1771 floppy controller questions

From: Allison <ajp166_at_bellatlantic.net>
Date: Tue Nov 20 11:56:34 2001

Intel never did a 1771 compatable chip. They did do the 8271 that was
FM only but totally incompatable with the 1771 socket.

The second source that did ship parts is SMC. The other supplier was
National Semi.

NEC Started with the D372, that was a hard/soft sector single density
controller that did find it's way into the first version of the IMSAI floppy
controller.

Allison

-----Original Message-----
From: Richard Erlacher <edick_at_idcomm.com>
To: classiccmp_at_classiccmp.org <classiccmp_at_classiccmp.org>
Date: Tuesday, November 20, 2001 12:05 PM
Subject: Re: 1771 floppy controller questions


>I don't know right offhand of any second sources, except for Intel, which
did,
>IIRC, make a 1771-equivalent/compatible for a time. They went the NEC
route
>when MFM became popular, however.
>
>WD also made a 1781 which was M2FM capable, and, as some folks will tell
you,
>THAT's a hard modulation scheme to support.
>
>As I mentioned before, it might be worthwhile to communicate with Tony
Duell
>regarding the expansion interface, as he recently admitted he'd actually
made
>the model-1 disk interface work as it was designed to work. A lot of
folks
>couldn't get reasonable reliability until they bought a third-party
enhancment
>for the floppy interface.
>
>Dick
>
>----- Original Message -----
>From: "Tothwolf" <tothwolf_at_concentric.net>
>To: <classiccmp_at_classiccmp.org>
>Sent: Tuesday, November 20, 2001 8:51 AM
>Subject: Re: 1771 floppy controller questions
>
>
>> On Tue, 20 Nov 2001, Richard Erlacher wrote:
>> > From: "Tothwolf" <tothwolf_at_concentric.net>
>> > > On Tue, 20 Nov 2001, Richard Erlacher wrote:
>> > >
>> > > > What is it that makes you believe that the 1771 s the problem?
>> > >
>> > > Well, I accidentally plugged the chip in backward when
troubleshooting the
>> > > floppy interface right after I got it. It turned out that the floppy
>> > > ribbon was bad, just due to age I guess. I don't think the chip let
out
>> > > its magic smoke, but it certainly does not work now ;)
>> >
>> > OK ... I can believe you'd reach that conclusion from what you
describe.
>I've
>> > done that on one of those "late nights" on more than one occasion.
It's
>> > reasonable to assume the part is toast, given that there are several
>supplies,
>> > each of which has been applied to the wrong pins. Too bad ...
>>
>> I'm really not too worried about it, since the 1771 does seem to be
>> available and I have the technical reference book for the expansion
>> interface. I don't think there are any unusual or proprietary chips used
>> in the expansion interface with the exception of the floppy controller.
If
>> it took out any other logic chips with it, I should be able to replace
>> those easily.
>>
>> It appears that my local vendor may have just assumed the part he has in
>> stock is a National, since I can't find any references to National ever
>> manufacturing a 1771, and the -B01 is a WD suffix.
>>
>> -Toth
>>
>>
>
Received on Tue Nov 20 2001 - 11:56:34 GMT