The infinitely profitable program

Fred Cisin cisin at
Sat Jul 2 13:43:33 CDT 2016

On Sat, 2 Jul 2016, Chuck Guzis wrote:
> Of course, this only works when the program doesn't clobber its own
> initialization code (to reclaim memory), which a lot of programs did in
> those memory-limited days.
OR, as part of the program's initialization code (starting at 100h) it 
clears the areas of the TPA used for holding the data/text/etc. that the 
program is working on.

> Regardless, neither CP/M-80 nor MSDOS requires that a .COM file have any
> particular structure--even MSDOS will try to run a zero-length .com file
> without complaint.

It was difficult to convince my students that they could not rely on 
memory being zeroed out before their programs ran.
"Yes, it worked.  Good start.  But will it work RELIABLY if you run it 
again, or run it after somebody else's program runs?"

Grumpy Ol' Fred     		cisin at

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