Date   : Sun, 01 May 1988 09:10:50 GMT
From   : portal!cup.portal.com!jwright@uunet.uu.net
Subject: TPA requirements

The first CP/M programs, WordStar, dBASEII, etc. were written to run
in 48k or less so that they would run under MP/M which only allowed
that much memory for the transient .COM file.  Some later offerings
(PerfectCalc comes to mind) were written without this consideration.
These seem to expect 56k or so of TPA.  Much the pity, they don't check
to see if they have enough memory, they simply run and then bomb out
In practice, there is no way to tell (unless, of course, you read the
manual) except to try it.  If you would write a CP/M program and limit
it to 48k of memory use, you can be fairly sure it will run everywhere.
Z-System (ZCPR3+, et. al.) provides means for the .COM to determine
dynamically how much memory is available and to size itself accordingly.