Theory - 82 :- What Is Computer System ? Introduction And Its Main Components

What is a computer system?

Definition: 

"All the different pieces of electrical hardware that join together to make up the complete computer system."

  A computer system is made up of 4 main types of components: 

1. Input Devices (keyboard, mouse etc)
2. Output Devices (monitor, speakers etc)
3. Secondary Storage Devices (hard disk drive, CD/DVD drive etc)
4. Processor and Primary Storage Devices (cpu, RAM)

Examples of common Computer Hardware (components):

 

Features of Internal Hardware Computer Components

Internal computer components are designed to fit INSIDE the computer system and they all carry out important roles. We will discuss the following:

• Motherboard (this does something with the data to make it useful information)
• Processor (central processing unit)
• Internal Memory (RAM and ROM)
• Video Card (aka graphics card)
• Sound Card
• Internal Hard Disk Drive

Motherboard

•    The motherboard is central to any computer system.

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• All components plug into the motherboard either directly (straight into the circuit board) or indirectly (via USB ports).

• Once connected to the motherboard, the components can work together to form the computer system.
• Components communicate and send signals to each other via the BUS Network.

Processor (CPU / Central Processing Unit)

The Central Processing Unit (CPU) is the brain of the computer.

 

The CPU 'controls' what the computer does and is responsible for performing calculations and data     processing. It also handles the movement of data to and from system memory.

CPU's come in a variety of speeds which are known as 'clock rates'. Clock rates are measured in 'Hertz'. Generally, the faster the clock rate, the faster the performance of the computer.

There are two main brands of CPU currently on the market... AMD and Intel:

Internal Memory (RAM and ROM)

There are two types of internal memory -

RAM and ROM.

• RAM and ROM are used to store computer data and this can be directly accessed by the CPU.
• RAM and ROM are sometimes referred to as 'Primary Storage'.

RAM (Random Access Memory)

• RAM is used to temporarily store information that is currently in use by the computer. This can include anything from word documents to videos.
• RAM can be read from and written to and so the information stored in RAM can change all the time (it depends what tasks you are using the computer for).
• RAM is a fast memory. Data can be written to and read from RAM very quickly. RAM is generally measured in GB (Gigabytes).
• RAM is Volatile Memory. This means that information stored in RAM is deleted as soon as the computer is turned off. 
• The more RAM you have installed in your computer -- the faster it can perform. You can open and use more programs at the same time without slowing the computer down.

ROM (Read Only Memory)

• ROM is used to permanently store instructions that tell the computer how to boot (start up). It also loads the operating system (e.g. Windows). These instructions are known as the BIOS (Basic input/output system) or the boot program.
• Information stored in ROM is known as READ ONLY. This means that the contents of ROM cannot be altered or added to by the user.
• ROM is fast memory. Data stored in ROM can be accessed and read very quickly.
• ROM is Non-Volatile memory. This means that stored information is not lost when the computer loses power.
• Other examples of ROM include:

• DVD/CD ROMS bought in stores containing pre-recorded music and movie files. These are played back at home but cannot be altered.       
• ROM in printers which is used to store different font types.

Video Card (aka graphics card)

Graphics cards are hardware devices that plug into the motherboard and enables the computer to display images on the monitor.

Graphics cards usually require the installation of software alongside the hardware. The software instructs the computer how to use the graphics card and also allows you to alter settings to change image quality and size.

See below for an example of graphics card software allowing the user to alter various graphical settings:

Sound Card

Sound cards are internal hardware devices that plug into the motherboard.

A sound card's main function is to allow the computer system to produce sound but they also allow users to connect microphones in order to input sounds into the computer.

Sound cards are also useful in the conversion of analogue data into digital and vice versa.

Storage Devices (secondary backing storage)

Secondary storage devices are used to store data that is not instantly needed by the computer.

Secondary storage devices permanently store data and programs for as long as we need. These devices are also used to back-up data

 in case original copies are lost or damaged.

Remember:

Temporary storage like RAM does not hold data for long periods. It is used to store only those programs and files that we are currently working on.

 There are two categories of storage devices:

Internal Storage - Internal Hard Disk Drives

External Storage - External Hard Disk Drive, Memory Stick etc 

Features of External Hardware Computer Components

External computer components connect to a computer system from OUTSIDE. They are not necessary for the system to function but make our experiences easier or better. We will discuss the following:

• Input Devices (used to get data into a computer)
• Output Devices (used to get information out of a computer)
• Peripherals

Input Devices

• Input devices are pieces of hardware that get raw data into the computer ready for processing.
• Processing involves taking raw data and turning it into more useful information.
• Input devices fall into two categories:
• Manual Input Devices - Need to be operated by a human to input information
  
  
  
• Automatic Input Devices - Can input information on their own. 
  
  
  

Output Devices

When inputted raw data has been processed it becomes usable information. Output devices are pieces of hardware that send this usable information out of the computer.

Some output devices send information out temporarily and some send information out permanently:

• Temporary Output Devices - E.g. Monitors which constantly refresh the outputted image on the screen
• Permanent Output Devices - E.g. Printers which output information onto paper as a hard copy.

Peripheral Devices

Almost all input and output devices are known as 'Peripheral devices'.

These are 'non-essential' hardware components that usually connect to the system externally.

Peripherals are called non-essential because the system can operate without them.

For example :

You can still use your computer without speakers... you will just have to do without high quality sound.

Examples of peripherals are shown below:

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Theory - 81.1 :- Computer Generations

Generation in computer terminology is a change in technology a computer is/was being used. Initially, the generation term was used to distinguish between varying hardware technologies. Nowadays, generation includes both hardware and software, which together make up an entire computer system.

There are five computer generations known till date. Each generation has been discussed in detail along with their time period and characteristics. In the following table, approximate dates against each generation have been mentioned, which are normally accepted.

Following are the main five generations of computers

First Generation Computers

The period of first generation was from 1946-1959. The computers of first generation used vacuum tubes as the basic components for memory and circuitry for CPU (Central Processing Unit). These tubes, like electric bulbs, produced a lot of heat and the installations used to fuse frequently. Therefore, they were very expensive and only large organizations were able to afford it.

In this generation, mainly batch processing operating system was used. Punch cards, paper tape, and magnetic tape was used as input and output devices. The computers in this generation used machine code as the programming language.

The main features of the first generation are:

• Vacuum tube technology
• Unreliable
• Supported machine language only
• Very costly
• Generates lot of heat
• Slow input and output devices
• Huge size
• Need of AC
• Non-portable
• Consumes lot of electricity

Some computers of this generation were:

• ENIAC
• EDVAC
• UNIVAC
• IBM-701
• IBM-750.

Second Generation Computers

The period of second generation was from 1959-1965. In this generation, transistors were used that were cheaper, consumed less power, more compact in size, more reliable and faster than the first-generation machines made of vacuum tubes. In this generation, magnetic cores were used as the primary memory and magnetic tape and magnetic disks as secondary storage devices.

In this generation, assembly language and high-level programming languages like FORTRAN, COBOL were used. The computers used batch processing and multiprogramming operating  system.

The main features of second generation are:

• Use of transistors
• Reliable in comparison to first generation computers
• Smaller size as compared to first generation computers
• Generates less heat as compared to first generation computers
• Consumed less electricity as compared to first generation computers
• Faster than first generation computers
• Still very costly
• AC required
• Supported machine and assembly languages

Some computers of this generation were:

• IBM 1620
• IBM 7094
• CDC 1604
• CDC 3600
• UNIVAC 1108

Third Generation Computers

The period of third generation was from 1965-1971. The computers of third generation used Integrated Circuits (ICs) in place of transistors. A single IC has many transistors, resistors, and capacitors along with the associated circuitry.  

The IC was invented by Jack Kilby. This development made computers smaller in size, reliable, and efficient. In this generation remote processing, time-sharing, multi-programming operating system were used. High-level languages (FORTRAN-II TO IV, COBOL, PASCAL PL/1, BASIC, ALGOL-68 etc.) were used during this generation.

The main features of third generation are:

• IC used
• More reliable in comparison to previous two generations
• Smaller size
• Generated less heat
• Faster
• Lesser maintenance
• Costly
• AC required
• Consumed lesser electricity
• Supported high-level language

Some computers of this generation were:

• IBM-360 series
• Honeywell-6000 series
• PDP (Personal Data Processor)
• IBM-370/168
• TDC-316

Fourth Generation Computers

The period of fourth generation was from 1971-1980. Computers of fourth generation used Very Large Scale Integrated (VLSI) circuits. VLSI circuits having about 5000 transistors and other circuit elements with their associated circuits on a single chip made it possible to have microcomputers of fourth generation.

Fourth generation computers became more powerful, compact, reliable, and affordable. As a result, it gave rise to Personal Computer (PC) revolution. In this generation, time sharing, real time networks, distributed operating system were used. All the high-level languages like C, C++, DBASE etc., were used in this generation.

The main features of fourth generation are:

• VLSI technology used
• Very cheap
• Portable and reliable
• Use of PCs
• Very small size
• Pipeline processing
• No AC required
• Concept of internet was introduced
• Great developments in the fields of networks
• Computers became easily available

Some computers of this generation were:

• DEC 10
• STAR 1000
• PDP 11
• CRAY-1(Super Computer)
• CRAY-X-MP(Super Computer)

Fifth Generation Computers

The period of fifth generation is 1980-till date. In the fifth generation, VLSI technology became  ULSI (Ultra Large Scale Integration) technology, resulting in the production of microprocessor chips having ten million electronic components.

This generation is based on parallel processing hardware and AI (Artificial Intelligence) software. AI is an emerging branch in computer science, which interprets the means and method of making computers think like human beings. All the high-level languages like C and C++, Java, .Net etc., are used in this generation

The main features of fifth generation are:

• ULSI technology
• Development of true artificial intelligence
• Development of Natural language processing
• Advancement in Parallel Processing
• Advancement in Superconductor technology
• More user-friendly interfaces with multimedia features
• Availability of very powerful and compact computers at cheaper rates

Some computer types of this generation are:

• Desktop
• Laptop
• Notebook
• Ultrabook
• Chromebook

 

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Theory - 81 :- Computer Advantage, Dis Advantage, Applications

Advantages of Computers

Following are certain advantages of computers.

High Speed

• Computer is a very fast device.
• It is capable of performing calculation of very large amount of data.
• The computer has units of speed in microsecond, nanosecond, and even the picoseconds.
• It can perform millions of calculations in a few seconds as compared to man who will spend many months to perform the same task.

Accuracy

• In addition to being very fast, computers are very accurate.
• The calculations are 100% error free.
• Computers perform all jobs with 100% accuracy provided that the input is correct.

Storage Capability

• Memory is a very important characteristic of computers.
• A computer has much more storage capacity than human beings.
• It can store large amount of data.
• It can store any type of data such as images, videos, text, audio, etc.

Diligence

• Unlike human beings, a computer is free from monotony, tiredness, and lack of concentration.
• It can work continuously without any error and boredom.
• It can perform repeated tasks with the same speed and accuracy.

Versatility

• A computer is a very versatile machine.
• A computer is very flexible in performing the jobs to be done.
•  This machine can be used to solve the problems related to various fields.
• At one instance, it may be solving a complex scientific problem and the very next  moment it may be playing a card game. 

Reliability

• A computer is a reliable machine.
• Modern electronic components have long lives.
• Computers are designed to make maintenance easy.

Automation

• Computer is an automatic machine.
• Automation is the ability to perform a given task automatically. Once the computer  receives a program i.e., the program is stored in the computer memory, then the program and instruction can control the program execution without human interaction.

Reduction in Paper Work and Cost

• The use of computers for data processing in an organization leads to reduction in paperwork and results in speeding up the process.
• As data in electronic files can be retrieved as and when required, the problem of maintenance of large number of paper files gets reduced.
• Though the initial investment for installing a computer is high, it substantially reduces the cost of each of its transaction.

Disadvantages of Computers

Following are certain disadvantages of computers.

No I.Q.

• A computer is a machine that has no intelligence to perform any task.
• Each instruction has to be given to the computer.
• A computer cannot take any decision on its own.

Dependency

• It functions as per the user’s instruction, thus it is fully dependent on humans.

Environment

• The operating environment of the computer should be dust free and suitable.

No Feeling

• Computers have no feelings or emotions.
• It cannot make judgment based on feeling, taste, experience, and knowledge unlike humans.

Application of Computers in Various Fields

Business 

A computer has high speed of calculation, diligence, accuracy, reliability, or versatility which has made it an integrated part in all business organizations. 

Banking 

Today, banking is almost totally dependent on computers. Banks provide the following facilities: Online accounting facility, which includes checking current balance, making deposits and overdrafts, checking interest charges, shares, and trustee records. ATM machines which are completely automated are making it even easier for customers to deal with banks.

Insurance 

Insurance companies are keeping all records up-to-date with the help of computers. Insurance companies, stock broking firms are widely using computers for their concerns. Insurance companies are maintaining a database of all clients with information showing:

Education 

The computer helps in providing a lot of facilities in the education system.  The computer provides a tool in the education system known as CBE (Computer Based Education). Computer education is rapidly increasing the graph of number of computer students. It is used to prepare a database about performance of a student and analysis is carried  out on this basis.

Marketing 

In marketing, uses of the computer are following:

1. Advertising - With computers, advertising professionals create art and graphics, write and revise copy, and print and disseminate ads with the goal of selling more products.
2. Home Shopping - Home shopping has been made possible through the use of  computerized catalogues that provide access to product information and permit direct  entry of orders to be filled by the customers. 

Healthcare 

Computers have become an important part in hospitals, labs, and dispensaries. They are being used in hospitals to keep the record of patients and medicines. It is also used in scanning and  diagnosing different diseases. ECG, EEG, ultrasounds and CT scans, etc. are also done by computerized machines.

Engineering Design 

Computers are widely used for Engineering purpose. One of the major areas is CAD (Computer Aided Design) that provides creation and modification of images. Some of the fields are: Structural Engineering Industrial Engineering Architectural Engineering

Military 

Computers are largely used in defense. Modern tanks, missiles, weapons, etc. Military also employs computerized control systems.

Communication 

Communication is a way to convey a message, an idea, a picture, or speech that is received and understood clearly and correctly by the person for whom it is meant. Some main areas in this category are: E-mail ,Chatting, Usenet, FTP, Telnet, Video-conferencing

Government  

Computers play an important role in government services. Some major fields in this category are:  Budgets , Sales tax department, Income tax department, Computation of male/female ratio, Computerization of voters’ lists, Computerization of PAN card, Weather forecasting

 

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Theory - 80 :- Computer - Definition, Function, Characteristics

What is a computer?.

Computer is an advanced electronic device that takes raw data as an input from the user and processes it under the control of a set of instructions (called program), produces a result (output), and saves it for future use. This tutorial explains the foundational concepts of computer hardware, software, operating systems, peripherals, etc. along with how to get the most value and impact from computer technology.

Charles Babbage is called the “Grand Father” of the computer. The First mechanical computer designed by Charles Babbage was called Analytical Engine. It uses read-only memory in the form of punch cards.

Functionalities of a Computer

There are three basic functionalities of a Computer System and they are

• Input
• Process
• Storage
• Output

But if we look at it in a very broad sense, any digital computer carries out the following five functions:

Step 1 - Takes data as input.

Step 2 - Stores the data/instructions in its memory and uses them as required.

Step 3 - Processes the data and converts it into useful information.

Step 4 - Generates the output.

Step 5 - Controls all the above four steps.

CHARACTERISTICS OF COMPUTER

• Speed The computer can process data very fast, at the rate of millions of instructions per second. Some calculations that would have taken hours and days to complete otherwise, can be completed in a few seconds using the computer. For example, calculation and generation of salary slips of thousands of employees of an organization, weather forecasting that requires analysis of a large amount of data related to temperature, pressure and humidity of various places, etc.
• Accuracy Computer provides a high degree of accuracy. For example, the computer can accurately give the result of division of any two numbers up to 10 decimal places.
• 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.
• Storage Capability Large volumes of data and information can be stored in the computer and also retrieved whenever required. A limited amount of data can be stored, temporarily, in the primary memory. Secondary storage devices like floppy disk and compact disk can store a large amount of data permanently.
• Versatility Computer is versatile in nature. It can perform different types of tasks with the same ease. At one moment you can use the computer to prepare a letter document and in the next moment you may play music or print a document.

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