Hi, Char.
Thanks for the explanation. It mostly fits with what I already knew.
Back in the day when 20 MB was a giant HDD and we were still using MS-DOS
and FAT(12) and Peter Norton really wrote Norton Utilities, especially
DiskEdit, I spent many tedious hours reading my disks, byte by byte. I was
amazed at how much "erased" data was still there. Nowadays, I seldom look
that closely at my disks, but I'm confident that many of my secrets that I
"deleted" months or even years ago are still there and readable by anyone
with the right tools (Yes, they are still available and some are built right
into Win7, as I'm sure you know.) and just a small amount of skill. (Even
before MS-DOS and hard drives, I did the same things on floppies with
SuperZap and other utilities for my TRS-80s. Aah...memories! <g> )
RC
--
R. C. White, CPA
San Marcos, TX
(e-mail address removed)
Microsoft Windows MVP
Windows Live Mail 2010 (15.3.2804.0607) in Win7 Ultimate x64)
"Char Jackson" wrote in message
Hi, Bob.
That's interesting! Could you explain what those dates mean? Does this
change the practice I described? Does the page file move to a new location
on each restart?
The pagefile is just a scratch pad, a dummy file that contains
temporary data. The OS maintains pointers to that data, and those
pointers are only valid for the duration of the current Windows
session. During every system boot those pointers are cleared and the
system starts fresh. At that moment, the pagefile still contains lots
of data, (only the pointers were cleared), but it is data from a
previous Windows session and is invalid in the current session and
therefore is not used.**
The pagefile never physically moves and doesn't routinely get deleted
or recreated. It's created once, then it's reused over and over again.
If you let Windows manage the size of the pagefile, it will
dynamically grow (and theoretically shrink), as needed, and there lies
the possible rub.
When Windows needs to grow the pagefile, some number of days, weeks or
months after Windows was installed, it may find that the contiguous
disk blocks are already in use, so it will fragment the pagefile. It's
this physical fragmentation of the pagefile that can slow down access
to the contents of the pagefile.
An obvious method of preventing pagefile fragmentation is to remove
the pagefile (or temporarily move it to another drive or partition),
defragment the partition where you want the pagefile to reside, then
create a new pagefile, but this time manually set a minimum and
maximum size rather than letting Windows manage the size. Since the
pagefile will never shrink or grow, it cannot become fragmented.
Windows will alert you if the pagefile is too small, so there's little
or no danger from manually setting the size.
**If you boot a live Linux OS on your Windows system you can examine
the contents of the pagefile, looking for text strings and other
goodies. It's somewhat surprising to see what's typically stored in
there.