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First-Generation: The first commercially successful digital computer
UNIVAC was the first computer constructed by Eckert-Mauchly Computer Corporation in 1951. It was 14.5 feet long, 7.5 feet high, and 9 feet wide. UNIVAC could read data at the rate of 7,200 characters per second, and complete 2.25 million instruction cylcles per second. The cost of a UNIVAC was about $930, 000.
*image citation: offthebroiler.files.wordpress.com/2006/05/uni -
First-Generation: Characterizations
These types of computers were characterized by their use of vacuum tubes and the custom application programs. -
First Generation: Prototype
ENIAC is the protoype for first-generation computers. It contained about 18,000 vacuum tubes, and every tube was replaced at leace once in the first year of operation. -
First-Generation: Vacuum tubes
Vacuum tubes are electronic devices that control the flow of electrons in a vacuum. The purpose of a vacuum tube is to store individual peices of data. The downfall of vacuum tubes is that they consume a large quantity of power and tend to burn out quickly. *image citation: people.uncw.edu/.../texnh/images/VacuumTube.jpg -
First-Generation: Technology Requirements
Computeres including UNIVAC, ENIAC, and the Harvard Mark I required a large amount of space and electrical power. As techology and knowledge advanced the vacuum tubes and relay switches were replaced with smaller components that did not need as much power. -
First-Generation: Custom Application Programs
Custom application programs were made to order for the specific task the computer was to perform. -
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Second-Generation: Characterizations
The characterizations for second-generation computers include the development and use of transistors, operating systems, and programming language compilers. -
Second-Generation: Transistors
Transistors regulate current or voltage flow and act as a switch for electronic signals. They performed similar functions like vacuum tubes but they were much smaller, cheaper, less power hungry, and more reliable. Second-generation computers used transistors in place of vacuum tubes as the processing and memory technolgy for most computers. -
Second-Generation: Programming Language Compilers
These compilers allowed programmers to write instructions using English-like commands rather than machine language. High-level languages including COBOL and Fortran were available on second-generation computers, and are still used today. -
Second-Generation: Operating Systems
Operating systems are the characterization for second-generation computers. First-generation computers did not have operating systems, and programmers learned very quickly that having just the instructions for each software application was not sufficient. Therefore, the programmers consolidated their print routines into programs that any application software could acess, which in turn became an operating system. -
Third-Generation Computers
Jack Kilby and Robert Noyce developed integrated circuits that lead to the third-generation of computers.
*image citation: www.wired.com/.../2008/02/integrated_circuit.jpg -
Third-Generation: Characterizations
Integrated circuit technology made it possible to pack the equivalent of thousands of vacuum tubes or transistors onto a single miniature chip, which reduced the size, weight, and power requirements for devices including computers. -
Third-Generation: Prototype
The first two computers to incorporate integrated circuits were the RCA Spectra 70, and the IBM 360. The first orders for IBM 360 computers were filled in 1965. -
Third-Generation: First Commercially Successful Minicomputer
The DEC PDP-8 was introduced in 1965. They were designed to be smaller and less powerful than mainframe computers, while maintaining the capability to run multiple programs for multiple users. The speed was very fast, it was a small size, and most the cost was reasonable, which attracted many customers.
*image citation: blog.iso50.com/.../uploads/2008/10/dec-pdp-8.jpg -
Fourth-Generation Computers
Ted Hoff developed the first general purpose microprocessor that lead to the technology of fourth-generation computers. It was called the Intel 4004.
*image citation: www.thg.ru/cpu/20051118/images/4004.jpg -
Fourth-Generation: Microprocessor Manufacturers
Intel, Zilog, Motorola, and Texas Instruments were early industry leaders for microprocessors. -
Fourth-Generation: Characterizations
The microprocessor dramatically changed the computer industry, resulting in fourth-generation microprocessor-based computer systems that were faster, smaller, and even less expensive than third-generation computers. -
Fourth-Generation: Motorola Microprocessor
In 1974, they released the 6800 8-bit microprocessor, then created an even better one, the 6502, that was used in the Apple II and Commodore personal computer systems. -
Fourth-Generation: Zilog Microprocessor
Zilog introducted the Z80, which was an enhanced 8080 microprocessor that was used in many early computer systems. -
Fourth-Generation: Advancement of Microprocessors
Intel and Motorola continued their development of advanced microprocessors. Both manufacturers developments lead to the use of their microprocessors in Apple Macintosh computers, plus the PowerPC processors developed in the early 1990's and used in Macintosh computer systems. -
Third-Generation: Minicomputers Manufactured by Mainframe Makers
IBM and other mainframe makers introduced their style of minicomputers that put DEC out of business. DEC was purchased by Compaq in 1998, then was later purchased by Hewlett-Packard. -
Third-Generation: Minicomputers Today
The IBM AS/400 also known as the iSeries 400, was one of the few remaining devices that could be classified as a minicomputer. Today minicomputers are being replaced with high-end personal computers and servers. -
Fourth-Generation: Microprocessors Today
Today microprocessors are a key component of all types of computers including PDA's and supercomputers. Intel is the world's leading microprocessor manufacturer. Some other manufacturers include Hitachi, Texas Instruments, Toshiba, AMD, Motorola, and Sun Microsystems.
*image citation: static.howstuffworks.com/gif/nehalem-micropro
