At 05:26 -0800 12/21/2002, Brian Murphy wrote: >Hi- > >I'm a long-time lurker here (since digest #67) and I have a question >I can't recall being answered here before: Can a 68-Pin Ultra Fast >Wide SCSI HD be used as a boot drive on the S900's bus 0? Is there >an alternative way of saying "68-Pin Ultra Fast Wide SCSI"? I'm >having trouble finding information on this standard on the Web. >(Hope this doesn't open too large a can of worms.)
You can shorten "68-Pin Ultra Fast Wide SCSI" considerable. First, Ultra and Fast are mutually exclusive (or one could argue that one is a subset of the other). Anyway, Fast SCSI was an earlier standard which allowed 10 MB/s transfers on 50 pin SCSI. Ultra is a later standard that allows 20 MB/s on 50 pin SCSI. In either case, double the maximum transfer speed if you combine it with Wide. So, nuke the word Fast. Or nuke Ultra. It's either Fast or it is Ultra. This is complicated by the fact that newer Ultra drives will support Fast if they are attached to old equipment which supports Fast but not Ultra. Second, Wide implies 68 pin. So get rid of 68 pin. So it's just Ultra-Wide SCSI. Then abbreviate and it's UW SCSI. At the end Umax shipped quite a few S900s with UW drives on SCSI bus 0. They put the UW drive on the end of the SCSI cable, enabled termination on the drive, and used a 50 pin to 68 pin adapter. Note that this only works at the end of the cable (and so, only for one drive at a time) because of termination issues. You can get around that limitation by using a 50 pin to 68 pin adapter which terminates the upper 18 pins of the drive, but then you pretty much must put the drive anywhere except the end of the SCSI cable and some other drive must be at the end of the cable to provide termination. This gets fairly complex fairly fast, which is why it's much better to not adapt drives. Of course, narrow (50 pin) drives are getting to be like hens teeth these days. Jeff Walther -- SuperMacs is sponsored by <http://lowendmac.com/> and... Small Dog Electronics http://www.smalldog.com | Refurbished Drives | Service & Replacement Parts [EMAIL PROTECTED] | & CDRWs on Sale! | Support Low End Mac <http://lowendmac.com/lists/support.html> SuperMacs list info: <http://lowendmac.com/supermacs/list.shtml> --> AOL users, remove "mailto:"; Send list messages to: <mailto:[EMAIL PROTECTED]> To unsubscribe, email: <mailto:[EMAIL PROTECTED]> For digest mode, email: <mailto:[EMAIL PROTECTED]> Subscription questions: <mailto:[EMAIL PROTECTED]> Archive: <http://www.mail-archive.com/supermacs%40mail.maclaunch.com/> --------------------------------------------------------------- >The Think Different Store http://www.ThinkDifferentStore.com ---------------------------------------------------------------
