FOURTH GENERATION COMPUTER

FOURTH GENERATION COMPUTER (1972-1984)

The fourth generation computer systems saw the use of large scale integration and very large scale integration the construction of computing elements. At this scale entire processors will fit in to a single chip, and for sample systems the entire Computer can fit on one chip. Gate delays dropped to about 1 ns per gate. Developments in software include very high level languages such as functional programming and programming in logic. These languages tend to use a declarative style a programmer gives a mathematical specification of what should be computed to the compiler and /or runtime systems. These languages are not jet in wide use, but are very promising as notations for programs that will run on massively parallel computers. Compilers for established languages started to use sophisticated optimization techniques to improve code, and compilers for vector processors were able to vectorize.

To important events marked the early part of the third generation: the development of the computer programming language and the UNIX operating system, both at Bell Labs. In 1972, Dennis Ritchie, seeking to meet the design goals of CPL and generalize Thompson's B developed the computer languages. In1982: AT&T agrees to give up 22Bell System companies in setting a 13-year old lawsuit brought by the Justice Department. Compaq computer incorporate. Sun Microsystems is founded. Microsoft licenses MS-DOS to 50 microcomputer manufacturers in the first 16^th month of availability. Time magazine names the computers it's Man of the year. U.S drops IBM antitrust suit begun in 1969. In 1983 Compaq ships its first computer in January and sells $111M, the greatest first year sales in the history of American business. Cray 2 computer introduced with one billion FLOPs performance rating. Lotus 1-2-3 replaces VisiCalc as the spreadsheet software of choice for microcomputers. NEC announces the SX-1and SX-2 supercomputers. Total computers in USE in the US exceed ten million units.

IN 1984 Apple introduces the Macintosh computer. IBM introduces the PC AT (Advanced Technology). IBM merges with Rolm Corp., which becomes a telecommunications subsidiary. The today 1000 personal computer becomes the#1 selling IBM PC- compatible in its first year MIDI (Musical Instrument Digital Interface) standards are developed for computers and digital music synthesizers.