Hardware

Overview of the CPU and its parts, memory, binary codes, peripheral devices, other system components

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Schematic model of a computer system

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COMPUTATION CYCLE

I-cycle E-cycle

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CPU

ALU control unit registers data buses Moore’s law: transistor density doubles

every 18 months (today >100 M/chip)

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HOW ARE THEY INTERCONNECTED?

Through the system bus

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Memory Main memory RAM

EDO RAM (Extended Data Out RAM)DRAM (Dynamic RAM – faster)SDRAM (Synchronous DRAM – even faster)

ROM PROM (WORM) EPROM PCMCIA cards (Personal Computer Memory Card

International Association) Flash memory – non-volatile chip – memory sticks

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Memory types

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Cache memory

Easily accessible fast memory for frequently used data; located near the CPU

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BINARY NUMBERS vs. BINARY CODES

Binary numbers Standard binary codes

» ASCII (American Std. Code for Information Interchange)

» EBCDIC (Extended Binary Coded Decimal Interchange Code)

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Abbreviations & numbers of bytes they represent

Abbreviations Full nameHow to compute Numbers of bytes

Approxi-mation

B Byte 1 1 One

KB Kilobyte 1024 1,024 Thousand

MB Megabyte 1024**2 1,048,576 Million

GB Gigabyte 1024**3 1,073,741,824 Billion

TB Terabyte 1024**4 1,099,511,627,776 Trillion

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SPEED OF COMPUTERS

CISC (Complex Instruction Set Computing)Using ALL instructions in the CPU (many PC’s)

RISC (Reduced Instruction Set Computing)Using only the necessary instructions in the CPU

(faster than CISC)

VLIW (Very Long Instruction Word)Including more words per instructions. (faster than

RISC)

Parallel processing (more processors)

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Classes of computer systemsFactors & System types PC's

Network systems

Work stations

Midrange (minis)

Main-frames

Super computers

CPU speed (MIPS) 5-20 1-5 50-100 25-100 40-4500

60B-3 Trillion IPS

RAM size (MB) 16-128 4-16 32-512 32-1024 512-10248192 and

more

Function

Personal productivity, home computing

Data entry, Internet connection

Engineering, science, sw development, graphics design

Small corporate computing

Enterprise systems, large firms, government

Science, climate modeling, product dev., mktg.

Largest manuafacturers

HP, Dell, Gateway Oracle, IBM

Sun, IBM, Toshiba

HP, IBM, NEC IBM, NEC Cray

Price range ($) 1000-5000 500-1500 4000-2500020000-130000 250k-3M 2M- 10M

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Types of storage devices

Magnetic disks (random access)o hard discso flexible disks

Memory sticks (random) Optical disks (random) Magnetic tapes (sequential)

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Hard disks

track/surface/cylinder concept read-write head column head-surface clearance removable hard disks data access times

– seek time– rotation time– transfer time

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Hard disks (cont’d)

physical sizes of hard disks storage capacities of hard disks will a disk twice the size store twice the

data?

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Flexible disks

Sizes Storage capacities

– HD diskettes – 1.44 MB– ZIP disks – 100, 250, 750 MB – Memory sticks – >512 MB

Formatting Access times for some types of disks:

– large DASD 1-10 msec– winchester 10-20 msec– floppy 175-300 msec– optical 100-500 msec

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Other disk technologies

Floptical disks (optical seek/magnetic store)– write & erase!

Cache disk (not a disk – it is a fast memory) RAID (Redundant Arrays of Inexpensive Disks) Expandable storage devices

– Disk cartridges

– ZIP

– Memory sticks

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Other disk technologies (cont’d)

Optical disks, CD’s (3-650 MB) WORM optical disks MO (Magneto-Optical) disks:

– Magnetic/CDROM technologies combined– write & erase!!

DVD (17 gig: a larger capacity CD-ROM) Indexed organization of disks for storage and retrieval SAN (Storage Area Networks) – networked storage

devices

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Tapes

Sequential access Method of storage and parity Tape cartridges Purpose and utility of tape

storage Blocking and density Capacity: about 10 GB

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Some features of some secondary storage devices

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Input devices

Keyboard Mouse Bar code scanner RFID receivers Voice recognition MICR reader OCR

Pen input Touch screen Iris scanners Magnetic card

scanners Image scanners ATM (I/O)

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MICR on checks

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Output devices

Monitors– CRT– LCD

Printers Plotters Sound

– Speakers– MP3

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Standards which ensure seamless operation & interfacing

Musical instruments digital standards Multimedia standards Plug and play standards Small Computer System Interface standards

(SCSI) Personal Computer Memory Card International

Association (PCMCIA) standards

End Hardware