VARDHAMAN COLLEGE OF ENGINEERING AUTONOMOUS Shamshabad 501 218 Hyderabad CS BLUEPRINTS DEPARTMENT OF INFORMATION TECHNOLOGY C PROGRAMMING C PROGRAMMING Page 1 UNIT I Computer systems A Computer is an electronic device which performs operations such as accepts data As an input store the data manipulate or process the data and produce the results an output Main task performed by a computer Accept the data Process or manipulate the data Display or store the result in the form of human understanding Store the data instructions and results A computer system consists of hardware and software Computer hardware is the collection of physical elements that comprise a computer system Computer software is a collection of computer programs and related data that provides the instructions for a computer what to do and how to do it Software refers to one or more computer programs and data held in the storage of the computer for some purpose C PROGRAMMING Page 2 Basically computer software is of three main types System Software System software is responsible for managing a variety of independent hardware components so that they can work together Its purpose is to unburden the application software programmer from the often complex details of the particular computer being used including such accessories as communications devices printers device readers displays and keyboards and also to partition the computer s resources such as memory and processor time in a safe and stable manner Device drivers Operating systems Servers Utilities Window systems Programming Software Programming Software usually provides tools to assist a programmer in writing computer programs and software using different programming languages in a more convenient way The tools include Compilers Debuggers Interpreters Linkers Text editors Application Software Application software is developed to aid in any task that benefits from computation It is a broad category and encompasses Software of many kinds including the internet browser being used to display this page This category includes Business software Computer aided design Databases Decision making software Educational software Image editing Computing Environment Computing Environment is a collection of computers machines software and networks that support the processing and exchange of electronic information meant to support various types of computing solutions Types of Computing Environments Personal Computing Environment C PROGRAMMING Page 3 Client Server Environment Time sharing Environment Distributed Environment Personal Computing Environment All of the computer hardware components are tied together in our personal computer A personal computer PC is a computer whose original sales price size and capabilities make it useful for individuals and intended to be operated directly by an end user with no intervening computer operator People generally relate this term with Microsoft s Windows Operating system Personal computers generally run on Windows Mac or some version of Linux operating system Desktop Desktop computer is just another version of Personal Computer intended for regular use from a single use A computer that can be fit on a desk can also be called as desktop Time Sharing Environment In the time sharing environment all computing must be done by the central computer The central computer the shared resources it manage the shared data and printing Employees in large companies often work in what is known as time sharing environment In the time sharing environment many users are connected to one or more computers These computers may be mini computers and central mainframes In this environment the output devices auxiliary storage devices are shared by all the users C PROGRAMMING Page 4 Client Server Environment Client Server computing environment splits the computing function between a central computer and user s computers The users are given personal computers or work stations so that some of the computation responsibility can be moved from the central computer and assigned to the workstations In the client server environment the users micro computers or work stations are called the client The central computer which may be a powerful micro computer minicomputer or central mainframe system is known as server Distributed Computing Environment A distributed computing environment provides a seamless integration of computing functions between different servers and clients The internet provides connectivity to different servers throughout the world This environment provides reliable scalable and highly available network C PROGRAMMING Page 5 COMPUTER LANGUAGES In order to communicate with the computer user also needs to have a language that should be understood by the computer For this purpose different languages are developed for performing different types of work on the computer Basically languages are divided into two categories according to their interpretation 1 Low Level Languages 2 High Level Languages Low Level Languages Machine Language Assembly Language Low level computer languages are machine codes or close to it Computer cannot understand instructions given in high level languages or in English It can only understand and execute instructions given in the form of machine language i e language of 0 and 1 There are two types of low level languages Machine Language It is the lowest and most elementary level of Programming language and was the first type of programming language to be Developed Machine Language is basically the only language which computer Can understand In fact a manufacturer designs a computer to obey just one Language its machine code which is represented inside the computer by a String of binary digits bits 0 and 1 The symbol 0 stands for the absence of Electric pulse and 1 for the C PROGRAMMING Page 6 presence of an electric pulse Since a computer is Capable of recognizing electric signals therefore it understand machine Language Advantages of Machine Language i It makes fast and efficient use of the computer ii It requires no translator to translate the code i e Directly understood by the computer Disadvantages of Machine Language i All operation codes have to be remembered iv These languages are machine dependent i e a particular Machine language can be used on only one type of computer Assembly Language It was developed to overcome some of the many inconveniences of machine language This is another low level but a very important language in
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