Computer Architecture Lecture Notes Spring 2005 Dr. Michael P. Frank Competency Area 1: Computer System Components Lecture 2

ENIAC - background Electronic Numerical Integrator And Computer Eckert and Mauchly University of Pennsylvania Proposed to develop a computer for the calculation of Trajectory tables for weapons during WWII (Army Ballistics Research Laboratory) Started 1943 Finished 1946 —Too late for war effort —Used to help determine feasibility of H-bomb Used until 1955

ENIAC - details Decimal (not binary) Its memory contained 20 accumulators of 10 digits. 10 vacuum tubes represented each digit. Programmed manually by switches 18,000 vacuum tubes 30 tons 1500 square feet 140 kW power consumption 5,000 additions per second

von Neumann/Turing Stored Program concept Main memory storing programs and data “Turing Machine” (Alan Turing): Given enough memory and sufficient time the general purpose computer can compute all functions that are computable. ALU operating on binary data Control unit interpreting instructions from memory and executing Input and output equipment operated by control unit Princeton Institute for Advanced Studies —IAS Computer (major components in a computer system) —Foundation for general-purpose computer Completed 1952

Picture of the IAS Computer Smithsonian Image

Structure of von Neumann machine

IAS - details 1000 x 40 bit words —1000 storage locations of 40-bit words —Binary number —2 x 20 bit instructions Set of registers (storage in CPU) —Memory Buffer Register (MBR) —Memory Address Register (MAR) —Instruction Register (IR) —Instruction Buffer Register (IBR) —Program Counter (PC) —Accumulator (AC) —Multiplier Quotient (MQ)

Structure of IAS – detail MBR Contains a word to be stored In memory, or is used to receive a Word from memory. MAR Specifies the address in memory of the word to be written from or into MBR IR Contains the 8-bit opcode instruction being executed IBR Temporarily holds the right hand instruction from a word in memory PC Contains the address of the next instruction pair to be fetched from memory

IAS - details The IAS computer had 21 instructions which are grouped as follows: —Data Transfer: Moves data between memory and ALU registers or between two ALU registers —Unconditional Branch: Changes the sequence of instructions to execute repetitive operations —Conditional Branch: The branch can be made dependent on a condition, thus, allowing decision points. —Arithmetic: Operations performed by the ALU — Address /modify: Permits addresses to be computed in the ALU and then inserted into instructions stored in memory.

Commercial Computers 1947 – Eckert-Mauchly developed their own Computer Corporation UNIVAC I (Universal Automatic Computer) Designed to perform mainly scientific calculations (e.g. US Bureau of Census 1950 calculations) Became part of Sperry-Rand Corporation Late 1950s - UNIVAC II —Faster —More memory

IBM Punched-card processing equipment the 701 —IBM’s first stored program computer —Scientific calculations the 702 —Business applications Lead to 700/7000 series

Transistors The second generation of technology: Transistors replaced vacuum tubes Smaller Cheaper Less heat dissipation Solid State device Made from Silicon (Sand) Invented 1947 at Bell Labs William Shockley et al. Discrete components

Transistor Based Computers Second generation machines More complex arithmetic and logic units Incorporated the use of high-level programming languages Also used system software with machines (e.g. operating systems) NCR & RCA produced small transistor machines IBM 7000 Series Digital Equipment Corporation (DEC) —Produced PDP-1 which began the minicomputer phenomenon

Transistors GenerationApproximate Dates TechnologyTypical Speed (ops/sec) Vacuum Tubes40, Transistor200, Small and medium scale integration 1,000, Large-scale integration (LSI) 10,000, Very LSI100,000,000 Computer Generations:

Microelectronics Up to this point, computers were manufactured using discrete components which was becoming more expensive and cumbersome as computers continued to improve in performance. Microelectronics dominated the next generation of computers. Literally - “small electronics” A computer is made up of gates, memory cells and interconnections These can be manufactured on a semiconductor e.g. silicon wafer

Generations of Computer Vacuum tube Transistor Small scale integration on —Up to 100 devices on a chip Medium scale integration - to 1971 —100-3,000 devices on a chip Large scale integration —3, ,000 devices on a chip Very large scale integration to date —100, ,000,000 devices on a chip Ultra large scale integration —Over 100,000,000 devices on a chip

Moore’s Law As microelectronics grew in the computer industry, an increase in the density of components on chip became evident. Gordon Moore - cofounder of Intel Gordon’s Observation: 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 Smaller size gives increased flexibility Reduced power and cooling requirements Fewer interconnections increases reliability

Moore’s Law Formal Consequences of Moore’s Law: 1.Cost of chip has remained relatively stable during a period of rapid growth in density. This implies the cost of computer logic and memory circuitry has fallen at a drastic rate. 2.Because logic and memory elements are placed closer together on more densely packed chips, the electrical path length is shortened, increasing operating speeds. 3.The computer becomes smaller, making it more convenient to placed in a variety of environments. 4.There is a reduction in power and cooling requirements. 5.The interconnections on the integrated circuit are much more reliable than solder connections. With more circuitry on each chip, there are fewer interchip connections.

Growth in CPU Transistor Count

IBM 360 series Introduced in 1964 Replaced (& not compatible with) 7000 series First planned “family” of computers —Similar or identical instruction sets —Similar or identical O/S —Increasing speed —Increasing number of I/O ports (i.e. more terminals) —Increased memory size —Increased cost Multiplexed switch structure The introduction of this family cemented IBM as a world leader in computer manufacturing industry.

Picture of IBM 360

DEC PDP-8 Also introduced in 1964 First minicomputer Did not need room w. A/C Small, could sit on a lab bench Relatively cheap: $16,000 —Compared to $100k+ for IBM 360 Embedded applications & Original Equipment Manufacturers (OEM) allowed users to buy PDP- 8 machines and integrate them into a total system for resale. BUS STRUCTURE

DEC - PDP-8 Bus Structure OMNIBUS Console Controller CPU Main Memory I/O Module I/O Module - Highly flexible - All systems share a common set of signal paths - Allows other modules to be plugged into the bus to create various configurations

Intel —First microprocessor —Whole CPU on a single chip —4 bit Followed in 1972 by 8008 —8 bit —Both for specific applications —Intel’s first general purpose microprocessor

Speeding it up Pipelining On board cache On board L1 & L2 cache Branch prediction Data flow analysis Speculative execution

Pentium Evolution (1) 8080 —first general purpose microprocessor —8 bit data path —Used in first personal computer – Altair 8086 —much more powerful —16 bit —instruction cache, prefetch few instructions —8088 (8 bit external bus) used in first IBM PC —16 Mbyte memory addressable —up from 1Mb —32 bit —Support for multitasking

Performance Introduced Clock Speeds 108 KHz 2 MHz5 MHz, 8MHz, 10MHz 5 MHz, 8MHz Bus Width4 bits8 bits 16 bits8 bits Number of Transistors ,000 Addressable Memory 640 bytes16 KBytes64 KBytes1 MB Virtual Memory s Processors:

Performance TM DX386TM SX486TM DX CPU Introduced Clock Speeds 6 MHz – 12.5 MHz 16 MHz-33 MHz 25 MHz- 50 MHz Bus Width16 bits32 bits16 bits32 bits Number of Transistors 134,000275, million Addressable Memory 16 MB4 GB Virtual Memory 1 GB64 TB 1980s Processors:

Performance 486TM SXPentium Pentium II Introduced Clock Speeds 16 MHz- 133MHz 60 MHz –166 MHz 150 MHz- 200MHz 200 MHz- 300MHz Bus Width32 bits 64 bits Number of Transistors million3.1 million5.5 million7.5 million Addressable Memory 4 GB 64 GB Virtual Memory 64 TB 1990s Processors:

Performance Pentium IIIPentium 4 Introduced Clock Speeds 450 MHz GHz Bus Width64 bits Number of Transistors 95 million42 million Addressable Memory 64 GB Virtual Memory 64 GB64 TB Recent Processors:

Performance Mismatch Processor speed increased Memory capacity increased Memory speed lags behind processor speed!!

DRAM and Processor Characteristics

Pentium Evolution (2) —sophisticated powerful cache and instruction pipelining —built in maths co-processor Pentium —Superscalar —Multiple instructions executed in parallel Pentium Pro —Increased superscalar organization —Aggressive register renaming —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 —Note Arabic rather than Roman numerals —Further floating point and multimedia enhancements Itanium —64 bit See Intel web pages for detailed information on processors

Intel Itanium 2 (McKinley) 64b Processor 221 million transistors! (~US adult population) How are they used? What will we do as transistor counts continue to grow? Most of chip is used for memories, inst. decoding, dynamic scheduling… Why is it done this way? How much more efficient could it be if more of area went to actual processing?

Even More Recent Example Runs 64-bit IA-64 ISA Die: 3.74 cm 2.13µ process 410M transistors 1.5GHz core 1.3V logic 130W power consumption! 6.4GB/s bus Cost: $2,247- $4,226 9MB L3 cache later this year…

Internet Resources —Computer Organization and Architecture —Search for the Intel Museum Charles Babbage Institute PowerPC Intel Developer Home