Path: utzoo!news-server.csri.toronto.edu!rpi!zaphod.mps.ohio-state.edu!unix.cis.pitt.edu!dsinc!bagate!cbmvax!daveh From: daveh@cbmvax.commodore.com (Dave Haynie) Newsgroups: comp.sys.amiga.hardware Subject: Re: SCSI-1 vs. SCSI-2 Message-ID: <19941@cbmvax.commodore.com> Date: 18 Mar 91 18:07:20 GMT References: <1991Mar8.200331.5111@javelin.es.com> <19745@cbmvax.commodore.com> <2216@wet.UUCP> Reply-To: daveh@cbmvax.commodore.com (Dave Haynie) Organization: Commodore, West Chester, PA Lines: 29 In article <2216@wet.UUCP> pk@wet.UUCP (Philip King) writes: >Dave, does this mean that Amiga hard disk controllers support synchronous >transfers? I don't think I've ever seen any of the host adaptor >manufacturers claim that. Sure do. Apparently, though, the our host adaptors won't normally request synchronous transfers. Some drives lock up, or otherwise misbehave, if you ask for synchronous transfers. There's a bit somewhere in A3000 battery backed RAM, last I heard, that will tell the scsi.device to automatically request synchronous transfers. If you set that, and you have the proper drive out there, you should be OK, but some drives will find this to be a problem. Of course, that's How I Understand It. I'm not the SCSI.Expert around here, others may have more to add to this. >I happen to have a drive that supports this, and I wouldn't at all mind >if I could speed it up! Chances are, going to synchronous mode won't result in much of a speedup anyway in a single drive system. In most cases, the drive is the limiting factor, not the SCSI bus. It might make a visible difference on high end drives with large caches. Randell or Steve may have looked at this question in greater detail. -- Dave Haynie Commodore-Amiga (Amiga 3000) "The Crew That Never Rests" {uunet|pyramid|rutgers}!cbmvax!daveh PLINK: hazy BIX: hazy "What works for me might work for you" -Jimmy Buffett