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From: boutell@brahms.udel.edu (Thomas B Boutell)
Newsgroups: comp.os.msdos.programmer
Subject: Re: TSR's - Must they be converted to .COM?
Keywords: TSR
Message-ID: <18798@brahms.udel.edu>
Date: 16 Feb 91 15:27:16 GMT
References: <3188@unccvax.uncc.edu>
Organization: University of Delaware
Lines: 14

In article <3188@unccvax.uncc.edu> cs00chs@unccvax.uncc.edu (charles spell) writes:
>
>If TSR's must be converted to .COM, why? I know that there are some .EXE
>files launch a TSR, how? Thanx in advance.

No, it is not necessary to convert TSRs to .COM. The problem is, or was, that
under DOS versions prior to 2.0, the only way to leave a TSR in memory was
a system call that would allocate only up to one 64k segment. .COM files must
fit within one 64k region, I believe. (Sorry, I can't find my DOS bible;
somebody borrowed it about a year ago. )-: Otherwise I'd give you the
interrupt number.) However, in versions of DOS from 2.0 on up, there is a
call that will allocate as many pages (16- byte increments) as you wish,
and of course nobody seriously uses versions of DOS prior to 2.0 any longer.
Nonetheless a lot of folks still use the earlier call.