(Excerpts from a message dated 10-21-99, Linda Proulx to Roy J.
Tellason.  Original topic: More Questions):

Hi Linda--

 RJT> Just clarifying things a bit here,  you're not talking about using a
 RJT> ram disk for your swap file,  are you?  That's not generally a real
 RJT> terrific idea,  if so...

LP>I was, but not a good idea, right?

    Even if it would work (Peter Knapper told you why he thinks it
wouldn't), it would be a very bad idea.  The swap file in OS/2 carries
the "overflow" from real (RAM) memory when you have over-committed it by
the workload you are carrying at the moment.  Under OS/2, the swap file
can grow to accommodate unusual loads.  (Look at how big your swap file
is after you have been Web surfing for a while with NetScape!)

    Under normal circumstances, OS/2 uses all of available real memory
before pushing anything into the swap file (SWAPPER.DAT).  A "ram disk"
uses real (non-swappable) memory, thereby reducing the amount of memory
available for useful applications, thereby requiring earlier (and more)
use of the swap file than you would otherwise need.  Even assuming that
you had enough real memory to be able to afford a ram drive big enough
to be a useful swap file under the worst possible case, the net effect
would be to reduce your system performance as compared to what it would
have been if you didn't have any ram disk and had left that memory to be
used for applications: you would be moving stuff around in real memory,
(and keeping records as to where it had been put) that otherwise
wouldn't have had to have been moved!

    Also, once the swap file has taken up all the available disk space
on that partition, your system will come to a screeching halt.  If you
have the "SWAPPATH=" string (in CONFIG.SYS) set properly, you will get a
warning to reduce the amount of memory you have committed before it is
too late (run "help swappath" from an OS/2 command line for a bare
minimum of useful information).  The system I am writing this on (a
ThinkPad 365XD) has 40MB of RAM.  In normal use, the only time anything
gets put into the swap file is when I am being frustrated by trying to
get some useful information off of the Web.  I use a swap file
initialized to 20 Megs, with the warning level set at 4 Megs.  I have
enough unused space in that partition to never have received the "low
disk space" warning.

    BTW, both the swap file and the spooler (printer) file grow and
shrink to meet current needs (the swap file shrinks very slowly, and
takes up valuable CPU cycles while it is growing or shrinking, so you
want to initialize it to a little larger than is usually needed.)  You
can get into trouble if both files are in the same partition and that
partition doesn't have enough spare space to handle both :-(.

    One more thought:  See if you can find one of the following two
books: "OS/2 Warp Unleashed" (ISBN 0-672-30545-3) or "OS/2 Warp Survival
Guide" (ISBN 0-471-06083-6).  Both deal with Warp 3, and (most likely)
both are out of print.  Either will answer a great many of your
questions, including some that you haven't thought of yet, and either
will be a good reference for later--when things go wrong :-(.  If you
decide on installing Warp 4, instead, get "Getting to Know OS/2 Warp 4"
(ISBN 0-13-842147-1).  This one is "official" (it is an IBM RedBook),
and may still be in print.  However, it discusses only those things that
are new to Warp 4, so is not a stand-alone text.  (My recommendation for
new-to-OS/2 Warp 4 users would be both the "Survival Guide" and the
Redbook.)  These books are not cheap, but (IMO) are well worth the
money.

    Regards,

        --Murray

___
 * MR/2 2.25 #120 * One printed manual is worth a thousand INF files

--- Maximus/2 2.02