Characteristics of Computers

A computer is an assembly of electronic hardware tjhat perform varity of operations faster with the help of a given set of instructions. These sets of instructions are called programs. To complete various tasks, a computer is made up of different parts.

Components of a Computer System

A computer is primarily made up of:

The Central Processing Unit
The Monitor
The Keyboard
The Mouse

To use the computer, you must first turn it ON. A computer works by receiving and executing instructions. These instructions cause the computer to start giving its own instructions to the internal parts. One set of instructions is called BIOS.

Depending on the computer you are using, when it comes up, it may directly display the desktop or it may ask you to login. If you are using Microsoft Windows 95, 98, Millennium or XP, the desktop may not display once the computer is ready.

Features
The characteristics of computers that have made them so powerful and useful are speed, accuracy, reliability, diligence, versatility and storage capacity.

Speed
Computers work at very fast speed. The speed with which it operates is beyond human capabilities. In just a second it can perform millions of operations.

The speed of the computer is expressed in milliseconds,nicroseconds, nanoseconds and picoseconds.

Accuracy
Despite of fast working, computers are extremely accurate. Errors that may occur can almost always be attributed to human error rather than technological weaknesses.

Diligence
Unlike human beings, computers are very reliable. They do not undergo the human qualities of dullness and tiredness that results in short attention. Computers score high over human beings in performing big and recurring jobs.

Versatility
Computers are flexible machines and are capable of performing any task as long as it can be broken down into a series of logical steps. Computers are used in Railway/Air reservation, banks, hotels, weather forecasting and many more areas.

Storage Capacity
Computers can store large volumes of data. In a computer, a piece of information once recorded will remain intact and will not be lost automatically.

Components of a Computer System

Computers process data under the control of sets of instructions called computer programs. These computer programs guide the computer through orderly sets of actions specified by people called computer programmers.

A computer comprises of various devices

Keyboard
Monitor
Mouse
Disks
Memory
CD-ROM
Processing Units

that are referred to as hardware. Computer programs that run on a computer are referred to as software.

Processing Unit

Processing unit is the main part of the computer system. Whatever data that is entered with the help of input devices needs to be edited, formatted, transformed or used in calculations. It is the raw information that we enter into a computer.

The computer takes the raw information in terms of numbers and words. With the help of the processor, the data is processed into useful information. The raw data is usually called the input. The processed data or information is usually called the output.

CPU

The brain of a computer system is the Central Processing Unit (CPU). The CPU processes data transferred to it from input devices. It is then transferred, either by an intermediate or final result of the CPU to one or more output devices.

For processing of data a Central Section is required to perform calculations or manipulation of data. The CPU is the computing center of the system. It consists of a control section and an arithmetic-logic section as shown

ALU

ALU stands or Arithemtic and Logic Unit. It performs arithmetic and logical operations on data. It is an electronic component based on the use of simple digital logic devices that can store binary digits and perform simple operations.

Figure given aside shows the arrangement of ALU with the rest of the processor. Data is presented to the ALU in registers and the results of an operation are stored in registers. These registers are temporary storage locations within the processor that are connected by signal paths to the ALU. The ALU may also set flags based on the result of an operation. For example, an overflow flag is set to 1 if the result of a computation exceeds the length of the register into which it is to be stored.

The arithmetic-logic section performs arithmetic oeprations, such as:

1. Addition
2. Subtraction
3. Multiplication
4. Division

As shown in the figure below, the arrows show the data flows between the arithmetic logic section and the memory section during processing. In this the data is transferred from the memory to the arithmetic logic section for processing.

Memory
Output
Arithmetic Logic Unit

After processing, the data is returned to memory again. It is seen that the data may be transferred back and forth between these two sections many times. Tje results are the transferred from memory to an output device. The binary addition and multiplication tables are:

0+0 = 0
0+1 = 1
1+1 = 2
1+0 = 1
0*0 = 0
0*1 = 0
1*1 = 1
1*0 = 0

Note that if carries are ignored, subtraction of two single-digit binary numbers gives the same bits as addition.

Control Unit

The control unit is an important part of Central processing unit that directs the flow of operations and data. It maintains order within the computer.

The flow of control is indicated by dotted lines in the figure. The Control section selects one program statement at a time from the program storage area, interprets the statemnt and sends it to the arithemtic-logic and memory to carry out instructions.

The control section does not perform the actual processing operations on the data. It instructs the input device on when to start and stop transferring data to the input storage area. It directs the output device when to start and stop receiving data from the output storage area.

Input

Home computers are called microcomputers. In microcomputers the input is supplied by using keyboard, mouse or other input devices. These input devices may be called peripheral devices.

Input Unit Storage Unit Output Unit Results
Control Unit
Arithmetic Logic Unit

A computer must receive both data and program to function properly and should be able to solve problems. Feeding of data and programs to a computer is facilitated by an input device as shown in the figure ahead.

When you input information into your computer with the mouse or keyboard, you are sending a signal to the CPU. The CPU has a logic unit that can do basic arithmetic.

The control unit directs the computer to execute programs that have been stored in memory. The speed by which a computer executes prgramme is measured in Millions of instructions per second (MIPS) whereas the processor\’s speed is measured in Gigahertz (GHz). When the information has been processed, it is output in a human-readable form through the monitor and speakers. It can also be stored again for later processing. A computer can also take data from a source, such as magnetic disks, CD\’s, Floppy disks, and DVD\’s and translate that data into electronic impulses for the CPU. Some typical input devices are keyboards, mouses or scanners that are used to input data directly to the computer.

Hardware : The physical parts such as keyboard, mouse, Monitor are called as Hardware.
Software : The programs that run on computer are called Computer Software.

Processing

Processing is done inside the computer in an area called as the Cental Processing Unit (CPU).
rocessing is the conversion of input information to output data.

Storage

Storage is basically holding or keeping the information somewhere. Data can be stored on a variety of fixed or removable media. The Hard rive is the main form of fixed data storage. Once the computer information is stored in files it is then organised in folders. No data or information on a hard drive can exist outside a file. Files can then be organised into folders.

When we look at a file in more detail, we see that data is represented by a string of zeros and ones. Each 0 or 1 is called a bit and is the smallest unit a computer can process. A group of eight bits is a byte and can represent a keyboard character or a command to the computer.

Folder contains many Files Zeros Ones
Bytes Represent Bits
All data is stored on a computer in bytes. File size is measured using the following:

Size Number of bytes

Kilobyte 1 KB = 1024
Megabyte 1 MB = 1048576
Gigabyte 1 GB = 1073741824

Output

Output is the result of a computer process. Output may be seen on a monitor screen, heard off through speakers, or printed on a printe

Output devices are hardware which are also considered to be the peripheral devices.

Applications of computers

There are so many applications of computers. Practically it is not possible to list call of them. Computers used in present days are faster, more reliable, effective and cheaper than they had ever been before.

Computers were used by the government agencies in the beginning for specific purposes. Business world started using computers for commercial purposes in the 1960s and invention of PC\’s (Personal Computers) brought about a revolution. It is seen that computers are very productive and efficient. Moreover, they really excel in certain areas. Some major applications of computers are given below.

Business : Businessmen use computers to make bar graphs and pie charts to convey their information. It helps in predicting future sales, profits, costs etc., and makes their companies more accurate in their accounts.
Buildings : Computers help in building maps which help architects to test possible exteriors. They help architects to create different buildings with greater accuracy and with better design.
Education : Computers are used in schools and colleges for studying online. With this, students can enhance their knowledge at much faster speed as compared to the old traditional methods. Computers also help in conducting online tests and examinations.
Retailing : Computers are nowadays used in retailing sector where most of the items are attached with bar coding. Bar coding helps in maintaing stock of procut and can be easily billed.
Energy: Energy companies use computers to find oil, coal, natural gas and uranium, Electic companies use computers to monitor vast power networks.
Law Enforcement : Computers are used to diagnose fingerprint files and other necessary models to catch the culprits. In addition, computers also contain databases of all the names of all the pictures and information of such people who choose to break the law.
Transportation : Computers are used in cars and in other vehicles to monitor fuel levels, temperatures and electrical systems. They are also used in air traffic control systems to control the flow if traffic among aeroplanes.
Money : Computers help banks in offering same-day services to the cleitns by maintaing all records. They help in online money transactions.
Agriculture : Famers use small computers to help with biing, obtaining crop information and cost per acre and also to check prices.
Government : In government, computers are used to: 1.Forecast weather information 2.Processing immigrants 3. Collecting taxes 4. Collecting bills online 5.Defence 6.Publicity 7. Research
Home : People use computers in the home to keep records, write letters, prepare budgets, produce presen-tations, draw pictures, publish newsletters and to write mail.
Health and Medicine : Doctors use computers to assist them in diagnosing diseases. Computers are used greatly in managing patients, doctors, wards and medicine records, as well as dealing with making appointments and in surgeries.
Manufacturing Industries : In Industries, computers are used to control the production of resources very precisely. All the stages of manufacturing from designing to production, can be done with the use of computer technology.
Scientific Research : Computers are used in research as they are very fast and accurate. They help scientists and researchers to prove their theories in a cost-effective manner.
Communication : Communication has become fast, cheap and reliable with the use of computers. E-mailing, teleconferencing and use of voice messages are very fast, effective and cheap.
Training : Nowadays training in Government and Private Sectors are conducted online. New computerized training equipment helps trainers to conduct training quickly and effectively.

Functions of a Computer

The computer is an electronic device that is commonly used nowdays in alomost every kind of work. The basic function of a computer is to perform different tasks with the help of set of instructions which are called programs. A computer is able to perform these tasks faster than human beings and that\’s why it is used in almost every working environment. You can check the balance of your account, purchase merchandise, send and receive messages, do research, process photographs, create music and store crucial data, and many other things. If you have essential computer skills, then you can find better employment for higher pay. Because computers are easily networked, they can help people from remote parts of the world communicate more quickly and easily than with traditional methods.

There are four stages for computer functioning:

Input
Processing
Storage
Output

Example

To understand the function of a computer, let us take a practical example of a teacher and a student. Suppose the teacher has given a Homework on computer to the student. The figure shows how the function is carried out.

Students willl be able to know :