swap file stuff from power win2000....
"Subject: POWER WIN2000 January 10, 2001 Vol. 3, No. 2
By Serdar Yegulalp, Winmag.com
SWAP FILE SECRETS THAT SAVE MEMORY
It's been a while since I've written about real nuts-and-bolts
Windows 2000 topics, so I thought I'd get back on track this issue.
During the past week I received a few tips in the mail that pertain
to the paging file, also known as the swap file or virtual memory
file, so I thought I'd make that this week's subject. (I'll return to
the topic I touched on last week -- applying profiles to users -- in
the future, and I'll also write about Active Directory.)
First, a quick recap of the basics. The swap file sits on a local
drive in your machine and is used to extend the amount of memory that
Win2K can access. There are almost inevitably going to be situations
that demand more memory of the system than is currently available.
When this happens, pieces of memory that aren't currently being used
are written to the swap file, in units called pages (hence the term
"paging"). Those bits of memory stay paged out until an application
or the system itself asks for them -- at which point they're swapped
in again, and replaced with some other bit of memory not currently in
use.
Since hard disk space is far cheaper but also far slower than hard
drive space, you can get a lot of mileage out of a good-sized swap
file -- but at the expense of speed. Many people seem to think that
all you need to do is buy a 100GB hard drive, and presto, they've got
100GB of memory! This is simply untrue, partly for reasons of speed
but also because it takes a certain amount of physical memory to
manage each block of swap space. After a while, you run into
diminishing returns if you try to stake out a mammoth swap file
(mammoth in proportion to your physical memory, that is) and use it
as a substitute for RAM by running memory-hungry programs like
Photoshop.
Setting the swap file size isn't hard. Right-click on the My Computer
icon, select Properties, click the Advanced tab, and press the
Performance Options button. The existing virtual memory size will be
listed there; to change it, click Change. You'll be able to specify
page file sizes for each volume in your system. The initial size
should be set to the "Recommended" number listed under "Total paging
file size for all drives," but the maximum size can be anything above
that you wish.
The most basic and obvious trick with the swap file: Don't put it on
the same hard drive as your operating system, if you can help it. If
you've only got one hard drive, but it has multiple partitions,
devote a partition at the front of the drive for the boot loader
files and the swap file, and nothing much else. The most efficient
thing you can do with a swap file is to put it on a drive other than
the drive holding Win2K itself. This will speed things up noticeably,
because two totally different physical drives will handle calls to
the OS and calls to the swap file.
You can place multiple swap files across multiple partitions or hard
drives, creating in effect one giant page file partitioned across
several volumes. This is a good idea if you've got space to burn on
multiple partitions, but bear in mind that the swap file cannot be
moved by the Microsoft-supplied defrag tool in Win2K (although it can
be defragmented by third-party programs.)
Note that if you're running Win2K as a server, or you're using a
system for development and testing, keep at least part of your page
file on your boot drive. In the event that Win2K crashes or issues a
blue- screen error, a copy of the system's memory gets dumped out to
that page file for debugging. This isn't an absolutely indispensable
feature, however. If you don't perform any debugging, you have no
obligation to keep a swap file on your boot drive. Put it anywhere
you choose.
When Windows NT was first introduced, computers with more than 32MB
of RAM were a rare item. Windows NT 4.0 needed 32MB or better to
perform halfway decently, and now Windows 2000 really needs 128MB or
better. (Notice a trend?) Although RAM still isn't cheap, computers
ship with more of it than ever, especially high-end servers, which
can ship with gigabytes of RAM. On higher-end systems, swap files can
get really huge. The recommended size for a swap file is around twice
your system memory size, but it can certainly be larger than that by
a few times, if you want it to be.
The controls for setting the swap file don't let you specify anything
larger than 4,096 MB or 4GB per volume, but as we mentioned before,
you can put swap files on more than one volume. If you want to make
individual swap files larger than 4GB, see Microsoft document
Q237740, "How to Overcome 4,095-MB Paging File Size Limit in Windows
2000" for details. I don't imagine there are very many people who
would be tempted to devote, say, an 8GB partition to nothing but swap
space. But then again, you never know!
The document can be found at
support.microsoft.com.
On a final note, I've had to boot a system into the Recovery Console
at least twice before, in an attempt to remove manually a paging file
to free up some room for an installation. Unfortunately, the file --
which is named PAGEFILE.SYS -- isn't visible from the Recovery
Console command line. Using ATTRIB -H doesn't reveal it either. After
some monkeying around, I broke down and did some research, and found
out that the only way to make the file visible is to copy another
file on top of it. It doesn't matter what file you copy. Once you do
that, PAGEFILE.SYS becomes visible again, and you can easily delete
it."
winmag.com
[note: my bolds]
:)
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