Re: MFM drive gone nuts

From: MikeS <>
Date: Mon, 21 Jul 2014 15:09:11 -0400
Message-ID: <75E13B497FAA4EBD9C95E3C73355431E@310e2>
I don't want this to turn into a flame war either so, even granting that
your difficulties and injuries were actually caused by the 'twist' and not
cheap cases and wrong cables, perhaps we can still salvage something
constructive out of this:

Assuming that it is a good thing to be able to just spin one drive at a time
instead of having to spin them all together, how would you go about it using
the stock Shugart-compatible drives of the day, e.g. the common TM-100?

What is at least one of your alternate possible "solutions"?


----- Original Message ----- 
From: <>
To: <>
Sent: Monday, July 21, 2014 2:06 PM
Subject: Re: MFM drive gone nuts

On 2014-07-21 at 17:51:30, MikeS ( wrote:

> IBM's introduction of the twisted cable and splitting the interface into
> separate A/B and C/D cables made it possible to turn each of the four
> possible drive motors on and off independently,

Of course it is not the only possible "solution"

> largely avoiding the
> start-up latency by turning on early and delaying turn-off.
> SD is certainly entitled to prefer fiddling with jumpers and needlessly
> spinning unselected diskettes,

"Fiddling" takes less than a minute.

> but at the time most folks thought individual
> motor control and jumperless installation were a good idea, not at all
> "stupid" or "utterly sick"; since few people made their own cables,
> whether
> it had a twist or not wasn't usually an issue at all.
> Maybe cutting his fingers on cheap cases and being unable to find a way to
> route cables is the reason for SD's passionate disdain, but I don't think
> that's really the fault of the twist... ;-)

Yes, I detest the "PC engineering solutions" big time. There is more than
this one. And to give credit where credit is due - CBM is not free of such
"solutions" either. But my scars (yes, to these days) ARE caused also by
that twist. A common situation: this drive has to be "A" and this has to be
"B" and can't be swapped. OK - but the cable is too short to reach the upper
drive with the middle connector. Hm.. let's go and get longer cable (who
will pay for that?) OK - got the longer cable. Nice, now I can plug the
"near" connector to the upper drive but.. uh-oh the "lower" drive is close
but its connector is directly below the upper one and now covered by the
cable! OK let's route this thing around that connector... damn - even if I
strain the cable to its limit I still can't twist it so as to safely reach
the lower connector so that... f..k another scar! Band-aid in place? OK, now
how do I do this? The cable from the board to the upper drive is now
long enough and has some buffer - let's move the connector down on the
cable. Damn - they are not meant for removal.. Go and get a new one now (who
is going to pay for it? me going, forget the connector) OK - got a new one
but no proper tool. Luckily I managed to master a method for cramping them
w/o proper tool.. OK - now I have three connectors (or two and ugly holes in
the cable) and can eventually somehow "fiddle" with the ribbon to connect
those things in the order which is enforced on me.

By that time I'd have "fiddled" with 20 drives and their jumpers. Really.
And wouldn't spill any blood around either.

> People like SD may bitch and moan because IBM deviated slightly from the
> Shugart standard (or just because they're IBM), but they did indeed bring
> some order to what had been pretty chaotic.

Mike, I will not comment on the above "chaos/order" stuff even if I have a
very different opinion, but..

.. I wrote I was sorry for using the words I used and promised not to
continue in this tone. Yet first you keep repeating them more than once
(once was still acceptable) and now I "bitch and moan". Since I don't want
any useless flame here, therefore unless you stop personal jaunts this very
moment, I won't see any better place for your posts than the trash folder.


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Received on 2014-07-21 20:00:02

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