Newsgroups: comp.sys.ibm.pc
Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!think.com!zaphod.mps.ohio-state.edu!sol.ctr.columbia.edu!bronze!shutton
From: shutton@bronze.ucs.indiana.edu (Scott K. Hutton)
Subject: Re: Device Driver or TSR?
Message-ID: <1991May21.190901.5035@bronze.ucs.indiana.edu>
Reply-To: mss2@quads.uchicago.edu
Organization: Indiana University, University Computing Services
Date: Tue, 21 May 91 19:09:01 GMT
Lines: 30

mss2@quads.uchicago.edu (Michael S. Schiffer) writes:
>Many device driver and similar programs seem to come in two forms:
>A TSR .com file and a .sys device driver to be placed in config.sys.
>I was wondering if someone would explain to me why they come in two
>flavors, and which is preferable.  (Or if one is preferable for one use,
>and one for another, please elaborate.)
>
>And as long as I'm asking Naive Beginner Questions (tm), do people
>generally define their hard drives as many, few, or one logical drive,
>and why?

SYS files are configured as devices-- you can write and/or read to
them as such.  SYS files are not normally unloadable, and can only be
placed in memory at boot-up.

COM files are executables (usually generated by the DEBUG utility).
Some COM files are able to <T>erminate and <S>tay <R>esident in
memory, to be called up for execution by some external event such as
an interrupt.  Some of the TSRs you'll be familier with are those
which ride on the keyboard interrupt and are sensitive to special
keystrokes like SHIFT-SHIFT or CTRL-ALT.  Others are sensitive to
input to a device (e.g., print spoolers).

Hope that helps.

  	
 _____________________________________________________________________________
  Scott K. Hutton, KA9WTR           Internet:  SHutton@UCS.Indiana.edu
  UCS Support Services                         SHutton@Bronze.UCS.Indiana.edu
  Indiana University                  Bitnet:  SHutton@IUIS, SHutton@IUBACS