H89 disk imaging

From: Steve Thatcher <melamy_at_earthlink.net>
Date: Tue Jul 27 22:37:41 2004

besides the fact that it isn't possible to read sd disks with a controller that can only do dd..

so what does the diagnostic track read function of the 765 do (given that it is trying to read dd data)?



-----Original Message-----
From: Fred Cisin <cisin_at_xenosoft.com>
Sent: Jul 27, 2004 11:01 PM
To: "General Discussion: On-Topic and Off-Topic Posts" <cctalk_at_classiccmp.org>
Subject: Re: H89 disk imaging

On Tue, 27 Jul 2004, Dan Lanciani wrote:
> Did you ever get this going? I'm looking at a different approach, reading
> the single density disks a track at a time in double density and then doing
> the data separation in software.

A double density read with a PC FDC isn't going to work.
In fact, the NEC 765 type FDC (as is used in ALL of the PCs)
doesn't HAVE a track read; instead it has a "smart"
multi-sector read.

OTOH, if you use different hardware than a PC type FDC,
a track read of flux transitions can work.
Received on Tue Jul 27 2004 - 22:37:41 BST