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DADDY BOB'S COMPUTER Q & A
January 7, 2007
Q. I have a very large file on my computer
called "pagefile.sys". What is this file and
can I delete it?
A. In
computer operating systems, memory is
allocated to programs by a rather
complicated algorithm that divides the
memory into small portions called pages. In
current computers, most pages are either
1024 or 2048 bytes in size.
A
computer uses two main types of memory. One
is RAM, short for Random Access
Memory. RAM allows the stored data to be
accessed in any order, that is, randomly and
not just in sequence. RAM is relative fast,
but volatile, meaning that it looses all
stored data when the power is removed.
RAM is
considered the main memory or the working
area used for loading, displaying and
running applications and data. RAM is
usually in the form of memory sticks or
modules generally referred to as Single
Inline Memory Modules (SIMMs) or Dual Inline
Memory Modules (DIMMs).
The
other type of memory is magnetic (the hard
drive) which is permanent but relative slow.
In order for a program or application to
work, it has to be located in the RAM
memory. If the RAM memory is not large
enough to facilitate the entire program, or
what it needs to work, a file is created on
the hard drive and used as "virtual" memory
to augment the RAM. This file is the Page
File and named pagefile.sys.
The operating system has to
keep track of what is in use and what will
not be used or has not been used for some
time. What is in use is stored in the RAM,
and what won't fit is relocated to the page
file. Then, when the operating system deems
fit, or when a program requests a page that
is in the page file, the operating system
swaps out a page to disk, and brings another
page into memory. Earlier versions of
Windows called the page file the "swap" file
for obvious reasons.
Using
the page file allows you to actually use
more memory than your computer physically
has. The main disadvantage of this
arrangement is that since the page file in
on the hard drive, it is very slow compared
to RAM. This is why increasing the
computer's RAM can sometimes greatly enhance
its performance.
The size of the page file is
based on how much RAM is installed in the
computer. By default, XP creates a page file
which is 1.5 times the amount of installed
RAM and places it on the hard drive where XP
is installed, usually in the C:\ drive.
As
for deleting this page file, the temptation
is always great when you have a RAM packed
machine of several gigabytes or more. It is
a system protected file so deleting it is
not easy, but even if you could, don't do
it. By design, some parts of in Windows XP
require a page file to exist, even if it is
never used to swap pages. Eliminating the
page file will most assuredly present you
with out of memory type errors for no
apparent reasons.
By
default, Windows is set to automatically
control the page file size, and it is a good
idea to keep this setting. Here's where this
setting is located:
Right
Click My Computer, and click the Advanced
tab. In the section called Performance,
click the Settings button, then the Advanced
tab. In the Virtual Memory section,
click the Change button. A dialog similar to
this should be displayed. Yours may vary
depending on your hardware.
To allow Windows to handle the page file
size as is recommended, click the dot in
front of "System managed size" if it is not
already selected, and click the Set button,
then OK out.
As a
final note, there are malware programs that
will turn this page file off and prevent you
from turning it back on. If you should
encounter not being able to allow the system
to manage the page file, it is a good
likelihood that you are infected with one of
these malware programs.
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