Disabling swapping (was Re: Swapping)

[T. William Wells]

In article <15161 at bfmny0.UU.NET> tneff at bfmny0.UU.NET (Tom Neff) writes:
: In article <PCG.90Feb5191855 at rupert.cs.aber.ac.uk> pcg at rupert.cs.aber.ac.uk (Piercarlo Grandi) writes:
: >Well, in most timesharing applications your system _should_ swap.
: >A very rough rule of thumb is that if a resource is less than 30%
: >used it is wasted (and if over 60% used it is insufficient, because
: >queues will form on a resource that is more than 60% committed on average).
: >
: >Given that the majority of processes in a timesharing system is
: >inactive, and possibly for fiarly long times, swapping/paging is
: >healthy. If it does not occur, than you have too much memory for
: >your application mix. If you don't want it to occur because it is
: >too slow, this means that the swap bandwidth is undersized.
:
: These principles apply to large multi-user timesharing systems but not
: to supermicro workstations, which are mostly where UNIX/386 runs.
:
: On a 386/486 workstation you should shoot for very little swapping.
: Memory is fairly cheap and performance already has enough bottlenecks
: to contend with.  AT386 bus and disk controller performance will definitely
: exact a penalty if you start swapping significantly.

Damn straight. When my system swaps, even a little, I really
notice. My system is disk bound even when there is no swapping
going on. Accordingly, every time that happens, I go out and buy
more memory.

Here's a question for you gurus: I *don't* want swapping. Of any
kind. I'm up to 12Meg now and when my system swaps it is
invariably because I've just run one of my data compressions that
takes all of memory for its data. And when that happens, I don't
want to wait for the program to finish (it won't in less than
geological time; these programs don't have enough locality of data
reference!) I just want it to die.

Can swapping be disabled? Can I reclaim the 16M of disk space
being wasted on the swap partition?

My system is a Microport SysV/386 3.0e and I have kernel source.

I've directed this discussion to comp.unix.wizards because I
suspect that most people who would have something useful to
contribute would be there.

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Bill                    { uunet | novavax | ankh } !twwells!bill
bill at twwells.com