partition : Computer Hardware Buyers’ Glossary

Each partition used by Windows gets assigned a drive letter, usually C:, D:, E: etc. You can put other operating systems, such an Ubuntu Linux, in other partitions.

Back in the days of DOS (Disk Operating System), allowing 4 partitions per disk seemed generous. Oddly that limit is still with us in the form of a maximum of 4 primary partitions per disk. If you need more, which you nearly always do, you designate one or more of your four primary partitions as an extended partition, then split it up into many subpartitions sometimes called secondary partitions or by old timers as logical volumes.

You must mark one of your four primary partitions as active. This means it’s operating system is the one that gets booted on power up. Partitions that contain a potentially bootable OS (Operating System) are marked bootable. Sometimes the boot invokes a tiny program called a boot manager that lets you dynamically choose which OS you want to boot. In theory you can’t boot a secondary partition, but in practice you can, by using a boot manager roosting in a primary partition that redirects to the secondary one.

You can reassign drive letters and examine your partition structure in Control Panel ⇒ Administrative Tools ⇒ Computer Management ⇒ Disk Management. Windows comes with extremely primitive command line tools FDISK and DISKPART to manage partitions. Pretty well you have to decide when you first set up the machine what your partitions will be then leave the intact ever after. About the only thing you can do is convert a FAT32 partition to NTFS (New Technology File System).

However with utilities like Acronis Disk Director or PartitionMagic you can create, delete, grow, shrink, shuffle, copy, split and merge partitions.

Since you can’t easily change a Windows partition while Windows is actively using it, you might find Linux partitioning utilities easier and safer to modify Windows partitions and Windows partitioning utilities easier and safer to modify Linux partitions.

Microsoft invented a proprietary partitioning scheme called dynamic disk that the partitioning utilities will not touch. Happily the home versions of XP/Vista don’t support it, so you don’t have to worry about it if you are using a home edition.

Why Partitions?

When you buy a computer, usually it comes with only one giant C: Windows partition. Why would you want it otherwise?

One analogy is why would an icebreaker have containment cells? If an iceberg rips one open, the ship won’t sink. The others are still intact. With computers, if one partition is corrupted, the data on other partitions may still be fine. If Windows is in its own partition, when it becomes corrupt your data is still fine.

Another analogy is a house with only one giant room with all your stuff scattered all over. How would you find anything quickly when it could be anywhere? If you wanted to disinfect, you would have to disinfect the whole thing every time. You probably would not bother very often. With a computer, you might put your most active files in their own partition. You can the defrag that partition daily rapidly. If you moved files you rarely used to their own attic partition, the disk arms would not have to shuffle over them when looking for active files.

Windows is not the only operating system. If you reserve some partitions for Ubuntu/Linux, you can gradually move away from Windows.

Partition Layout

My Layout