Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!swrinde!mips!apple!uokmax!servalan!epmooch!ben From: ben@epmooch.UUCP (Rev. Ben A. Mesander) Newsgroups: comp.periphs.scsi Subject: Re: Diff. between SCSI I & II Message-ID: Date: 4 Oct 90 02:14:40 GMT References: <1990Oct4.003204.20738@idt.unit.no> Lines: 48 >In article <1990Oct4.003204.20738@idt.unit.no> bernhard@mime.idt.unit.no (Kjetil Bernhard Thomassen) writes: >I would like to know the difference between SCSI I and SCSI II. > >Is there anobody out there who has the details? > No. Nobody knows the details. :-) There is an ANSI (American National Standards Institute) document that covers SCSI-2. I'm not positive of this, but there should be a European spec. as well (There was one for SCSI-1). > >Is SCSI II 32 bit, or what? > Or what. Sometimes. SCSI-2 has 16 and 32 bit options. They require different cabling than SCSI-1, and are not commonly used (yet). SCSI-1 uses an 8 bit bus. > >What is the teorethical throughput? > Well, ethically speaking, that depends on another "or what". There are several options for SCSI-2, including something called "fast SCSI", and the 16 and 32 bit data paths. I can't remember the exact numbers right now, and I'm too sleepy to dig into my SCSI-2 manual. Suffice to say that the maximum throughput is a lot faster than real-world disk drives can sustain. > >How many peripherals is it possible to connect to the same controller >without using any kind of "undocumented features"? > The commonly used method allows 8 devices on a SCSI bus. There may be up to 2048 (I think...) sub-devices for each LUN. I've never seen this feature implemented. Anyone using "undocumented features" on the SCSI bus should be summarily executed. >Kjetil Bernhard Thomassen >bernhard@idt.unit.no >bernhard@solan.unit.no -- | ben@epmooch.UUCP (Ben Mesander) | "Cash is more important than | | ben%servalan.UUCP@uokmax.ecn.uoknor.edu | your mother." - Al Shugart, | | !chinet!uokmax!servalan!epmooch!ben | CEO, Seagate Technologies |