Xerox 820 family almost complete

From: Richard Erlacher <edick_at_idcomm.com>
Date: Wed Feb 24 23:46:46 1999

Keep in mind that the 820 is from Xerox and the 802/803/806 . . . are from
Televideo. The TVI stuff is MUCH more sophisticated in design and
packaging, not to mention capabilities. The TVI models used the 1793 and
5.25" DSDD while the XEROX used the 1771 with 8" SSSD . . .

Dick
----------
> From: Don Maslin <donm_at_cts.com>
> To: Discussion re-collecting of classic computers
<classiccmp_at_u.washington.edu>
> Subject: Re: Xerox 820 family almost complete
> Date: Wednesday, February 24, 1999 1:38 PM
>
> On Wed, 24 Feb 1999, Joe wrote:
>
> > At 10:45 PM 2/23/99 -0800, George wrote:
> >
> > >Is there still a source for 5.25 inch CP/M for the Xerox 820?
> > >
> >
> > Will the CPM for the 803 or one of the other models work on the 820?
> > Does anyone know what the capability is between the various Televiedo
models?
>
> No, and for a variety of reasons, Joe. First. the 820 can only read
single
> density disks and the TeleVideo disks are all double density. Even the
> DD 820-II disk uses a single density first track, so it would choke too.
> Second, the Xerox 820 disks read all of the first side before even
> venturing into the second side, whereas, the TeleVideo machines read the
> tracks on both sides of the disk before moving the heads to the nexr
> track. Third, there are other format differences also. Different number
> of sectors per track, different skew, ...
>
> As to the Televideo disks, most of the machines can read/write another
> models disks. However, there is much less commonality between CP/M
> operating systems used. A few will interchange, others will not.
>
> - don
>
Received on Wed Feb 24 1999 - 23:46:46 GMT