Problems reading older disk on newer drive

[Paul Koning]

>>>>> "Nico" == Nico de Jong <nico at farumdata.dk> writes:

 Nico> From: "Vintage Computer Festival" <vcf at siconic.com> Subject:
 Nico> 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?

 Nico> Normally, there would not be a problem, supposing it is a 360K
 Nico> disk (I guess you are talking about 5.25" disks).  What I
 Nico> _have_ seen, is that "modern" BIOS'es have problems / cannot
 Nico> read disks formatted as 320K. Back in the old days, 5.25" disks
 Nico> came in even more flavours, like 160K (I've never seen an 80K
 Nico> 5.25" though)

 Nico> I cant find my DOS manuals right now, but there used to be a
 Nico> function in DEVICE in CONFIG.SYS where you could do some rather
 Nico> clever things with regard to disk formats.

In Linux you can get the floppy driver to read all sorts of weird
formats; check out the docs.  (I forgot where the details are.)  For
example, I found that I could have Linux read and write DEC RX50
format floppies, which are 5.25 inch floppies with 10 sectors (not the
usual 9) per track.

      paul