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Path: euryale.cc.adfa.oz.au!newshost.anu.edu.au!harbinger.cc.monash.edu.au!news.rmit.EDU.AU!news.unimelb.EDU.AU!munnari.OZ.AU!spool.mu.edu!howland.reston.ans.net!newsfeed.internetmci.com!in1.uu.net!van-bc!portal.ca!not-for-mail From: curt@portal.ca (Curt Sampson) Newsgroups: comp.os.linux.advocacy,alt.os.linux,comp.unix.bsd.freebsd.misc,comp.unix.bsd.netbsd.misc Subject: Re: a monthly FreeBSD magazine (and other *BSD's too) Date: 6 Jan 1996 16:28:56 -0800 Organization: Internet Portal Services, Ltd. Lines: 54 Message-ID: <4cn448$ou8@cynic.portal.ca> References: <4ajc07$sb7@unix2.glink.net.hk> <4cfq48$9lg@news1.halcyon.com> <1996Jan4.140833.18166@wavehh.hanse.de> <4cllf3$7k8@pell.pell.chi.il.us> NNTP-Posting-Host: cynic.portal.ca Xref: euryale.cc.adfa.oz.au comp.os.linux.advocacy:32256 alt.os.linux:6934 comp.unix.bsd.freebsd.misc:11593 comp.unix.bsd.netbsd.misc:1735 In article <4cllf3$7k8@pell.pell.chi.il.us>, Orc <orc@pell.chi.il.us> wrote: > I dunno; given the collection of widely varying new SCSI >proposals out there, what's the chance that your narrow SCSI >devices will be useful a decade from now? SCSI has had a >fantastic time of surviving and being upward compatable for >over a decade, but when you start seeing fiber channel, >differential, and so on variants of SCSI, the generic SCSI-1 and >narrow SCSI-2 devices out here start to have a somewhat doomed >look to them. This is getting a bit silly. Differential SCSI has been around since the beginning of the SCSI-1 standard. It's not at all popular, and it is incompatable, but it's certianly not new, and it's not likely ever to become very popular given that we now have better ways of extending busses. So yes, if you have differential SCSI devices, you may have a problem in the future. How many differential SCSI CD-ROMs have you ever seen, though? Yes, we do have new SCSI bus hardware in coming up. However, nobody's going to replace cheap ribbon cable with expensive fibre just for the heck of it. Very few installations out there have a problem with current bus length limitations. Speed is a problem in some circumstances, and will become more so as time passes, but that is solved in two ways. One is switching to, say, a high-speed fibre-optic bus, but in that case you'd probably still keep a second SCSI controller in the system with a low-speed copper bus so that you don't radically jack up the price of low-speed peripherals, like CD-ROM drives and tape drives. The second is to allow faster clock rates on synchronous transfers and widen SCSI. This is backward compatable with the old peripherals, so you'll be able to continue to use them. Wide SCSI is entirely compatable with narrow SCSI; the devices can be co-mingled in a single SCSI chain. SCSI devices have so far prooved to have a much longer lifetime than any other type except RS-232 serial and Centronics parallel. I still have five year old SCSI devices in use, and the ability to move the device to different hardware (such as putting that old, slow disk on the Sun 3 that happened to show up the other day) is extremely handy. How many MFM, RLL or ESDI disks are in use these days? I know personally of only one ESDI disk, and that's on an Emulex bridge controller to make it a SCSI drive. cjs -- Curt Sampson curt@portal.ca Info at http://www.portal.ca/ Internet Portal Services, Inc. Vancouver, BC (604) 257-9400 De gustibus, aut bene aut nihil.