justpassingby

That's only one tiny visible aspect of what partitions are. Partitions are very helpful !

There's no point in having one single 250GB partition for windows XP on a 250GB HDD, in the end it will only cause problems : system files, programs and updates from windows update will end up scattered all accross the drive and separated from each other by non system files. Instead of having to search a little 30GB partition, usually the first of the disk and thus the fastest one, the hard disks heads will have to cross the whole disk to access the needed files.
+ Having a dynamic swap file, the system restore points, the temporary files from IE and your current downloads constantly writing on the disk at the same time will make quite a mess of it. Single files will end up fragmented in tiny bits that may also be scattered at both ends of the disk.
+ Once you want to clean that mess, defragmentation will take hours !

So that's where partitions come into play. A good partition scheme for a single disk system might be one small partition for only your OS and programs that start automatically with windows. One partition for other programs you don't use every day (games for example). One partition for downloads and those things that cause quick fragmentation. One last partition for backup of documents or media files. That scheme ensures that all system files which location directly impacts on system performances stay in the same small space, hence faster seek times, and that those files will also benefit from the fastest transfer rate of the disk, the first partition being on the outer part of the platter.

Another use of the partitions is when you have more than one operating system installed on one disk. Each OS will want to have its own partition.

Though partitions should not be abused of. They have to be treated as different places where different things occur. If you want to use them as compartiments, you're better using a simple folder instead.