🚀 go-pugleaf

In article <1340@umd5>, jay@umd5 (Jay Elvove) writes:
> 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.-- 




 I will try and give a very brief reason as to what happend when the DOS
version on the drive was 3.1 (this is what it was formatted with) vs the
files on the drive (format,fdisk,chkdsk,etc..) were DOS 2.1.  One major
difference between DOS 2 and DOS 3 is that under DOS 3 the harddisk when
it is formatted it allocates the disk clusters in sizes of 2048 bytes,
unlike DOS 2 which alocates clusters in sizes of 4096 bytes. The only time
that DOS 3 will allocate 4096 byte clusters is when it is a 10meg drive.
So what you did was to format the drive with 3.x and have it set the 
cluster sizes to 2048 bytes, then you reloaded 2.x which believed that a
DOS partition wold contain clusters sized at 4096, and that is why you got
it telling you that the drive was not a DOS partition. Believe it or not
you did not destroy the disk (if there was important data on it), all you
would of have to do is to re-SYS the 3.x DOS back onto the harddisk. Instead
of installing 2.x back on the drive as the OS, what you should have done was
to replace the 2.x commands (format,fdisk,copy,chkdsk,tree,etc..) with
the appropriate 3.x commands, this would have solved your problem. One 
last thing, the reason the 2.x commands would not run was due to the fact
that all OS commands have there version included in them, and DOS checks
this when it goes to execute the commands. When it noticed that they were
not the same it halted execution and gave you a message saying ' Incorrect
DOS Version '...


 I hope this helps you out...



-- 
					Sincearley,
					Howard D. Leadmon
					Fast Computer Services
					PATH: ..cp1!tekline!howardl