We in today’s world use storage mechanisms and they store more information that a byte, storage mechanisms like CD-ROM’s, Hard Drives, Flash Drives etc. They hold more information than they byte, therefore the derivation of, kilobyte, megabyte, gigabyte, terabyte.

The definition of the above mentioned kilobyte, megabyte, gigabyte and terabyte is 1024 bytes, 1024 kilobytes, 1024 megabytes and 1024 gigabytes respectively. There is a difference in how people perceive these numbers though. It is generally calculated by people like: KB = 1000B, MB = 1000 KB, GB=1000MB, TB=1000GB. The corrective numbers for these mistakes are mentioned above.

We would often wonder the reason for this. It is because there are only two numbering systems in play at the moment in computers. Strictly in "computerese", a base 2 system is in play, so that one kilobyte is 2 to the power of 10 bytes, or 1024 kilobytes. But still, there are a few misconceptions like many hardware manufacturers, including hard drive manufacturers take a KB as 1000B, or 10 raised to 3 Bytes.

This phenomenon is followed across with MB, GB, TB and so on. The best example we can get about being confused about the amount of space on the hard disk, essentially understood wrong by the hardware people is when we buy the Hard Disk. They would mention that it is of a particular capacity, whereas it might not be so.

Type | Storage Capacity
Kilobyte | 10 or 1,024 1/2 page
Gigabyte | 230 or 1,073,741,824 500,000 pages or 1,000 thick books
Terabyte | 240 or 1,099,511,627,776 1,000,000 thick books
Petabyte | 250 or 1,125,899,906,842,624 180 Libraries of Congress
Exabyte | 260 or 1,152,921,504,606,846,976 180 thousand Libraries of Congress
Zettabyte | 270 or 1,180,591,620,717,411,303,424 180 million Libraries of Congress
Yottabyte | 280 or 1,208,925,819,614,629,174,706,176 180 billion Libraries of Congress

To understand the working of computers in the way we talk, rather the language the computer communicates with us in, the groups of bits are joined into bytes. Each Byte is made up of 8 bits. This combination of 8 bits was chosen because it provides 256 total possibilities which is enough for letters, numbers, punctuation and other characters.

Here is a very interesting example in the following sentence. This very sentence, for example is composed of 125 bytes because there are 125 letters, digits, spaces and punctuation marks.
Ensuring the fact that we are discussing purely text only the result of the above sentence will be the same. But, there are exceptions, if you use many other word processors which might indulge into formatting of your sentence, or might add more functions to mere text, which then makes the file size much larger than it generally would have appeared