[comp.sys.ibm.pc] Device Driver or TSR?

mss2@quads.uchicago.edu (Michael S. Schiffer) (05/07/91)

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?

Mike
-- 
Michael S. Schiffer, LHN	"Well, _I_ believe in solipsism--
aq578@cleveland.freenet.edu	 but that's just one man's
Mike_Schiffer@ub.cc.umich.edu	 opinion."  -- Craig Neumeier, LHN
mss2@usite-next.uchicago.edu

mig@cunixb.cc.columbia.edu (Meir) (05/10/91)

In article <1991May7.163424.20942@midway.uchicago.edu> 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?
>
>Mike
>-- 
>Michael S. Schiffer, LHN	"Well, _I_ believe in solipsism--
>aq578@cleveland.freenet.edu	 but that's just one man's
>Mike_Schiffer@ub.cc.umich.edu	 opinion."  -- Craig Neumeier, LHN
>mss2@usite-next.uchicago.edu

In my humble opinion, a .COM can be loaded after bootup and aded later,
whereas a .SYS can only be loaded AT bootup and cannot be unloaded at all.
.SYS files usually take up less memory (they are smaller) but probably cannot
be moved to high memory, if your system is capable of that.

Hmm.  There.  I said it.  Please correct any errors or misleading statements
I might have made.

 * * * * * * *  ======================= Meir Green                 
* * * * * * * * ======================= mig@cunixb.cc.columbia.edu 
 * * * * * * *  ======================= N2JPG                      

shutton@bronze.ucs.indiana.edu (Scott K. Hutton) (05/22/91)

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.

  	
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