Illegal Operation! Fatal Exception!
Error, Error Will Robinson!
Accent on Computers to the rescue! 203-625-7575.
October 5, 2007
Your Computer’s Cache Advance
Dear Larry,
I’ve been told that it’s a good thing to restart my
computer at least once a day. But I find that after I restart, my computer
actually seems to run slower than usual. What’s up with that?
F. C.
Dear F. C.,
Windows XP and Vista computers can go days without a reboot,
but when they do restart, it’s still like a comforting shower, a morning wake-up
call if you will that cleans out the pipes and gets the computer ready for a
bright new day.
But you’re right. For a period of time following the reboot,
your computer actually runs slower than what you’re accustomed to. That first
click on America Online or Microsoft Word following a restart seems to require
an inordinate amount of time before the program starts up and is ready for use.
Yet if you close it and reopen it, it starts up lickety-split! What’s going on
here?
As you know, your computer’s hard drive is used for long term
storage—sort of like your filing cabinet—and the computer’s memory is akin to
the top of your desk where the work actually takes place. When you need to work
on a particular project, you retrieve its folder from your filing cabinet and
open it on your desk. As you need to work on other projects, other files are
recovered from the filing cabinet. The bigger your desk—i.e., the more memory
your computer has—the faster and more efficient your work. As your desk gets
overcrowded, you have to start putting files back in the filing cabinet to make
room, and all that extra effort slows you down. Same with your computer. A
restart clears the computer’s memory the same as if you cleared off your desk at
the end of a long day. The next morning, your computer has to retrieve programs
and files from the hard drive in the same way you have to go back to your filing
cabinet to start the day’s work. It’s this initial startup that you’re
perceiving as your computer running slower than usual.
Your computer’s memory is significantly faster than the hard
drive. Moreover, your computer has special memory assigned to it, memory that’s
even faster (and more expensive) than regular memory. Your computer uses this
speedy memory to cache (pronounced “cash”) data retrieved from the slower memory
and the even slower hard drive.
A cache is like a smart librarian. When a patron asks for the
latest Harry Potter book, the librarian goes looking for it on the shelves
(i.e., the hard drive) and comes back with it along with the other Harry Potter
books that were filed around it. This material is kept in a special place behind
the desk (cache memory) so that when other patrons ask for a Harry Potter book,
the librarian can retrieve it much more quickly. An efficient system indeed!
This is Larry Schneider, logging off.
