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Matakuliah
Tahun
Versi
: H0472 / Konsep Sistem Informasi
: 2006
:1
Pertemuan 3
Komputer H/W, S/W, Network &
Telekomunikasi
1
Learning Outcomes
Pada akhir pertemuan ini, diharapkan mahasiswa
akan mampu :
• Menerangkan teknologi komputer dalam
mendukung konsep work sistem
2
Outline Materi
• Overview sistem komputer
• Overview S/W, programming
• Overview Telekomunikasi
3
COMPUTER GENERATIONS
1. VACUUM TUBES: 1946-1959
4
COMPUTER GENERATIONS
1. VACUUM TUBES: 1946-1959
2. TRANSISTORS: 1957-1963
5
COMPUTER GENERATIONS
1. VACUUM TUBES: 1946-1959
2. TRANSISTORS: 1957-1963
3. INTEGRATED CIRCUITS: 1964-1979
6
COMPUTER GENERATIONS
1. VACUUM TUBES: 1946-1959
2. TRANSISTORS: 1957-1963
3. INTEGRATED CIRCUITS: 1964-1979
4. VERY LARGE-SCALE INTEGRATED
(VLSI) CIRCUITS: 1980- PRESENT
*
7
SUPERCOMPUTER
TERAFLOP: TRILLION CALCULATIONS/SECOND
•
•
•
•
•
•
HIGHLY SOPHISTICATED
COMPLEX COMPUTATIONS
FASTEST CPUs
LARGE SIMULATIONS
STATE-OF-THE-ART COMPONENTS
EXPENSIVE
*
8
MAINFRAME
• LARGEST
ENTERPRISE COMPUTER
MIPS: Millions of Instructions per second
• 5O MEGABYTES TO OVER ONE
GIGABYTE RAM
• COMMERCIAL, SCIENTIFIC, MILITARY
APPLICATIONS
• MASSIVE DATA
• COMPLICATED COMPUTATIONS
*
9
MINICOMPUTER
• MIDDLE-RANGE
• 10 MEGABYTES TO OVER ONE
GIGABYTE RAM
• UNIVERSITIES, FACTORIES, LABS
• USED AS FRONT-END PROCESSOR
FOR MAINFRAME
*
10
MICROCOMPUTER
• DESKTOP OR PORTABLE
• 64 KILOBYTES TO OVER 128
MEGABYTES RAM
• PERSONAL OR BUSINESS
COMPUTERS
• AFFORDABLE
• MANY AVAILABLE COMPONENTS
• CAN BE NETWORKED
*
11
LAPTOPS & SMALLER
• LAPTOP (OR NOTEBOOK): Briefcase
type package, very portable, can be
inexpensive, can connect to other
computers or networks
• HAND-HELD (OR PALMTOP): Subminiature, wireless computer. Growing in
sophistication and connectivity
*
12
BASIC COMPONENTS OF
COMPUTER SYSTEMS
•
•
•
•
UNDERLYING STRUCTURE
INPUT/OUTPUT
BITS & CODING SCHEMES
ARITHMETIC LOGIC UNIT
*
13
CENTRAL PROCESSING UNIT
CONTROL UNIT
ROM
(CPU)
ARITHMETIC/LOGIC
UNIT
CLOCK
RAM
PRIMARY (MAIN) MEMORY
14
BUSES
PRIMARY
CPU
STORAGE
DATA BUS
ADDRESS BUS
CONTROL BUS
INPUT
OUTPUT
SECONDARY
DEVICES
DEVICES
STORAGE
15
TYPES OF MEMORY
• RAM : Random Access Memory
– Dynamic: Changes thru processing
– Static: Remains constant (power on)
• ROM : Read Only Memory
(preprogrammed)
– PROM: Program can be changed once
– EPROM: Erasable thru ultraviolet light
– EEPROM: Electrically erasable
*
16
INPUT/OUTPUT
•
•
•
•
•
TERMINAL
POINT-OF-SALES TERMINALS
AUTOMATIC TELLER MACHINES
PUNCHED CARDS
MAGNETIC INK CHARACTER RECOGNITION
(MICR): Used by banks to process checks
*
17
INPUT/OUTPUT
• OPTICAL CHARACTER RECOGNITION:
Scanned material translated into computer
characters
• IMAGING: Forms, documents, photos digitized
for computer use
• BAR CODE LABEL: Product label information
read into computer. Can be used to track
inventory
*
18
INPUT/OUTPUT
• COMPUTER OUTPUT MICROFILM (COM):
Computer rapidly generates microfilm
documents for archive copies in small space
• VOICE RESPONSE UNITS: Computer
recognizes, generates verbal messages
• MULTIMEDIA: Combines text, graphics, sound
still images, animations, video
*
19
HOW CHARACTERS ARE STORED IN
COMPUTER MEMORY
• BIT: Binary Digit. On/Off, 0/1, Magnetic/Not
• BYTE: Group of bits for one character
– EBCDIC- Extended Binary Coded Decimal
Interchange Code (8 bits per byte)
– ASCII- American Standard Code for
Information Exchange (7 or 8 bits per byte)
• PARITY BIT: extra bit added to each byte to
help detect errors
*
20
EXAMPLES OF BYTES
EBCDIC
ASCII
(assume even-parity system)
C: 1100 0011 0
100 0011 1
A: 1100 0001 1
100 0001 0
T: 1110 0011 1
101 0100 1
Note how sum for each byte is an EVEN
number
*
21
ALU & CONTROL UNIT
• ARITHMETIC- LOGIC UNIT: CPU
component performs logic and arithmetic
operations
• CONTROL UNIT: CPU component
controls, coordinates other parts of
computer system
*
22
COMPUTER FILES
• RECORD: Data about a transaction
arranged in a set of FIELDS, each holding
a datum
• FILE: A group of similar records, such as
accounts receivable or payroll
• DATABASE: The files of an organization,
an electronic library
*
23
COMPUTER FILES
• SEQUENTIAL ACCESS: A sequence of
files arranged in order, say alphabetically.
Usually stored on magnetic tape or
cartridge
• DIRECT ACCESS: Records stored on a
DIRECT ACCESS STORAGE DEVICE
(DASD). Can move directly to any record
*
24
DIRECT ACCESS STORAGE DEVICE
• HARD DISK: Steel platter array for large
computer systems
• RAID: Redundant array of Inexpensive
Disks
• FLOPPY DISK: Removable disk for PC
*
25
DISK PACK STORAGE
•
•
•
•
•
•
LARGE SYSTEMS
RELIABLE STORAGE
LARGE AMOUNTS OF DATA
QUICK ACCESS & RETRIEVABLE
TYPICAL: 11 2-SIDED DISKS
CYLINDER: SAME TRACK ALL SURFACES
READ/WRITE
HEADS
DISK 1
DISK 2
DISK 3
DISK 4
DISK 5
CYLINDER 10: TRACK 10 (TOP AND BOTTOM OF EACH DISK)
26
THE STORED PROGRAM CONCEPT
• COMPUTER IS A BINARY SYSTEM
• PROGRAM: A set of instructions telling the
computer what to do
• INSTRUCTION: Individual step or
operation in a program
• MACHINE LANGUAGE: Translated
instruction understood by particular model
of computer
*
27
CONTROLLER
• LINK FOR INPUT/OUTPUT OR FILE
DEVICES: To CPU and memory of large
computer systems
• HIGHLY SPECIALIZED PROCESSOR:
Manages the operation of attached
devices to free the CPU from these tasks
*
28
DATA CHANNEL
• SPECIALIZED INPUT/OUTPUT
PROCESSOR (A COMPUTER): Takes
over function of device communication
from the CPU
• CORRECTS FOR SPEED MISMATCH
BETWEEN SLOW PERIPHERAL
DEVICES AND VERY FAST CPU
*
29
SYMMETRIC MULTIPROCESSOR
• PROCESSORS (CPUs) ARE IDENTICAL,
WITH EACH PROCESSOR OPERATING
INDEPENDENTLY OF THE OTHERS
• USED IN MOST MAINFRAMES AND
SOME MIDRANGE MACHINES
*
30
PARALLEL PROCESSOR (PP)
• MULTIPLE CPUs INSTALLED AS PART
OF A SINGLE COMPUTER SYSTEM:
Gives separate piece of program to each
of the processors so that work on the
program can proceed in parallel on the
separate pieces
*
31
MASSIVELY PARALLEL
PROCESSOR (MPP)
PARALLEL PROCESSING COMPUTER WITH
MANY PARALLEL PROCESSORS:
• 32 OR MORE: Different CPUs capable of
performing different instructions at the same
time
• 1000 OR MORE: CPUs must all carry out the
same instruction at the same time
*
32
THE STORED PROGRAM CONCEPT
• COMPUTER IS A BINARY SYSTEM
• PROGRAM: A set of instructions telling the
computer what to do
• INSTRUCTION: Individual step or
operation in a program
• MACHINE LANGUAGE: Translated
instruction understood by particular model
of computer
*
33
Computer Software
34
EVOLUTION OF COMPUTER
SOFTWARE
• FIRST GENERATION: Machine language binary language designed for particular
computer
• SECOND GENERATION: Assembly
language - substituted mnemonic operation
codes and addresses, translated to machine
language by assembler
*
35
EVOLUTION OF COMPUTER
SOFTWARE
• THIRD GENERATION: Procedural language
- FORTRAN, COBOL, C - translated to machine
language by compiler or interpreter. Example:
COBOL
• FOURTH GENERATION: Nonprocedural
language. Tell what to do, not how to do it, order
not important. Translate to machine language
by compiler or interpreter. Example: FOCUS
*
36
KEY TYPES OF SOFTWARE
• APPLICATION SOFTWARE: Programs
written to accomplish particular tasks for
computer users
• SUPPORT SOFTWARE: Programs that
support application software in producing
needed output. Does not directly produce output
needed by users
*
37
APPLICATION SOFTWARE
•
•
•
•
WORD PROCESSING
SPREADSHEETS
DATABASE MANAGEMENT SYSTEMS
PRESENTATION GRAPHICS
*
38
APPLICATION SOFTWARE
•
•
•
•
WORLD WIDE WEB BROWSERS
ELECTRONIC MAIL, GROUPWARE
DESKTOP PUBLISHING
APPLICATION SUITES
*
39
SUPPORT SOFTWARE
• OPERATING SYSTEMS: Helps maximize
work done, eases workload of users
• JOB CONTROL LANGUAGE: Allows
users to communicate with operating systems
• MULTIPROGRAMMING: Large
computers can run multiple programs
simultaneously. Time-driven approach is timesharing
*
40
SUPPORT SOFTWARE
• MULTITASKING: Allows small computers to
work on several programs interactively
• VIRTUAL MEMORY: Allows computer to run
portions of a large program as required, saving
use of main memory
• MULTIPROCESSING: Multiple CPUs divide
workload, increases efficiency
*
41
SOURCES OF OPERATING
SYSTEMS
• PROPRIETARY: Written for particular
computer class or system. Examples: Windows
98, Windows 2000
• OPEN SYSTEM: Not tied to specific platform.
Examples: UNIX, Linux
• NETWORK OPERATING SYSTEM
(NOS): Manages network resources, local
area networks
*
42
GRAPHICAL USER INTERFACE
(GUI)
• MOUSE: A standard pointing device
• ICON: Graphic or label on screen associated
with task or operation
• 32-BIT OPERATING SYSTEM: Operating
system handles 32 bits at a time
• CLICKING MOUSE ON ICON INITIATES
TASK
*
43
OBJECT-ORIENTED
PROGRAMMING (OOP)
• COMPUTER PROGRAMMING BASED
ON CREATING, USING SET OF
OBJECTS: Object combines data and
methods (or chunks of programs)
• EXAMPLES: C++, Smalltalk, Java
*
44
OTHER LANGUAGES
• NATURAL LANGUAGES: User types in or
speaks English, computer evolves program
• HYPERTEXT MARKUP LANGUAGE
(HTML): Code used to develop World
Wide Web (WWW) pages and sites
• eXtensible Markup Language (XML): Used
for data exchange on WWW
*
45
DATABASE MANAGEMENT
SYSTEM (DBMS)
• SUPPORT SOFTWARE USED TO
CREATE, MANAGE, AND PROTECT
ORGANIZATIONAL DATA
• DBMS: Software that manages a
database, works with operating system to
store and modify data and to make data
accessible in authorized ways
*
46
TYPES OF DBMSs
• HIERARCHICAL: Data arranged in a topdown, organization chart fashion
• NETWORK: Data arranged like cities on a
highway systems, often with multiple paths
between pieces of data
• RELATIONAL: Data arranged into simple
tables, and records are related by storing
common data in each of the associated tables
*
47
FILING METHODS
• INDEXED SEQUENTIAL ACCESS METHOD
(ISAM) :
– EACH RECORD IDENTIFIED BY KEY
– GROUPED IN BLOCKS AND CYLINDERS
– KEYS IN INDEX
• VIRTUAL STORAGE ACCESS METHOD
(VSAM) :
– MEMORY DIVIDED INTO AREAS & INTERVALS
– DYNAMIC FILE SPACE
VSAM WIDELY USED FOR RELATIONAL
DATABASES
• DIRECT FILE ACCESS METHOD
48
COMPONENTS OF DBMS:
• DATA DEFINITION LANGUAGE: Defines
data elements in database
• DATA MANIPULATION LANGUAGE:
Manipulates data for applications
• DATA DICTIONARY/DIRECTORY: Formal
definitions of all variables in database, controls
variety of database contents
*
49
STRUCTURED QUERY LANGUAGE (SQL)
EMERGING STANDARD
DATA MANIPULATION LANGUAGE
FOR RELATIONAL DATABASES
*
50
ADVANTAGES OF
RELATIONAL DBMS
• NEW DATA ELEMENTS CAN EASILY BE
ADDED AS NEW NEEDS ARISE
• NEW RELATIONSHIPS CAN BE CREATED AS
NEW QUERY/REPORTING NEEDS CHANGE
• FEWER DATA CONSISTENCY PROBLEMS
DUE TO LESS REDUNDANT DATA STORAGE
• MORE “USER FRIENDLY” TOOLS
*
51
COMPUTER-AIDED SOFTWARE
ENGINEERING (CASE)
• HELPS AUTOMATE SOFTWARE
DEVELOPMENT: Used by computer
professionals to help automate software
development
• MAY INCLUDE:
– upper-CASE (requirements definition and design)
– lower-CASE (code generation)
– I-CASE or integrated-CASE
*
52
CHANGING NATURE OF SOFTWARE
• MORE HARDWIRING OF SOFTWARE AND
MORE MICROCODE
• MORE COMPLEXITY OF
HARDWARE/SOFTWARE ARRANGEMENTS
• LESS CONCERN WITH MACHINE
EFFICIENCY
*
53
CHANGING NATURE OF SOFTWARE
• MORE PURCHASED APPLICATIONS AND
MORE PORTABILITY OF THESE
APPLICATIONS FROM ONE COMPUTER
PLATFORM TO ANOTHER
• MORE PROGRAMMING USING OBJECTORIENTED AND VISUAL LANGUAGES, IN
LARGE PART BECAUSE OF EMPHASIS ON
GUIs
*
54
CHANGING NATURE OF SOFTWARE
• MORE EMPHASIS ON APPLICATIONS THAT
RUN ON INTRANETS AND THE INTERNET
• MORE USER DEVELOPMENT
• MORE USE OF PERSONAL PRODUCTIVITY
SOFTWARE ON MICROCOMPUTERS,
ESPECIALLY PACKAGES WITH A GUI
*
55
Telecommunications &
Networking
56
TELECOMMUNICATIONS &
NETWORKING
• TELECOMMUNICATIONS:
Communications (both voice and data) at
a distance
• NETWORKING: Electronic linking of
geographically dispersed devices
*
57
THE NEED FOR NETWORKING
• SHARING OF TECHNOLOGY RESOURCES
• SHARING OF DATA
• DISTRIBUTED DATA PROCESSING AND
CLIENT/SERVER SYSTEMS
• ENHANCED COMMUNICATIONS, INCLUDING
ELECTRONIC DATA INTERCHANGE (EDI)
AND ACCESS TO THE INTERNET
*
58
KEY ELEMENTS OF TELECOMMUNICATIONS &
NETWORKING
• ANALOG SIGNALS: Continuous waveform,
passes thru system. Example: voice
communications
• DIGITAL SIGNALS: Discrete waveform
two discrete states (1-bit & 0-bit, on / off
pulse). Data communication. Uses modem to
translate analog to digital, digital to analog
*
59
MODEM
• ABBREVIATION FOR MODULATOR/
DEMODULATOR
• DEVICE THAT CONVERTS DATA FROM
DIGITAL FORM TO ANALOG FORM TO
BE SENT OVER ANALOG TELEPHONE
NETWORK (RECONVERTS DATA AFTER
IT HAS BEEN TRANSMITTED)
*
60
SPEED OF TRANSMISSION
• BANDWIDTH: Difference between highest
and lowest frequencies (cycles per second) that
can be transmitted on a particular medium; a
capacity measure
• HERTZ: Cycles per second
• BAUD: Signals sent per second
• BITS PER SECOND (bps): Common measure
*
61
TYPES OF TRANSMISSION LINES
•
•
•
•
•
PRIVATE, OR DEDICATED, LINES
SWITCHED LINES
SIMPLEX TRANSMISSION
HALF-DUPLEX TRANSMISSION
FULL-DUPLEX TRANSMISSION
*
62
TRANSMISSION MEDIA
• TWISTED PAIR
• COAXIAL CABLE: Baseband and
broadband
• WIRELESS: Cordless phone, cellular
phone, wireless LAN, infrared devices
• SATELLITE: Microwave, line of sight
• FIBER OPTICS
*
63
ORBITING SATELLITES
MICROWAVE
TRANSMISSION
UPLINK
DOWNLINK
64
NEW SATELLITES
• OVER A DOZEN NEW PROJECTS
PROPOSED
• LOW EARTH ORBIT (LEO) SATELLITES:
Only 400 to 1000 miles above the earth,
compared to geosynchronous satellites at
22,000 miles above the equator. 1,700 satellites
to be launched by 2006
*
65
NEW SATELLITES
• IRIDIUM: 66 satellites offered mobile
telephony, paging, and data communications.
Bankrupt by 1999.
• TELEDESCIC: Will include 288 LEO to
provide low-cost, high-speed Internet access,
networking, teleconferencing
*
66
TELECOMMUNICATIONS
TRANSMISSION SPEEDS
•
•
•
•
•
•
•
•
•
Twisted pair - voice telephone
14.4 kbps -56 kbps
Twisted pair - conditioned
56 kbps - 144 kbps
Twisted pair - LAN
4 mbps - 100 mbps
Coaxial cable - baseband
10 mbps - 2 gbps
Coaxial cable - broadband
10 mbps - 550 mbps
Radio frequency wireless LAN
1 mbps - 11 mbps
Infrared light wireless LAN
4 mbps - 16 mbps
Microwave / Satellite
64 kbps - 100 mbps
Fiber optic cable
100 mbps - 100 gbps
*
67
TOPOLOGY OF NETWORKS
•
•
•
•
•
•
BUS TOPOLOGY
RING TOPOLOGY
STAR TOPOLOGY
TREE, OR HIERARCHICAL, TOPOLOGY
MESH TOPOLOGY
MORE COMPLEX TOPOLOGIES
*
68
NETWORK TYPES
• COMPUTER TELECOMMUNICATIONS
NETWORK
• PRIVATE BRANCH EXCHANGE (PBX)
NETWORK
• LOCAL AREA NETWORK (LAN)
*
69
NETWORK TYPES
• BACKBONE NETWORK
• WIDE AREA NETWORK (WAN)
• INTERNET
*
70
LOCAL AREA NETWORKS
• CONTENTION BUS NETWORK: Uses
CSMA/CD protocol. Example: Ethernet
• TOKEN BUS NETWORK: Central to
Manufacturing Automation Protocol (MAP)
• TOKEN RING NETWORK: Used in LAN;
unidirectional data flow
*
71
NEW LAN TECHNOLOGY
• FAST ETHERNET: Ethernet operating at
speeds up to 100 mbps
• FIBER DISTRIBUTED DATA
INTERFACE (FDDI): Token ring
architecture delivered on a dual ring at
speeds up to 100 mbps
*
72
BACKBONE NETWORKS
• MIDDLE DISTANCE NETWORKS:
Interconnect LANs in a single organization with
each other and with the organization’s WAN and
Internet
• EMPLOY HIGH-END LAN
TECHNOLOGY, OFTEN OPERATING AT
100 MBPS OR MORE
*
73
BACKBONE NETWORK
TERMINOLOGY
• HUB: Simple device connecting one section of a LAN to
another
• BRIDGE: Connects two LAN segments when the LANs
use the same protocols
• ROUTER, OR GATEWAY: Connects two or more
LANs together. Networks may use different protocols
• SWITCH: Connects more than two LANs that use the
same protocol into a backbone network
*
74
WIDE AREA NETWORKS
•
•
•
•
•
•
DIRECT DISTANCE DIALING (DDD)
WIDE AREA TELEPHONE SERVICE (WATS)
LEASED LINE: Most common, T-1 lines
SATELLITE: C-Band, KU-Band
VALUE ADDED NETWORK (VAN)
INTEGRATED SERVICES DIGITAL NETWORK
(ISDN)
*
75
VALUE ADDED NETWORK (VAN)
• DATA-ONLY, PRIVATE, NONREGULATED
TELECOMMUNICATIONS NETWORK: Uses
packet switching
• AN ORGANIZATION MAY CHOOSE TO BUY
SERVICES OF A VAN TO IMPLEMENT ITS
WIDE AREA NETWORK (WAN)
*
76
PACKET SWITCHING
• INFORMATION DIVIDED INTO PACKETS
OF SOME FIXED LENGTH, SENT OVER
NETWORK SEPARATELY
• PERMITS MORE EFFICIENT USE OF
THE NETWORK
*
77
INTEGRATED SERVICES DIGITAL
NETWORK (ISDN)
• EMERGING SET OF INTERNATIONAL
STANDARDS
• USING PUBLIC TELEPHONE NETWORK
• EXTENSIVE NEW TELECOMMUNICATIONS
CAPABILITIES
• SIMULTANEOUS TRANSMISSION OF VOICE
AND DATA OVER SAME LINE TO TELEPHONE
USERS WORLDWIDE
*
78
USES OF ISDN
• CUSTOMER SERVICE APPLICATION:
Customer’s records automatically sent to service
representative’s workstation when customer
calls in
• SOLVES DIAL-IN PROBLEMS INTO
CORPORATE NETWORK FOR
TELECOMMUTERS, BRANCH OFFICES
*
79
NEW WAN AND LAN
TECHNOLOGY
ASYNCHRONOUS TRANSFER MODE
(ATM): Switching technology employing fast
packet switching. Emerging standard for
broadband ISDN. Speeds from 1.544 mbps to
622 mbps. Represents the future for both LANs
and WANs
*
80
PROTOCOL
RULES & PROCEDURES
TO GOVERN TRANSMISSION
BETWEEN COMPONENTS
IN A NETWORK
*
81
NETWORK PROTOCOLS
• OPEN SYSTEMS INTERCONNECTION (OSI):
Reference model, emerging standard
• TRANSMISSION CONTROL PROTOCOL / INTERNET
PROTOCOL (TCP/IP): Standard used on the Internet
• SYSTEMS NETWORK ARCHITECTURE (SNA): IBM
standard
• FILE TRANSFER PROTOCOL (FTP): Allows file transfer
on Internet
*
82
INTERNET
• NETWORK OF NETWORKS THAT USE THE
TCP/IP PROTOCOL, WITH GATEWAYS
(CONNECTIONS) TO OTHER NETWORKS
THAT DO NOT USE TCP/IP
• INTERNET APPLICATIONS: e-mail, Usenet
newsgroups, listserv, FTP, Gopher, Archie,
Veronica, World Wide Web
*
83
CONNECTIONS TO INTERNET
•
•
•
•
•
•
PHONE LINE MODEM
CABLE MODEM
DIGITAL SUBSCRIBER LINE (DSL)
T-1 DATA PHONE LINE
SATELLITE
FIBER OPTICS
*
84
INTRANET
• A NETWORK OPERATING WITHIN AN
ORGANIZATION EMPLOYING TCP/IP
PROTOCOL
• ORGANIZATION USES SAME WEB
BROWSER, CRAWLER, SERVER SOFTWARE
AS IT WOULD ON THE INTERNET, BUT
INTRANET IS NOT ACCESSIBLE FROM
OUTSIDE THE ORGANIZATION
*
85
CONNECTIVITY
MEASURE OF ABILITY OF COMPUTING
DEVICES TO PASS & SHARE
INFORMATION WITHOUT HUMAN
INTERVENTION
OPEN SYSTEMS: Software able to
function on different computer platforms.
Nonproprietary operating systems,
applications, protocols
*
86
Closing
• Overview sistem komputer
• Overview S/W, programming
• Overview Telekomunikasi
87