Article View: comp.sys.mac
Article #2229Re: Hopping on the SCSI bus (uptown)
From: Joel B Levin
Date: Tue, 01 Aug 1989 13:52
Date: Tue, 01 Aug 1989 13:52
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In article <3262@internal.Apple.COM> teener@apple.com (Michael Teener) writes:
|Here is some useful information for SCSI configuration problems:
. . .
|What all this means is: (1) put a device you will always want powered on
|at the far end of the SCSI chain *and attach a terminator* and (2) if you
|do not have an internal drive do the same for the first peripheral device
|(terminator + always powered on).
. . .
|(Note: if you have non-Apple peripherals then there is no guarantee that
|terminators follow our philosophy ... read the manual and note any
|comments about termination and power-on requirements.)
I have just been through some of this, and can concur. I have an SE
with internal HD and have just attached an external foreign drive.
The new drive comes with terminators, and there is a jumper to select
whether the terminators receive power from the drive or from the SCSI
cable. Currently they are powered from the drive; when that is turned
off the SCSI bus is dead and the Mac will only boot from and recognize
floppies. Unfortunately, I am told, neither the SE nor the Plus puts
terminator power out on the cable (possibly because there are fewer
pins at the Mac end), so changing the jumper would be worse; then the
terminators would never get power. So I have to live with
disconnecting the drive from the bus if I wish to run with it powered
down.
/JBL
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Path: arc1-ca.pugleaf.net!utzoo!attcan!utgpu!jarvis.csri.toronto.edu!mailrus!iuvax!cica!gatech!bbn!bbn.com!levin From: levin@bbn.com (Joel B Levin) Newsgroups: comp.sys.mac Subject: Re: Hopping on the SCSI bus (uptown) Message-ID: <43584@bbn.COM> Date: 1 Aug 89 13:52:37 GMT References: <8907312149.AA18252@ucbvax.Berkeley.EDU> <3262@internal.Apple.COM> Sender: news@bbn.COM Reply-To: levin@BBN.COM (Joel B Levin) Organization: BBN Communications Corporation Lines: 30