Computer
Computer: A computer is a machine that manipulates
Computer: A computer is a machine that manipulates
data according to a list of instructions. Although
mechanical examples of computers have existed
throughout history, the first resembling a modern
computer were developed in the mid-20th century
(1940–1945). The first electronic
computers were the size of a large room,
consuming as much
power as several hundred modern personal
computers (PC).[1] Modern computers based on tiny
integrated circuits are millions to billions of times more
capable than the early machines, and occupy a fraction
of the space.[2] Simple computers are small enough to
fit into a wristwatch, and can be powered by a watch battery.
Personal computers in their various forms are icons of the
Information Age, what most people think of as a "computer", but the embedded computers found in devices ranging from fighter aircraft to industrial robots, digital cameras, and children's toys are the most numerous.
HISTORY OF COMPUTER:
Main article: History of computer hardware
The Jacquard loom was one of the first programmable devices.
The first use of the word "computer" was recorded in 1613, referring to a person who carried out calculations, or computations, and the word continued to be used in that sense until the middle of the 20th century. From the end of the 19th century onwards though, the word began to take on its more familiar meaning, describing a machine that carries out computations.[3]
The history of the modern computer begins with two separate technologies—automated calculation and programmability—but no single device can be identified as the earliest computer, partly because of the inconsistent application of that term. Examples of early mechanical calculating devices include the abacus, the slide rule and arguably the astrolabe and the Antikythera mechanism (which dates from about 150–100 BC). Hero of Alexandria (c. 10–70 AD) built a mechanical theater which performed a play lasting 10 minutes and was operated by a complex system of ropes and drums that might be considered to be a means of deciding which parts of the mechanism performed which actions and when.[4] This is the essence of programmability.
The "castle clock", an astronomical clock invented by Al-Jazari in 1206, is considered to be the earliest programmable analog computer.[5] It displayed the zodiac, the solar and lunar orbits, a crescent moon-shaped pointer travelling across a gateway causing automatic doors to open every hour,[6][7] and five robotic musicians who played music when struck by levers operated by a camshaft attached to a water wheel. The length of day and night could be re-programmed to compensate for the changing lengths of day and night throughout the year.[5]
The end of the Middle Ages saw a re-invigoration of European mathematics and engineering. Wilhelm Schickard's 1623 device was the first of a number of mechanical calculators constructed by European engineers, but none fit the modern definition of a computer, because they could not be programmed.
In 1801, Joseph Marie Jacquard made an improvement to the textile loom by introducing a series of punched paper cards as a template which allowed his loom to weave intricate patterns automatically. The resulting Jacquard loom was an important step in the development of computers because the use of punched cards to define woven patterns can be viewed as an early, albeit limited, form of programmability.
It was the fusion of automatic calculation with programmability that produced the first recognizable computers. In 1837, Charles Babbage was the first to conceptualize and design a fully programmable mechanical computer, his analytical engine.[8] Limited finances and Babbage's inability to resist tinkering with the design meant that the device was never completed.
In the late 1880s Herman Hollerith invented the recording of data on a machine readable medium. Prior uses of machine readable media, above, had been for control, not data. "After some initial trials with paper tape, he settled on punched cards ..."[9] To process these punched cards he invented the tabulator, and the key punch machines. These three inventions were the foundation of the modern information processing industry. Large-scale automated data processing of punched cards was performed for the 1890 United States Census by Hollerith's company, which later became the core of IBM. By the end of the 19th century a number of technologies that would later prove useful in the realization of practical computers had begun to appear: the punched card, Boolean algebra, the vacuum tube (thermionic valve) and the teleprinter.
During the first half of the 20th century, many scientific computing needs were met by increasingly sophisticated analog computers, which used a direct mechanical or electrical model of the problem as a basis for computation. However, these were not programmable and generally lacked the versatility and accuracy of modern digital computers.
Alan Turing is widely regarded to be the father of modern computer science. In 1936 Turing provided an influential formalisation of the concept of the algorithm and computation with the Turing machine. Of his role in the modern computer, Time Magazine in naming Turing one of the 100 most influential people of the 20th century, states: "The fact remains that everyone who taps at a keyboard, opening a spreadsheet or a word-processing program, is working on an incarnation of a Turing machine." [10]
George Stibitz is internationally recognized as a father of the modern digital computer. While working at Bell Labs in November of 1937, Stibitz invented and built a relay-based calculator he dubbed the "Model K" (for "kitchen table", on which he had assembled it), which was the first to use binary circuits to perform an arithmetic operation. Later models added greater sophistication including complex arithmetic and programmability.[11]
Defining characteristics of some early digital computers of the 1940s (In the history of computing hardware)
Name
First operational
Numeral system
Computing mechanism
Programming
Turing complete
Zuse Z3 (Germany)
May 1941
Binary
Electro-mechanical
Program-controlled by punched film stock (but no conditional branch)
Yes (1998)
Atanasoff–Berry Computer (US)
1942
Binary
Electronic
Not programmable—single purpose
No
Colossus Mark 1 (UK)
February 1944
Binary
Electronic
Program-controlled by patch cables and switches
No
Harvard Mark I – IBM ASCC (US)
May 1944
Decimal
Electro-mechanical
Program-controlled by 24-channel punched paper tape (but no conditional branch)
No
Colossus Mark 2 (UK)
June 1944
Binary
Electronic
Program-controlled by patch cables and switches
No
ENIAC (US)
July 1946
Decimal
Electronic
Program-controlled by patch cables and switches
Yes
Manchester Small-Scale Experimental Machine (UK)
June 1948
Binary
Electronic
Stored-program in Williams cathode ray tube memory
Yes
Modified ENIAC (US)
September 1948
Decimal
Electronic
Program-controlled by patch cables and switches plus a primitive read-only stored programming mechanism using the Function Tables as program ROM
Yes
EDSAC (UK)
May 1949
Binary
Electronic
Stored-program in mercury delay line memory
Yes
Manchester Mark 1 (UK)
October 1949
Binary
Electronic
Stored-program in Williams cathode ray tube memory and magnetic drum memory
Yes
CSIRAC (Australia)
November 1949
Binary
Electronic
Stored-program in mercury delay line memory
Yes
HISTORY OF COMPUTER:
Main article: History of computer hardware
The Jacquard loom was one of the first programmable devices.
The first use of the word "computer" was recorded in 1613, referring to a person who carried out calculations, or computations, and the word continued to be used in that sense until the middle of the 20th century. From the end of the 19th century onwards though, the word began to take on its more familiar meaning, describing a machine that carries out computations.[3]
The history of the modern computer begins with two separate technologies—automated calculation and programmability—but no single device can be identified as the earliest computer, partly because of the inconsistent application of that term. Examples of early mechanical calculating devices include the abacus, the slide rule and arguably the astrolabe and the Antikythera mechanism (which dates from about 150–100 BC). Hero of Alexandria (c. 10–70 AD) built a mechanical theater which performed a play lasting 10 minutes and was operated by a complex system of ropes and drums that might be considered to be a means of deciding which parts of the mechanism performed which actions and when.[4] This is the essence of programmability.
The "castle clock", an astronomical clock invented by Al-Jazari in 1206, is considered to be the earliest programmable analog computer.[5] It displayed the zodiac, the solar and lunar orbits, a crescent moon-shaped pointer travelling across a gateway causing automatic doors to open every hour,[6][7] and five robotic musicians who played music when struck by levers operated by a camshaft attached to a water wheel. The length of day and night could be re-programmed to compensate for the changing lengths of day and night throughout the year.[5]
The end of the Middle Ages saw a re-invigoration of European mathematics and engineering. Wilhelm Schickard's 1623 device was the first of a number of mechanical calculators constructed by European engineers, but none fit the modern definition of a computer, because they could not be programmed.
In 1801, Joseph Marie Jacquard made an improvement to the textile loom by introducing a series of punched paper cards as a template which allowed his loom to weave intricate patterns automatically. The resulting Jacquard loom was an important step in the development of computers because the use of punched cards to define woven patterns can be viewed as an early, albeit limited, form of programmability.
It was the fusion of automatic calculation with programmability that produced the first recognizable computers. In 1837, Charles Babbage was the first to conceptualize and design a fully programmable mechanical computer, his analytical engine.[8] Limited finances and Babbage's inability to resist tinkering with the design meant that the device was never completed.
In the late 1880s Herman Hollerith invented the recording of data on a machine readable medium. Prior uses of machine readable media, above, had been for control, not data. "After some initial trials with paper tape, he settled on punched cards ..."[9] To process these punched cards he invented the tabulator, and the key punch machines. These three inventions were the foundation of the modern information processing industry. Large-scale automated data processing of punched cards was performed for the 1890 United States Census by Hollerith's company, which later became the core of IBM. By the end of the 19th century a number of technologies that would later prove useful in the realization of practical computers had begun to appear: the punched card, Boolean algebra, the vacuum tube (thermionic valve) and the teleprinter.
During the first half of the 20th century, many scientific computing needs were met by increasingly sophisticated analog computers, which used a direct mechanical or electrical model of the problem as a basis for computation. However, these were not programmable and generally lacked the versatility and accuracy of modern digital computers.
Alan Turing is widely regarded to be the father of modern computer science. In 1936 Turing provided an influential formalisation of the concept of the algorithm and computation with the Turing machine. Of his role in the modern computer, Time Magazine in naming Turing one of the 100 most influential people of the 20th century, states: "The fact remains that everyone who taps at a keyboard, opening a spreadsheet or a word-processing program, is working on an incarnation of a Turing machine." [10]
George Stibitz is internationally recognized as a father of the modern digital computer. While working at Bell Labs in November of 1937, Stibitz invented and built a relay-based calculator he dubbed the "Model K" (for "kitchen table", on which he had assembled it), which was the first to use binary circuits to perform an arithmetic operation. Later models added greater sophistication including complex arithmetic and programmability.[11]
Defining characteristics of some early digital computers of the 1940s (In the history of computing hardware)
Name
First operational
Numeral system
Computing mechanism
Programming
Turing complete
Zuse Z3 (Germany)
May 1941
Binary
Electro-mechanical
Program-controlled by punched film stock (but no conditional branch)
Yes (1998)
Atanasoff–Berry Computer (US)
1942
Binary
Electronic
Not programmable—single purpose
No
Colossus Mark 1 (UK)
February 1944
Binary
Electronic
Program-controlled by patch cables and switches
No
Harvard Mark I – IBM ASCC (US)
May 1944
Decimal
Electro-mechanical
Program-controlled by 24-channel punched paper tape (but no conditional branch)
No
Colossus Mark 2 (UK)
June 1944
Binary
Electronic
Program-controlled by patch cables and switches
No
ENIAC (US)
July 1946
Decimal
Electronic
Program-controlled by patch cables and switches
Yes
Manchester Small-Scale Experimental Machine (UK)
June 1948
Binary
Electronic
Stored-program in Williams cathode ray tube memory
Yes
Modified ENIAC (US)
September 1948
Decimal
Electronic
Program-controlled by patch cables and switches plus a primitive read-only stored programming mechanism using the Function Tables as program ROM
Yes
EDSAC (UK)
May 1949
Binary
Electronic
Stored-program in mercury delay line memory
Yes
Manchester Mark 1 (UK)
October 1949
Binary
Electronic
Stored-program in Williams cathode ray tube memory and magnetic drum memory
Yes
CSIRAC (Australia)
November 1949
Binary
Electronic
Stored-program in mercury delay line memory
Yes
No comments:
Post a Comment