Troubleshooting an IBM 5155 - (portable personal computer)

From: Tom Jennings <>
Date: Tue Jan 18 19:17:20 2005

On Mon, 17 Jan 2005, Tony Duell wrote:

>>> b) There is no useful signal from the side-1 head (this is the head on
>>> the top surface of the disk, of course),
>> For all the possibilities you state, likely cause.
> Sure, _IF_ that would cause the MS-DOS format program to assume the disk
> is single-sided.

We're getting into the area where my memory is doing the
remembering and not me, but I believe that with 5.25" diskettes,
you the human tell the formatter, with the appropriate command
line switch, which sidedness you want to use. If you in fact have
SS drives physically installed, you will get a FORMAT ERROR iff
you use /V (note the formal iff).

That advice, plus $3.50, buys you coffee at Starbucks. Easy to
check but I ain't got me no peecee no more.

>> Likewise! On my very first own computer, SWTPC 6800, I debugged
>> the fact I miswired the (20mA loop) tty using a Tek 555 scope to
> Yo uhad a 555? I managed (then) without a 'scope at all. Now my 555 is
> alongside me with a good selection of plug-ins. I don't use it all that
> much -- I find a logic analyser to be a more useful instrument, but anyway.

Oh! No, I did it at work! It wasn't a 555, it was a 564, the
storage job. Sorry for the confusion doubled. I do own a 564 now,
since they are umm let's say heavily discounted today.

>> Now I buy only laptops, nearly impossible to even open them, and
> Yuck! I'd not want a computer I couldn't easily pull apart, and I'd not
> want one without proper expansion (not Useless Serial Botch). Heck, I've
> even played about with the processor bus in HP handheld calculators...

My laptop is purely a software machine. In fact, it's purely a
*text* machine; I run freeBSD, everything stored as ASCII, perl
scripts to drive anything complex. Portable from machine to
machine. I have things that are purely hardware too.

> The stuff I want is rarely built in, because no sane person would want it...

Sane people? Who needs them? From them we get malls, fast food
insurance forms, and warfare.
Received on Tue Jan 18 2005 - 19:17:20 GMT

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