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Defragmentation is something that is required from time to
time on your hard disk drive (HDD).
When a drive is empty it is easy to find space to store files
anywhere on the disk. As files are erased they leave empty
spaces between the files next to them. As you write and erase
files over time, many of these empty spaces are created. If a
file being written is bigger than the largest free space, then
it must be broken up into smaller pieces and stored in a number
of these empty spaces.
Fragmentation
This process of files being broken up and stored in a number
of smaller pieces is called fragmentation. A section of the
disk contains what is called the File Allocation Table (FAT).
It is a file system that keeps track of where all the files
are stored on the hard drive.
Eventually a condition exists where there are many fragmented
files and empty spaces scattered all over the disk. When this
happens the HDD is said to be very fragmented. The FAT has to
work very hard to manage these chopped up files.
Instead of writing and reading files that are contiguous (in
one piece), the read/write head in the HDD must move up and
down and jump all over the disk from fragment to fragment to
access the file. This takes a lot of time!
It's like Restaurant Seating
The FAT does the same thing as the person who seats you at a
restaurant.
When the restaurant is empty it's easy. There are plenty of
tables that will fit your group. They find you a table big
enough, or maybe even slightly bigger than you need and you
all sit down.
As the restaurant fills up it gets more difficult to find the
right sized table quickly. A couple of things can happen when
you show up to be seated.
- The greeter checks for space and finds a table that has
just freed up and will fit all the people in your party.
They seat you as soon as the table is emptied and made ready
for your group.
- Or they may say, 'We don't have a table big enough to
seat all of you, the wait is 25 minutes. Hang out in the in
the lounge and we'll call you when we have space.'
Let's seat your Group in Fragments
Files don't care whether they are fragmented, or located
together in a contiguous space of the disk. We know people do
care, but let's imagine the people in this restaurant don't
care either.
So instead of making you wait for a big enough table the
greeter says 'we don't have space enough for your party of
five at one table, but two of you can fit at this table, one
at that table and two more can fit at the table in the back.'
So you go and get split up at different tables. Your party has
been fragmented.
The greeter continues seating new people this way until
waiters are getting confused with which food goes with which
party, who gets the bill and so on. The whole process bogs
down and eventually grinds to a halt.
The same thing happens on your HDD. The PC spends more and
more time working with the FAT to find all the pieces of the
file you're attempting to access.
Defragmentation
Finally the restaurant manager says, 'Wait a minute,' just as
you might say when it seems to take longer and longer to read
and write files on your PC.
He says 'We are going to defragment this place.' He has
everyone get up, move to one side together with their original
group. He then figures out how many 1, 2, 3 etc. person groups
he has and how they will best fit into his tables. He reseats
each group at an optimum sized table. He now even has some
spare tables open for new guests. Everything flows along
smoothly again.
Running a defragmentation program on your PC reorganizes the
files on the HDD so that each file is located in one
contiguous space. All the free space is grouped together on
the disk as well.
How do I Defragment my Drive?
- Go to the desktop and double-click 'My Computer'.
- Right click the drive you want to defragment, (C:) in
most cases.
- In the drop down menu that appears, click 'Properties'.
- Click the 'Tools' Tab in the dialog box that appears.
- In the Tools section, select 'Defragment Now' and
defragmentation begins.
NOTE: Don't defragment a drive you want to use anytime soon.
It can easily take a couple of hours on a large, fragmented
drive. The end of the day is a great time to kick this
maintenance routine off.
P.S. You should not defragment your drive more often than
once a month. If you use your computer very little, then once
every six months is ok. |
