William Stallings Computer Organization and Architecture

Chapter 2Computer Evolution and Performance

2.1 A BRIEF HISTORY OF COMPUTER

The First Generation: Vacuum Tubes ENIAC - background

Electronic Numerical Integrator And ComputerDesigned and constructed Under the

supervision of Eckert and Mauchly at University of Pennsylvania

Trajectory tables for weapons Started 1943Finished 1946

Too late for war effort

Used until 1955

ENIAC - details

Decimal (not binary)20 accumulators of 10 digits

Its memory consisted of 20 “accumulators”, each capable of holding a 10-digit decimal number. Each digit was represented by a ring of 10 vacuum tubes.

Programmed manually by switches18,000 vacuum tubes30 tons15,000 square feet140 kW power consumption5,000 additions per second

The von Neumann/TuringStored Program conceptMain memory storing programs and dataALU operating on binary dataControl unit interpreting instructions from memory and executingInput and output equipment operated by control unitPrinceton Institute for Advanced Studies

the the IASIAS computer computer Completed 1952 The IAS computer is the prototype of all subsequent general-purpose computer.

Structure of von Neumann machine

Structure of IAS –detail

IAS - details 1000 x 40 bit words

Binary number 2 x 20 bit instructions

Each words can contain two instructions (p21 Figure 2.2)8-bit operation code specifying the operation to be performed and a 12-bit address designating one of

the words in memory

Set of registers (storage in CPU) Memory Buffer Register (MBR) Memory Address Register (MAR) Instruction Register (IR) Instruction Buffer Register (IBR): Employed to hold temporarily the right-hand instruction from a word in

memory. Program Counter (PC) Accumulator (AC) Multiplier Quotient (MQ)

The IAS computer had a total of 21 instructions (p24 Table 2.1).

Sign BitSign Bit

Figure2.2 IAS Memory FormatFigure2.2 IAS Memory Format

(b) Instruction Word(b) Instruction Word

Commercial Computers

1947 - Eckert-Mauchly Computer Corporation

UNIVAC I (Universal Automatic Computer)US Bureau of Census 1950 calculationsBecame part of Sperry-Rand CorporationLate 1950s - UNIVAC II

Faster More memory

IBM

Punched-card processing equipment1953 - the 701

IBM’s first electronic stored-program computer Scientific calculations

1955 - the 702 Business applications

Lead to 700/7000 series

The Second Generation: Transistors

Replaced vacuum tubesSmallerCheaperLess heat dissipationSolid State deviceMade from Silicon (Sand)Invented 1947 at Bell LabsWilliam Shockley et al.

Transistor Based Computers

Second generation machinesNCR & RCA produced small transistor

machinesIBM 7000DEC (Digital Equipment Corporation)-

1957 Produced PDP-1

Generations of Computer

Vacuum tube - 1946-1957 Transistor - 1958-1964 Small scale integration - 1965 on

Up to 100 devices on a chip

Medium scale integration - to 1971 100-3,000 devices on a chip

Large scale integration - 1971-1977 3,000 - 100,000 devices on a chip

Very large scale integration - 1978 to date 100,000 - 100,000,000 devices on a chip

Ultra large scale integration Over 100,000,000 devices on a chip

MicroelectronicsLiterally - “small electronics”A computer is made up of gates, memory cells

and interconnections. A gate is a device that implements a simple

Boolean or logical function. Gates are responsible for controlling data flow.

The memory cell is a device that can be in one of two stable states, can store one bit of data.

These can be manufactured on a semiconductore.g. silicon wafer Figure 2.7 Relationship between Wafer, Chip and Gate

Moore’s Law

Increased density of components on chip Gordon Moore - cofounder of Intel 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

Growth in CPU Transistor Count

Figure2.8

Growth in CPU

transistor Count

IBM 360 series1964Replaced (& not compatible with) 7000 seriesFirst planned “family” of computersThe characteristics of a family

Similar or identical instruction sets Similar or identical OS Increasing speed Increasing number of I/O ports (i.e. more terminals) Increased memory size Increased cost

Multiplexed switch structure

DEC PDP-8

1964 First minicomputer Did not need air conditioned room Small enough to sit on a lab bench $16,000 (cheaper)

$100k+ for IBM 360

Embedded applications & OEMs The PDP-8“established the concept of

minicomputers, leading the way to a multibillion dollar industry.”

BUS STRUCTURE

DEC - PDP-8 Bus Structure

OMNIBUS

ConsoleController

CPU Main Memory I/OModule

I/OModule

Figure 2.9 PDP-8 Bus Structure

The PDP-8 bus , called the omnibusomnibus, consists of 96 separate signal paths, used to carry control, address, and data signals.

Semiconductor Memory

In 1970, Fairchild produced the first relatively capacious semiconductor memory.

Size of a single core i.e. 1 bit of magnetic core storage

Holds 256 bitsNon-destructive readMuch faster than coreCapacity approximately doubles each year

Semiconductor Memory

Since 1970, semiconductor memory has Since 1970, semiconductor memory has been through 10 generations: 1K, 4K, 16K, been through 10 generations: 1K, 4K, 16K, 64K, 256K, 1M, 4M, 16M, 64M, and as of 64K, 256K, 1M, 4M, 16M, 64M, and as of this writing, 256M bits on a single this writing, 256M bits on a single chip(1K=2chip(1K=21010, 1M=2, 1M=22020).).

Each generation has provided Each generation has provided four timesfour times the storage density of the previous the storage density of the previous generation, accompanied by declining generation, accompanied by declining cost per bit and declining access time.cost per bit and declining access time.

Microprocessors Intel 1971- 4004

First microprocessor All CPU components on a single chip The 4004 can add two 4-bit numbers and can multiply only by

repeated addition.

Followed in 1972 by 8008 8-bit microprocessor The 4004 and the 8008 both designed for specific applications

1974 - 8080 Intel’s first general purpose microprocessor

2.2 DESIGNING FOR PERFORMANCEMicroprocessor Speed

PipeliningOn board cacheOn board L1 & L2 cacheBranch prediction

predicts which branches, or groups of instructions, are likely to be processed next…

Prefetch the correct instruction and buffer them so that the processor is kept busy.

Increase the amount of work available for the processor to execute.

Microprocessor SpeedData flow analysis

Analyze the dependent relationship among the instructs.

Create an optimized schedule of instruction independent of the original program order

To prevent unnecessary delay.Speculative execution( 推测执行 )

Using branch prediction and data flow analysis Execute instructions ahead of their actual

appearance To keep processor busy

Performance Mismatch

Processor speed increasedMemory capacity increased Memory speed lags behind processor Memory speed lags behind processor

speedspeed

DRAM and Processor Characteristics

Trends in DRAM use Solid black lines for a fixed-size memory

The shaded bands for a particular type of system

Solutions

Increase number of bits retrieved at one time Make DRAM “wider” rather than “deeper” and by

using wide bus data paths

Change DRAM interface a cache or other buffering scheme on the DRAM chip

Reduce frequency of memory access More complex cache and cache on chip

Increase interconnection bandwidth High speed buses Hierarchy of buses

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

80286 16 Mbyte memory addressable

80386 32 bit Support for multitasking

Pentium Evolution (2)80486

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 （多媒体增强指令集） 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 chapter 15

See Intel web pages for detailed information on processors

Internet Resources

http://www.intel.com/ Search for the Intel Museum

http://www.ibm.comhttp://www.dec.comCharles Babbage InstitutePowerPCIntel Developer Home