generations of computers bca– i st fundamentals of computers
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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.
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
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
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
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
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
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
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