bershad@ucbcad.UUCP (Brian Bershad) (07/25/85)
I am having problems with two 750's hanging at boot time.
Right after the line printer (lp0) is configured, everything
stops until you hit a key (any key) on the console. It
then proceeds fine with "Automatic reboot in progress..."
It only does this on the machines with lp interfaces...
Any ideas??
--
Brian Bershad
------------
UCB Computer Systems Support Group
arpa: bershad@berkeley
uucp: {ihnp4,decvax}!ucbvax!bershadguy@sun.uucp (Guy Harris) (07/28/85)
> I am having problems with two 750's hanging at boot time. > Right after the line printer (lp0) is configured, everything > stops until you hit a key (any key) on the console. It > then proceeds fine with "Automatic reboot in progress..." This is a common problem. It occurs if you have a slow printer as your console which is set up to transmit XOFF and XON for flow control, and if you're running an operating system that does a lot of printing before it starts the terminal driver running normally on the console (like 4.xBSD which prints a lot of messages while doing autoconfiguration). The DECwriter sends an XOFF, which is ignored by UNIX at that point; it probably sends lots more XOFFs. Once the terminal driver is started up, it receives an interrupt because of the XOFF in the receiver buffer. It dutifully stops all output. For some reason, no matching XON makes its way into the driver. Typing any character tells the driver to restart output. > It only does this on the machines with lp interfaces... This is probably because if you don't have an lp interface it doesn't print enough to overrun the DECwriter's buffer. One solution is to tell your console not to transmit XOFFs (it is a SET-UP option on the DECwriter). Another option might be to start the terminal driver up sooner... Guy Harris