Generations of Computers

BCA– Ist Fundamentals of Computers

Evolution of Computers

Blaise Pascal invented the first mechanical adding machine in 1642

Baron Gottfried Wilhelm von Leibniz invented the first calculator for

multiplication in 1671

Keyboard machines originated in the United States around 1880

Around 1880, Herman Hollerith came up with the concept of punched cards that

were extensively used as input media until late 1970s

Evolution of Computers

Charles Babbage is considered to be the father of modern digital computers

He designed “Difference Engine” in 1822

He designed a fully automatic analytical engine in 1842 for performing basic

arithmetic functions

His efforts established a number of principles that are fundamental to the

design of any digital computer

Some Early Computers

• The Mark I Computer (1937-44): The IBM Automatic Sequence Controlled

Calculator (ASCC), called Mark I by Harvard University's staff, was a general

purpose electro-mechanical computer that was used in the war effort

during the last part of World War II. The original concept was presented to IBM

by Howard Aiken in November 1937.

• The Atanasoff-Berry Computer (1939-42): The Atanasoff–Berry computer (ABC)

was the first automatic electronic digital computer. The ABC's priority is debated

among historians of computer technology, because it was not programmable.

THE MARK 1 THE ABC

Some Early Computers

• The ENIAC (1943-46): Electronic Numerical Integrator And Computer) was the

first electronic general-purpose computer. It was Turing-complete, digital, and

capable of being reprogrammed to solve "a large class of numerical problems."

• The EDVAC (1946-52): (Electronic Discrete Variable Automatic Computer) was

one of the earliest electronic computers. Unlike its predecessor the ENIAC, it

was binary rather than decimal, and was a stored program compute

THE ENIAC THE EDVAC

Some Early Computers

• The EDSAC (1947-49): Electronic Delay Storage Automatic Calculator was an early

British computer. The machine was constructed by Maurice Wilkes and his team at

the University of Cambridge Mathematical Laboratory in England. EDSAC was the

second electronic digital stored-program computer to go into regular service

• Manchester Mark I (1948): The Manchester Mark 1 was one of the earliest stored-

program computers, developed at the Victoria University of Manchester from

the Small-Scale Experimental Machine (SSEM) or "Baby" (operational in June 1948).

It was also called the Manchester Automatic Digital Machine, or MADM

THE EDSAC THE MANCHESTER MARK 1

Some Early Computers

• The EDSAC (1947-49): Electronic Delay Storage Automatic Calculator was an early

British computer. The machine was constructed by Maurice Wilkes and his team

at the University of Cambridge Mathematical Laboratory in England. EDSAC was

the second electronic digital stored-program computer to go into regular service

• Manchester Mark I (1948): The Manchester Mark 1 was developed at

the Victoria University of Manchester from the Small-Scale Experimental

Machine (SSEM) or "Baby" (operational in June 1948). It was also called the

Manchester Automatic Digital Machine, or MADM.

Some Early Computers

• The UNIVAC I (1951): The UNIVAC I (UNIVersal Automatic Computer I) was the

first commercial computer produced in the United States. It was designed

principally by J. Presper Eckert and John Mauchly, the inventors of the ENIAC.

Design work was started by their company, Eckert–Mauchly Computer

Corporation, and was completed after the company had been acquired

by Remington Rand (which later became part of Sperry, now Unisys). In the

years before successor models of the UNIVAC I appeared, the machine was

simply known as "theUNIVAC".

COMPUTER GENERATIONS

“Generation” in computer talk is a step in technology. It provides a framework

for the growth of computer industry

Originally it was used to distinguish between various hardware technologies, but

now it has been extended to include both hardware and software

Till today, there are five computer generations

COMPUTER GENERATIONS

COMPUTER GENERATIONS

COMPUTER GENERATIONS

COMPUTER GENERATIONS

COMPUTER GENERATIONS

DRUM PRINTERS

Line printers that print one line at a time

Have a solid cylindrical drum with characters embossed on its surface in the

form of circular bands.

Set of hammers mounted in front of the drum in such a manner that an inked

ribbon and paper can be placed between the hammers and the drum

Can only print a pre-defined set of characters in a predefined style that is

embossed on the drum

Impact printers and usually monochrome

Typical speeds are in the range of 300 to 2000 lines per minute

DRUM PRINTERS

CHAIN/ BAND PRINTERS

Line printers that print one line at a time

Consist of a metallic chain/band on which all characters of the character set

supported by the printer are embossed

Also have a set of hammers mounted in front of the chain/band in such a

manner that an inked ribbon and paper can be placed between the hammers

and the chain/band

CHAIN/ BAND PRINTERS

Can only print pre-defined sets of characters that are embossed on the

chain/band used with the printer

Cannot print any shape of characters, different sizes of print, and graphics such

as charts and graphs

Are impact printers and can be used for generating multiple copies by using

carbon paper or its equivalent

Are usually monochrome

Typical speeds are in the range of 400 to 3000 lines per minute

LEASER PRINTER

Page printers that print one page at a time

Consist of a laser beam source, a multi-sided mirror, a photoconductive drum

and toner (tiny particles of oppositely charged ink)

To print a page, the laser beam is focused on the electro statically charged drum

by the spinning multi-sided mirror

Toner sticks to the drum in the places the laser beam has charged the drum’s

surface.

Toner is then permanently fused on the paper with heat and pressure to

generate the printer output

Laser printers produce very high quality output having resolutions in the range

of 600 to 1200 dpi

LEASER PRINTER

Can print many special characters, different sizes of print, and graphics such as

charts and graphs

Are non-impact printers

Most laser printers are monochrome, but color laser printers are also available

Low speed laser printers can print 4 to 12 pages per minute. Very high-speed

laser printers can print 500 to 1000 pages per minute

More expensive than other printers

LEASER PRINTER

PLOTTERS

• Plotters are an ideal output device for architects, engineers, city planners, and

others who need to routinely generate high-precision, hard-copy graphic output

of widely varying sizes

• Two commonly used types of plotters are:

– Drum plotter, in which the paper on which the design has to be made is placed

over a drum that can rotate in both clockwise and anti-clockwise directions

– Flatbed plotter, in which the paper on which the design has to be made is spread

and fixed over a rectangular flatbed table

DRUM PLOTTER

FLATBET PLOTTER