Chapter 2

Technology

Computer categories

Mainframes

Minicomputers

Microcomputers

• Traditional categories:small , mid-range and large mainframes andsuper computers

• Application categories:host-computers, database servers, transaction systems and central systems

• Traditional categories:minicomputers, mid-rang systems

• Application categories :departmental systems, network servers, technical workstations , workgroup systems

• Traditional categories :portable , desktop and minitower-computers

• Application categories :personal computers, multi-user systems, netwerk-serverstechnical , office and professional workstations

O’Brien 48

Trends in Computer Characteristics

Size Room Closet Desk Dessktop Credit card?

Generation Fist Second Third Fourth Fifth

Reliability Hours Days weeks Months Years?

Instuct/sec Hundreds Thousands Milions Tens of millions Billions?

Circuitry Vacuum Tubes Transistors IC’s LSI’s VLSI

Memory Thousands 10s Thousands 100s Thousands Millions Billions?

Price/M instr $ 10 $ 1.0 $ 0.1 $ 00.01 $ 0.0001?

O’Brien p 50

Categories

Microcomputers or personal computers

Midrange computers or minicomputers

Mainframe computers

Supercomputers

Computer Networks

client/server systems

network computers

O’Brien 51-54

Client/Server

Host systemsuper server

ClientServer

• types• Functionality

O’Brien p 55

Multimedia Computersystemen

O’Brien p 56

Multimedia

Technologies : Languages HTML, JAVA Hypertex Hypermedia

Elements CDI compact disk interactive Compressed audio Computer edit systems Digital audio DVI digital video interactive MIDI musical instrument digital interface Sound card Video capture card

O’Brien p 57-58

Design of a computer systemCentral processing unit

CPU

Input deviceinputs data and

instructionsinto the CPU

• Keyboard• mouse• touch screen• optical scanner• light pen• speech input• barcode• ....

Control UnitTranslates instructions and manages processing

Arithmetic/Logicalunit (ALU)

Executes arithmeticoperations and compares

Internal storage unitStores data and instructions

during execution

Output device

• video screen• printer• loudspeaker• video• ...

External storageStores data andprograms for

the applications

O’Brien 60

Peripheral Devices

terminals video, hand terminals, intelligent terminals,

transaction-terminals (POS), ... Pointing devices

pictogram, mouse, trackball, joystick, touch-sensitive, light pen, graphical tablet

Terminal input/output LCD, plasma, video-output, impact printers, laser printer,

inktjet printer Speech input/output Optical and magnetic recognition (OCR , MICR) Storage: tape, magnetic disk , optical disk (ROM , WORM)

O’Brien 63 - 79

The “Von Neumann” Computer

INTERFACE

INTERFACE

Data memory

Arithmetic unit

Control unit

Program memory

Programmer Interface

DATA

RESULTS

Computer Architecture

Input and Output Converters translate the external representation into an

internal representation or the other way around.

eg: keyboards, video screens , printers, barcode readers, magnetic cards, sensors, ...

Data memory Temporary storage of data

. intermediate results ( eg. program variables )

. input/output buffers

Computer Architecture 2

Program memoryContains the instructions that go via the program interface to

the CPU and that will be executed one by one.

Central memory

A set of numbered cells that can contain a binary number.

Terminology: . word

. address

Program variables represent an address

Central Memory

25 200 314 24 573

73 55 478 900

00 01 02 03 04 05 06

10 11 12 13 14 15

20 21 22 23 24 25

addresscontents

In most computers , data memory and program memory are only logically separated

Storage

Semiconductormemory

Magnetic disks

Magnetic tape

Optical disk

Acces

s spee

d incr

ease

s

Stora

ge ca

pacity

dec

reas

es

Cost/b

yte i

ncrea

ses

RAMROM

Primary

Secondary

Tekst: O’Brien p 74

Computer Architecture 3

Arithmetic and Logical Unit

This unit is responsible for the processing of the data read from, and rewritten into the data memory.

The unit can compare the contents of memory cells and execute basic operations.

The Control Unit

This unit reads the instructions one by one from the program memory , decodes them and sends the appropriate signals to the other components.

Peripheral Memory

. Uses no electrical energy

. Usually stored in blocks of hundreds of words , which are moved as one block into the central memory

. Magnetic material in permanent movement

- disk memory < 1/10 sec : allows " random access "

- Magnetic tapes : sequential memory

. Optical material

- CD-ROM : to distribute large amounts of data

- WORM : archiving

Usage of Memory

Registers

central memory

Mass storage( disk - tape )

Priceper bit

AccessTime

Registers: Very fast memory ( < 100 ns ) in arithmetic and control unit

Central memory: ( between 50 and 500 ns )

These types of memory use integrated circuits and use electrical energy. The content is lost with a power supply interruption.

Units

Memory capacity

Kilobyte: one thousand bytes Megabyte: one million bytes Gigabyte: one billion bytes Terabyte: one trillion bytes

Time

Millisecond: one thousandth of a second Microsecond: one millionth of a second Nanosecond: one billionth of a second Picosecond: one trillionth of a second

O’Brien 61

Memory Access Time

price

access time

100

10

1

10 10 10 10 1s

-8 -6 -4 -2

I.C.

Disk

CD-ROM

Tape

Coding Data

Numerical Data

- integer : binary numbers

1. 2 + 0. 2 + 1. 2 + 0. 2 + 1. 2 =

10101 b = 21 d

- real numbers

mantissa and exponential part

4 3 2 1 0

ASCII computer codes

0 048 30 060 00110000 1 049 31 061 00110001 2 050 32 062 00110010 3 051 33 063 00110011 4 052 34 064 00110100 5 053 35 065 00110101 6 054 36 066 00110110 7 055 37 067 00110111 8 056 38 070 00111000 9 057 39 071 00111001 : 058 3A 072 00111010 ; 059 3B 073 00111011 .....

A 065 41 101 01000001 B 066 42 102 01000010 C 067 43 103 01000011 D 068 44 104 01000100 E 069 45 105 01000101 F 070 46 106 01000110 G 071 47 107 01000111 H 072 48 110 01001000 I 073 49 111 01001001 J 074 4A 112 01001010 K 075 4B 113 01001011 L 076 4C 114 01001100 .....

char dec hex oct binary char dec hex oct binary

O’Brien 61

Complex Configuration

LAN/WAN Remote

DataBase

Hardware Schema Microcomputer

System bus

...

othersystem management

and equipment

CentralMicroprocessor

SupportingMicroprocessor

RAM ROM

Keyboard Interface

DisplayInterface

CD-ROMInterface

SerialInterface

DiskdriveInterface

ParallelInterface

Keyboard Video screen CD-ROM Modem Diskette station Printer

...

Internal memory

Instructions

Information processing instructions

opc. op.1 op.2 res next

opc. op.1 op.2 next1next2

Control instructions

opc. = operation code

op.1 = address in memory of the first operand

op.2 = address in memory of the second operand

next = address in the program memory of the next instruction

next1 = address of the next instruction if a condition is true

next2 = address of the next instruction if a condition is false

Program Example

Data memory

Arithmetic unit

Control unit

Program memory

Programmer Interface

1 2 3

4 5 6

7 8 9

* 0 #

1 2 3

4 5 6

7 8 9

* 0 #

Computer controlled door

Computer Controlled Door

1

2

3

4

5

6

7

8

9

STO

STO

EQ?

MUL

ADD

ADD

NE?

NE?

STO

0

0

KFL

D2

D2

D1

D1

D2

1

-

-

0

10

KDA

1

3

207

-

D1 P2

D2 P3

P3 P4

D2 P5

D2 P6

D1 P7

P3 P8

P1 P9

DDA P1

KFL key flag

KDA key data

DDA door data

D1 number of digits read

D2 value read

Usage of P-register

P - register or ordinal counter

Control Unit

+1

P-register

I-register

Program Memory

opc.

op.1

op.2

res

opc.

op.1

op.2

next

Control instructions

Information processing instructions

Door program with P-register

1

2

3

4

5

6

7

8

9

10

STO

STO

EQ?

MUL

ADD

ADD

NE?

NE?

STO

JMP

0

0

KFL

D2

D2

D1

D1

D2

1

-

-

-

0

10

KDA

1

3

207

-

-

D1

D2

P3

D2

D2

D1

P3

P1

DDA

P1

Client server

Clients

Clients

comm.server

comm.server

DB.server

DB.server

DB.server

O.A.server