stepping machanism of Apple Disk ][ drive (was Re: Heatkit 51/4 floppies)

From: Derek Peschel <dpeschel_at_u.washington.edu>
Date: Fri Apr 9 11:59:39 1999

> No, I have no personal conflict with an Apple employee. The problem to
> which I refer was all to common back in the '70's. Perhaps it was because
> of the way in which the various program vendors wrote their software, but
> I'd bet it's because they weren't left much choice. The detail to which I
> refer is the absence of a message like the infamous IBM-PC's ". . . Abort,
> Retry, Fail . . ." message. Once the Apple encountered a read error of some
> type, it seemed that it couldn't recover without a restart. I don't know
> the details, but I saw it every day that I was in the same room with an
> Apple that was not idle. It seemed that the only way to avoid this type of
> problem was to avoid the Apple, so, with one notable exception, that was
> what I did. These things are based on perceptions, though, not necessarily
> a sound and rigorous evaluation of the facts.

I'm glad you agree that you're basing your statements on perceptions. For
the record, I never encountered any disk errors of the kind you mentioned
(on the Apple ][+ or //e my family owned) though I did encounter other
kinds. Actually, I found lock-ups quite rare. Crashes into the machine-
language monitor happened more often. My usage was probably lighter than
yours.

I agree with the person who said that your software may have been flaky.

In my experience, disk errors fall into a couple of categories:

VERY MINOR: Hit "retry" once or twice and the error goes away.

MINOR: It is OK to choose "fail", though of course you're still taking a risk.
You can "retry" if you want, but it probably won't work.

MAJOR: Forget about retrying. Even "fail" may be dangerous since the damnge
is so widespread that your bad data will have further bad effects.

On my CP/M machine with flaky drives, very minor errors happen more than
they should (but the machine does the retrying, so the problem solves itself
after some uncomfortable noises from the drive). Minor errors happen
sometimes too; some of my disks have bad sectors in the .COM files but if I
continue after the error message, the programs run anyway. This is risky.
I may have had some major errors. I don't trust the drives enough to put
vital data on them, so I haven't lost any data yet.

On the lab PCs, which are heavily abused, when my disks get corrupted and an
error pops up, the damage is usually already done (the drive has zapped my
disk or whatever).

On my Mac (or the lab Macs), the situation is less drastic than on the PCs,
but I've occasionally had disks get munched. Hard-drive problems are always
file-system-related which is a different issue entirely.

So my point is that a change in the Apple OS may not have helped you at all;
you might have been running into serious disk errors anyway. I still
believe that some local software of yours was at fault for locking up, but
I'm also saying that in your situation the only real remedy would be to make
backups. Sometimes there is not really an easy solution to these problems.

My other point is that I wonder if an "abort/retry/fail" message is as
useful as some people say it is. I guess that depends on the type of errors
each user tends to encounter.

[Macs gave a lot of trouble]

I have noticed the paradox that one person will find a product completely
stable and someone else will see it as a pile of junk, and both people can
be right. Usually all impressions fall at the extreme end of the scale.

You are right to fault Apple's company policy; you could complain about the
design and construction of the Macs (or the inability of the software to
handle serious loads). You could even complain about the attitude of
Apple's system-software designers (on the Mac) having been influenced by the
philosophy of the Apple ][. But it is wrong to think, "The Apple ][ did
this, and the Mac does the same thing, therefore the problem is the same."
There are at least 7 years of evolution between the two machines (1977-1984)
and probably more. That doesn't leave you much ground for an "equal
footing" conparison, since the machines are NOT on equal footing.

> The bias I held against Apple products was based on the perception that lots
> of features and performance were sacrificed in favor of the rather lame
> color display, which I then felt was useful for games and other forms of
> entertainment, which I felt were out of place in the office.

Remember that the Apple was a product of its time. The Apple II and I had a
number of features that made them "super-whizbang" when the Apples were new
(one-board construction, BASIC in ROM, machine-language monitor that
replaced a front panel, "intelligent terminal" features, cassette/disk,
etc.). What was that, 1977 or 1979? The Apples were designed when the
"hobbyist computer user" mentality still prevailed. Its features didn't
evolve that cleanly into the //e, //gs, etc. -- that's partly Apple's fault
but partly just the nature of backward compatibility. Computers that were
designed _from scratch_ a few years after the Apple were much more advanced.
(I'm thinking of the BBC Micro, especially, which is very well-done. It's
not a business machine though.)

I would like to eliminate your bias or reduce it. Even if that doesn't
happen, you should at least have some facts and perpsective to go with your
bias.

-- Derek
Received on Fri Apr 09 1999 - 11:59:39 BST