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.