19 Dec
2004
19 Dec
'04
12:25 a.m.
From: "Vintage Computer Festival" <vcf(a)siconic.com>
Subject: Problems reading older disk on newer drive
I'm trying to read a disk an old double-density PC
formatted disk on a
high-density drive. I can read the directory and certain small files just
fine, but any files that are larger than a few sectors (or perhaps that
span a track) return "Sector Not Found" errors.
This is under DOS 6.22. Is there a way to get DOS to recognize that this
is a double-density disk and to perform whatever internal magic is
necessary to read the disk properly? Or is this an issue of hardware?
Normally, there would not be a problem, supposing it is a 360K disk (I guess
you are talking about 5.25" disks).
What I _have_ seen, is that "modern" BIOS'es have problems / cannot read
disks formatted as 320K. Back in the old days, 5.25" disks came in even more
flavours, like 160K (I've never seen an 80K 5.25" though)
I cant find my DOS manuals right now, but there used to be a function in
DEVICE in CONFIG.SYS where you could do some rather clever things with
regard to disk formats.
If your Octopus system had been working, you could have done a Transfer /
Input / Floppy / Analyse. This will also reveal if it is a proper MS-DOS /
PC-DOS disk, or some knock-off. There were some DOS OEM versions around
(Sord, for one), which could read and write 360K disks, but puked when
presented for 1.2M disks.
Nico