what is computer 1

Word Computer

The Word Computer comes from word “Compute”

Computer

The Word Compute mean to calculate

Computer

Def1

Computer is a calculating device that can perform Arithmetic Operation at enormous speed.

Computer

Def2

More accurately, a computer may be defined as device that operates upon information of data

Computer

Def 3

Computer can be defined as an electronic device thatperforms rapid computations and generates desired outputfor users based on input data and programs. Computer cancapture, store, retrieve and process data. The data may benumbers, characters, audio, video, images etc. Basically,computer can recognize only two states – whether a signal ispresent or not. These two states are represented using binarydigits 1 and O. All forms of data are finally converted intobinary digits for the computer to recognize and process.Instructions are also converted into binary digits. Digitalcomputer has the capability to manipulate series of binarydigits according to the instructions (software) given to it.

Computer

Def 4

Computer is an electronic device that input data, process it, store it , and produce out with high speed and accuracy that is useful to the human being

Computer

Def

The Study of computer and what they can do

The study of Computers, Computer Construction and what they can do.

Computer Science

Speed

Modern computers have incredible speed of processing. Computer speed is measured in units of

millisecond (one thousandth of a second),

microsecond (one millionth of a second),

nanosecond (one billionth of a second),

and picosecond (one trillionth of a second). Advanced computers, including recent microcomputers called super microcomputers, operate in nanoseconds and can carry out millions of instructions per second (MIPS).

Characteristics of Computer

Accuracy

Computer can ensure consistently very high degree of accuracy in computations. It processes data according to the sequence of instructions . Hence, if input data and procedures are correct, the output will be consistently accurate.


Huge storage and fast retrieval

Computer has huge storage capability. For a personal

computer, 128 MB RAM is almost a standard toady. The main memory can be upgraded further by inserting RAM chips that are available in modules of 64 MB, 128 MB and so on. Cache memory is also available in Pc. Cache memory is faster access memory device and hence it improves processor performance. Secondary or auxiliary storage devices are used for permanent storage. Modern computers have enormous secondary storage capacity, e.g., a PC hard disk can store more than 80 GB of data. Pen drives, DVDs, CD-ROMs, CD-Rs, magnetic tapes etc.


Versatility

Though computers are basically designed to carry out only arithmetic operations, yet they are capable of performing almost any task that has a series of finite logical steps. Computers can be used for communications, process control, research, weather forecasting, healthcare, online trading, education, training, defense applications and so on.


Free from fatigue

Computer is free from fatigue. It does not get tired of

work and never loses concentration. It can perform basic arithmetic operations with the same degree of speed and accuracy for any extent of time continuously, with the same amount of efficiency as the first transaction.


Programmable

Computer can be programmed to function automatically and this differentiates it from any other calculation device. It functions as programmed for any stretch of time until the condition to terminate is satisfied.

Characteristics of computer

Networking capability

Computers can be interconnected into a network. Network in turn can be connected to other networks. Networks extend the capability of computers. The networks provide the basic infrastructure for electronic communications, electronic commerce, online trading and information services.


1. Computer cannot think on its own. It has to be

given instructions to perform any operation. Research is currently underway to impart artificial intelligence to computer. Once this becomes possible computer will be thinking on its own, then it will be a reasonable replication of human mind.

2. It does not have intuition. It cannot draw a conclusion without going through all intermediate steps.

Limitations of Computer

3. It can do a task only if it can be expressed in a series

of finite steps leading to the completion of the task.

4. Similarly, it cannot handle a situation where a finite number of steps generate an impossibly large number of computational operations.

5. It cannot learn from experience. It will commit the

same error repeatedly and cannot learn from experience. But changes are taking place in this area as research progresses on artificial intelligence.

Limitations of Computer

A complete Computer consists of four parts1. Hardware2. Software3. Data 4. User

1. Hardware

The mechanical devices that make up the computer are called hardware. Hardware is any part of the computer you can touch. A computer hardware consists of interconnected electronic devices that you can use to control the Computer’s operation, input, and out put

Parts of computer

1. Input hardware

2. Output hardware

3. Storage hardware

4. Communication hardware

5. Processing hardware

1. Input hardware:- A type of hardware that is used to

enter data or commands into Computer. E.g Mouse Keyboard etc.

2. Output Hardware:- A type of Hardware that is used to get information from computer and display to the user.

2.1- Softcopy output Hardware:- It is type of Hardware whose output can only be seen but

can not be touched(Monitor).

2.2- Hardcopy output Hardware:-It is type of Hardware whose output can only be seen as well

touched(Monitor).

Types of computer Hardware

3. Memory/Storage Hardware:- A device that can accept data, hold

them, and deliver on demand at a later time.3.1- Primary Memory:- This types of hardware is

used to store data/instruction temporarily . Such storage devices are volatile i.e. if the power isinterrupted, then the data are lost(RAM).

3.2- Secondary Memory:- Secondary memory is used store data/instruction permanently. Secondary storage device are non volatile i.e. if the power isinterrupted, then the data are not lost. Secondarymemory can not be processed directly by the processor.It must be first copied into main memory(Hard disk).

Types of Computer Hardware

4. Communication hardware:- These types of hardware are

used to transfer data between two computers or between two units of a computer.

4.1- Internal communication hardware:- it is type of hardware that is used to transfer data from one unit to another unit of computer. This communication hardware is composed of various parallel lines know as bus.4.2- External Communication hardware:- it used to transfer data from one computer to another computer 5. Processing hardware:- It is type of hardware used to

process data according to the given instruction to generate output (microprocessor).

Types of computer hardware

2. Software:

A software is (1)instruction(computer programs) that when executed provide desired features, function and performance;(2) data structure that enable the programs to adequately manipulate information; and(3) documents that describe the operation and use of programs.

Parts of Computer

1. System software.

2. Application software.

1. System Software:- System software is any program

that controls the computer’s hardware or that can be used to maintain the computer in some way so that it runs more efficiently.

Types of software

Basic Types of System Software• Operating System:- Operating is used to control the over all operation of

the computer, and act as an interface between the computer hardware and software. Operating system provides an environment in which the other executer and terminate properly.

• Translator/Language Processor:- Translator is system program the converts the program from one language to another language.

• Utility :- Utility is Program that makes the computer system easier to use or performs high specialized function. Utilities are used to manage disks, troubleshoot hardware problem.

• Device Driver:-A device driver, often called a driver for short, is a computer program that is intended to allow another program (typically, an operating system) to interact with a hardware device. Think of a driver as a manual that gives the operating system (e.g., Windows) instructions on how to use a particular piece of hardware. A device driver essentially converts the more general input/output instructions of the operating system to messages that the device type can understand.

Types of software

2. Application Software:-Application software tells the

compute how to accomplish specific tasks, such as word processing or drawing, for the user. Some Major categories of application software.

• Word Processing software:- It is used for creating text-based documents such as newsletters.

• Spreadsheets Software:- Spreadsheets is used for creating numeric-based documents such as budgets.

• Data Base Management Software for building and manipulating large set of data.

• Presentation:- Presentation programs are used for creating and presenting electronic slide shows

Types of Software

3. Data

Data consist of individual facts or pieces of information that by themselves may not make much sense to a person. A computer primary job is to process these tiny pieces of data in various way, converting them into useful information.

Parts of computer

4. Users

People are the computer operators, also known as users.

Parts of Computer

• Using all parts of computer together , a computer converts data into information by performing various action on data.

• A set of steps a computer follows to receive data , process the data according instruction from program, display the resulting information to user, and store the result

Figure

Information processing Cycle

Input Processing Output

Storage

Input:- during this part of the cycle, the computer

accepts data from some source, such as the user or program, for processing.

Processing:- During this part of the cycle, the computer’s processing components perform action on the data, based on the instruction from the user or program.

Information Processing Cycle

Output:- Here the computer may be required to

display the results of its processing. For example , the result may as text, number, or graphics on the computer screen.

Storage:- In this step, the computer permanently store the result of its processing on a disk , tape, or some other kind of storage medium.

Information Processing Cycle

Central Processing Unit(CPU)

The Computer’s primary processing device, which interprets and execute program instructions and manages the function of input, output, and storage devices. The CPU is composed of CU,ALU , built in main memory, and supporting circuitry such as a dedicated math processor.

Organization of Computer

Computer Organization

Central Processing Unit(CPU)

Arithmetic Logic Unit (ALU) Control Unit(CU) Main Memory

Primary Memory

A memory or store is required in a computer to store programs and the data processed by programs. The main memory is made up of a large number of cells with each cell capable of storing one bit. The cells may be organized as a set of addressable words, each word storing a string of bits. The main memory provides random access. The main memory is divided into Random Access Memory (RAM) and Read Only Memory (ROM). RAM is dynamic and volatile. ROM is read only memory and this memory cannot be erased and rewritten. That is, ROM is non-volatile.


Arithmetic Logic Unit (ALU)

ALU does all the arithmetic and logical operations.

Arithmetical operations involve manipulation of numerical data such as addition, subtraction, division and multiplication. Logical operations compare relative magnitudes of two numeric, alphabetic or alphanumeric data items such as greater than, less than, and equal to.


Control Unit (CU)

The control unit controls and co-ordinates all the operations of the CPU and peripheral devices. Its functions are to ensure that the program instructions are carried out in the desired sequence and to control and co-ordinate the flow of data between the CPU and the input-output devices.


External Devices:

I/O operations are accomplished through a wide arrangement of external devices that provides a means of exchanging data between the external environment and the computer. An external device attaches to the computer by a link to an I/O module. The link is used to exchange control, status, and data between the I/O Module and the external devices. An external device connected to an I/O module is often referred to as Peripheral.


I/O Module:- One of the major component of computer. It is responsible for the control of one or more external devices and for exchange data between those devices and main memory and/or CPU registers.


External Devices Classification

External device are broadly classified into Three Categories

1. Human readable:- Suitable for the communication with computer user e.g. VDT(Video Display terminals) and Printer(Plug and play , None Plug and play I/O Devices).

2. Machine Readable:- Suitable for communicating with equipment e.g. Magnetic Disk.


External Devices Classification

3. Communication:- Suitable for communication with remote devices, which may be a human-readable device, such as terminal, machine-readable device, or even another computer


Secondary Memory:

Limitation of Primary Memory

Volatile

Expensive

Capacity


Secondary memory:-

Memory located outside the computer system itself; that is, it can not be process directly by the processor. It must be first copied into main memory. Example includes disk and tape.

Secondary storage is thus supplementary to primary storage. It is, therefore, also called auxiliary storage. Secondary storage has larger storage capacity and is cheaper than primary storage. But access to secondary storage is slower than that to primary storage. Hence, secondary storage holds data and programs not currently in use.


what is computer 1

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