"Windows\Prefetch" directory

[Dave]

Hi

Does anyone know what the following directory is usered
for on Windows XP?

"C:\WINDOWS\PREFETCH"

The directory contains a list of recently used programs
with their .EXE extention followed by a number then a .PF
extention. For example:

CMD.EXE-123456.PF

I'm wondering if this is a genuine windows directory or
one that was put there by a trojan/virus.

Thanks in advance for any assistance on this.

Dave

 

[Wesley Vogel]

Dave;

It' legitimate.

Optimizing Startup Times by Using Defragmentation Tools
[[Windows XP Professional monitors the files that are used when the computer
starts and when you start applications. By monitoring these files, Windows
XP Professional can prefetch them. Prefetching data is the process whereby
data that is expected to be requested is read ahead into the cache.
Prefetching boot files and applications decreases the time needed to start
Windows XP Professional and start applications.

Prefetching is further improved if the files are located next to each other
on the outer edge of the disk. Windows XP Professional optimizes the
location of boot files and applications when the computer is idle. The
optimization occurs in the background and lasts only a minute or two; you
might hear the hard disk being accessed when optimization occurs. After the
initial optimization takes place, subsequent optimization occurs, at most,
every three days.

When you run the Disk Defragmenter tools that are included with Windows XP
Professional, they can perform any optimization updates that are scheduled
to take place during the next idle period. The Disk Defragmenter tools do
not disturb the existing layout of optimized boot files and applications.

Note
Computers running Windows XP Home Edition also prefetch and optimize boot
files and applications.]]

 

[Dave]

Wes,

Thank you for your in depth description of the prefetch
directory, it was of great use.

Cheers
Dave

-----Original Message-----
Dave;

It' legitimate.

Optimizing Startup Times by Using Defragmentation Tools
[[Windows XP Professional monitors the files that are used when the computer
starts and when you start applications. By monitoring these files, Windows
XP Professional can prefetch them. Prefetching data is the process whereby
data that is expected to be requested is read ahead into the cache.
Prefetching boot files and applications decreases the time needed to start
Windows XP Professional and start applications.

Prefetching is further improved if the files are located next to each other
on the outer edge of the disk. Windows XP Professional optimizes the
location of boot files and applications when the computer is idle. The
optimization occurs in the background and lasts only a minute or two; you
might hear the hard disk being accessed when optimization occurs. After the
initial optimization takes place, subsequent optimization occurs, at most,
every three days.

When you run the Disk Defragmenter tools that are included with Windows XP
Professional, they can perform any optimization updates that are scheduled
to take place during the next idle period. The Disk Defragmenter tools do
not disturb the existing layout of optimized boot files and applications.

Note
Computers running Windows XP Home Edition also prefetch and optimize boot
files and applications.]]

--
Hope this helps. Let us know.
Wes

In Dave <[email protected]> hunted and pecked:

Hi

Does anyone know what the following directory is usered
for on Windows XP?

"C:\WINDOWS\PREFETCH"

The directory contains a list of recently used programs
with their .EXE extention followed by a number then a .PF
extention. For example:

CMD.EXE-123456.PF

I'm wondering if this is a genuine windows directory or
one that was put there by a trojan/virus.

Thanks in advance for any assistance on this.

Dave

.

 

[Wesley Vogel]

Dave;

You bet.
Copy and Paste is a wonderful thing.

So is Search. ;o)

--
Hope this helps. Let us know.
Wes

In

Wes,

Thank you for your in depth description of the prefetch
directory, it was of great use.

Cheers
Dave

-----Original Message-----
Dave;

It' legitimate.

Optimizing Startup Times by Using Defragmentation Tools
[[Windows XP Professional monitors the files that are used when the
computer starts and when you start applications. By monitoring these
files, Windows XP Professional can prefetch them. Prefetching data
is the process whereby data that is expected to be requested is read
ahead into the cache. Prefetching boot files and applications
decreases the time needed to start Windows XP Professional and start
applications.

Prefetching is further improved if the files are located next to
each other on the outer edge of the disk. Windows XP Professional
optimizes the location of boot files and applications when the
computer is idle. The optimization occurs in the background and
lasts only a minute or two; you might hear the hard disk being
accessed when optimization occurs. After the initial optimization
takes place, subsequent optimization occurs, at most, every three
days.

When you run the Disk Defragmenter tools that are included with
Windows XP Professional, they can perform any optimization updates
that are scheduled to take place during the next idle period. The
Disk Defragmenter tools do not disturb the existing layout of
optimized boot files and applications.

Note
Computers running Windows XP Home Edition also prefetch and optimize
boot files and applications.]]

--
Hope this helps. Let us know.
Wes

In Dave <[email protected]> hunted and pecked:

Hi

Does anyone know what the following directory is usered
for on Windows XP?

"C:\WINDOWS\PREFETCH"

The directory contains a list of recently used programs
with their .EXE extention followed by a number then a .PF
extention. For example:

CMD.EXE-123456.PF

I'm wondering if this is a genuine windows directory or
one that was put there by a trojan/virus.

Thanks in advance for any assistance on this.

Dave

.

 

[Alex Nichol]

Does anyone know what the following directory is usered
for on Windows XP?

"C:\WINDOWS\PREFETCH"

When a program is loaded, a record is put, or updated, in the
corresponding file in Prefetch, detailing what files it uses, in what
order. Boot of the system has such a record, too

From that two things happen.

One - when a load is started in future, the system arranges to get the
expected files into RAM straight away, without waiting to be asked, and

Two - every three days, a sort of semi-defrag run is done in a quiet
period, which arranges files so that such sets will be able to load as a
smooth stream without need to hunt around the disk for them. The boot
side of this speeds load of the system: the Bootvis program does a
preliminary optimisation of their layout, but it will take place, and
better, through the automatic process. The details of the best layout
are kept in the layout,inf file which is checked and updated each time
this optimisation runs, for the best overall performance. This can be
used for optimisation alternatively by some third party defrag programs,
eg Perfect Disk Pro

Two points:

Contrary to what is said , it is *not* necessary to empty prefetch.
Any program that does not get used for a week will have its file dropped
out anyway: ones that are rarely used get low priority in optimisation

and:
The optimisation at regular intervals is initiated by task scheduler so
you need to have it running for this to work (also for System Restore
to make its daily restore point) even though no scheduled task appears
if you look in control Panel - Scheduled tasks. Check the Advanced menu
there, and if it says 'Start Using. . ' click that so it says 'Stop
using . . .' It then looks for a time when the system is quiescent (I
think it waits for 15 mins of no disk activity, but am not sure on
that). This is one reason for the query 'my hard disk goes chattering
when I am doing nothing'; the other being search engine indexing.