CM VIII - Binary Number System - BITS and BYTES

CM VIII - Binary Number system - BITS and BYTES

Jyoti: How does a computer store music and audio? Moz: Computer understands only numbers. Hence all data like information, instructions, files, images, sound, video is stored as numbers. How are numbers say for example “234” made of? Tejas: Digits 2, 3 and 4. Moz: Right. Since computers only understand numbers made up of digits, the computers are called digital devices. Jyoti: Does it have some code to represent each letter in the alphabets. Using these it must be saving a text document. Moz: You are right. Tejas: To represent an image each pixel or the coloured dots need to have a code. Jyoti: Different sounds in a music file have to be given a code. Moz: Yes. Everything is a number. And these numbers are formed by the two numbers 0 and 1 called the binary numbers.

Tejas: Wow. Only the two numbers. Is it because the components in a computer are all electronic devices? Moz: You are right. The electronic devices like CPU and RAM, in a computer which store data have parts which can be switched on or off. Off = 0 and On = 1. Using a combination of on and off the data is easily represented. Each of these digit is called a BIT which derives from Binary DigIT. The following could be codes for some text, or they could be the codes for some pixels in an image, or they could just be numbers.

Jyoti: Why are they always grouped into 8. Moz: BITs are usually grouped into a group of 8 and each group is called a Byte. Tejas; Oh! So when a file has a size of 1 KB then it means the file has 1000 bytes which means 1000 multiplied by 8 = 8000 bits. Moz: Right. Write down the table of bits and bytes starting from Kilobytes to Terrabytes. Note that bits are abbreviated by 'b' and bytes by 'B'.

Concept: Binary numbers A binary number is formed by the combination of '0' and '1'. Bit 0 1 A bit is the smallest unit of data in computer processing.  Bit is derived from the words Binary digIT.  A bit represents a digit in the binary system.  A bit can only have the value 0 or 1.  An example: 1101 is a binary number 4 bits long and can represent data like text, pixels, sound in a computer.

Byte 0 1 1 0 1 1 1 0 A Byte is a group of 8 bits.  Bytes are the standard unit of storage in a computer.  An example: 10110111 is a byte and can represent data like text, pixels, sound in a computer.

Standard units of measure:

 A Kilobyte (KB) is 2^10 bytes or approximately 1024 bytes.  A Megabyte (MB) is 1024 kilobytes.  A gigabyte (GB) is 1,024 megabytes.

 A terabyte (TB) is 1,024 Gigabytes. Some examples of usage binary system:  Main memory (RAM), Storage (hard disk, pen drive, CD/DVD).  Network access: The speed at which we connect to the network or internet is measured as bits per second. (Ex: 2 Mbps means 2 megabits of data per second is transferred). Worksheets

1. Fill in the blanks

a) _____ and ______are digits in the binary system. b) Binary numbers can represent data like ______, ______and ______in computers. ______. c) A Byte is a group of ___ bits.

Match the following

KB 1024 megabytes Byte 1024 bytes GB 1024 gigabytes MB 1024 kilobytes TB 8 bits