🚀 go-pugleaf

I really blew it.  I tried to do a friend a favor after the store where
he purchased a Leading Edge Model D w/hard disk put the wrong version
of MS-DOS on his machine.  All of his utilities were set to run with
version 2.11; the store installed MS-DOS version 3.1 which made it
impossible to run many of these programs.  I used the SYS command to
install the earlier level over the more recent release, which resulted
in (according to the store) the complete loss of all data on the hard disk.
The symptoms I witnessed were the following: 1) certain interrupt vectors
were being zeroed out???, 2) the FDISK command did not recognize the
hard disk as belonging to DOS (non-DOS partition, or some such message), 3)
DOS (as a result) would not acknowledge the fact that the hard disk was
even attached to the system.  Does anyone know why installing an earlier
version of DOS over a more recent (and, presumably larger) version should
cause any problems?  I can understand why the converse might be true, since
the later levels of DOS tend to grow by leaps and bounds.  Please respond
via mail.  Thanks very much.-- 
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Jay Elvove       jay@umd5.umd.edu
c/o Systems, Computer Science Center, U. of MD.