From: utzoo!decvax!ucbvax!info-vax Newsgroups: fa.info-vax Title: Re: Using Versatec Model 121 Article-I.D.: ucbvax.7823 Posted: Tue Jun 29 16:26:51 1982 Received: Wed Jun 30 04:49:06 1982 >From mo@LBL-UNIX Tue Jun 29 16:24:59 1982 Confusus say: Interrupt-per-character interface in PIO-mode on FAST peripheral mean CPU get shit kick out of it servicing interrupts. Answer: Modify driver to fill printer buffer before returning from interrupt. Such fixes can cut overhead VERY large amount; you might even get a cycle or two at lower than IPL 15.