The document summarizes the generations of computer architecture from the mechanical computers of the 17th century to the development of personal computers in the late 20th century. It outlines the key developments, people involved, and technologies that defined each generation including the transition from vacuum tubes to transistors to integrated circuits. Major computers and innovations within each generation are highlighted such as the ENIAC, EDSAC, IBM System/360, and the development of the personal computer by Apple and IBM.

1. Perez, Raphael Ray L.Prof. Flordeliz Garcia<br />BSCP / 3rd yr. – 3sCOMP 1013 - Intro to I.C.T. with Lab.<br />MILESTONES OF COMPUTER ARCHITECTURE<br />Generations of Computer ArchitectureDevelopmentsPeople InvolvedThe Zeroth Generation- Mechanical Computers (1642-1945)Working Calculating Machine is build which entirely composed of gears, and powered by a hand-operated crank. This machine could only do addition and subtraction.Another mechanical machine is built that could multiply and divide then later it was built the equivalent of a four-function pocket calculator.A mechanical engine called Difference Engine is developed which could only add and subtract designed to compute tables of numbers useful for naval navigation. Because of it’s single algorithm, it was known as the Analytical Engine which composed of four components: the store (memory), mill (computation unit), the input section (punched card reader) and output section (punched printed output).Since the Analytical Engine was programmable in a simple assembly language, it needed software. Babbage hired a young woman who became the world’s first computer programmer.A German engineering student built a series Automatic Calculating Machines using electromagnetic relays.An advanced machine is developed which used binary arithmetic and had capacitors for memory, which were periodically refreshed to keep the charge from leaking out, a process called “jogging the memory”.MARK I is completed at Harvard University in 1944 which had 72 words of 23 decimal digits each, and had an instruction time of 6 secs.Blaise Pascal (1623-1662)Baron Gottfried Wilhelm Von Leibniz (1646-1716)Charles Babbage (1792-1871)Ada Augusta LovelaceKonrad ZuseJohn AtanasoftHoward AikenThe First Generation – Vacuum Tubes (1945-1955)An electronic computer which called ENIAC (Electronic Numerical Integrator and Computer) is developed during this time. It consisted of 18,000 vacuum tubes and 1,500 relays; weighed 30 tons of consumed 140 kilowatts of power. Architecturally, the machine had 20 registers, each capable of holding 10-digit decimal numbers. The ENIAC was programmed to by setting up 6,000 multiposition switches and connecting a multitude of sockets with a verifiable forest of jumper cables.The first operational electronic computer, was the EDSAC (Electronic Delay Storage Automatic Calculator/ Computer built at the University of Cambridge.Neumann Machine is used in the EDSAC, the first storage program computer which consist of 5 basic parts: the memory, the arithmetic logic unit, the control unt, the control unit, the input and output equipment.The memory consisted of 4,096 words holding 40 bits, each is 0 or 1. Each word hold either two 20-bit instruction type, and 12 bits for specifying one of the 4,096 memory words.John Mauchley and his graduated student J. Presper EckertMaurice Wilkes John Von Neumann and Herman GoldstineThe Second Generation – Transistors (1955-1965)The transistors was invented at Bell Labs in 1948 which they awarded the Nobel Prize in Physics.Transistors revolutionized computers sublimed the use of vacuum tubes. The first transistorized computer was built in M.I.T.’s Lincoln Laboratory known as TX-0 (Transistorized Experimental Computer 0).Digital Equipment Corporation (DEC) is formed in 1957 to manufacture a commercial machine like the TX-0. It was 4 yr. before this machine, the PDP-1 finally appeared in 1961 which has 4k of 18-bit words and a cycle life of microseconds.DEC introduced PDP-8 which has a single bus, and the omnibus. 1401 is a machine that could read a write magnetic tapes, and read and punch cards, and print output almost one fourth as 7094. It is perfect only for business record keeping.Control Data Corporation (CDC) introduced the 6600, a machine that was nearly an order of magnitude faster than the mightier 7094. It’s highly parallel machine is the secret of highspeed and thus, 6600,7600, and Cray-1 are known as the supercomputers.John Bordeen, Walter Brattain, and William ShockleyKenneth OlsenSeymour CrayThe Third Generation- Integrated Circuits (1965-1980)Silicon Integrated Circuit is invented to allow dozens of transistors to be put on a single chip. This packaging made it possible to build computers that were smaller, faster, and cheaper than their transistorized predecessors.IBM introduced a single product line, the System 360, based on integrated circuits that was designed for both scientific and commercial computing. Another major innovation in the 360 was multi-programming, having several programs in memory at once so that when one is waiting for input/ output to complete, another could compute. The 360 also were the first machine that could emulate (stimulate) computer. Emulators was easy on the 360 because all the initial models and most of the later models were microprogrammed. Robert NoyceThe Fourth Generation – Very Large Scale Integration (1980-?)This generation made possible to put first tens of thousands, then hundreds of thousands and finally millions of transistors on a single chip, which led to smaller and faster computers. Personal computers were used in a very different way than larger computers. They were used for word processing, spreadsheets, and numerous application that the large computers could not handle well. The first personal computers were sold as kit. Each kits contained a printed circuit board, a bunch of chips typically including an Intel 8080, some cables, power supply, and 8-inch floppy disk.Software was not supply during this time, then later,the CP/m operating system became popular on 8080’s. It was true floppy disk operating system, with a file system and user commands typed in from keyboard.Each personal computer was the Apple and later the Apple II, designed by Steve Jobs and Steve Wozniac in the proverbal degree. This machine was enormoursly popular with have users and schools and made Apple a serious player overnight.IBM became dominant force in computer industry, finally decided to engage into the personal business. The initial version of IBM PC came equipped with the MS-DOS operating system supplied by ten-tiny Microsoft Corporation. Garry Kildall