January 18, 2004
The
compression discussed in this guide is present in Windows XP Professional
only. It is not available in Windows XP Home.
Remember the old school hard
disk compression schemes back in the day? There were complicated
programs to compress your hard drive, and the CPU's were so slow that anytime
you wanted to compress or decompress a file, it would take forever.
These days, hard drives are so inexpensive that when people run out of
space, people tend to simply buy more space. Nobody really thinks
about file compression anymore. Well, why am I writing about it then?
A couple of reasons.
-
CPU's have gotten so fast that
the time to compress and decompress most files on the fly is fairly low.
-
It is free compared to buying
a new hard drive.
-
Windows XP Professional makes
compression extremely easy and almost invisible.
-
Drive compression may or may
not be for you, but take a look and see what you think.
Windows XP Professional allows
you to compress files, folders, or entire drives. It's setup so that
you don't have to change any of your work habits. When you transfer
a file to a hard drive that is compressed, it is compressed on the fly
and then written to the drive. If you read a file from a compressed
hard drive, it is decompressed on the fly and then you can work with it.
Now mind you, working with file compression is always going to be slower
than working with none compressed files since it takes CPU time to compress/decompress.
But when you think about it, many of the files we work with are already
in compressed format, for example, JPEG and MPEG files are compressed files
and decompress when you access them.
The amount that you'll be
able to compress your hard drive depends significantly on the file types
you are using. If you have tons of MP3's then compression is useless
and will waste your time since Windows XP will spend a lot of CPU time
trying to compress a file that is already compressed and can't be shrunk
any more. However, if you have a drive full of Word or Powerpoint
files, you can possibly compress those files up to 80%.
Good
candidates for compression:
-
Files that are not natively
compressed: text files, documents, programs
-
Files that are not frequently
used
Bad candidates
for compression:
-
Files that are already compressed:
MP3's, video files, ZIP files, installation programs
-
Files that are accessed frequently
-
Files that need to be read and
written to the hard drive as quickly as possible, such as video capture,
video editing.
Hardware wise, the hard drive
that you want to compress must be formatted in NTFS. Also, you should
have a relatively fast CPU so that the compression/decompression on the
fly doesn't take too much time.
If you think compression
is for you, give it a shot. Reversing it is easy.
Let's do it.
Open up "My Computer".
Right click on the hard drive you want to compress and select "Properties".
At the bottom, check the
"Compress drive to save disk space box".
Now click "Apply".
You'll be asked if you want to compress just the files in the root drive
or all the folders and sub directories. Pick the second one which
is "Apply changes to D:\, sub folders and files". Click "OK".
If you have files in the drive already, it will take some time to compress
all the files. It is probably a good idea to compress the drive while
it is still empty.
Click "OK" until the windows
are closed. When you go to "My Computer", you'll see that the drive
you just compressed is now in blue. That's just for you to remember
that it is compressed.
When you add files to the
compressed drive, the files are compressed on the fly and then written
to disk. When you read files from a compressed disk, they are read
from disk, and then decompressed on the fly. This compression/decompression
takes CPU time and may be fairly noticeable if you do a lot of file transfers.
The amount of space you gain
is dependent on the file types you are working with. Here is a small
test to see the different compression ratios I get.
In the "Test" directory,
I have various programs, documents, and random stuff. You can see
that the size of the folder is 42.5 MB. The size on disk (compressed
size) is 18.8 MB. Not bad.
In the next directory, I
have all MP3's. The size of the folder is 51.7 MB. The size
on disk (compressed size) is 51.4 MB. There is virtually no compression
in this case. This is because MP3's files are already very compressed
and there isn't much room to squeeze them down any further.
Based on this, you should
pay attention to the type of data you are going to store on this compressed
drive. If you have a ton of MP3's that you want to back up, a compressed
drive isn't a good idea, you'll simply waste compression and decompression
time. The same is true for compressed images such as large JPEG's.
Almost all other non compressed file type is fair game on a compressed
drive.
If you ever choose to decompress
the drive, all you have to do is uncheck the box "Compress drive to save
disk space". You'll have to be careful about the amount of data you
have on the drive since the decompressed size might be larger than the
disk itself.
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