The Complete Codes

How Computers Represent Data All symbols, pictures, or words must be reduced to a string of binary digits. A binary digit is called a bit and represents either a 0 or a 1. These are the only digits in the binary or base 2, number system used by computers. A string of eight bits used to store one number or character in a computer system is called a byte. One byte for character A 01000001 The computer representation in ASCII for the name Alice is 01000001 = A 01001100 = L 01001001 = I 01000011 = C 01000101 = E To represent the numbers 0 through 9 and the letters  a  through  z  and  A  through  Z , computer designers have created coding systems consisting of several hundred standard codes. In one code, for instance, the binary number 01000001 stands for the letter  A . Two common coding systems are Extended Binary Coded Decimal Interchange Code (EBCDIC) and American Standard Code for Information Interchange (ASCII). EBCDIC represents every number, alphabetic character, or spe

Software Software is a collection of sets of programs, which are used to execute all kinds of specific instruction. It consists of a number of machine instructions, and arrays in a specific order to perform a particular task. Software is used to describe all the programs and their associated documents which run on a computer. So, a computer needs both software and hardware for its proper functioning. Software means computer instructions or data. Anything that can be stored electronically is software. Firmware is software (programs or data) that has been permanently written onto read-only memory (ROM) All software falls into two general types or categories: System Software and Application Software. System software consists of low-level programs that interact with the computer at a very basic level. This includes operating systems, compilers, and utilities for managing resources. On the other hand, application software includes database programs, word processors, and spreadsheets. Typ

General Software Features and Trends Introduction Nowadays software projects are becoming more and more complex — in size, sophistication, and technologies used. Most software products are used by a huge number of people, not only that, this software support different national languages and comes in different sizes and shapes — desktop, standard, professional, Enterprise Resource Planning (ERP) packages, and so on. Almost all application software products (like word processors, and ERP packages) support more than one hardware and/or software platform. For example, we have web browsers for the PC and Mac; we have database management systems that run on VMS, UNIX, Windows NT, Linux, and so on. The competition and the advancements in technology are driving software vendors to include additional functionality and new features to their products— just to stay in business. Information Technology is revolutionizing the way we live and work. Digital technology has given mankind the ability to

Why CISC? •            Compiler simplification? –           Disputed… –           Complex machine instructions harder to exploit –           Optimization more difficult •            Smaller programs? –           Program takes up less memory but… –           Memory is now cheap –           May not occupy less bits, just look shorter in symbolic form •            More instructions require longer op-codes •            Register references require fewer bits •            Faster programs? –           Bias towards use of simpler instructions –           More complex control unit –           Microprogram control store larger –           thus simple instructions take longer to execute –           It is far from clear that CISC is the appropriate solution

Introduction to Computer A computer is an electronic device capable of performing arithmetic and logical operations. It can also store a large volume of information . Characteristics of Computer SPEED The speed with which the computer works can be understood by the units of measurement of time within a computer. They are : MILLI SECOND – 1/1000 TH OF A SECOND MICRO SECOND – 1/1000 TH OF A MILLI SECOND NANO SECOND – 1/1000 TH OF A MICRO SECOND PICO SECOND – 1/1000 TH OF A NANO SECOND STORAGE As already discussed a computer can store a large volume of information. The factors to be considered for storage are : •           RETREIVAL – IMMEDIATE •           SPACE – VERY LITTLE •           MEDIA – MAGNETIC MEDIA •           LONGIVITY – FOR EVER ACCURACY The accuracy of the computers is consistently high. Errors in the machinery may occur, but due to efficient error-detecting techniques, these very seldom lead to wrong results. Errors in computing are due to human rather than techno