Re: System Hard Drive RPMs
- From: "Peter Larsen" <plarsen@xxxxxxxxxxxx>
- Date: Tue, 23 Oct 2007 02:16:05 +0200
Scott Dorsey wrote:
Nope. The virtual memory space is always 4GB (or whatever it is on
your os). No "available" or not about it. How much of it is mapped
onto physical resources is another matter.
That's not how it is.
That's the "address space" of the machine.
Lets limit this to 32 bit Windows. Each process gets a 4 GB address space,
unless a special switch is enabled when booting two of those are for the OS
and the other two for the application.
But plenty of it is not mapped to a physical resource,
You gotta see it the other way around, physical memory - be it disk or ram,
there is - grossly oversimplified and generalized - no way for the
application to know whether it is ram or disk - is mapped to the address
space of the process when it gets its timeslice. The OS will generally
prefer phýsical ram, but there is no guarantee - consequently it is possible
for a program that allocates too much of its own cache to end up getting
that cache paged to disk.
and if you attempt to use so much of
it that physical resources are exhausted, you will get a
"PROCESS ABEND-- OUT OF MEMORY" or similar error message.
What is technically referred to as A problem can indeed occur.
You're falsely extrapolating how a system with inadequate physical
memory gets by into how a modern system will behave. Windows isn't
perfecy, but I think it's a lot cleverr than you give it credit for
:-)
No, I'm explaining how virtual memory works. And the PROBLEM is that
Windows is very clever. If you are running realtime applications,
you don't WANT a lot of that cleverness going on.
Yes. Fix the pagefile. If possible on your windows version: fix the cache
size, check the gadgets on the sysinternals pages, now at microsoft.com. Get
pagefile defrag while you are there, it is a must have, but may have been
integrated in Bloatware V 6. ie. Vista, an OS that is designed to actually
use the power of a modern machine and with 5387254.78 new ways of knowing
better than the owner/operator. It seems to be very much designed with
running Office 2007 in mind and not very much with people who need to do
something to humonguous amounts of audio and video data. Reckon I'll have to
read a book or two to come to grips with it.
No matter HOW much physical resource is available, developers and
users will find they want to do something that requires more.
Yes. But investigate border conditions prior to encountering them in a
productivity situation. Filling the OS disk to the brink with temp files is
not advisable, always have space free. I killed a NT4 server - terminal
overwriting of system files - in MCSE training, 4 zipping processes running
concurrently and making large tempfiles on the OS partition did it, the OS
did not react to the disk full situation in time.
In my experience the OS should have a pagefile because it will become too
timid with ram allocation if it hasn't got one that it can dump a few .dll's
to, but it may not be relevant to make it as large as Windows suggests.
--scott
Kind regards
Peter Larsen
.
- References:
- Re: System Hard Drive RPMs
- From: Laurence Payne
- Re: System Hard Drive RPMs
- From: Scott Dorsey
- Re: System Hard Drive RPMs
- From: Laurence Payne
- Re: System Hard Drive RPMs
- From: Scott Dorsey
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