Cosc 2150: Computer Organization

Cosc 2150:Computer Organization

Chapter 1: Introduction, History, and Performance

Overview

• Why study computer organization and architecture?—Design better programs, including system

software such as compilers, operating systems, and device drivers.

—Optimize program behavior.—Evaluate (benchmark) computer system

performance.—Understand time, space, and price tradeoffs.

Overview (2)

• Computer organization—Encompasses all physical aspects of computer

systems.—E.g., circuit design, control signals, memory

types.– How does a computer work?

• Computer architecture—Logical aspects of system implementation as

seen by the programmer.—E.g., instruction sets, instruction formats, data

types, addressing modes.– How do I design a computer?

Computer Components

• There is no clear distinction between matters related to computer organization and matters relevant to computer architecture.

• Principle of Equivalence of Hardware and Software:—Any task done by software can also be done

using hardware, and any operation performed directly by hardware can be done using software.

+ Assuming speed is not a concern

Computer Components (2)

• At the most basic level, a computer is a device consisting of three pieces:—A processor to interpret and execute programs—A memory to store both data and programs—A mechanism for transferring data to and from

the outside world.

An Example System

GHz??

GB??

PCI??USB??

L1 Cache??

What does it all mean??

Consider this advertisement:

Measures of capacity and speed:• Kilo- (K) = 1 thousand = 103 and 210

• Mega- (M) = 1 million = 106 and 220

• Giga- (G) = 1 billion = 109 and 230

• Tera- (T) = 1 trillion = 1012 and 240

• Peta- (P) = 1 quadrillion = 1015 and 250

• Exa- (E) = 1 quintillion = 1018 and 260

• Zetta- (Z) = 1 sextillion = 1021 and 270

• Yotta- (Y) = 1 septillion = 1024 and 280

Measurements

Whether a metric refers to a power of ten or a power of two typically depends upon what is being measured.

Measurements (2)

• Hertz = clock cycles per second (frequency)—1MHz = 1,000,000Hz—Processor speeds are measured in MHz or

GHz.

• Byte = a unit of storage—1KB = 210 = 1024 Bytes—1MB = 220 = 1,048,576 Bytes—1GB = 230 = 1,099,511,627,776 Bytes—Main memory (RAM) is measured in GB—Disk storage is measured in GB for small

systems, TB (240) for large systems.

Measurements (3)

• Measures of time and space:—Milli- (m) = 1 thousandth = 10-3

—Micro- () = 1 millionth = 10-6

—Nano- (n) = 1 billionth = 10-9

—Pico- (p) = 1 trillionth = 10-12

—Femto- (f) = 1 quadrillionth = 10-15

—Atto- (a) = 1 quintillionth = 10-18

—Zepto- (z) = 1 sextillionth = 10-21

—Yocto- (y) = 1 septillionth = 10-24

Measurements (4)

• Millisecond = 1 thousandth of a second—Hard disk drive access times are often 10 to

20 milliseconds.

• Nanosecond = 1 billionth of a second—Main memory access times are often 50 to 70

nanoseconds.

• Micron (micrometer) = 1 millionth of a meter—Circuits on computer chips are measured in

microns.

An Example System

• We note that cycle time is the reciprocal of clock frequency.

• A bus operating at 133MHz has a cycle time of 7.52 nanoseconds:

Now back to the advertisement ...

133,000,000 cycles/second = 7.52ns/cycle

An Example System (2)

The microprocessor is the “brain” of the system. It executes program instructions. This one is a Pentium (Intel) running at 3.06GHz.


• Computers with large main memory capacity can run larger programs with greater speed than computers having small memories.

• RAM is an acronym for random access memory. Random access means that memory contents can be accessed directly if you know its location.

• Cache is a type of temporary memory that can be accessed faster than RAM.


… and two levels of cache memory, the level 1 (L1) cache is smaller and (probably) faster than the L2 cache. Note that these cache sizes are measured in KB and MB.

This system has 4GB of (fast) synchronous dynamic RAM (SDRAM) . . .


This one can store 500GB. 7200 RPM is the rotational speed of the disk. Generally, the faster a disk rotates, the faster it can deliver data to RAM. (There are many other factors involved.)

Hard disk capacity determines the amount of data and size of programs you can store.


ATA stands for advanced technology attachment, which describes how the hard disk interfaces with (or connects to) other system components.

A DVD can store about 4.7GB of data. This drive supports rewritable DVDs, +/-RW, that can be written to many times.. 16x describes its speed.


This system has ten ports.

Ports allow movement of data between a system and its external devices.


• Serial ports send data as a series of pulses along one or two data lines.

• Parallel ports send data as a single pulse along at least eight data lines.

• USB, Universal Serial Bus, is an intelligent serial interface that is self-configuring. (It supports “plug and play.”)


System buses can be augmented by dedicated I/O buses. PCI, peripheral component interface, is one such bus.

This system has two PCI devices: a video card and a sound card.


The number of times per second that the image on a monitor is repainted is its refresh rate. The dot pitch of a monitor tells us how clear the image is.

This one has a dot pitch of 0.24mm and a refresh rate of 75Hz.

The video card contains memory and programs that support the monitor.


• Throughout the remainder of the course you will see how these components work and how they interact with software to make complete computer systems.

This statement raises two important questions:

What assurance do we have that computer components will operate as we expect?

And what assurance do we have that computer components will operate together?

Standards Organizations

• There are many organizations that set computer hardware standards—to include the interoperability of computer

components.

• Throughout your career, you will encounter many of them.

• Some of the most important standards-setting groups are . . .

Standards Organizations (2)

• The Institute of Electrical and Electronic Engineers (IEEE)—Promotes the interests of the worldwide

electrical engineering community.—Establishes standards for computer

components, data representation, and signaling protocols, among many other things.


• The International Telecommunications Union (ITU)—Concerns itself with the interoperability of

telecommunications systems, including data communications and telephony.

• National groups establish standards within their respective countries:—The American National Standards Institute

(ANSI)—The British Standards Institution (BSI)


• The International Organization for Standardization (ISO)—Establishes worldwide standards for

everything from screw threads to photographic film.

—Is influential in formulating standards for computer hardware and software, including their methods of manufacture.

Note: Iso is not an acronym. Iso comes from the Greek, isos, meaning “equal.”

HISTORY

Historical Development

• To fully appreciate the computers of today, it is helpful to understand how things got the way they are.

• The evolution of computing machinery has taken place over several centuries.

• In modern times computer evolution is usually classified into four generations according to the salient technology of the era.

We note that some of the following dates are approximate and this is not a complete list.

“Calculators”

• Abacus— Was used as early as 2400BC in Babylon

• Slide Rule—William Oughtred, 1625

• There were varying “calculators” through out history.

• There are having been many “robots” in early history as well—Dating back to ancient Egypt —Leonardo da Vinci created a self propelled

mechanical lion that could be programmed to walk around.

– Presented to King Francis I of France in 1515.

Mechanical Era (1600s-1940s)

• Wilhelm Schickhard, 1623—Automatically add, subtract, multiply and divide—Up to six digits, base 10 machine.

• Blaise Pascal, 1642—Mass produced first working machine (about 50 of

them)—could only add and subtract, up 8 digits

• Gottfired Liebniz, 1672—Improved Pascal’s machine—add, subtract, multiply and divide—Leibniz once said "It is unworthy of excellent men to

lose hours like slaves in the labor of calculation which could safely be relegated to anyone else if machines were used.”

—Also the co-inventor of calculus

• Charles Babbage, 1822 or 34 and Ada Lovelace—Considered the father of modern Computer—wanted better accuracy in calculations—Used a Difference Engine and a Analytic

engine– Could perform any math operation– Used punch card

—Used the modern structure, I/O, storage, ALU

—The machine would do an addition in 3 seconds and a multiplication or division in 2-4 minutes.

• George Boole, 1847—Mathematical of laws of logic

• Herman Hollerith, 1889—Used modern day punch card —Formed Tabulating Machine Computer (now called IBM)—Used his machine for the Census

– Estimated 7.5 years by hand for the 1890 census– His machine figured it in 2 months

• Konrad Zuse, 1938—Built the Z1, the first binary machine.

—A reproduction of Z1 in Technik Museum in Berlin

• Howard Aiken, 1943—Designed the Mark I, based of Baggage’s machine

• Summary:—Designed to reduce time of calculations and increase

accuracy—Problems:

– Used gears and pulleys, prone to mechanical failures– Cumbersome and expensive– Worst: Unreliable

The Electronic Era

• Generation 1: Vacuum Tube(1945 – 1958)• ENIAC - background

—Electronic Numerical Integrator And Computer—Eckert and Mauchly—University of Pennsylvania—Trajectory tables for weapons —Started 1943—Finished 1946

– Too late for war effort

—Used until 1955

ENIAC - details

• Decimal (not binary)• 20 accumulators of 10 digits• Programmed manually by switches• 18,000 vacuum tubes, 10K capacitors, 6K

switches, 70K resistors• 30 tons• 15,000 square feet (30 x 50 feet)• 140 kW power consumption• 5,000 additions per second

von Neumann/Turing

• Stored Program concept• Storing programs and data in main

memory • 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

• Completed 1952

• Basis for virtually all computers designed since then

• Major features—Data and instructions (programs) are stored in

read-write memory—Memory contents are addressable by location

regardless of where it is located at.—Sequential execution!—Stored-program concept

Fetch execute cycle

• In it’s simplest form—Read in an instruction—Execute the instruction—Repeat

• We will add to this cycle through out the semster

• Von Nueman machine has 21 instructions—Loads, stores, condition/unconditional

branches (jumps), arithmetic, and address modify

Structure of von Neumann machine

IAS - details

• 1000 x 40 bit words—Binary number—2 x 20 bit instructions

• Set of registers (storage in CPU)—Memory Buffer Register—Memory Address Register—Instruction Register—Instruction Buffer Register—Program Counter—Accumulator—Multiplier Quotient

Structure of IAS – detail

1944 Harvard Mark I• the Harvard Mark-1 was a

room-sized, relay-based calculator. The machine had a fifty-foot long camshaft that synchronized the machine’s thousands of component parts. The Mark-1 was used to produce mathematical tables but was soon superseded by stored program computers.

• Created by Howard Aiken and Grace Hopper

Commercial Computers

• 1947 - Eckert-Mauchly Computer Corporation

• UNIVAC I (Universal Automatic Computer)• US Bureau of Census 1950 calculations• Became part of Sperry-Rand Corporation• Late 1950s - UNIVAC II

—Faster—More memory

IBM

• Punched-card processing equipment• 1953 - the 701

—IBM’s first stored program computer—Scientific calculations

• 1955 - the 702—Business applications

• Lead to 700/7000 series

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.

Transistor Based Computers

• Second generation machines• High level languages introduced• Floating point arithmetic • NCR & RCA produced small transistor

machines• IBM 7000• DEC - 1957

—Produced PDP-1

Microelectronics

• 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 - 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

Moore’s Law (1965)• 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

Rock’s Law

• Rock’s Law —Arthur Rock, Intel financier—“The cost of capital equipment to build

semiconductors will double every four years.”—In 1968, a new chip plant cost about $12,000.

• As a Note:— At the time, $12,000 would buy a nice home in the suburbs.— An executive earning $12,000 per year was “making a very comfortable

living.”

• Rock’s Law

—In 2010, a chip plants under construction cost well over $4 billion.

—For Moore’s Law to hold, Rock’s Law must fall, or vice versa. But no one can say which will give out first.

$4 billion is more than the gross domestic product of some small countries, including Barbados, Mauritania, and Rwanda.

Rock’s Law (2)

IBM 360 series

• 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

DEC PDP-8

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

—$100k+ for IBM 360

• Embedded applications & OEM• BUS STRUCTURE

DEC - PDP-8 Bus Structure

Semiconductor Memory

• 1970• Fairchild• Size of a single core

—i.e. 1 bit of magnetic core storage

• Holds 256 bits• Non-destructive read• Much faster than core• Capacity approximately doubles each year

Intel

• 1971 - 4004 —First microprocessor—All CPU components on a single chip—4 bit

• Followed in 1972 by 8008—8 bit—Not the successor to 4004, independently

designed.—Both designed for specific applications

• 1974 - 8080—Intel’s first general purpose microprocessor

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—up from 1Mb

• 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 technology—graphics, video & audio processing

• Pentium III—Additional floating point instructions for 3D

graphics

• Pentium 4—Further floating point and multimedia

enhancements

• Duo, Quad, and 6 core Processors—Similar design to P4, but more “processing units”.

• Itanium—64 bit, see later lectures

• See Intel web pages for detailed information on processors

PERFORMANCE

Computer Performance Measures

• Still have problems assessing differing architectures—How well (fast) will the machine work?

• Can view a machines performance in two (competing) ways:—Increase in overall throughput—Increase in response time to an individual job

CPU performance

• Performance can be defined in Millions of instructions per second (MIPS)—Rarely used by modern processors as a

benchmark—Very popular with embedded processors

• Also can be measured in Millions of floating point operations per second (MFLOPS)—Common benchmark for modern processors

– Almost never used with embedded processors+ Why?

• Does a faster clock cycle improve performance?—Not always

Faster computers

• Improved Bus speed and Width• Faster and/or more effective memory

—Move more data to and from CPU, minimize latency and kept the CPU busy as much as possible.

• Assembly language/ machine code—RISC vs CISC code

Other Considerations

• Cost—Design—purchase—components—Maintenance

• Compatibility and software availability

Cosc 2150: Computer Organization

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