Floppy Disc Capacities [was Pictures of My Machine Room (So Far)] - test-drb@ccmp.vtda.org

18 Jun 2007

...
  Date: Mon, 18 Jun 2007 22:08:44 -0700
 From: "Chuck Guzis" <cclist at sydex.com>
 Subject: Re: Floppy Disc Capacities [was Pictures of My Machine Room
        (So     Far)]
 To: "General Discussion: On-Topic and Off-Topic Posts"
        <cctalk at classiccmp.org>
 Message-ID: <4677026C.408.5FBF8B36 at cclist.sydex.com>
 Content-Type: text/plain; charset=US-ASCII
 On 18 Jun 2007 at 21:36, Wayne Smith wrote:
  My first iteration of Windows 95 was on 3.5 inch
floppy   diskettes.  At
  some point, I wanted to make a backup copy on
diskettes but couldn't
 because the file sizes of the Windows distribution floppies was
 1.8-1.9MB each.  At the time I thought it was some sort of copy
 protection.  I assume they must have been able to format   the discs for a
  higher capacity - close to 2MB.
 Does anyone know how? 
 Uh-yup.  Microsoft used a format they called DMF, for about 1.68MB--
 21 sectors per track, with a very small gap between sectors.  IBM had
 a rather more complicated format called XDF, which used one 8K, one
 2K, one 1K and one 512 byte sector on a track for about 1.84MB.
 Handling the DMF format wasn't too hard, although if your drive was
 marginal, it could create problems.  The XDF actually used larger gap
 sizes, but required special drivers.  There was also an XDF format
 for 5.25 HD that was about 1.6MB and one for 3.5 DSED which was about
 3.84MB.
 If you want to pack an amazing amount of data on a 3.5" DSHD, I
 believe that there's a program for the Catweasel that will give you
 something close to 4MB using a few tricks.
 Cheers,
 Chuck
  
Cool.  Great info.  Thanks!
-W