Dec 30, 2015
Evolution of computers andComputers Todaywww.apepanthiya.com
HistoryThe history of any area is important in understanding it. Knowledge about the history will give you an overall idea (or the big picture) of how the computers today has evolved to this extent. The knowledge about history will help us in understanding the computers today and the significant milestones they have achieved from its inception.
Key developmentsMany new ideas have contributed significantly to the development of computer systems. Some of the key developments of computer systems from the past are:
Key Developments ctd..Abacus - calculating device (3000 BC)Pascaline - mechanical adding machine (1642)Babbage - analytical engine (1830s)Ada - first programmer (1800s)Punched cards - data storage (1800s)Hollerith - tabulating machine (1890s)Mark I - general purpose computer (1944)ENIAC - electronic computer (1946)UNIVAC - US Census Department (1951)EDVAC - Stored Program Concept (1951)
Key Developments ctd..Classification of ComputersMicroprocessor chipFloppy disk for data storagePocket CalculatorApple II - first personnel computerIBM PCPortable computersLaser Printing and Desktop PublishingMultimedia desktop computersHome video computersVideo conferencing
Abacus (3000 BC)Abacus is an ancient calculating device. This is still being used in China, Russia and the Far East
Pascaline (1642)Pascaline is a desktop mechanical addingmachine. This was developed by Blaise Pascal.
Punched Cards (1800s)A card punched with holes in certain places so that a computer can read data coded from the combination of holes.This was first used by Joseph Jacquard to automate his weaving factory.
Ada (1800s)This is probably the worlds first computer programmer. Collaborated with Charles Babbage.
Difference EngineIn 1822 Charlet Babbage introduces the Difference Engine and later the Analytical Engine (as he called them), a general purpose computing machine.
Difference Engine ctd..
Functionality of Difference EngineThe difference engine consists of a number of columns, numbered from 1 to N. Each column is able to store one decimal number. The only operation the engine can do is add the value of a column n+1 to column n to produce the new value of n. Column N can only store a constant, column 1 displays (and possibly prints) the value of the calculation on the current iteration. Subtraction can be accomplished through the use of the Method of complements, or ten's complement arithmetic, which works in exactly the same manner that modern computers perform subtraction, known as two's complement.
Analytical Engine (1830s)This was invented by Charles Babbage who is known as the father of computers. Designed to store one thousand 50 digitnumbers for calculations and decisions
Analytical EngineThe Analytical Engine included the units which a general purpose computer has today. Therefore it is considered the real predecessor for general purpose computers used today. The units included were: An input device: Punched cards provided the input.A control unit: A unit used to control or program the processor.
Analytical EngineA processor (or calculator) : A unit which consisted mechanical parts to process data. Storage: A unit which could hold 1000 50-digit numbers.An output device: Used to print the final results.Any how this computer was not completed, due to the problems of the technology availability at that period
Tabulating machine (1890s)This was invented by Herman Hollerith totabulate 1890 US census data. It was electrically powered and, used punched cards.
Atanasoff-Berry Computer (ABC)In 1937 John V. Atanasoff created the Atanasoff-Berry Computer (ABC).This is considered as the first electronic computer.
AtanasoffBerry Computer (ABC)Electronic computers based on digital switchingThe first true digital electronic computer was created by John V Atanasoff during 1937-1942.The Atanasoff-Berry Computer was the first to use modern digital switching techniques. Vacuum tubes were used as switches (the needs of switches are explained later). The concepts of using binary arithmetic and logic circuits were introduced to computing world by this ABC.
Mark I (1944)This was invented in 1944 by Dr. Howard Aiken. The idea is based on programmable, general purpose computer.
Mark IThe IBM Automatic Sequence Controlled Calculator (ASCC), called the Mark I by Harvard University,was the first large-scale automatic digital computer in the USA. It is considered by some to be the first universal calculator.The electromechanical ASCC was devised by Howard H. Aiken created at IBM, shipped to Harvard in February 1944, and formally delivered there on August 7, 1944. The main advantage of the Mark I was that it was fully automaticit didn't need any human intervention once it started. It was the first fully automatic computer to be completed. It was also very reliable, much more so than early electronic computers. It is considered to be "the beginning of the era of the modern computer" and "the real dawn of the computer age".
Von - NeumanIn 1945 John von Neuman specified the architecture of the EDVAC, which introduced the stored-program computer concept
VON Neuman ArchitectureIn 1945 John von Neuman specified the architecture of the EDVAC, which introduced the stored-program computer conceptJohn Von Neumann introduced the idea of using the computer as a fixed physical structure and to use programmed control, without the need for any change in hardware. This allowed executing many different programs (tasks) without changing the physical structure of the computer. The Von Neumanns idea is known as the stored-program technique (figure 2.10. This idea became the base for the future generation high-speed computers and is used by modern day computers.
ENIAC (Electrical Numerical Integrator and Calculator) In 1946 John Mauchly and J. Presper Eckert introduced the ENIAC, an electronic computing machine.
ENIACThis was a valve based computer and now referred to as a first generation computer. ENIAC had the following characteristics:Operated on 10-digit numbers and could multiply two such numbers at the rate of 300 products per second. Was about 1000 times faster than the previous generation of electromechanical relay computers.Was a valve based computer.Used approximately 18,000 vacuum tubes, and occupied 1,800 square feet of floor space and consumed around 180,000 watts of electrical power.Punch cards were used as input and output and registers served as adders and also as quick-access read/write storage.The executable instructions of a program were created using specified wiring and switches that controlled the flow of computations through the machine.AS such, ENIAC had to be rewired and switched for each program to be run.
UNIVACUNIVAC to the modern day computers At around 1947 computers started to use these ideas mentioned above such as stored-program technique. They are now considered as first generation computers. Some machines introduced at this time are EDVAC and UNIVAC (Universal Automatic Computer ). These computers used the concept of RAM (Random Access Memory) for the first time. The RAM was used to store programs and data when the computer is functioning. They used the machine language to write programs and later computers started to use high-level languages.UNIVAC was the first true general-purpose computer which was able to manipulate both alphabetical and numerical programs. This made computers available not only for science and military, but also for business.*EDVAC and UNIVAC was created in 1951
In 1947 William Shockley, Walter Brattain and John Bardeen was successful in testing the point-contact transistor. This made the semiconductor revolution which helped to reduce the size of computers.
From Univac to computers TodayGenerations of computersThe development of computers and the consideration of key developments haveenabled computers to be categorized into various generations. Following is summary of the generations of computers.
First Generation (1951-1958)
Used vacuum tubes for internal operationsUsed low-Level languages for programming (machine language)Used magnetic drums for primary memory.Primary memory was limited.Heat and maintenance problems were there.Used punch cards for input and outputs.Input and output was slow.e.g. UNIVAC I, EDVAC
Second Generation (1958-1964)
Used transistors for internal operations.Increased use of high level languages.Used magnetic cores for primary memory.Increased memory capacity.Binary coded data were used.Increasing processing speed.Used magnetic tapes and disks for secondary storageE.g. IBM 1620 , UNIVAC 1108.Transisters
Third Generation (1965-1970)
Used (ICs) on silicon chips for internal operations.Memory capacity was increased.Minicomputers became a common use.Software industry emerged.Reduction in size and cost of computers happened.Increase in speed and reliability.E.g. HONEY WELL-6000 SERIES
HONEYWELL 600 SeriesIC
Fourth Generation (1971-today)
Used Large Scale Integration (LSI) and Very Large Scale Integration (VLSI) for internal operations.Development of the microprocessor happened.Introductions of micro and super computers.Increase in speed, power and storage capacity.