Computers and Information Processing Laudon & Laudon CH 4.

Computers and Information Processing

Laudon & Laudon CH 4

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L&L 4: What is a computer system?

CPU

Secondary Storage

Primary Storage

Input Devices

Output Devices

Communication Devices

Buses

-Data Bus

-Address Bus

-Control Bus

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L&L 4: What is a computer system?L&L 4: What is a computer system?

Information (words, numbers, pictures) has to be “coded” to Bits (Binary digits)

possible Codesystems: Morse code? Baudot code? ASCII- American Standard Code for Information Exchange (7

bits per byte) EBCDIC- Extended Binary Coded Decimal Interchange Code

(8 bits per byte)

Characters are represented by a group of 7/8 bits (Byte)

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L&L 4: What is a computer system?

10 10 Sixteen Combinations

Sixty four Combinations

1010 10

Four Combinations

10

Two Hundred Fifty Six Combinations

10 10 10 10

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L&L 4: What is a computer system?L&L 4: What is a computer system?

Examples of bytes

EBCDICEBCDIC ASCII ASCII C - 1100 0011 101 0011

A - 1100 0001 101 0001

T - 1110 0011 110 0011

Parity Bit: extra bit added to each byte to help detect errors

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ARITHMETIC/LOGICARITHMETIC/LOGICUNITUNIT

PRIMARY (MAIN) MEMORYPRIMARY (MAIN) MEMORY

ROMROMRAMRAM

CONTROL UNITCONTROL UNIT

CLOCCLOCKK

L&L 4: What is a computer system? CENTRAL PROCESSING UNIT (CPU) L&L 4: What is a computer system? CENTRAL PROCESSING UNIT (CPU)

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RAM : Random Access Memory volatile memory with direct access to any

randomly chosen location (DRAM, SRAM)

ROM : Read Only Memory preprogrammed memory, e.g. manufacturer-

specific microcode (BIOS)

L&L 4: What is a computer system? TYPES OF PRIMARY STORAGE

L&L 4: What is a computer system? TYPES OF PRIMARY STORAGE

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Each location has an Address Each location can hold one Byte

101101 102102 103103

201201

301301

202202 203203

302302 303303

L&L 4: What is a computer system? PRIMARY STORAGE (RAM)

L&L 4: What is a computer system? PRIMARY STORAGE (RAM)

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Byte 8 Bit Kilobyte (KB): 210 bytes... “1000” bytes Megabyte (MB): 210 KB... ”million” bytes Gigabyte (GB): 210 MB... ”billion” bytes Terabytes (TB): 210 GB... ”trillion” bytes

L&L 4: What is a computer system? COMPUTER STORAGE CAPACITIY

L&L 4: What is a computer system? COMPUTER STORAGE CAPACITIY

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Word length (number of bits processed at one time) Megahertz (cycle speed to proceed one word length) Data bus width (max. number of bits moved between

cpu & other devices) Reduced Instruction Set Computing (RISC,

embedding only most frequently used instructions on chip)

Multimedia Extension (MMX, optimizes processing of visually intensive applications)

L&L 4: What is a computer system?WHAT DETERMINES PROCESSING POWER? L&L 4: What is a computer system?WHAT DETERMINES PROCESSING POWER?

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Word Data Bus Clocklength width speed

( Mhz)

Chip Manufacturer Used in

Pentium

Pentium IIPentium III

PowerPC

Alpha 21364

AMD Athlon

Intel

IntelIntel

Motorola, IBM, Apple

Compaq

Advanced Micro Devices

Motorola, IBM, Apple

DEC

32

3232

32/64

64

32

64

6464

64

64

64

75-200

233-450800+

100-400

1000+

600-1000

PCs

PCsHigh End PCsservers

PCs, workstations

Compaq Servers, Workstations

High-end PCs, workstations

L&L 4: What is a computer system? COMMON MICROPROCESSORS

L&L 4: What is a computer system? COMMON MICROPROCESSORS

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SEQUENTIAL PARALLELSEQUENTIAL PARALLEL

ProgramProgram

CPUCPUTASK 2TASK 2

CPUCPUTASK 3TASK 3

CPUCPUTASK 1TASK 1

RESULTRESULT

TASK 1

RESULT

ProgramProgram

CPUCPU

TASK 2

RESULT

ProgramProgram

CPUCPU

L&L 4: What is a computer system? Sequential & Parallel Processing

L&L 4: What is a computer system? Sequential & Parallel Processing

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L&L 4: Secondary Storage

Magnetic disk hard disks floppy disks zip-disk

Optical Storage CD-ROM, WORM, DVD

Tape

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Magnetic Diskhard disks

thin steel platters with iron oxite coating read/write heads “fly” over the spinning disks,

recording/ reading information in cylinder (same track all surfaces)

recommended size:>10 GB, access speed: <=10msec

DISK 1DISK 1DISK 2DISK 2DISK 3DISK 3DISK 4DISK 4DISK 5DISK 5

READ/WRITEREAD/WRITEHEADSHEADS

L&L 4: Secondary Storage

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Magnetic disks hard disks floppy disks

polyester film with magnetic coating much slower access, capacity from 360KB to 2,8 MB

TRACKSTRACKS

SECTORSECTOR

EACH TRACK EACH TRACK HOLDS SAME HOLDS SAME AMOUNT OF AMOUNT OF DATADATA

L&L 4: Secondary Storage

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Optical storage CD-ROM

store up to 800 megabytes binary information data are read by a lower power laser (<=48x)

WORM(write once / read many),CD-R(CD-recordable),

CD-RW (CD-rewritable)

DVD (digital video disk, up to 10 GB)

L&L 4: Secondary Storage

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Magnetic tapes inexpensive storage media data stored/ accessable just sequentially used as backup media

L&L 4: Secondary Storage

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L&L 4: Overview: Data Storage in a Microcomputer

Speed CostRegisters

Cache

RAM

Hard Disk

Optical Disk

Floppy Disk

Magnetic Tape

Primary Storage

Secondary Storage

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L&L 4: Input and Output Devices

Input Devices Mouse (pointing device) Touch screens Source data automation

data are captured in computer-readable form examples:

magnetic ink character recognition (MICR) optical character recognition (OCR, barcode,scanner)

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L&L 4: Input and Output Devices Input Devices

Source data automation data are captured in computer-readable form examples:

pen-based input Digital scanners Voice input Sensors

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L&L 4: Processing Input Data

Batch processing accumulated transactions over a period of

time processed to update “master” files

On-line (real time) processing (immediately processing of transactions)

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L&L 4: Input and Output Devices Output Devices

Video display terminals (VDTs) cathode ray (CRT), flat panel (LCD) resolution -- pixels by pixels

Printers Impact (dot matrix) Nonimpact (laser, inkjet, thermal) Plotters

Other Output Devices voice output device (converts digital output into spoken

words)

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Interactive Multimedia Integration of two or more types of media

(text, graphics, sound, video, animation) multimedia: foundation of new consumer

products/ services (e-books,e-presentation technologies, e-learning, video-conferencing)

most promising for training and presentation (multimedia integration allows interaction and captures students imaginations)

most difficult element to integrate: full motion video (much data must be brought under digital control)

L&L 4: Input and Output Devices

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Interactive Multimedia web pages make video/ audio available by

streaming technology (data are processed as steady and continuous stream, e.g. Real player or Echo)

web allows for downloading digital products such as software or digitized music clips (MP3-format, e.g. Audiogalaxy)

L&L 4: Input and Output Devices

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L&L 4: Types of Computer Systems L&L 4: Types of Computer Systems

Mainframe Largest computer, used for commercial,

scientific, military applications Multi-User System

Minicomputer mid-range computer, used in academic

institutions and factories Multi-User System

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L&L 4: Types of Computer Systems

Workstations desktop computer, used for powerful

graphics processing (CAD) and complex simulations

single-user System Microcomputer (PC)

desktop or portable, used for different personal and business applications

single-user System

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L&L 4: Types of Computer SystemsL&L 4: Types of Computer Systems

Supercomputer especially powerful computer, used for

extremely complex computations parallel processing systems used e.g. for weapons research or weather

forecasting