Problems reading older disk on newer drive

From: Nico de Jong <nico_at_farumdata.dk>
Date: Sun Dec 19 00:25:54 2004

From: "Vintage Computer Festival" <vcf_at_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
Received on Sun Dec 19 2004 - 00:25:54 GMT