Apple Lisa . Officially “Lisa” stood for “Local Integrated Software Architecture”. Prior to the Lisa, all computers were text – based (Command line interface only). Lisa as the first commercial computer with GUI, allows you to point and click at any picture on the screen with a “mouse”. Lisa offered multitasking, a page white screen and the ability to copy and paste things between applications. Unfortunately, Lisa turned out to be an unpopular system, due to its high price and few available software applications.
References: http://oldcomputers.net/lisa.html
(3.3.2011 6:26PM) http://fp3.antelecom.net/gcifu/applemuseum/lisa2.html
(3.3.2011 6:58PM)
In lectures we discussed three different generations of computer architectures, explain what instigated the evolutionary jump for each generation of computer architecture.
The term generation means improvement in the development of a product.
The First Generation: 1946 – 1958 (The Vacuum Tube Years)The first generation computers were huge, slow, expensive, and produced great deal of heat. The main elements were vacuum tubes. Vacuum tubes purpose was to act like an amplifier and a switch. They could amplify the signal, and also they could stop and start the flow of electricity (switch).
ENIAC (Electronic Numerical Integrator and Calculator) was built at the University of Pennsylvania between 1943 and 1945 by John Mauchly and Presper Eckert. ENIAC contained 17,468 vacuum tubes, 7,200 crystal diodes, 1,500 relays, 70,000 resistors, 10,000 capacitors and around 5 million hand-soldered joints. It weighed 27 tons, took up 680 square feet (63 m2), and consumed 150 kW of power.
ENIAC had an inflexible architecture which essentially required rewiring to change its programming. And ENIAC produced so much heat that it had to be cooled by gigantic air conditioners.
Reprogramming ENIAC involved a hike [U.S. Army photo]
The Second Generation: 1959 – 1964 (Era of transistors)
Transistors were a milestone in the history of computers. They were invented by American physicists John Bardeen, Walter H. Brattain and Eilliam Shockley at AT&T's Bell Labs in 1947.
Transistors in a comparison to vacuum tubes are faster, smaller, cheaper and more reliable. They conduct electricity faster and better than vacuum tubes and they produce minimum heat. Transistors are made from silicon that makes them cheaper.
Without transistors the space travel could be impossible in 1960's.
The Third Generation: 1965 - (Integrated Circuits – Miniaturizing the Computer)
Transistors were very successful and with still alive trend “smaller, faster and cheaper” it became impossible to implement millions of transistors into a small chip manually. Invention of integrated circuits was another big step in the evolution of computers.
Robert Noyce of Fairchild Corporation and Jack Kilby of Texas Instruments independently discovered the potential of integrated circuits by placing the large number of transistors onto a single chip. This discovery had increased the power of a computer and lowered its cost considerably. Since then the number of transistors placed on a chip has doubled every two years. The size of the machines dropped to the size of small file cabinets.
(3.3.2011 10:47PM)
Draw a detailed diagram of the Von Neumann machine, illustrating the flow of communication. How is this related to more recent machines?
John von Neumann the Hungarian mathematician (1903 – 1957) developed a basic model of computer architecture that is in use today.
Von Neumann computer systems contain three main building blocks:
- the central processing unit (CPU),
- memory,
- and input/output devices (I/O).
- These three components are connected together using the system bus.
The most prominent items within the CPU are the registers: they can be manipulated directly by a computer program.
Von Neumann computer systems
Components of the Von Neumann model:
- Memory: Storage of data/program.
- CPU(Central Processing Unit): Computation / Processing data.
- Input devices: Getting the information to the computer.
- Output devices: Getting the information out from the computer.
- Control Unit: Makes sure that every part of the computer performs its task correctly.
Components of the Von Neumann model:
References:
(4.3.2011 9:35PM)
“Civilization advances by extending the number of important operations which we can perform without thinking about them.” Draw a comparison to the evolution of computing by taking into account Moore's law and the exponential growth of transistors in computers.
Moore's law is dead, according to Gordon Moore, its inventor.
“The extrapolation of a trend that was becoming clear even as long ago as 1965, and has been the pulse of the IT industry even since will eventually end, said Moore, who is now retired.”
The Moore's Law
"The number of transistors incorporated in a chip will approximately double every 24 months." —Gordon Moore, Intel Co-Founder
This forecast was more than just a prediction. Essentially, it described the basic business model for the semiconductor industry. Nowadays the technology is approaching atomic dimensions.
References:
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