led the WWII research group that broke the code for the Enigma machine proposed a simple abstract universal machine model for defining computability devised the “Turing hypothesis” for AI Alan M. Turing (1912 – 1954)

constructed an electronic computing machine (1943) used to decrypt German coded messages Turing and Colossus

his Cambridge group constructed EDSAC in 1949 the first stored program, general- purpose electronic digital computer first to use symbolic programs (assembly) Maurice Wilkes ( )

first commercial general- purpose computer system successor to Mauchly- Eckert BINAC delivered in 1951 used to forecast the 1952 presidential election UNIVAC-1

FIRST GENERATION (1950s) vacuum tube technology SECOND GENERATION (early 1960s) solid-state technology, magnetic core memories THIRD GENERATION (1964 – 1970) integrated circuitry (SSI), dynamic memories LATER GENERATIONS (1970s – ) VLSI, microprocessors, ultra large-scale integration Computing Generations

built using solid-state circuitry family of computer systems with backward compatibility established the standard for mainframes for decades IBM/360

“minicomputers” offered mainframe performance at a fraction of the cost introduced the unibus architecture for CPU interconnections DEC PDP Series

high-performance systems used for scientific applications advanced designs (pipelining, parallelism, etc.) Control Data Corporation, Cray Research, and others Supercomputers

microprocessors all-in-one designs, performance/price tradeoffs aimed at mass audiences personal computers workstations Desktop Computers

How do they rate in cost and performance? Comparison Shopping

Moore’s Law increased density of components on chip Gordon Moore: “Number of transistors on a chip will double every year.” since 1970’s development has slowed a little Number of transistors doubles every 18 months cost of a chip has remained almost unchanged higher packing density means shorter electrical paths, giving higher performance trends: smaller size, reduced power and cooling requirements, fewer interconnections

DRAM and Processor Characteristics

Improving Memory Performance increase the number of bits per word, width of data paths employ cache structures to reduce the frequency of memory operations increase the bandwidth of interconnections

Pentium Evolution (1) 8080 first general purpose microprocessor 8 bit data path 8086, bit instruction cache, prefetch few instructions 8088 (8 bit external bus) used in first IBM PC Mbyte memory addressable bit Support for multitasking

Pentium Evolution (2) sophisticated cache and instruction pipelining built in math co-processor Pentium superscalar, multiple instructions executed in parallel Pentium Pro increased superscalar organization branch prediction data flow analysis speculative execution

Pentium Evolution (3) Pentium II MMX technology graphics, video & audio processing Pentium III additional floating point instructions for 3D graphics Pentium 4 more floating point and multimedia enhancements Itanium 64 bit