Monday, April 30, 2012

2.1.3 Introduction To Binary Coding

2.1.3.1 Explain the function of ASCII code
WHAT IS ASCII?


ASCII pronounced as "ask-key" stands for the American Standard Code for Information Interchange and was proposed by ASA (American Standard Association) in 963 and was finalised in 1968.ASCII is a standard of 7-bit code used to represent characters, which include letters, numbers and punctuation marks.
7 bits allow the computer to encode a total of 128 characters for the numbers 0-9, uppercase and lowercase letters A-Z and a few punctuation symbols. However this 128 bit code only suitable for english language speaking users.

IBM and Apple expanded the amount of space reserved for the character codes to 8-bits, equivalent to 1 byte.
FUNCTIONS OF ASCII

ASCII was established to achieve compatibility between various types of data processing equipment making it possible for the components to communicate with each other successfully.
ASCII enables manufacturers to produce components that are assured to operate correctly in a computer.
ASCII makes it possible for humans to interact with a computer. It also enables users to purchase components that are compatible with their computer configurations



HOW ASCII WORKS IN A COMPUTER SYSTEM?

When you press a key, for example the letter D on your keyboard, the electronic signal is sent to the CPU for the computer to process and store in memory. Every character is converted to its corresponding binary form. The computer the processes the letter as a byte., which actually a series of on and off of electrical states. When the computer is finished processing the byte, the software installed in the system convert the byte back which is then displayed in the screen. In this example, the letter D is converted to 01000100.

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