Compressing?

Question

On the C: drive properties (the place you go to defragment) it says under the space useage, "Compress files to save disk space" What does this mean, what will it do if I click it?

Answer 1

It uses a lossless compression algorithm to reduce the space taken by uncompressed files. It does vastly more than remove the unused space, if you fill a text file with figure '2's, millions of them, and then compress it, it will compress to almost nothing. The driver level deals with the compression and decompression. If you push the button you'll gain some drive space.

Why don't we compress the files all the time? It adds complexity and memory usage. It has not been an issue for me, but I only compressed my archive drives. What it does to system performance depends on how fast your processor is compared to your disk, in the past it has been faster to read less data and expand it than to read the uncompressed file, I suspect that is still true because CPU performance has grown much faster than disk performance.

It won't reduce the space taken by MP3s, compressed movies, zip files and JPEG images. All of those are compressed already, as are many other formats. So your mileage may vary, as they say.

Answer 2

It will put the files through a program that makes them smaller without losing information. It's like squeesing the air out of a sponge, it just gets smaller. This means your files will take up less space on your hard drive, but your comp will run slower because the comp has to "decompress" them when it wants to use them.

Answer 3

It uses an algorithm that removes all of the blank space from the files making them smaller. This is only useful if you have a small hard drive. It slows down the use of those files. I'd just buy a bigger hard drive if it came down to that.