1.1 Introduction • HM Deitel, PJ Deitel. 2004, Java How to Program

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1.1 Introduction
• H. M. Deitel, P. J. Deitel. 2004, Java How to
Program, Sixth Edition
– Java 2 Standard Edition
– Object-oriented programming
• Java tutorial: http://download.oracle.com/javase/tutorial/
• Arnold, K., Gosling, J., and Holmes, J. 2005. The Java™
Programming Language, 4th Edition. Addison Wesley
Professional.
• Zakhour, S., et al. 2005. The Java™ Tutorial Fourth
Edition: A Short Course on the Basics. Addison Wesley
Professional.
 2003 Prentice Hall, Inc. All rights reserved.
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1.2
What Is a Computer?
• Komputer:
– Peranti/peralatan yang mampu melaksanakan perhitungan
(komputasi) dan membuat keputusan logika
• Program Komputer (Computer Program):
– Sekumpulan instruksi yang mengontrol pemrosesan data yang
dilakukan komputer.
• Hardware:
– Sekumpulan peralatan yang membentuk komputer.
– Misal: keyboard, mouse, CPU, monitor, CD-ROM, Hard Disk,
Floppy Disk, DVD-ROM, RAM, printer, scanner dsb.
• Software:
– Program yang berjalan di atas komputer.
 2003 Prentice Hall, Inc. All rights reserved.
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1.3
•
1.
Computer Organization (1)
Secara logis komputer dibagi menjadi 6 bagian:
Input Unit
– Bagian Penerimaan – Receiving Section
– Mendapatkan informasi dari peranti masukan seperti:
keyboard, mouse, microphone, scanner, networks, …
 2003 Prentice Hall, Inc. All rights reserved.
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1.3
2.
Computer Organization (2)
Output Unit
– Bagian Pengiriman – Shipping Section
– Mengambil informasi yang diproses komputer
– Menempatkan informasi pada peranti-peranti
keluaran (output devices), seperti: monitor, printer,
dsb
 2003 Prentice Hall, Inc. All rights reserved.
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1.3
Computer Organization (3)
3. Memory Unit
– Akses yang cepat (rapid access) –
Warehouse Section yang memiliki
kapasitas relatif rendah
– Menyimpan informasi dari input unit –
secara langsung tersedia bagi proses
yang ada
– Menyimpan informasi yang telah
diproses – sampai selesai ditempatkan
pada output unit
– Berupa memory (RAM), primary
memory (cache memory pada processor)
 2003 Prentice Hall, Inc. All rights reserved.
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1.3
Computer Organization (4)
4. Arithmetic and Logic Unit (ALU)
– Bagian Fabrikasi – Manufacturing Section
– Melaksanakan proses perhitungan aritmatika dan
keputusan logika
5. Central Processing Unit (CPU)
– Bagian Administratif / Administrative Section
– Mengawasi dan mengkoordinasi bagian-bagian lain di
dalam komputer
 2003 Prentice Hall, Inc. All rights reserved.
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1.3
Computer Organization (5)
6. Secondary Storage Unit
– “Warehouse Section” yang memiliki kapasitas besar,
waktu yang lama.
– Sebagai penyimpan – program atau data yang sedang
tidak aktif
– Peranti penyimpan sekunder – Disks (hard disk, floppy
disk, compact disc dsb
– Lebih lama waktu aksesnya dan lebih mahal harganya
daripada primary memory
 2003 Prentice Hall, Inc. All rights reserved.
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1.4
Evolution of Operating Systems
• Batch processing
– One job (task) at a time
– Operating systems developed
• Programs to make computers more convenient to use
• Switch jobs easier
• Multiprogramming
– “Simultaneous” jobs
– Timesharing operating systems
 2003 Prentice Hall, Inc. All rights reserved.
1.5
Personal, Distributed and Client/Server
Computing
• Personal computing
– Computers for personal use
• Distributed computing
– Computing performed among several computers
• Client/server computing
– Servers offer common store of programs and data
– Clients access programs and data from server
 2003 Prentice Hall, Inc. All rights reserved.
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1.6 Machine Languages, Assembly
Languages and High-Level Languages
• Machine language
– “Natural language” of computer component
– Machine dependent
• Assembly language
– English-like abbreviations represent computer operations
– Translator programs convert to machine language
• High-level language
– Allows for writing more “English-like” instructions
• Contains commonly used mathematical operations
– Compiler convert to machine language
• Interpreter
– Execute high-level language programs without compilation
 2003 Prentice Hall, Inc. All rights reserved.
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Bahasa Mesin (Machine Language)
•
•
•
•
•
Bahasa asli komputer – “Native Computer
Language”.
Ditentukan oleh perancangan hardware dan
tergantung pada jenis mesinnya – “machinedependent”.
Umumnya terdiri dari deretan angka-angka –
hampir keseluruhan adalah 0 dan 1 saja.
Menginstruksikan kepada komputer untuk
melaksanakan proses-proses dasar - sekali dalam
satu waktu.
Sulit bagi manusia
 2003 Prentice Hall, Inc. All rights reserved.
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Bahasa Rakitan (Assembly Language)
•
•
•
•
•
Menggunakan singkatan-singkatan dalam bahasa
Inggris untuk menggambarkan operasi-operasi
komputer dasar
Lebih jelas bagi manusia
Assembly Language memerlukan beberapa perintah
untuk 1 tugas sederhana
Tidak dimengerti komputer -> perlu translator
(assembler) -> mengkonversi ke bahasa mesin
Misal:
– MOV DX, 100;
 2003 Prentice Hall, Inc. All rights reserved.
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Bahasa Tingkat Tinggi
(High-Level Language)
•
•
•
•
Menggunakan istilah-istilah dalam bahasa Inggris dan
notasi matematis umum
Satu pernyataan menyelesaikan tugas-tugas substantial
Program translator (compiler)  mengkonversi ke
bahasa mesin
Program interpreter mengeksekusi perintah satu
persatu dalam bahasa tingkat tinggi secara langsung
 2003 Prentice Hall, Inc. All rights reserved.
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1.13 Basics of a Typical Java Environment
• Java programs normally undergo five phases
– Edit
• Programmer writes program (and stores program on disk)
– Compile
• Compiler creates bytecodes from program
– Load
• Class loader stores bytecodes in memory
– Verify
• Verifier ensures bytecodes do not violate security requirements
– Execute
• Interpreter translates bytecodes into machine language
 2003 Prentice Hall, Inc. All rights reserved.
Phase 1
Editor
Disk
Phase 2
Compiler
Disk
Program is created in an
editor and stored on disk
in a file ending with
.java.
Compiler creates
bytecodes and stores them
on disk in a file ending with
.class.
Primary
Memory
Phase 3
Class Loader
Disk
Phase 4
Bytecode Verifier
. ..
. .
.
Class loader reads
.class files
containing bytecodes
from disk and puts
those bytecodes in
memory.
Primary
Memory
Bytecode verifier
confirms that all
bytecodes are valid and
do not violate Java’s
security restrictions.
. ..
. .
.
Primary
Memory
Phase 5
Interpreter
. ..
..
.
Fig. 1.1 Typical Java environment.
 2003 Prentice Hall, Inc. All rights reserved.
Interpreter reads
bytecodes and
translates them into a
language that the
computer can
understand, possibly
storing data values as
the program executes.
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