Prefetch and its relation to Task Scheduler

[Michael]

WinXP Home. What exactly is the C:\WINDOWS\Prefetch directory and the pf
files held there and what function do they have. All these files are old and
dated to a time before I disabled the Task Scheduler service. Do I need
these files and do I really need Task Scheduler running in the background
even if I do not have any scheduled tasks. Thanks.

 

[Rick \Nutcase\ Rogers]

Hi Michael,

They (the *.pf files) are a cache of files the system has reason to believe
it may need. Like any cache, the design is to make retrieval of the item
faster. The prefetch files can be removed if desired. You can disable the
Task Scheduler service as well, but be aware that if any routine in the
system has a dependency on this service, it will fail. As it takes almost no
resources to load, disabling it will likely have little affect on your
system's efficiency.

--
Best of Luck,

Rick Rogers, aka "Nutcase" - Microsoft MVP

Associate Expert - WindowsXP Expert Zone

Windows help - www.rickrogers.org

 

[Rock]

WinXP Home. What exactly is the C:\WINDOWS\Prefetch directory and the pf
files held there and what function do they have. All these files are old and
dated to a time before I disabled the Task Scheduler service. Do I need
these files and do I really need Task Scheduler running in the background
even if I do not have any scheduled tasks. Thanks.

See this link for some information on prefetch and it's use:
http://msdn.microsoft.com/library/d..._0eecebea-e58b-4c95-8520-9b1dc2bc6196.xml.asp

Here is a "tiny" version of that url: http://tinyurl.com/3uqyp

 

[Alex Nichol]

WinXP Home. What exactly is the C:\WINDOWS\Prefetch directory and the pf
files held there and what function do they have. All these files are old and
dated to a time before I disabled the Task Scheduler service. Do I need
these files and do I really need Task Scheduler running in the background
even if I do not have any scheduled tasks. Thanks.

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.

So do NOT disable task scheduler The optimisation then comes in every
three days, and 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.