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From: rob@uokmax.ecn.uoknor.edu (Robert K Shull)
Newsgroups: comp.sys.mac.hardware
Subject: Re: REMOVABLES TRASHING HARD DISKS ???!!!
Message-ID: <1990Sep21.173055.6496@uokmax.ecn.uoknor.edu>
Date: 21 Sep 90 17:30:55 GMT
References: <9549.26f8a1f0@rsmas.miami.edu> <1990Sep21.140502.8273@ariel.unm.edu>
Organization: Engineering Computer Network, University of Oklahoma, Norman, OK
Lines: 31

In article <1990Sep21.140502.8273@ariel.unm.edu> wilcox@hydra.unm.edu (Sherman Wilcox) writes:
>In article <9549.26f8a1f0@rsmas.miami.edu> miller@rsmas.miami.edu writes:
>>[...]
>>
>>So, the obvious question is "Are removables (perhaps Syquest's in particular)
>>trashing hard drives for no reason?". 
>>Let's hear from any others who have had similar problems to those described
>>above AND LET'S HEAR FROM _COMPANIES_ _WHICH_ *SELL* _REMOVABLES_, particularly
>>DPI and Syquest.
>I'd like to second the plea to hear from others concerning Sysquest
>removeables. Do they trash hard drives? Should I, yet again, re-consider
>by backup decision?

No problems here. I have an Alliance Peripherals removeable (Syquest
mechanism). I'm using it on a Mac II with 100 meg internal. The main
difference (I gather) from the DPI everyone's talking about is that the
APS has external termination, and the DPI apparently has internal.
This could be the problem. At least one of the complaints about trashed
hard drives involved a DPI (internal termination) being powered off
while the other hard drive was in operation. If I understand termination
properly, internal terminators draw power from the device they're
attached to, so that if that device is powered off, the bus would no
longer be terminated correctly. On the other hand, some (which?) models
of Macintosh supply terminator power for external terminators, so on those
models it doesn't matter whether or not the drive is powered on (as long
as the termination is external).
I'm sure everyone will correct me if I'm wrong :-)
	Robert
-- 
Robert K. Shull
rob@uokmax.ecn.uoknor.edu				chinet!uokmax!rob