Computershavememoryaddressesof

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Unformatted text preview: has a decimal equivalent of 1,048,576 and is abbreviated to 1 Mega 230 has a decimal equivalent of 1,073,741,824 and is abbreviated to 1 Giga 240 has a decimal equivalent of 1,099,511,627,776 and is abbreviated to 1 Tera Ali Raza Computer System Hexadecimal Long binary numbers can be difficult to read correctly. Computers have memory addresses of 2 or 4 bytes long which give addresses of 16 or 32 bits. Hexadecimal is base 16 and organises the bits into groups of four. The conversion between base 2 and base 16 is very simple. Hex needs the digits 0­9 and letters A­F. E.g. 11010100010110010011001010010110 becomes 1101 0100 0101 1001 0011 0010 1001 0110 which in Hex is D459 3256 Ali Raza Computer System Why Binary? Logic circuits based on two state logic – use only 0 and 1. We only need two voltages 0 and a voltage of any value = 1 Ali Raza Computer System Text ASCII Each character is stored in an 8 bit binary code called the ASCII system. E.g. A is stored as 65 (01000001 in Binary). 1 byte can store 256 different characters – enough for all the keys on the keyboard and several foreign symbols (for currency etc.). Ali Raza Computer System Bit The basic and the smallest unit of computer memory is called bit, that stands for binary digit. As we know that computer internally represents its data in the form of binary zeros and ones, these bits are the primary sources of such representation. A bit may have two possible states i.e. 0 or 1. 0 is used for circuit off where as 1 is used for circuit on. Thus a single bit may have two possible representations of data 0 and 1. Ali Raza Computer Platforms Think of this as a bit either being on or off, light or dark, true or false. For example, the number 10010111 is 8 bits long, or in most cases, one modern PC byte. Binary digits are a basic unit of information storage and communication in digital computing and digital information theory. Ali Raza Computer Platforms Nibble One nibble is the combination of 4 bits. It can have 16 possible representations of data as 24 = 16. An example is the hexadecimal number system, which is composed of numbers from 0 i.e. 0000 to F i.e. 1111. Ali Raza Computer System Byte A byte may be defined as “ the memory required to store a single alphanumeric character of data”. Here alphanumeric character may be any digit from 0,1,2,3, …..,9 or an alphabet from a to z or A to Z or any other special symbol like , : / ? + ­ * etc. Ali Raza Computer System A...
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This document was uploaded on 03/16/2014.

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