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AME 150 L

The Digital Computer

and the

Internet

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Digital Computers

CPULogic, Control

& Arithmetic

Memory System

InputOutputSystem

MassStorage

Human Interface

Communications

Other Stuff

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Central Processing Unit (CPU)

• The “brain” of the system

• Coordinates Logic AND Control AND Arithmetic

• Determines the architecture– Organization of Storage– Instruction Set– Features (Multiple CPU, Vector Operations…)

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Is it a Brain?

• Short answer -- NO [ not yet ! ]

• Role is similar to Human Brain, but behavior is very different

• Many control functions are delegated

• Brain has much greater parallism and complexity

• It may just be a matter of time ...

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Arithmetic & Logical Unit (ALU)

• Heart of computer (another anthropomorphic analogy)

• Almost all computers now are binary– Believe it or not, there were decimal digital

computers!

• Arithmetic {+, -, (*), (/) some, not all}• Logic { >, =, <, , , , AND, OR, NOT …}• Control { Skip, Jump, Branch, Execute …}

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The Architecture

• All modern computers maintain instructions and data in memory (Von Neuman)

• Types of operations are generally the same

• Differences in– Addressing modes (both data and instructions)– Representations of data (only integers obvious)– Concurrency (parallelism)

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Families of Computers - Chips

• Intel Computers (80x86PentiumI,II,III...)– Pentium Clones (AMD, Cyrix, …)

• Sun Microsystems - SPARC• Hewlett-Packard - PA-RISC• Silicon Graphics - MIPS• IBM RS6000/PowerPC (Motorola/Apple)

• Compaq (DEC) Alpha

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Memory• RAM - Random Access Memory (Fast)

– Started as Mechanical systems (relays,…)– Next came Magnetic Cores (still called core)– Integrated Circuits-Manufacturing Technology– Technology still advancing

• ROM - read only memory

• WORM - Write Once, Read Many

• Flash Memory (doesn’t need power to hold)

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Memory Organization• Dedicated memory (on-chip - fast - Cache)

• Shared Memory (accessed by many CPU’s or other devices)

• Distributed Memory

• Cycle Speed {80 nSec (slow) to ~1 nSec}

• Access Width [word size] (8-16-32-64-…)

• Error correction

• About $1 to $1.50 / Mbyte retail (today)

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• 10 deka da .1 deci d• 100 hecto h .010 centi c• 1000 kilo k .001 milli m• 1024 Kilo K 210

• 106 Mega M 10-6 micro • 109 Giga G 10-9 Nano n• 1012 Tera T 10-12 Pico p• 1015 Peta P 10-15 Femto f• 1018 Exa E 10-18 Atto a• 1021 Zetta Z 10-21 Zepto z• 1024 Yotta Y 10-24 Yocto y

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Input/Output (I/O)• It is very easy to make a computer if it only

has to talk to itself

• Computers talking to people is harder

• Input means getting information INTO the computer

• Output means getting stuff OUT

• Often a direct path to/from memory

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Mass Storage

• The computer needs more information storage capability than it has memory– Intermediate results– temporary storage

• Moving Magnetic Storage– Magnetic Drums, Disks, Tapes {CD, DVD…}– Technology -- About $10 / Gbyte retail (today)

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I/O with Humans +

• Historical– Paper Tape, Punched Cards, Line Printers

• Continuing– CRT’s, Pen Plotters, Terminals & Keyboards– Modems, communications control, ADC/DAC

• More Recent– Graphic Terminals, sound, video, mice, MIDI

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Other Stuff

• Power Systems (Mwatts watts)

• Cabinets and Furniture (Room Pockets)

• Communications Lines & Media– Acoustic Modems Fiber Optics– GPS systems, satellites

• Monitors (Paper CRT LCD)

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Enabling Technologies

• Electronics Transistors ICs VLSI

• Effected by Consumer Electronics– Mass storage (Disks, CDs, DVDs,…)– Displays (CRTs, LCDs, etc)– Memory ! (TIVO?)

• Other Technologies– Digital Cameras, GPS, ...

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Moore’s LawMoore's Law is that the pace of microchip technology change is such that the amount of data storage that a microchip can hold doubles every year or at least every 18 months. In 1965 when preparing a talk, Gordon Moore noticed that up to that time microchip capacity seemed to double each year. The pace of change having slowed down a bit over the past few years, the definition has changed (with Gordon Moore's approval) to reflect that the doubling occurs only every 18 months.

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Moore’s Law (Consequences)• Price of equivalent technology decreases

• Performance of constant cost technology increases

• More computing power is available for user interface

• More storage capacity increases problem sizes

• And there’s moore …

•

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Control of Computers• Native Machine Language

– Close to hardware -- depends on architecture– Can take advantage of system’s features– Often, the fastest implementation

• Low level Compilers– Fortran (1950’s, Basic/COBOL (60’s), C (70’s)– Algol, Pascal, ADA, Smalltalk, C++ (OOPS)

• Primitive Structured Object Oriented

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Computing Environment & History

• 40s-50s-Patch Cables

• 50s-60s-Punch cards

• 60s-70s-timeshared mainframes

• 70s-80s-minicomputers & supercomputers

• 80s-90s-microcomputers & parallel systems

• 90s+ … Graphic user interface (GUI)

•