arbab%USC-CSE@USC-ECL.ARPA (07/25/84)
I have an XT in my office and I run both DOS and PC/IX. I keep getting very strange "hardware problems" that come with no reason and go away with even less reasonable explanation. One recurring problem has to do with the async port, knwon to DOS as com1, or tty0 to PC/IX. The problem is that apparently neither connect nor uucp can detect a carrier on the line. Neither diagnostics (standard and advanced) shows anything wrong with the system or the port. This problem occurs almost consistently, roughly once every 12 hours. The interesting thing is that Kermit under DOS has no problem with the port and always establishes a connection. The problem does not go away by itself. I have to unplug the cable from the wall and the back of the XT and plug it back in again. For the past two weeks this ritual of unpluging has always succeeded to exorcise the evil spirits trapped in the cable, but somehow I don't trust this as a permanent solution. I changed my cable once, but that did not do any good, other than the fact that it lead to the unplugging ritual. I have checked the card, it is properly placed and the screw is tight. Jiggling the connectors in place never works anyway. Let me repeat that Kermit never complains and always works properly. In the presence of the evil spirit, even after Kermit establishes a connection, PC/IX connect is unable to connect. By the way, the port is connected to a micro switch at 9600 baud, and after exorcism connect and uucp work fine until the next visit of the spirit. The other problem really started two days ago. I turn the color monitor on, then turn the system on and wait for PC/IX to boot. The power on diagnostics go through, I get the "booting unix from partition 1" message, the 25th line message, and that is it. Yesterday, it was pure silence. I could not reboot through the keyboard, so I powered off and on and everything went fine this time. I didn't think much of it then. But today it happened again. First the boot messages and then a ceaseless beep. Power off, power on a second time, got as far as the "Checking file system consistency" message, and all activity ceased. Back to the advanced diagnostics floppy, power off, power on, run diagnostics, everything is fine, type 9 to exit from the diagnostics. The screen flashed once with green sync lines, reverted to its previous state, I am left with a dead system. Power off, power on, run advanced diagnostics on the monitor and its interface, everything is fine, type 9 to exit, it works this time. PC/IX is booted from partition 1, file system consistency check succeeds, I am up and running now. I am writing this message on our vax to which I am connected through PC/IX (I had to exorcise the spirit again today after all of this, before I could connect). My XT has a math co-processor as well. Needless to say, diagnostics run fine for the co-processor too. Any hints, suggestions, reports of similar incidents, or sympathy notes would be appreciated. Farhad
papa%USC-CSE@USC-ECL.ARPA (07/25/84)
From: Marco Papa <papa%USC-CSE@USC-ECL.ARPA> I have a similar problem with the XT that has both DOS and PC/IX on it: I have a graphics program that uses both mono and color screens. If run on an XT with only DOS on it it works fine. If run on the one with DOS and PC/IX, after returning to DOS the system crashes and I have to reboot. The only difference between the two systems (besides the number of operating systems on them) is that the one that crashes has a math chip on it. I'll try to take it out and see what happends. Marco