1. Computer Architecture Computer Generations  First Generation (1945 – 1955)  Second Generation (1955 – 1965)  Third Generation (1965 – 1975)  Fourth Generation (1975 – Present)

2. Computer Architecture Before the Computer Generations  Born in England in 1791, Charles Babbage conceptualizes a difference engine. In 1830 he enthusiastically began to build a full-scale working version, using a grant from the British government – He fails

3. Computer Architecture Before the Computer Generations  He conceived another machine, called the analytical engine and receive the support of Ada, the countess of Lovelace, which is considered the first computer programmer in history. Ada developed the instructions for doing computations on the analytical engine. The machine was never completed. In 1991, London Science Museum constructs the Analytical Engine in memory of Charles Babbage

4. Computer Architecture Before the Computer Generations  Herman Hollerith builds the Tabulating Machine and won the 1890 census contest  In 1880 United States census took 7.5 years to complete the calculation  With Hollerith machine, the 1890 census calculation took 6 weeks

5. Computer Architecture Before the Computer Generations  In 1896, Hollerith established the Tabulating Machine Company to market the product  In 1924, the company merges with two other companies and form the International Business Machines Corporation - IBM

6. Computer Architecture Before the Computer Generations  Thomas J Watson Sr. rules IBM for more than 30 years (1924 – 1956) and finances a project conducted by young Harvard professor of mathematics, Howard Aiken  In 1936 Howard reads the notes of Lady Lovelace and proposes the construction of a machine, for which Watson gave him $1 million. Harvard Mark 1 was born

7. Computer Architecture Before the Computer Generations  Harvard Mark 1 is 8 feet high and 55 feet long of steel and glass. It was released in 1944.  In early 1940s, the American military approaches Dr. John Mauchly at University of Pennsylvania to calculate trajectories for military missiles & artillery

8. Computer Architecture Before the Computer Generations  Dr. Mauchly builds the ENIAC (Electrical Numerical Integrator and Calculator) based on the previous work of Dr. John V Atanasoff (professor of physics at Iowa State University) called ABC (Atanasoff- Berry Computer) in the late 1930s

9. Computer Architecture First Generation  The ENIAC later evolved into UNIVAC (Universal Automatic Computer) 1, which was the first commercial general purpose computer sold in June 14, 1951 to the US Bureau of the Census  Key concept of stored program introduced by John von Neumann

10. Computer Architecture First Generation  Introduction of Assembly Language  Vacuum tube technology was used to implement logic functions  The I/O uses typewriter-like input and output devices  The Vacuum tubes produce great deal of heat and causing many problems in temperature regulation and climate control

11. Computer Architecture First Generation  The UNIVAC uses Magnetic core memories. It consisted of small doughnut-shape rings about the size of pinheads strung like a beads on intersecting wires  Magnetic tape device were also developed in 1957

12. Computer Architecture Second Generation  In late 1940s, AT&T Bell Laboratories scientists (J. Bardeen, H. W. Brattain and W. Shockley) invent the Transistor, replacing vacuum tubes. They get Nobel Prize for their invention.  They need no warm-up time, consumed less energy, were faster and more reliable

13. Computer Architecture Second Generation  Magnetic core memories and magnetic drum storage are widely used  Evolution from Machine Language to Assembly Language (which were also called Symbolic Languages) and then evolve to High-level languages (Fortran - 1954 and COBOL - 1959)

14. Computer Architecture Second Generation  System programs called compilers were developed to translate these high-level language programs into corresponding assembly language program  Separate I/O processors were developed and in 1962 the first removable disk pack was marketed  IBM became major computer manufacturer and most computer systems are used by government, business and universities

15. Computer Architecture Third Generation  The development of silicon chip, called the integrated circuit technology  Silicon is the most abundant element in earth’s crust. In the beach sands, rocks and clay.  In 1965, the principal site for manufacturing the silicon chip is Santa Clara County, 30 miles south San Francisco. Later nicknamed Silicon Valley

16. Computer Architecture Third Generation  IC memories replace magnetic core memories and IC technology replaces discrete transistor technology  In 1964, IBM 360 series mainframe, called System/360 dominates the market. The equipment is housed inside blue cabinets and IBM begins to be known as “Big Blue”  PDP minicomputer from Digital Equipment Corporation also widely used by businesses in this period.

17. Computer Architecture Third Generation  IBM also unbundled the software in its System/360, selling the software separately from the hardware and beginning the creation of today’s software industry  Operating system software allows efficient sharing of computer system  Introduction of microprogramming, parallelism, and pipelining  Cache and virtual memories were developed

18. Computer Architecture Third Generation  Bill Gates, went off to Harvard in 1974 and hooks up with Paul Allen. When the MITS Altair was for sale (January 1975), both Bill and Paul moved to Albuquerque, wrote software for MITS and formed their own company called Microsoft

19. Computer Architecture Fourth Generation  Early 1970s, IC fabrication techniques evolved into VLSI (Very Large Scale Integration) and enable the fabrication of the microprocessor  Apple Computer founded in 1977 by Steve Jobs and Steve Wozniak to market their Apple 1 (and fails) and Apple 2

20. Computer Architecture Fourth Generation  When MITS failed, Microsoft moved their operation to their native Bellevue, Washington with their 32 employees (1980).  IBM came and offered a chance to develop the operating system for IBM's soon-to-be personal computer

21. Computer Architecture Fourth Generation  Placing the whole company at risk, Gates purchased an existing operating system, which was reworked to produce MS-DOS (Microsoft Disk Operating System)  IBM PC launched in 1981 and rose to the top of best seller list in 18 months

22. Computer Architecture Fourth Generation  Intel, National Semiconductor, Motorola, Texas Instruments, Advanced Micro Device (AMD).  Computer organizational concepts developed such as concurrency, pipelining, cache, virtual memories.  Portable notebook, desktop, workstation, local area networks (LAN), wide area networks (WAN), Internet.