28 Jun
2001
28 Jun
'01
1:29 p.m.
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(a)hotmail.com>
To: <classiccmp(a)classiccmp.org>
Sent: Thursday, June 28, 2001 11:54 AM
Subject: Re: Xerox 820
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.
>
> _________________________________________________________________
> Get your FREE download of MSN Explorer at http://explorer.msn.com
>
>
>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