powermac 7200 hdd

Lewis G Rosenthal hfs-interest@ccs.neu.edu
Thu, 10 Aug 2000 10:39:02 -0400


michael.conry@softhome.net wrote:


> I turned the
> burner on during boot, and also had it terminated. Both these are no-no's for
> the machine (although i am consoled by others that scsi SHOULD be hot
> swappable, and termination should not damage hardware).
>
I turn my burner on and off while the system is up all the time; this
doesn't cause a problem. Obviously, if it's not on when the system
starts, my CD writer filesystem driver can't find it, so turning it on
later is useless; but if it's on at boot, I can turn it right off (my
unit has a very noisy fan!) and then on again when I want to use it.

You can have multiple terminators on the same end of the SCSI chain, and
though this is incorrect, it has no impact on hardware whatsoever; the
bus will just be physically terminated at the first terminator on that
end of the chain, so nothing after it will be recognized (unless you
have a mix of narrow and wide devices, and you use a narrow terminator
which doesn't have the sense to terminate the high byte on the cable -
this will leave data trailing through to the following devices, giving
you false termination).

In any event, I sincerely doubt that anything you did cooked any
hardware. The PRAM is probably screwed up (this is a Mac, after all), so
Command-Option-P-R during a cold restart cycle should clear it.

> What i do have is my linux box (Dell precision 410) with
> Adaptec 2940 U2W and Adaptec 2940 UW SCSI controllers on the
> motherboard. I know from reading around, that it should be possible
> to mount the disk if i can get it to work in the pc. what i don't know
> is how safe it is to do something like this (is the disk real scsi).
>
Yes, the disk is "real" SCSI. The same disks go into Macs as into any
other system running SCSI.

> Will i end up with two broken machines rather than one if i connect
> the drive to the pc controllers?!
>
No, certainly not if you don't try to write to the drive. However, you
should be aware that different controllers low level format differently,
and just because the drive was low leveled on the Mac might make it
unreadable by your 2940 card(s). I recently upgraded a server with a
29040UW to a Compaq ProLiant with onboard SCSI. I needed to completely
reformat the drives, as the Compaq couldn't even read them. So, the
bottom line with your situation is that you can't tell reliably whether
the drive is damaged unless you connect it to the same type controller
that originally formatted it (e.g., another 7200 machine).

HTH
--
Lewis
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Lewis G Rosenthal, CNA
   Rosenthal & Rosenthal
Accountants / Network Consultants
  New York / Northern Virginia
Team OS/2 / NetWare Users International
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