Path: utzoo!utgpu!news-server.csri.toronto.edu!rutgers!usc!samsung!uunet!munnari.oz.au!labtam!scott
From: scott@labtam.oz (Scott Colwell)
Newsgroups: comp.sys.apollo
Subject: Re: DN2500 disk cables
Summary: watch that disk orientation
Message-ID: <5116@labtam.oz>
Date: 16 Aug 90 01:04:32 GMT
References: <9008141821.AA31711@richter.mit.edu>
Organization: Labtam Limited., Melbourne, Australia
Lines: 35

In article <9008141821.AA31711@richter.mit.edu>, krowitz@RICHTER.MIT.EDU (David Krowitz) writes:
.. referring to the new Quantum disk connected to the DN2500...
> It runs *hot*! I don't have a mounting bracket made up
> yet, so I've got it lying in the DN2500 with the disk
> logic board facing up with the DN2500's cover off. The
> disk is quite hot, but the logic board doesn't seem any
> warmer than the DN2500's CPU board.

Please check the drive manufacturers specification on allowable mounting
orientation. They all (with perhaps the exception of drives for laptops)
have only a few allowed orientations and I have never seen them allow
the drive to be mounted upside down (i.e. with the logic board up).

Putting it up the other way doesn't mean that you will have problems but
it may. Also I would be concerned if you formatted the drive this way and
even more concerned about the temperature. Drives are more sensitive to
temperature than nearly all other components in the machine (tape is bad too),
check the temp range in the spec for confirmation.

My concern with formatting is that the read/write electronics temp and
head position would be quite different when the disk was formatted than
when it is properly mounted. This is probably less of a concern than running
it upside down for extended periods because I believe the orientation spec
is due to the spindle bearings rather than the head forces or temperature.

I may be being 'picky' but I do prefer formatting in the final mounting
arrangement and I definitely don't run drives upside down for long.

(p.s. the sensitive electronics is inside the disk enclosure, not on the
logic board.)

-- 
Scott Colwell
Labtam Information Systems P/L	net:	scott@labtam.oz.au
Melbourne, Australia 		phone:	+61-3-587-1444