At 12:35 PM 6/28/01 -0600, you wrote:
>I'm not sure where they are, at the moment, but I have a couple of
>daughterboards that fit via cable into the 1771 socket but allow the use of a
>179x device for double-density recording. I'm not at all sure that the
>2.5 MHz
>Z80 can manage the data transfer rate for DD 8" diskettes, but it's possible
>that there's an associated update for the CPU that makes it
>possible. OTOH, DS
>5-1/4" diskettes benefit greatly from DD recording. Unfortunately, I haven't
>seen the one-page doc that goes with those boards in a long time, and I've
>never
>seen the software update to support DD diskettes.
>
>Dick
FWIW Those devices are probably used to update an 820 to an 820-II.
I'm not sure about the 820 but the 820-II supported both 5 1/4" and 8"
disks. The 820-II could format the 8" disks as SS-SD, SS-DD, DS-SD or
DS-DD. But the 820 only supported single density disk (SS or DS). On the
820-II the DD 5 1/4" disks held 155k or 322k (single or double sided) and
the 8" DD disks held 482k or 980k (single or double sided).
Joe
>----- Original Message -----
>From: "Steve Robertson" <steven_j_robertson_at_hotmail.com>
>To: <classiccmp_at_classiccmp.org>
>Sent: Thursday, June 28, 2001 11:54 AM
>Subject: Re: Xerox 820
>
>
> > >Thousands of these were sold as bare boards with limited doc's. I
> > >frequently ran into folks using them, yet never saw one in the original
> > >Xerox enclosure. The Xerox box was just too expensive. Once they were no
> > >longer a major product, they were surplussed out as bare boards. I
> think it
> > >was through BG Micro.
> > >
> >
> > I got several of the bare boards in a lot of XEROX stuff that bought
> several
> > years ago. Haven't looked in those boxes in a long time but if I recall
> > correctly, the DOCS were *minimal*.
> >
> > If someone really wanted them, I'd be willing to part with the boards.
> >
> >
> > SteveRob
> >
> >
> >
> > >----- Original Message ----- From: "Rich Beaudry" To: Sent: Thursday, June
> > >28, 2001 9:12 AM Subject: Xerox 820
> > >
> > >
> > > > Hello all, > > Recently I acquired a Xerox 820, but as a single board,
> > >w/ power supply. I > also received many docs (including a tech manual with
> > >Monitor listings and > schematics). I know originally these were
> > >"all-in-one" computers, but many > appear at ham fests in exactly the same
> > >shape as mine -- as a single board > computer.
> >
> > _________________________________________________________________
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> >
> >
Received on Thu Jun 28 2001 - 20:29:53 BST