bin@rhesus.primate.wisc.edu (Brain in Neutral) (07/26/88)
Anyone seen this one? I had the DEC field service engineer come in to replace the keyboard on my VAXstation 2000 (Ultrix 2.2 Worksystem V1.1, running X) because it was too bouncy (e.g., you type abc and get abbc). After unplugging the old keyboard and plugging in the new, the return key worked only *every other* time. After logging out (all windows disappear and new login window appears) the return key worked again. Unplugging and plugging in the *same* keyboard while logged in produced the same effect. Again, logging out solved the problem. A test with a third keyboard produced the same result, so clearly this is not a keyboard hardware problem. What's going on? The engineer said that this didn't occur when he swapped a keyboard on a running VMS VS2000.
jg@jumbo.dec.com (Jim Gettys) (07/30/88)
Swapping keyboards while power is still applied is a very bad idea, just like recabling any part of any computer while power is applied is a bad idea. In any case, the bug is that the device driver is not listening for the power up sequence of the keyboard and setting it to the right mode. It only does "the right thing" once, and presumes the keyboard will remember what it is told. I believe the bug dates back to the days of prototype VAXstation 2/GPX's. The prototypes, before more protection was added to the line drivers for production, were liable to blow the keyboard uart in the GPX if you swapped keyboards while power was applied. This highly discouraged working on the device driver in this area at the time. (not nice to damage expensive hardware that isn't yet in production). By the time the GPX went into production, additional protection was added to prevent damage. I recommend reporting this (antique) bug. And recabling with power applied is in general asking for trouble. You don't know what might short to what while fiddling with a connector. Jim Gettys Systems Research Center Digital Equipment Corporation
bin@rhesus.primate.wisc.edu (Brain in Neutral) (08/04/88)
>From article <51457@felix.UUCP>, by jg@jumbo.dec.com (Jim Gettys): > Swapping keyboards while power is still applied is a very bad idea, just > like recabling any part of any computer while power is applied is a bad > idea. > > ... > > And recabling with power applied is in general asking for trouble. You > don't know what might short to what while fiddling with a connector. I believe it. On the other hand, *DEC field service* swapped the keyboard with me, and didn't say anything about powering down! (Neither of two different field engineers.) Yippee! Yours, Paul DuBois dubois@rhesus.primate.wisc.edu rhesus!dubois bin@rhesus.primate.wisc.edu rhesus!bin