By: Mandip Gill

I.T 9

HISTORY OF COMPUTERTECHNOLOGY

OVERVIEW Computers started with the development of the abacus several thousand years

ago

The abacus lets us do computations fast by sliding beads arranged on a rack; this has been around for thousands of years

Later, machines of different sorts eventually replaced early mechanical tools like the abacus

In 1642, Blaise Pascal invented a numerical wheel calculator to help his father who was a French tax collector to compute taxes each citizen owed

The Pascaline used a system of movable dials to add numbers with as many as eight digits

In 1812, Charles Babbage began to develop a machine called the Difference Engine which was intended to have a stored program and to perform calculations and print the results, but after 10 years of work, he left this machine and started working on a more better and revised one: the Analytical Engine

In 1820, Charles Xavier Thomas de Colmar invented the arithometer, a mechanical calculator that was able to perform the four basic mathematical functions: addition, subtraction, multiplication, and division

The arithometer was improved many times and it was used a lot until World War I

Herman Hollerith worked for the U.S. Census Bureau in 1889 and before in 1880 it had taken 7 years to count the census

Then Hollerith invented a quicker way to count the census which only took 6 weeks

First Generation Computers These modern computers were introduced during World War II

In England, a device called Colossus was made to decode encrypted German messages and that was the only thing it did but it was a marvel to the Allies and they had an advantage in war

The U.S. Army Ordnance Department and the University of Pennsylvania together developed the ENIAC

The project to develop ENIAC started in 1943 and was completed in 1946

It was difficult to operate but the ENIAC could perform calculations faster than any other calculating device that existed then

It could calculate a 60-second trajectory in 30 seconds

The ENIAC weighed over 30 tons, contained 19,000 transistor tubes, 1,500 relays, and consumed nearly 200 kilowatts of power

The ENIAC eventually gave way to more powerful computers

The EDVAC, designed by John Von Neumann had a central processing unit

The UNIVAC, built by Remington Rand was the first commercially computing device available

Second Generation Computers Starting about 1956, the second generation of computers was marked by the shift from large,

bulky, failure-prone vacuum tubes to transistors

Transistors use an electric charge, allowing it to alternate between an insulator and a conductor

As a conductor, the transistor is said to be in an "on" state letting another current to pass through it, and as an insulator, the current is stopped, placing the transistor in an "off" state

Transistors paved the way for much smaller, faster computers

Early supercomputers were used by atomic energy laboratories and the U.S. Navy Research and Development center to do the hard calculations associated with atomic weapons research

During this time, printers, disk and tape storage, memory and stored programs allowed computers to become multifunctioning devices,

Computer programming also changed during this time

Machine language (a system of 1s and 0s that communicates instructions directly to the computer's hardware) gave way to assembly languages

An assembly language uses human readable codes, to represent a series of 1s and 0s and each assembly instruction goes along with one machine-language instruction

As time passed, computer scientists invented high-level languages such as COBOL used in writing programs for business use, and FORTRAN used in writing programs for scientific research

Third Generation Computers Jack Kilby and Robert Noyce invented the integrated circuit (IC) in the late 1950’s

They produced much less heat than transistors

Less heat allowed more components to fit into a single chip

A chip is a semiconducting substance (such as silicon), made in a tiny package that looks like a thin wafer

Microchips have allowed computers to shrink to the size of today’s laptop computers, which have more power than their enormous ancestors

Computers have become even smaller and more reliable

Fourth Generation Computers Computers became readily available (in terms of size, cost, and

reliability) to smaller businesses, and eventually to people

The first (PC) appeared in 1974

In the following years, the Apple I and II and the Commodore PET, were introduced

By 1990, 65 million PCs were in use

20 years after the first PCs, 1 billion personal computers were in use worldwide

While computer hardware was evolving, computer software and operating systems were too

Computers allow us to do many things, It is hard to imagine our world without them

COMPUTER HARDWAREAND SOFTWARE

Define Hardware And Input/output Devices

Hardware is the physical components of the computer

The principal concepts and technology behind this hardware remain essentially the same

The most popular and most used input devices include the keyboard and mouse, and there are other technologies that are used too

It would be nearly impossible to work with computers without input and output devices

Input devices allow you to enter information so that the computer can do the work it is designed to do

Without output devices, we would have no idea whether the computer was doing the right thing

Output is feedback; it lets us know what is happening on the inside of the computer

Today, the most common output device is your computer monitor

Another modern output device is the printer

Processors And Memory The single most important component of a computer is the central processing unit (CPU)

The CPU is basically the brains of the computer

The CPU performs very basic functions but performs these operations millions and even billions of times every second

Transistors lie at the heart of the CPU and they can be in either one of two states, on (when they are conducting electricity) and off (when they are not conducting electricity)

The CPU has no memory, it forgets the last calculation and starts the new one

Random-access memory (RAM) is a storage unit for data going to and coming from the CPU

RAM can hold a large quantity of data, but it can't store it long-term

Whenever you turn your computer off, all the information stored in RAM is lost and gone

Even when the computer is on, data stored in RAM are being changed and updated quickly

Hard Drives And Removable Storage

To store data long term your computer uses hard drives, CD-ROMs, and floppy disks

Each of these uses different techniques for storing and retrieving data

Storage capacity is a measure of how many bits of data the medium can store

The primary storage device in a computer is the hard drive

Hard drives store data on a series of magnetic recording platters made of high-precision aluminum or glass

Hard drives are not portable from one computer to another

A storage device in use today, the recordable CD (CD-R), records data onto a disk

Other types of removable storage include optical drives, Zip drives, and USB drives

Networks Networking is the most explosive growth area of the

computer industry

Networks connect computers together to share files, programs, and other resources

Media are the physical connections that join all the network’s parts so they can communicate

Most networks use a sort of cabling, such as a twisted-pair wire or coaxial cable and the growing number of networks transmit data by wireless links

The media connects the network to the individual computers, which are called nodes and each one contains a network interface card (NIC)

Operating Systems Operating Systems(OS), often called platforms do two important jobs

They manage the hardware and software on your computer system and provide a consistent interface for applications

Operating systems fall into many categories, single user, multitasking, and multiuser and the one most know about is the single user, multitasking operating system

In this system, a user can tap the resources of a single computer to perform multiple tasks, mostly at the same time and MacOS and Windows are examples

Multiuser operating systems, allow multiple users to tap resources of a single, powerful computer and each user must have sufficient resources available to meet his or her needs

Examples of operating systems include UNIX/Linux, MacOS, and DOS/Windows

Software Applications The type of software that you buy at a nearby computer store is

generally called desktop software

Desktop hardware runs on minimal hardware, and usually must be installed on the computer to run

Desktop software is categorized by the type of function it serves and there are database applications, word processing applications, image editing applications, and utility applications and each group may have many divisions in it

Some software does not run on your computer at all and web applications can run entirely on a Web server and you can access this through a standard Web browser

The line between desktop applications and Web-based applications is blurring fast

Web services provide applications with a standardized way of exchanging information across the Internet