info-mac@uw-beaver (12/31/84)
From: Michael Beeler <beeler@bbn-vax>
Is there a Mac disk exerciser available, either free or for purchase?
An "exerciser" does more than check that a disk's files are OK, and
does somewhat less than an engineer would need to fix hardware with
an oscilloscope and logic analyzer. A good exerciser would write and
read back all sectors, using various data patterns, ensuring that
read and write with the various patterns works, that seeking does
go to the right (at least a repeatable and distinct) place, and that
errors are few. It would display some indication (but not voluminous)
of what it's doing, and summarize its results when done.
An exerciser is helpful when the hardware and/or disks seem to be
flaky, but not failing solidly. ("Did I do something wrong, or is
it acting strange on its own?")
Of course there's a chicken and egg problem in loading an exerciser,
especially in a one-drive Mac. Since failure is presumed intermittent,
it will probably load in a few tries. It should be suspicious, however,
and checksum itself when it starts.
A pointer to an exerciser would be great; if none, any volunteers?
Thanks,
-- Mike Beeler
[Apple service centers have a MacTest program that does just what
you want. Most centers use it in a Go/NoGo mode which hides a
lot of useful diagnostic information; however, you can put it
in a mode that will allow individual disk tests to run along
with error messages. --bc]