Preparation
With the big hard disks that are available, it is tempting to just format the whole disk as one massive drive. Doing this, however, can waste an enormous amount of space due the way the system stores data. This is due to something known as clusters.
A cluster is used by the system to (among other things), record the disk address of the file. Large disks need large addresses and these take up space. So what does this mean in real terms? You can try a little experiment . . . .
Experiment
Run a DOS window (Start . . . Programs . . . DOS). You will most likely see C:\WINDOWS\> as your prompt. Type in DIR. Make a note of the number of bytes free (write it down, as it will be a BIG number!).
Now open Notepad and type a letter "A." Now save the file (call it A.TXT and save it within C:\WINDOWS). Now this file only contains the letter "A," which the computer will store in one byte.
Now go back to your DOS windows and type DIR once more. Now you would expect the space to be one less as we have just created a 1-byte file. Check it and see!
Before: 231,079,936 bytes free After: 231,063,552 bytes free
Difference: 16384 bytes
These are the figures from my C: drive. 16384 bytes for a single letter — seems a bit excessive! This is because of the cluster size, which is dependent upon the size of the partition or hard drive.
So if you have lots and lots of small files that you think won't take up a lot of space, think again!
Cluster Sizes
The size of the cluster is dependent on the size of disk. Here is the size of cluster you will get for disk capacities.
Less than 512 MB = 8 KB
512 MB to 1 GB = 16 KB
Greater than 1GB = 32 KB
From this table, you can tell that my C: drive is between 512 MB and 1 GB in size as my one single file took up 16 kilobytes.
Partitions
So we have a brand new 4 GB drive. Clearly, if we just have this as one massive disk, it is very inefficient. The way around it is to partition the one physical drive into smaller logical drives. Instead of just a C: drive, we could split the drive into 4 x 1 GB drives, which will give us a C:, D:, E:, and F: drive.
