PCOEN@DRUNIVAC.BITNET (Paul R. Coen) (04/06/91)
The Zenith versions of MS-DOS are a little different than the
"standard" MS- and PC-DOS.
On earlier versions (3.2 and 3.21 -- I haven't used any earlier ones),
the current time and date was occasionally saved to the boot sector.
That's how the disks "remembered" the approximate time of last use on
boot-up (assuming no real-time-clock).
This caused the boot sector checksum to change. Frequently. It
really freaked me out the first time I noticed it :-).
Zenith DOS 3.3+ (equivalent to Compaq 3.31) does away with this. I
guess they assume that everyone has real-time clocks in their pc's
these days. All of the new Zeniths are shipped with them, anyway. By
the way, different releases of 3.3+ leave very different amounts of
free memory (some use up to 20K of RAM more than others).
I'd assume Zenith 4.01 acts the same way as 3.3+. I have this
aversion to to DOS 4.01, so I haven't tested it extensivly.
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Brought to you from Drew University, land of the 2,000+ Zeniths.
Paul Coen -- Drew University Academic Computer Center
pcoen@drunivac.bitnet pcoen@drunivac.drew.edu