Path: utzoo!utgpu!water!watmath!clyde!feg
From: feg@clyde.ATT.COM (Forrest Gehrke)
Newsgroups: comp.sys.ibm.pc
Subject: Re: DOS 4.0 Compatibility Issues (LONG)
Summary: Not Norton's problem; it's Microsoft's.
Message-ID: <32382@clyde.ATT.COM>
Date: 1 Sep 88 14:59:28 GMT
References: <2644@ukecc.engr.uky.edu>
Distribution: na
Organization: AT&T Bell Labs, Whippany NJ
Lines: 33

In article <2644@ukecc.engr.uky.edu>, kenny@engr.uky.edu (Kenny Pitt) writes:
|> I have a bone to pick with Peter Norton.  I decided to do it here since I am
|> using this as an opportunity to let you all know about some of the software
|> incompatibilities I have discovered with DOS 4.0.
|> 
|>     [quoted from Norton's book].......  Any DOS function that is not
|>     publicly advertised as an available service cannot be relied upon
|>     to be usable in future revisions of DOS.
|> 
|> Now we all know that Peter Norton knows about as much about the IBM PC as
|> anyone and has provided us with an invaluable tool in his famous Norton
|> Utilities.  Unfortunately, this is one time where Peter didn't practice what
|> he preaches.  Several of his Norton Utilities make calls to the undocumented
|> DOS function 1fh in order to obtain some information about disk format.  In
|> DOS 4.0, the table returned by this function has changed from the format in
|> the DOS 2.x and 3.x versions.  This means that all programs that rely on this
|> table for information are now incompatible with DOS 4.0.

This is problem for any program which must read disk information.  There
are no other means than these undocumented functions, except to look at
the disk boot record and the FAT itself.  If what you have described is
the case, these latter methods will fail also, because the formats of
the boot record and FAT must also have been changed.

Norton describes the organization of the boot record and FAT in his
book.  With DEBUG you could look at these sectors to see how these 
have been changed.  I am sure this information would be of interest.

Presumably, then the fault  must be laid at Microsoft's door for 
not having come up with a scheme which is downwardly compatible (or 
having failed to think big enough back at dos 2.0).

   Forrest Gehrke