320GB hard drive showing only 298GB only..!!!

One of my friend recently contacted me and asked a question that why his 320GB hard disk shows only 298GB of available space. He wanted to know whether the hard disk has some problems or his computer.

Actually, this is not a very big issue and its a normal thing.

The companies who sell hard disk consider the following:

1KB = 1000 Bytes
1MB = 1000 KB
1GB = 1000 MB
1TB = 1000 GB and further…

But, the Operating System or Computer System consider the following:

1KB = 1024 Bytes
1MB = 1024 KB
1GB = 1024 MB
1TB = 1024 GB and further…

Lets take an example.

Consider that you have bought a 1GB pen-drive.
So, According to company it is 1*1000 = 1000 MB and 1000 * 1000 = 1000000 KB and 1000000*1000 = 1000000000 Bytes.
So, when we divide 1000000000 Bytes according to computer system, its
1000000000/1024 = 976562.5 KB = 953.7 MB = 0.93 GB

So, the actual available space in a 1GB storage device is 0.93GB

Similarly, the actual available space in a 320GB hard disk is 298GB.