Chapter 2
Technology
Computer categories
Mainframes
Minicomputers
Microcomputers
O’Brien 48
• Traditional categories:
small , mid-range and large mainframes and
super 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-servers
technical , office and professional workstations
Trends in Computer Characteristics
Generation
Fist
Size
Circuitry
Reliability
Room
Second
Closet
Vacuum Tubes Transistors
Hours
Days
Desk
Fourth
IC’s
LSI’s
VLSI
weeks
Months
Years?
Hundreds
Memory
Thousands 10s Thousands 100s Thousands Millions
O’Brien p 50
$ 10
$ 1.0
Fifth
Dessktop Credit card?
Instuct/sec
Price/M instr
Thousands
Third
Milions
$ 0.1
Tens of millions Billions?
$ 00.01
Billions?
$ 0.0001?
Categories

Microcomputers or personal computers

Midrange computers or minicomputers

Mainframe computers

Supercomputers

Computer Networks
 client/server
 network
O’Brien 51-54
systems
computers
Client/Server
Host system
super server
Client
Server
• 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 system
O’Brien 60
Central processing unit
CPU
Input device
inputs data and
instructions
into the CPU
Control Unit
Translates instructions
and manages processing
Output device
Arithmetic/Logical
unit (ALU)
Executes arithmetic
operations and compares
Internal storage unit
Stores data and instructions
during execution
•
•
•
•
•
•
•
•
Keyboard
mouse
touch screen
optical scanner
light pen
speech input
barcode
....
External storage
Stores data and
programs for
the applications
• video screen
• printer
• loudspeaker
• video
• ...
Peripheral Devices

terminals




pictogram, mouse, trackball, joystick, touch-sensitive, light
pen, graphical tablet
Terminal input/output


video, hand terminals, intelligent terminals,
transaction-terminals (POS), ...
Pointing devices


O’Brien 63 - 79
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)
The “Von Neumann” Computer
D
A
T
A
I
N
T
E
R
F
A
C
E
Data memory
Arithmetic unit
Control unit
Program memory
Programmer
Interface
I
N
T
E
R
F
A
C
E
R
E
S
U
L
T
S
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 memory
Contains 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
00
01
25
10
200
11
73
20
02
314
12
55
21
03
24
13
478
22
04
05
06
address
contents
573
14
15
24
25
900
23
In most computers , data memory and program memory are
only logically separated
Storage
Semiconductor
memory
RAM
ROM
Primary
Magnetic disks
Magnetic tape
Optical disk
Tekst: O’Brien p 74
Secondary
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
Price
per bit
Registers
Access
Time
central memory
Mass storage
( disk - tape )
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
O’Brien 61
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
Memory Access Time
price
100
I.C.
10
1
Disk
Tape
CD-ROM
-8
10 -2
1s
10
-6
10
-4
10
access time
Coding Data
Numerical Data
- integer :
4
1. 2
binary numbers
3
2
1
0
+ 0. 2 + 1. 2 + 0. 2 + 1. 2
= 10101 b = 21
d
- real numbers
mantissa and exponential part
ASCII computer codes
char dec
A 065
B 066
C 067
D 068
E 069
F 070
G 071
H 072
I 073
J 074
K 075
L 076
.....
hex
41
42
43
44
45
46
47
48
49
4A
4B
4C
oct
101
102
103
104
105
106
107
110
111
112
113
114
binary
01000001
01000010
01000011
01000100
01000101
01000110
01000111
01001000
01001001
01001010
01001011
01001100
char dec
hex
0 048 30
1 049 31
2 050 32
3 051 33
4 052 34
5 053 35
6 054 36
7 055 37
8 056 38
9 057 39
: 058 3A
; 059 3B
.....
oct
060
061
062
063
064
065
066
067
070
071
072
073
O’Brien 61
binary
00110000
00110001
00110010
00110011
00110100
00110101
00110110
00110111
00111000
00111001
00111010
00111011
Complex Configuration
LAN/WAN Remote
Data
Base
Hardware Schema Microcomputer
Central
Microprocessor
Supporting
Microprocessor
RAM
ROM
other
system management
and equipment
Internal memory
System bus
Keyboard
Interface
Display
Interface
CD-ROM
Interface
Serial
Interface
Diskdrive
Interface
Parallel
Interface
...
...
Keyboard
Video screen
CD-ROM
Modem
Diskette station
Printer
Instructions
Information processing instructions
opc. op.1 op.2 res next
Control instructions
opc. op.1 op.2 next1next2
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
Computer controlled door
Data memory
1
1 2
2 3
3
Arithmetic unit
4 5 6
Control unit
7 8 9
Program memory
*
* 0
0 #
#
Programmer
Interface
Computer Controlled Door
1
STO
0
-
D1
P2
2
STO
0
-
D2
P3
3
EQ?
KFL
0
P3
P4
4
MUL
D2
10
D2
P5
KDA key data
5
ADD
D2
KDA
D2
P6
DDA door data
6
ADD
D1
1
D1
P7
7
NE?
D1
3
P3
P8
8
NE?
D2
207
P1
P9
9
STO
1
-
DDA
P1
KFL
key flag
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
Information processing instructions
op
c.
op.
1
op.
2
res
Control instructions
op
c.
op.
1
op.
2
nex
t
Door program with P-register
1
STO
0
-
D1
2
STO
0
-
D2
3
EQ?
KFL
0
P3
4
MUL
D2
10
D2
5
ADD
D2
KDA
D2
6
ADD
D1
1
D1
7
NE?
D1
3
P3
8
NE?
D2
207
P1
9
STO
1
-
DDA
10 JMP
-
-
P1
Client server
Clients
DB.
server
comm.
server
DB.
server
Clients
DB.
server
O.A.
server
comm.
server