Xref: utzoo comp.unix.i386:558 comp.unix.xenix:7764 Path: utzoo!attcan!utgpu!jarvis.csri.toronto.edu!mailrus!cs.utexas.edu!uunet!nuchat!steve From: steve@nuchat.UUCP (Steve Nuchia) Newsgroups: comp.unix.i386,comp.unix.xenix Subject: Re: Mylex SCSI Controller Message-ID: <14944@nuchat.UUCP> Date: 24 Sep 89 22:07:30 GMT References: <111006@nstar.UUCP> <653@fiver.UUCP> Reply-To: steve@nuchat.UUCP (Steve Nuchia) Organization: Houston Public Access Lines: 24 In article <653@fiver.UUCP> palowoda@fiver.UUCP (Bob Palowoda) writes: >From article <111006@nstar.UUCP>, by larry@nstar.UUCP (Larry Snyder): >> Does ESIX directly support the 16550A in their ASY drivers? I wish >> that SCO did. >Actually the problems are nothing but setting up the correct >conditions. No, there is more to it than turning on the FIFO's. A driver that was written without considering a FIFO will in general not try to do enough work on each interrupt. To take full advantage of the 550A's fifo you have to make different tradeoffs than you do for 8250's. In particular, if you know you are likely to be working with 4-16 characters at a time you spend a lot more code setting up pointers and such than you will if you expect 1, sometimes 2 characters. Some drivers will even return from the interrupt service routines before completely filling/emptying the queues. -- Steve Nuchia South Coast Computing Services uunet!nuchat!steve POB 890952 Houston, Texas 77289 (713) 964 2462 Consultation & Systems, Support for PD Software.