Re: Looking for H/D patch for DOS 3.3

[dempson@actrix.gen.nz (David Empson)]

<Jim.Low@logicbbs.org> wrote:

> Although DOS 3.3 is limited to a maximum volume size of 400k, it allows up
> to 254 volumes to be accessed from one computer.

Actually, DOS 3.3 itself doesn't do this.  This is a feature of the
various hard drive patches to DOS 3.3.  The volume number was not much
use, so it was "borrowed" to select the drive.  The problem with this is
that it is not supported by all software - programs which access RWTS
directly might try to use a different volume number (e.g. 254) and would
fail to access the correct "partition".

The standard function of the volume number is to check that you haven't
put the wrong 5.25" disk into the drive.  If the volume number has been
set explicitly, then accessing a disk with a different volume number
will produce a VOLUME MISMATCH error.  If the volume number is set to
254 (the default), then any volume is accepted.

-- 
David Empson
dempson@actrix.gen.nz
Snail Mail: P.O. Box 27-103, Wellington, New Zealand