine, and they're talking with the Powers That Be, but no big buffers yet (they're researching possible bad side effects). I'm stuck too for packetized uploading, and so use KERMIT for all uploads requiring error-checking. (KERMIT's packet length can be adjusted, so I routinely set them for 48 or so -- works fine.) For other uploads when the lines are clear, I engage flow control (FIS on my system) so the TAC give me XON/XOFFs (so as not to overflow its buffers), and upload right into a text editor -- works fine. If I want a binary upload, I use the PD utility UNLOAD to change my binary file back to hex (ASCII), upload into the text editor, and send it that way for the other end to LOAD or MLOAD (another PD utility) back to binary. There's also a problem when uploading through a TAC -- the TAC's Intercept Character. I've patched both KERMIT and MDM730 to check each character sent (in automated, bulk uploads) for the TAC Intercept Char, and if found, to send it twice. This insures that character gets to the far end and the TAC doesn't choke. If you need more details on this, yell. Hope this helps. Regards, David Kirschbaum Toad Hall ABN.ISCAMS@USC-ISID
avrunin@Nalcon.ARPA (06/11/84)
From: "I. Larry Avrunin" <avrunin@Nalcon.ARPA> Gerry; When using the TAC put it into Binary mode with @B O S and @B I S to get it through. You will not be able to give TAC commands afer that. Also be sure your umodem has the 4.2 changes to it. Good Luck Larry Avrunin -------