Path: utzoo!attcan!uunet!lll-winken!lll-tis!helios.ee.lbl.gov!pasteur!ucbvax!RADC-TOPS20.ARPA!GUBBINS
From: GUBBINS@RADC-TOPS20.ARPA (Gern)
Newsgroups: comp.sys.zenith.z100
Subject: Z-100 1.2MB AT format disks
Message-ID: <12404360146.9.GUBBINS@RADC-TOPS20.ARPA>
Date: 6 Jun 88 21:05:22 GMT
Sender: daemon@ucbvax.BERKELEY.EDU
Organization: The Internet
Lines: 19

Pat Swayne's 1.2MB disk read patch is on page 53 of the JUN-86 issue
of REMark Magazine.    The PC-AT 1.2MB drive is a 5.25" version of
the DSDD 8" drive (both electronically and timming), and so (with a
special cable) can be directly connected to the Z-100 8" connection
on the controller.    The problem is in the formats used by the software.
The Z-100 formats (and expects) the standard 8" (IBM) disk format of
77 tracks/side at 8 sectors of 1024 bytes.   The AT high density format
is 80 tracks/side at 15 sectors of 512 bytes.  The Z-100 BIOS is table
driven and so the patch simply finds and alters the table entries to
either the standard Z-100 or AT type format.   The FORMAT command would
also have to be altered to format to the AT type on a Z-100 (no
patches yet known).   After running the patch, you can read and write
to the AT type format (but not the Z-100 type), and running the counter-
patch program, revert back to the Z-100 format.

I do not have the programs typed in yet, if anyone has them, please
post!

Gern
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