20 Nov
2001
20 Nov
'01
6:02 a.m.
Yeah ... I wasn't sure about that, though I know they sold their Intel-numbered
version of the WD HDC chips (1010 and 2010).
Didn't NEC also make a uPD371 that was for small tape drives? I know they made
something on that order, but I never got to play with them.
Dick
----- Original Message -----
From: "Allison" <ajp166(a)bellatlantic.net>
To: <classiccmp(a)classiccmp.org>
Sent: Tuesday, November 20, 2001 10:56 AM
Subject: Re: 1771 floppy controller questions
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(a)idcomm.com>
To: classiccmp(a)classiccmp.org <classiccmp(a)classiccmp.org>
Date: Tuesday, November 20, 2001 12:05 PM
Subject: Re: 1771 floppy controller questions
If
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(a)concentric.net>
To: <classiccmp(a)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(a)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. 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