DaveP wrote: > > In all my limited SCSI experience I've found it is the last Physical > device on the cable that needs terminated... Shouldn't matter if the > farthest one from the bus is device 1 or 7, if it's on the end, it gets > terminated. And that doesn't mean the last plug on the cable, it means > the last USED plug on the cable. If I'm off-base, please feel free to > correct me. My SCSI is pretty limited. > > DaveP > > > > From: Ron <[EMAIL PROTECTED]> > > Subject: Re: [PCI] 8500 no-start_update + chain terminations > > > > SCSI is much simpler than you all think it is: > > > > The SCSI chain needs termination at each end. > > > > Normally the disk is at 0 (terminated) and the CPU is at 7, also > > terminated. > > > > Anything in between should not be terminated. > > This may be good practical advice. But I have been supposing you can > terminate anything. As long as it is just one thing (apart from the Mac > itself). And that is what I have done. In fact my CDs were terminated in > a couple of 7300s (meaning that no other HDs were or should be) > If the CD was terminated, and at the typical ID-3, it seems to me that if you put an un-terminated HDD in ID-0, 1 or 2, it would be the device farthest from the Mac, ID-7, and IT should be the one to be terminated. Someone on the list said that Apple CD-ROMs are self-terminating and has only Termination Power jumper pins- to be on or off. I think David Elmo said only one device in a chain should be getting termination power. Damage could result if too much termin. power was in the chain, IIRC.
> I would set your CD to the default settings which IIRC includes having > Term PWR and Parity jumped. > > Speculation on my part but stock Apple CDD's my be self terminating so > you may want to take termination off your HDD and re-cable (if possible) > so your CDD is the last (terminating) drive on the chain. I don't know if > this will work but it may be worth a try as a last resort. Placing CD at lowest ID=0 with TP and Parity enabled makes sense, as long as it *does terminate* for the chain above it. Maybe the CD only takes care of *itself/automatically* and shouldn't be a chain terminator. I wonder if the device that is *TE/enabled* has to be the same one which is getting TP/power (on)? [Possibly, the TP can be on any device (?) in the chain, ie, CD @ ID-3], while the TE/terminated device must be the farthest from the Mac. Each of 3 Apple CD drives I checked had a jumper on the Termination Power. If the [above] is true, then it seems best to give the TP to the CD, and NOT have TP/power going to any other device. A lot of us need to get TP and TE separated, understood and implimented- if not, we'll suffer a fate worse than death > Staring at a [grey screen]. I still think my HDD file corruption was caused by improper TE and TP sets on my drive(s). It took 1 week +help from you all to find problem. * I'm going now to this link >>> Glen posted: "SCSI termination power"- <http://www.lowendmac.com/tech/termination.shtml> Thanks >Glen< (and then the Parity questions, after in-termination-ables are solved.) -- PCI-PowerMacs is sponsored by <http://lowendmac.com/> and... Small Dog Electronics http://www.smalldog.com | Refurbished Drives | -- Sonnet & PowerLogix Upgrades - start at $169 | & CDRWs on Sale! | Support Low End Mac <http://lowendmac.com/lists/support.html> PCI-PowerMacs list info: <http://lowendmac.com/lists/pci-powermacs.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/pci-powermacs%40mail.maclaunch.com/> iPod Accessories for Less at 1-800-iPOD.COM Fast Delivery, Low Price, Good Deal www.1800ipod.com
