Date: Thu, 7 Sep 1995 13:11:04 -0700 (PDT) From: Jake Hamby <jehamby@lightside.com> To: "Don's FList drop" <freelist@elf.kendall.mdcc.edu> Cc: Poul-Henning Kamp <phk@critter.tfs.com>, "Christoph P. Kukulies" <kuku@gilberto.physik.rwth-aachen.de>, freebsd-hackers@freefall.freebsd.org Subject: Re: higher density diskettes Message-ID: <Pine.AUX.3.91.950907125330.15927A-100000@covina.lightside.com> In-Reply-To: <Pine.BSF.3.91.950907150829.10158A-100000@elf.kendall.mdcc.edu>
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On Thu, 7 Sep 1995, Don's FList drop wrote: > > On Thu, 7 Sep 1995, Poul-Henning Kamp wrote: > > > > Microsoft has switched to using so called DMF format > > > (Distribution Media Format - 1,716,224 bytes 1.63 MB) on > > > diskettes for the WIN95 distrubution disks. > > > > This is very interesting. If it works for them, we can do that too. > > The changes to the floppy-build procedure is rather few, but I still > > suggest we hang in there until we hear how much trouble MS has with it... > > It's actually not a terribly new idea. I've seen utilities to format > diskettes at slightly higher capacities for almost as long as I've had a > PC. I remember 420k 5.25 floppy formatters....... This is a great idea, with one possible problem. Formerly, I used a program called 2M to format disks to higher capacity but it required a TSR in order to be able to READ the disks you had formatted. That meant that I couldn't read the disks I had written on other people's computers! The designer thoughtfully wrote a custom boot sector which allowed you to boot from one of these disks and it would install the TSR virus-like into the system so you could read the disk! Before that I used a different program which required a device driver to read its disks. The problem is that most BIOS's will not support these extra-high density disks in DOS without some special patch. Curiously the 2M TSR could not read the disks formatted by the other program, and vice versa! Fortunately, Microsoft's DMF format (which has been around for at least a year, and has been used in the floppy version of Microsoft Office, as well as other large programs) seems to be readable on all systems without any BIOS patch. > The primary difficulty is that of being unable to use traditional disk > copying utilities (ie ones that don't do verbatim sector copies) to > duplicate the disks. An Inforworld correspondant pointed out with some > humor that MS continues to distribute instructions in their install > literature asking users to make backups before installing even though > this new thing prevented users from doing so. <grin> Just like Microsoft.. <g> The primary difficulty with distributing FreeBSD in this format is that people are NOT going to be able to create boot disks from, for example a Sun (although recent Solaris patches have fixed this so people can install Microsoft Office from DMF into Sun's Windows emulator, WABI). Even with an operating system capable of reading/writing this format, you still have to actually FORMAT the disk first, and as mentioned earlier, this requires a _DOS_ formatter which may or may not be a problem. And there's always the chance that a particular brand of computer might not support DMF. My advice is: if putting the FreeBSD boot disk in DMF format shrinks it from two floppies to one, then do it, but have a non-DMF two-disk version available as a backup!!! > If anyone can do a back serch of their old PC Weeks, Jim Louderbach > included a location of a freeware program that would create the larger > disk format. Or perhaps grep the simtel index for 'format'.... > I think I got 2M from a BBS, it might be difficult to grep for it because the name is so short. I'm sure there are others, but be advised that there are MANY variations on this format. Best to find one that is truly DMF compatible since Microsoft seems to have the most luck with that format. ---Jake Hamby jehamby@lightside.com
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