How does the Computer Store Information in Bits and Bytes?



1: Unsigned integer format for representing a limited non-negative integers: By using powers of 2 instead of 10 to encode integers, the computer uses a binary number system to encode an integer in bits of 0ís and 1ís (instead of 10 different digits in the decimal system).


2: ASCII code for western characters and symbols: Character are encoded in 8 bits (i.e. 1 byte) as numbers using the ASCII character set encoding that maps a character into a number in the range of 0 to 255. The size of a pure text file (.txt file) in bytes is close to the number of characters in the file since each character in a plain text file is encoded in 1 byte of memory.




3:  BMP format for representing images: The size of a picture in the 24-bit BMP file format in bytes is about 3 times the number of pixels since the color of each pixel is encoded in terms of 24 bits, i.e. 3 bytes. With 8 bits each for representing the intensity of each of the RGB components of the color.




Common units of storage

       KB: ††† About 1 thousand bytes††††††††††††††††††††† (210=1024 bytes)

       MB:†††† About 1 million bytes†††††††††††††††††††††††† (220=1,048,576 bytes)

       GB: ††† About 1 billion bytes††††††††††††††††††††††††† (230=1,073,741,824 bytes)

       TB: †††† About 1 tera bytes††††††††††††††††††††††††††††† (240 bytes)