Path: utzoo!news-server.csri.toronto.edu!cs.utexas.edu!oakhill!motaus!skipper From: skipper@motaus.sps.mot.com (Skipper Smith) Newsgroups: comp.sys.amiga.hardware Subject: Re: SCSI-1 vs. SCSI-2 Message-ID: <1991Mar11.190828.21607@motaus.sps.mot.com> Date: 11 Mar 91 19:08:28 GMT References: <1991Mar8.200331.5111@javelin.es.com> Organization: Motorola Semiconductor, Austin, Texas Lines: 58 In article andrewsr@u2.rutgers.edu (Rich Andrews) writes: >Hello All! > >What is the difference between SCSI and SCSI-2? (My guess: SCSI is >16bit and SCSI is 32bit). Bzzzt! SCSI-1 and SCSI-2 are both 8 bit. 16 bits and wider come under the domain of "wide" SCSI. SCSI-2 is a better definition than SCSI-1 ever was and will allow people to make compatible drives and controllers easier since they have a stricter standard to adhere to (hopefully :-). SCSI-2 also makes a few modifications to the timing diagrams for faster throughput- SCSI-1 maxed out at about 1.2 Mb/sec async and 4 Mb/sec sync whereas SCSI-2 achieves (in theory) 2 Mb/sec asynch and 5 Mb/sec synch (this is all according to a Quantum brochure that I have so blame any mistakes on them). Sure wish somebody would come out with a syncronous drive controller for SCSI-2... it would easily blow away the HardFrame (all of those reports were in MegaBYTES, not bits). > >Does the A3000 have a SCSI-2 port? No, the drive controller on the A3000 is SCSI-1, but it probably could be replaced with a SCSI-2 chip without difficulty (though I will leave it up to the designer to state whether or not that is the case). > >How much better is the performance of a SCSI-2 over a SCSI? See above. > >Where can I get SCSI-2 drives? (Looking for ~200MB, maybe Quantum). Almost all companies have switched over to making SCSI-2 specification drives since they are backwards compatible with SCSI-1 (although you only get the bonus speeds when you have a SCSI-2 compatible controller which nobody makes yet for the Amiga). Quantum, Micropolis, Maxtor, Conner... they are all making SCSI-2 compliant drives. > >How much more expensive is SCSI-2 than SCSI? No reason for them to be anymore expensive. SCSI-2 requires a tighter spec be adhered to, not that additional hardware be used (and any additional hardware used to make a drive achieve SCSI-2 compliance would mostly be very inexpensive like capacitors to reduce ringing and noise, etc...). > >If there are no good (or too expensive) SCSI-2 drives around, is it >worth waiting for them to come out (or drop in price)? > >Thanks in advance for any help! >-Rich >-- > // Rich | "have you ever noticed that opinion without knowledge is >\X/ Andrews | always a shabby sort of thing?" - Socrates -- Skipper Smith | skipper@motaus.sps.mot.com Motorola Technical Training | 8945 Guilford Rd Ste 145 All opinions are my own, not my employers | Columbia, MD 21046