Computer Basics:Week 1-2

  COMPUTER OVERVIEW                                                                                                                                                                                    

Computer is an advanced electronic device that takes raw data as input from the user and processes it under the control of set of instructions (called program), gives the result (output), and saves it for the future use.

Computer is an electronic data processing device which

• Accepts and stores data input,
• Processes the data input, and
• Generates the output in a required format. 

ELEMENTS OF COMPUTER

There are two elements of computer:

·         Hardware: is a physical appearance of computer.

·         Software: is a program that computer need in order to function

Any digital computer carries out five functions in gross terms:

• Takes data as input.
• Stores the data/instructions in its memory and use them when required.
• Processes the data and converts it into useful information.
• Generates the output
• Controls all the above four steps.

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. But nowadays, generation includes both hardware and software, which together make up an entire computer system.

There are totally five computer generations known till date. Each generation has been discussed in detail along with their time period and characteristics. Here approximate dates against each generations have been mentioned which are normally accepted.
Following are the main five generations of computers

	GENERATION OF COMPUTER

1	First Generation The period of first generation: 1946-1959. Vacuum tube based.
2	Second Generation The period of second generation: 1959-1965. Transistor based.
3	Third Generation The period of third generation: 1965-1971. Integrated Circuit based.
4	Fourth Generation The period of fourth generation: 1971-1980. VLSI microprocessor based.
5	Fifth Generation The period of fifth generation: 1980-onwards. ULSI microprocessor based

HISTORY OF COMPUTER

History of Computers - Long, Long Ago
The Abacus

• beads on rods to count and calculate
• still widely used in Asia!

History of Computers - Way Back When
The Slide Rule 1630

• based on Napier’s rules for logarithms
• used until 1970s

History of Computers - 19th Century
Jacquard Loom

• used metal cards with punched holes to guide weaving process
• first stored program - metal cards
• first computer manufacturing
• still in use today!

Charles Babbage - 1792-1871
Difference Engine c.1822

• huge calculator, never finished

Analytical Engine 1833

• could store numbers
• calculating "mill" used punched metal cards for instructions
• powered by steam!
• accurate to six decimal places

Ada Augusta - First Programmer

• Worked with Charles Babbage
• Programmed Analytical Engine

Vacuum Tubes - 1930 - 1950s

• First Generation Electronic Computers used Vacuum Tubes
• Vacuum tubes are glass tubes with circuits inside.
• Vacuum tubes have no air inside of them, which protects the circuitry.

UNIVAC - 1951

• First commercially available computer
• sold to censu bureau
• "a big pocket calculator"
• until 1970 was standard computer, but very expensive
• http://www.letsfindout.com/subjects/space/univac.html

First Computer Bug - 1945

• Relay cards carried information
• Grace Hopper found an actual moth stuck to card responsible for a malfunction
• Called it "debugging" a computer

First Transistor

• Uses Silicon
• developed in 1948
• won a Nobel prize
• on-off switch
• Second Generation Computers used Transistors, starting in 1956

Integrated Circuits
 

• Third Generation Computers used Integrated Circuits (chips).
• Integrated Circuits are transistors, resistors, and capacitors integrated together into a single “chip”

Birth of Personal Computers -
Kenbak I - 1971

• Very primitive, just flashing lights and buttons
• about $750

MITS Altair - 1975 (pictured)

• 256 byte memory
• 2 MHz Intel 8080 chips
• Just a box with flashing lights
• cost $395 kit, $495 assembled.

The First Microprocessor - 1971
 

• The Intel 4004 had 2,250 transistors
• four-bit chunks (four 1’s or 0’s)
• 108Khz
• 0.6 Mips (million instructions/sec)
• Pentium 133 - 300 Mips
• Called "Microchip"

 

TYPES OF COMPUTER

The computer sitting on the desk in your classroom is a microcomputer. It is a small, powerful piece of equipment. Even so, the power of the microcomputer is not enough for most large organizations. The computer industry consists of more than just microcomputers.

Any classification of computers is somewhat arbitrary. Computer can be classified it to following basis defined below.

·         On the basis of functionality

·         On the basis of Size, Speed and Cost.

ON BASIS OF FUNCTIONALITY

• Analog
• Digital
• Hybrid

Analog Computers

Analog computers are used to process analog data. Analog data is of continuous nature and which is not discrete or separate. Such type of data includes temperature, pressure, speed weight, voltage, depth etc. These quantities are continuous and having an infinite variety of values.

It measures continuous changes in some physical quantity e.g. The Speedometer of a car measures speed, the change of temperature

is measured by a Thermometer, the weight is measured by Weights machine. These computers are ideal in situations where data can be accepted directly from measuring instrument without having to convert it into numbers or codes.

Analog computers are the first computers being developed and provided the basis for the development of the modern digital computers. Analog computers are widely used for certain specialized engineering and scientific applications, for calculation and measurement of analog quantities. They are frequently used to control process such as those found in oil refinery where flow and temperature measurements are important. They are used for example in paper making and in chemical industry. Analog computers do not require any storage capability because they measure and compare quantities in a single operation. Output from an analog computer is generally in the form of readings on a series of dial (Speedometer of a car) or a graph on strip chart.

Digital Computers

A Digital Computer, as its name implies, works with digits to represent numerals, letters or other special symbols. Digital Computers operate on inputs which are ON-OFF type and its output is also in the form of ON-OFF signal. Normally, an ON is represented by a 1 and an OFF is represented by a 0. So we can say that digital computers process information which is based on the presence or the absence of an electrical charge or we prefer to say a binary 1 or 0.

A digital computer can be used to process numeric as well as non-numeric data. It can perform arithmetic operations like addition, subtraction, multiplication and division and also logical operations. Most of the computers available today are digital computers. The most common examples of digital computers are accounting machines and calculators.

The results of digital computers are more accurate than the results of analog computers. Analog computers are faster than digital. Analog computers lack memory whereas digital computers store information. We can say that digital computers count and analog computers measures.

Hybrid Computers

A hybrid is a combination of digital and analog computers. It combines the best features of both types of computers, i-e. It has the speed of analog computer and the memory and accuracy of digital computer. Hybrid computers are used mainly in specialized applications where both kinds of data need to be processed. Therefore, they help the user, to process both continuous and discrete data. For example a petrol pump contains a processor that converts fuel flow measurements into quantity and price values. In hospital Intensive Care Unit (ICU), an analog device is used which measures patient's blood pressure and temperature etc, which are then converted and displayed in the form of digits. Hybrid computers for example are used for scientific calculations, in defense and radar systems.

ON THE BASIS OF SIZE, SPEED AND COST: 

•  PC (Personal Computer)
• Work Station
• Mini Computer
• Main Frame
• Supercomputer

PC (Personal Computer)

A PC can be defined as a small, relatively inexpensive computer designed for an individual user. PCs are based on the microprocessor technology that enables manufacturers to put an entire CPU on one chip. Businesses use personal computers for word processing, accounting, desktop publishing, and for running spreadsheet and database management applications. At home, the most popular use for personal computers is playing games and surfing Internet.

Although personal computers are designed as single-user systems, these systems are normally linked together to form a network. In terms of power, now-a-days High-end models of the Macintosh and PC offer the same computing power and graphics capability as low-end workstations by Sun Microsystems, Hewlett-Packard, and Dell.

Workstation

Workstation is a computer used for engineering applications (CAD/CAM), desktop publishing, software development, and other such types of applications which require a moderate amount of computing power and relatively high quality graphics capabilities.
Workstations generally come with a large, high-resolution graphics screen, large amount of RAM, inbuilt network support, and a graphical user interface. Most workstations also have a mass storage device such as a disk drive, but a special type of workstation, called a diskless workstation, comes without a disk drive.

Common operating systems for workstations are UNIX and Windows NT. Like PC, Workstations are also single-user computers like PC but are typically linked together to form a local-area network, although they can also be used as stand-alone systems.

Minicomputer

It is a midsize multi-processing system capable of supporting up to 250 users simultaneously.

Mainframe

Mainframe is very large in size and is an expensive computer capable of supporting hundreds or even thousands of users simultaneously. Mainframe executes many programs concurrently and supports many simultaneous execution of programs

Supercomputer

Supercomputers are one of the fastest computers currently available. Supercomputers are very expensive and are employed for specialized applications that require immense amount of mathematical calculations (number crunching). For example, weather forecasting, scientific simulations, (animated) graphics, fluid dynamic calculations, nuclear energy research, electronic design, and analysis of geological data (e.g. in petrochemical prospecting).



 HARDWARE PARTS OF COMPUTER

Hardware represents the physical and tangible components of a computer i.e. the components that can be seen and touched.
Examples of Hardware are following:

• Input devices -- keyboard, mouse etc.
• Output devices -- printer, monitor etc.
• Secondary storage devices -- Hard disk, CD, DVD etc.
• Internal components -- CPU, motherboard, RAM etc.

SOFTWARE PARTS OF COMPUTER

Software is a set of programs, which is designed to perform a well-defined function. A program is a sequence of instructions written to solve a particular problem.
There are two types of software

• System Software
• Application Software

System Software

The system software is collection of programs designed to operate, control, and extend the processing capabilities of the computer itself. System software are generally prepared by computer manufactures. These software products comprise of programs written in low-level languages which interact with the hardware at a very basic level. System software serves as the interface between hardware and the end users.
Some examples of system software are Operating System, Compilers, Interpreter, Assemblers etc.




Features of system software are as follows:

• Close to system
• Fast in speed
• Difficult to design
• Difficult to understand
• Less interactive
• Smaller in size
• Difficult to manipulate
• Generally written in low-level language

Application Software

Application software products are designed to satisfy a particular need of a particular environment. All software applications prepared in the computer lab can come under the category of Application software.
Application software may consist of a single program, such as a Microsoft's notepad for writing and editing simple text. It may also consist of a collection of programs, often called a software package, which work together to accomplish a task, such as a spreadsheet package.
Examples of Application software are following:

• Payroll Software
• Student Record Software
• Inventory Management Software
• Income Tax Software
• Railways Reservation Software
• Microsoft Office Suite Software
• Microsoft Word
• Microsoft Excel
• Microsoft Powerpoint

Features of application software are as follows:

• Close to user
• Easy to design
• More interactive
• Slow in speed
• Generally written in high-level language
• Easy to understand
• Easy to manipulate and use
• Bigger in size and requires large storage space

IMPACTS OF COMPUTER

Advantages

Following list demonstrates the advantages of computers in today's arena.

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 picosecond.
• It can perform millions of calculations in a few seconds as compared to man who will spend many months for doing 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 correct input has been given.

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 and many others.

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 do repeated work with 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 means ability to perform the given task automatically.
• Once a program is given to computer i.e., stored in computer memory, the program and instruction can control the program execution without human interaction.

Reduction in Paper Work

• The use of computers for data processing in an organization leads to reduction in paper work and results in speeding up a 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.

Reduction in Cost

• Though the initial investment for installing a computer is high but it substantially reduces the cost of each of its transaction.

Disadvantages

Following list demonstrates the disadvantages of computers in today's arena

No I.Q

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

Dependency

• It functions as per a user’s instruction, so it is fully dependent on human being

Environment

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

No Feeling

• Computers have no feelings or emotions.
• It cannot make judgement based on feeling, taste, experience, and knowledge unlike a human being.
  APPLICATION OF COMPUTER
  

  Business

  A computer has high speed of calculation, diligence, accuracy, reliability, or versatility which made it an integrated part in all business organisations.
  Computer is used in business organisations for:
• Payroll calculations
• Budgeting
• Sales analysis
• Financial forecasting
• Managing employees database
• Maintenance of stocks etc.

Banking

Today banking is almost totally dependent on computer.
Banks provide following facilities:

• Banks provide online accounting facility, which includes current balances, deposits, overdrafts, interest charges, shares, and trustee records.
• ATM machines 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. The insurance companies, finance houses and stock broking firms are widely using computers for their concerns.
Insurance companies are maintaining a database of all clients with information showing

• procedure to continue with policies
• starting date of the policies
• next due installment of a policy
• maturity date
• interests due
• survival benefits
• bonus

Education

The computer has provided a lot of facilities in the education system.

• The computer provides a tool in the education system known as CBE (Computer Based Education).
• CBE involves control, delivery, and evaluation of learning.
• The computer education is rapidly increasing the graph of number of computer students.
• There are number of methods in which educational institutions can use computer to educate the students.
• It is used to prepare a database about performance of a student and analysis is carried out on this basis.

Engineering Design

Computers are widely used in Engineering purpose.
One of major areas is CAD (Computer aided design). That provides creation and modification of images. Some fields are:

• Structural Engineering - Requires stress and strain analysis for design of Ships, Buildings, Budgets, Airplanes etc.
• Industrial Engineering - Computers deal with design, implementation and improvement of integrated systems of people, materials and equipments.
• Architectural Engineering - Computers help in planning towns, designing buildings, determining a range of buildings on a site using both 2D and 3D drawings.