P G D C A Semester No 01

Computer Fundamentals

UNIT-01(Introduction of Computer)    

( Introduction, Definition, Characteristics of Computer, Functions of computer, Application of computer, Classification Of Computer, Generation of Computer, Computer Memory Unit, Components of a computer (Board Overview): Input Unit, Processing unit (memory Unit, Control Unit, ALU), Output Unit, Components of a computer (Detailed Overview): SMPS, Motherboard (North Bridge, South bridge, Chipset, 20 pin ATX power connector, CMOS, Ports and other connected devices)   )          

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The literal meaning of computer is a device that can calculate. However, modern computers can do a lot more than calculate.

 Computer is an electronic device that receives input, stores or processes the input as per user instructions and provides output in desired format.

Computers are everywhere: at work, at school, and at home. In the workplace, employees use computers to create correspondence such as e-mail messages, memos, and letters; manage calendars; calculate payroll; track inventory; and generate invoices. At school, teachers use computers to assist with classroom instruction. Students use computers to complete assignments and research. People also spend hours of leisure time using a computer. They play games, communicate with friends and relatives online and using e-mail, purchase goods online, converse in chat rooms, listen to music or radio broadcasts, watch or create videos and movies, read books and magazines, share stories, research genealogy, retouch photos, and plan vacations. At work, at school, and at home, computers are helping people do their work faster, more accurately, and in some cases, in ways that previously would not have been possible.

 A computer is an electronic device, operating under the control of instructions stored in its own memory, that can accept data (input), process the data according to specified rules (process), produce results (output), and store the results (storage) for future use. Generally, the term is used to describe a collection of electric, electronic, and mechanical components known as hardware.

Why this chapter ?

 Computers are an integral part of our lives. Wherever we are—sitting in our homes, working in the office, driving on roads, sitting in a movie hall, staying in a hotel, etc.—our lives are directly or indirectly affected by the computers. In this era of information, we are dependent on the storage, flow and processing of data and information, which can only be possible with the help of computers. The purpose of this chapter is to introduce you to the “computer”.

Computers perform Five basic operations — input, process, output, storage & Control. These operations comprise the information processing cycle. Collectively, these operations process data into information and store it for future use.

DIGITAL AND ANALOG COMPUTERS

A digital computer uses distinct values to represent the data internally. All information are represented using the digits Os and 1s. The computers that we use at our homes and offices are digital computers.

Analog computer is another kind of a computer that represents data as variable across a continuous range of values. The earliest computers were analog computers. Analog computers are used for measuring of parameters that vary continuously in real time, such as temperature, pressure and voltage. Analog computers may be more flexible but generally less precise than digital computers. Slide rule is an example of an analog computer.

Input-Process-Output Model

Computer input is called data and the output obtained after processing it, based on user’s instructions is called information. Raw facts and figures which can be processed using arithmetic and logical operations to obtain information are called data.

The processes that can be applied to data are of two types −

• Arithmetic operations − Examples include calculations like addition, subtraction, differentials, square root, etc.

• Logical operations − Examples include comparison operations like greater than, less than, equal to, opposite, etc.

The corresponding figure for an actual computer looks something like this −

The basic parts of a computer are as follows −

• Input Unit − Devices like keyboard and mouse that are used to input data and instructions to the computer are called input unit.

• Output Unit − Devices like printer and visual display unit that are used to provide information to the user in desired format are called output unit.

• Control Unit − As the name suggests, this unit controls all the functions of the computer. All devices or parts of computer interact through the control unit.

• Arithmetic Logic Unit − This is the brain of the computer where all arithmetic operations and logical operations take place.

• Memory − All input data, instructions and data interim to the processes are stored in the memory. Memory is of two types – primary memory and secondary memory. Primary memory resides within the CPU whereas secondary memory is external to it.

CHARACTERISTICS OF COMPUTER

A computer derives its power from its capability to perform the information processing cycle with amazing speed, reliability (low failure rate), and accuracy; its capacity to store huge amounts of data and information; and its capability to communicate with other computers.

• Speed − Typically, a computer can carry out 3-4 million instructions per second.

• Accuracy − Computers exhibit a very high degree of accuracy. Errors that may occur are usually due to inaccurate data, wrong instructions or bug in chips – all human errors.

• Diligence − When used for a longer period of time, the computer does not get tired or fatigued. It can perform long and complex calculations with the same speed and accuracy from the start till the end. 

• Reliability − Computers can carry out same type of work repeatedly without throwing up errors due to tiredness or boredom, which are very common among humans.

• Versatility − Computers can carry out a wide range of work from data entry and ticket booking to complex mathematical calculations and continuous astronomical observations. If you can input the necessary data with correct instructions, computer will do the processing.

• Storage Capacity − Computers can store a very large amount of data at a fraction of cost of traditional storage of files. Also, data is safe from normal wear and tear associated with paper.

• Computers have several limitations too. Computer can only perform tasks that it has been programmed to do. Computer cannot do any work without instructions from the user. It executes instructions as specified by the user and does not take its own decisions.

• Advantages of Using Computer

  Now that we know the characteristics of computers, we can see the advantages that computers offer−

  • Computers can do the same task repetitively with same accuracy.

  • Computers do not get tired or bored.

  • Computers can take up routine tasks while releasing human resource for more intelligent functions.

  Disadvantages of Using Computer

  Despite so many advantages, computers have some disadvantages of their own −

  • Computers have no intelligence; they follow the instructions blindly without considering the outcome.

  • Regular electric supply is necessary to make computers work, which could prove difficult everywhere especially in developing nations.