DISCOVERING COMPUTERS
A World of Computers
Computers are everywhere: at work, at school, and at home. As shown in
Figure 1-1, people use all types and sizes of computers for a variety of
reasons and in a range of places. While some computers sit on top of a desk or
on the floor, mobile computers and mobile devices are small enough to carry.
Mobile devices, such as many cell phones, often are classified as computers.
Computers are a primary means of local and global communication for billions of
people. Consumers use computers to correspond with businesses, employees with
other employees and customers, students with classmates and teachers and family
members and military personnel with friends and other family members. In
addition to sending simple notes, people use computers to share photos,
drawings, documents, calendars, journals, music, and videos. Through computers,
society has instant access to information from around the globe. Local and
national news, weather reports, sports scores, airline schedules, telephone
directories, maps and directions, job listings, credit reports, and countless
forms of educational material always are accessible. From the computer, you can
make a telephone call, meet new friends, share opinions or life stories, book
flights, shop, fill prescriptions, file taxes, take a course, receive alerts,
and automate your home.
At home or while on the road, people use computers to manage schedules and
contacts, listen to voice mail messages, balance checkbooks, pay bills,
transfer funds, and buy or sell stocks. Banks place ATMs (automated teller
machines) all over the world, so that customers can deposit Vehicles include
onboard navigation systems that provide directions, call for emergency
services, and track the vehicle if it is stolen. In the workplace, employees
use computers to create correspondence such as e-mail messages, memos, and
letters; manage calendars; calculate payroll; track inventory; and generate
invoices. At school, teachers use computers to assist with classroom instruction.
Students complete assignments
and conduct research on com puters in lab rooms, at home, or elsewhere.
Instead of attending
class on campus, some students take entire classes directly from their
computer. People also spend hours of leisure time using a computer. They play
games, listen to music or radio broadcasts, watch or compose videos and movies,
read books and magazines, share stories, research genealogy, retouch photos,
and plan vacations. As technology continues to advance, computers have become a
part of everyday life. Thus, many people believe that computer literacy is
vital to success in today’s world.
Computer literacy,
also known as digital literacy, involves having a current knowledge and understanding of
computers and their uses. Because the requirements that determine computer
literacy change as technology changes, you must keep up with these changes to remain
computer literate. This book presents the knowledge you need to be computer
literate today. As you read this first chapter, keep in mind it is an overview.
Many of
the terms and concepts introduced in this chapter
will be discussed
in more depth later in the book.
What Is a Computer?
A computer is an electronic
device, operating under the control of instructions stored in its own memory,
that can accept data, process the data according to specified rules,
produceresults, and store the results for future use.
Data and Information
Computers process data into information. Data is a collection of unprocessed items,which can include text, numbers, images, audio,and video. Information conveys meaning and is useful to
people.Many daily activities either
involve the use ofor depend on information from a computer.
in the form of a cash register receipt.
Information Processing Cycle
Computers process data (input) into information (output). Computers carry
out processes using instructions, which are the steps that tell the computer how to perform
a particular task. A collection of related instructions organized for a common
purpose is referred to as software. A computer often holds data, information, and
instructions in storage for future use. Some people refer to the series of
input,
process, output, and storage activities as the information processing cycle. Most computers
today communicate with other computers. As a result, communications also has
become an essential element of the information processing cycle.
The Components of a Computer
A computer contains many electric, electronic, and mechanical components
known as hardware.
These components include input devices, output devices, a system unit,
storage devices, and communications devices
Input Devices
An input device is any hardware
component that allows you to enter data and instructions into a computer. Five
widely used input devices are the keyboard, mouse, microphone, scanner, and Web
cam (Figure 1-3). A computer keyboard contains keys you press to enter data
into the computer. For security
purposes, some keyboards include a fingerprint reader, which allows you to
work with the computer
only if your fingerprint is recognized. A mouse is a small handheld device.
With the mouse, you control movement of a small symbol on the screen, called
the pointer, and you make selections from the screen.
A microphone allows you to speak into the computer. A scanner converts
printed material (such as text and pictures) into a form the computer can use. A
Web cam is a digital video camera that allows you to create movies or take
pictures and store them on the computer instead of on tape or film.
Output Devices
An output device is any hardware component
that conveys information to one or more people. Three commonly used output devices
are a printer, a monitor, and speakers
A printer produces text and graphics on a physical medium such as paper. A
monitor displays text, graphics, and videos on a screen. Speakers allow you to
hear music, voice, and other audio (sounds).
System Unit
The system unit is a case that
contains the electronic components of the computer that are used to process
data. The circuitry of the system unit usually is part of or is connected to a
circuit board called the
motherboard. Two main components on the motherboard are the processor and
memory. The processor,
also called a CPU (central processing
unit), is the electronic component that interprets and carries out
the basic instructions that operate the computer. Memory consists of electronic components
that store instructions waiting to be executed and data needed by those
instructions. Although some forms of memory are permanent, most memory keeps
data and instructions temporarily, which means its contents are erased when the
computer is shut off.
Storage Devices
Storage holds data, instructions, and information for future use. For
example, computers can store hundreds or millions of customernames and
addresses. Storage holds these items permanently. A computer keeps data,
instructions, and information on storage media . Examples of storage
media are USB flash drives, hard disks, optical discs, and memory cards. A storage device records
(writes) and/or retrieves (reads) items to and from storage media. Drives
and readers/writers, which
are types of storage devices , accept a specific kind of storage media. For
example, a DVD drive (storage device) accepts a DVD (storage media). Storage
devices often function as a source of input because they
transfer items from storage to memory. A USB flash drive is a portable
storage device that is small and lightweight enough to be transported on a
keychain or in a pocket. The average USB flash drive can hold about 4 billion
characters. You plug a USB flash drive in a special, easily accessible opening on
the computer. A hard disk provides much greater storage capacity than a USB
flash drive. The average
hard disk can hold more than 320 billion characters. Hard disks are
enclosed in an airtight, sealed case. Although some are portable, most are
housed inside the system unit. Portable hard disks are either external or removable.
An external hard disk is a separate, freestanding unit, whereas you insert and
remove a removable hard disk from the computer or a device connected to the
computer. An optical disc is a flat, round, portable metal disc with a plastic
coating. CDs, DVDs, and Blu-ray Discs are three types of optical discs. A CD can
hold from 650 mil lion to 1 billion characters. Some DVDs can store
two full-length movies or 17 billion characters. Blu-ray Discs can store
about 46 hours of standard video, or 100 billion characters.
Some mobile devices, such as digital cameras, use memory cards as the
storage media. You can
use a card reader/writer to transfer the stored items, such as digital
photos, from the memory card to a computer or printer.
Communications Devices
A communications device is a hardware component that enables a computer to send (transmit) and
receive data, instructions, and information to and from one or more computers
or mobile devices. A widely used communications device is a modem. Communications
occur over cables, telephone lines, cellular radio networks, satellites, and other
transmission media. Some transmission media, such as satellites and cellular
radio networks, are wireless, which means they have no physical lines or wires.
Computer Software
Software, also called a program, consists of a series of related
instructions, organized for a common purpose, that tells the computer what tasks
to perform and how to perform them. You interact with a program through its
user interface. The user interface controls how you enter data and instructions
and how information is displayed on the screen. Software today often has a
graphical user interface. With a graphical user interface (GUI pronounced gooey), you interact with the software using
text, graphics,
and visual images such as icons. An icon is a miniature image that represents a program, an instruction,
or some other object. You can use the mouse to select icons that perform
operations such as starting a program. The two categories of software are
system software and application software. Figure 1-10
shows an example of each of these categories of software, which are
explained in the following sections.
System Software
System software consists of the
programs that control or maintain the operations of the computer and its
devices. System software serves as the interface between the user, the
application software, and the computer’s hardware. Two types of system software
are the operating system and utility programs.
Operating System An operating system is a set of programs that coordinates all the activities among computer
hardware devices. It provides a means for users to communicate with the
computer and other software. When a user starts a computer, portions of the
operating system are copied into memory
from the computer’s hard disk. These parts of the operating system remain
in memory while the computer is on.
Utility Program A utility program allows a user to perform maintenance-type tasks usually related to managing
a computer, its devices, or its programs. For example, you can use a utility
program to transfer digital photos to an optical disc. Most operating systems
include several utility programs for managing disk drives, printers, and other
devices and media. You also can buy utility programs that allow you to perform
additional computer management functions.
Application Software
Application software consists of
programs designed to make users more productive and/ or assist them with
personal tasks. A widely used type of application software related to
communications is a Web browser, which allows users with an Internet connection
to access and view Web pages or access programs. Other popular application
software includes word processing software, spreadsheet software,
database software, and presentation software. Many other types of
application software exist that enable users to perform a variety of tasks.
These include personal information management, note taking, project management,
accounting, document management, computeraided design, desktop publishing,
paint/image editing, photo editing, audio and video editing, multimedia
authoring, Web page authoring,
personal finance, legal, tax preparation, home design/landscaping, travel
and mapping, education, reference, and entertainment (e.g., games or
simulations, etc.). Software is available at stores that sell computer products
and also online at many Web sites.
Ejaan yang Disempurnakan
Pemakaian huruf :
-
Huruf Abjad
-
Huruf Vokal
-
Huruf Konsonan
-
Diftong
-
Gab. Huruf Konsonan
-
Pemenggalan Kata
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Huruf Miring
-
Penulisan Kata
-
Kata Dasar
-
Kata turunan
-
Bentuk Ulang
-
Partikel : lah, kan & pen
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Gab. Kata
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Kata Ganti : ku, mu & nya
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Kata Depan : di, ke & dari
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Kata Si & Sang
-
Singkatan & Akronim
MATEMATIKA DASAR
Sistem bilangan desimal/persepuluhan adalah system bilangan yang
menggunakan 10 macam angka dari 0,1, sampai 9. Setelah angka 9, angka
berikutnya adalah 1 0, 1 1, dan seterusnya (posisi di angka 9 diganti dengan
angka 0, 1, 2, .. 9 lagi, tetapi angka di depannya dinaikkan menjadi 1). sistem
bilangan desimal ditemukan oleh Al-Kashi,ilmuwan persia Sistem bilangan desimal
sering dikenal sebagai sistem bilangan berbasis 10, karena tiap angka desimal
menggunakan basis (radix) 10, seperti yang terlihat dalam contoh berikut:
angka desimal 123 = 1*102 + 2*101
+ 3*100
Berikut adalah tabel yang
menampilkan sistem angka desimal (basis 10), sistem bilangan biner (basis 2), sistem bilangan/ angka oktal (basis
8), dan sistem angka heksadesimal (basis 16) yang merupakan dasar pengetahuan untuk
mempelajari komputer digital. Bilangan oktal dibentuk
dari bilangan biner-nya dengan mengelompokkan tiap 3 bit dari ujung kanan
(LSB). Sementara bilangan heksadesimal juga dapat dibentuk dengan mudah dari
angka biner-nya dengan mengelompokkan tiap 4 bit dari ujung kanan.
Desimal
|
Biner (8 bit)
|
Oktal
|
Heksadesimal
|
0
|
0000 0000
|
000
|
00
|
1
|
0000 0001
|
001
|
01
|
2
|
0000 0010
|
002
|
02
|
3
|
0000 0011
|
003
|
03
|
4
|
0000 0100
|
004
|
04
|
5
|
0000 0101
|
005
|
05
|
6
|
0000 0110
|
006
|
06
|
7
|
0000 0111
|
007
|
07
|
8
|
0000 1000
|
010
|
08
|
9
|
0000 1001
|
011
|
09
|
10
|
0000 1010
|
012
|
0A
|
11
|
0000 1011
|
013
|
0B
|
12
|
0000 1100
|
014
|
0C
|
13
|
0000 1101
|
015
|
0D
|
14
|
0000 1110
|
016
|
0E
|
15
|
0000 1111
|
017
|
0F
|
16
|
0001 0000
|
020
|
10
|
konvensi masalah
konversi bilangan desimal ke oktal.
Proses konversinya mirip dengan proses konversi desimal ke biner, hanya saja kali ini pembaginya adalah 8. Misalkan angka yang ingin saya konversi adalah 3310. Maka :
33 : 8 = 4 sisa 1.
4 : 8 = 0 sisa 4.
0 : 8 = 0 sisa 0….(end)
418!!!
konversi desimal ke heksadesimal…
Misalkan bilangan desimal yang ingin saya ubah adalah 24310. Untuk menghitung proses konversinya, caranya sama saja dengan proses konversi desimal ke biner, hanya saja kali ini angka pembaginya adalah 16. Maka :
243 : 16 = 15 sisa 3.
15 : 16 = 0 sisa F. —-> ingat, 15 diganti jadi F..
0 : 16 = 0 sisa 0….(end)
Nah, maka hasil konversinya adalah F316. Mudah, bukan? 8)
konversi bilangan biner ke desimal. Proses konversi bilangan biner ke bilangan desimal adalah proses perkalian setiap bit pada bilangan biner dengan perpangkatan 2, dimana perpangkatan 2 tersebut berurut dari kanan ke kiri bit bernilai 2o sampai 2n. Langsung saja saya ambil contoh bilangan yang merupakan hasil perhitungan di atas, yaitu 110012. Misalkan bilangan tersebut saya ubah posisinya mulai dari kanan ke kiri menjadi seperti ini.
1
0
0
1
1
Nah, saatnya mengalikan setiap bit dengan perpangkatan 2. Ingat, perpangkatan 2 tersebut berurut mulai dari 2o sampai 2n, untuk setiap bit mulai dari kanan ke kiri. Maka :
1 ——> 1 x 2o = 1
0 ——> 0 x 21 = 0
0 ——> 0 x 22 = 0
1 ——> 1 x 23 = 8
1 ——> 1 x 24 = 16 —> perhatikan nilai perpangkatan 2 nya semakin ke bawah semakin besar
Maka hasilnya adalah 1 + 0 + 0 + 8 + 16 = 2510.
konversi bilangan biner ke oktal.
Untuk merubah bilangan biner ke bilangan oktal, perlu diperhatikan bahwa setiap bilangan oktal mewakili 3 bit dari bilangan biner. Maka jika kita memiliki bilangan biner 1101112 yang ingin dikonversi ke bilangan oktal, langkah pertama yang kita lakukan adalah memilah-milah bilangan biner tersebut, setiap bagian 3 bit, mulai dari kanan ke kiri, sehingga menjadi seperti berikut :
110 dan 111
Sengaja saya buat agak berjarak, supaya lebih mudah dimengerti. Nah, setelah dilakukan proses pemilah2an seperti ini, dilakukan proses konversi ke desimal terlebih dahulu secara terpisah. 110 dikonversi menjadi 6, dan 111 dikonversi menjadi 7. Hasilnya kemudian digabungkan, menjadi 678, yang merupakan bilangan oktal dari 1101112… 8)
“Tapi, itu kan kebetulan bilangan binernya pas 6 bit. Jadi dipilah2 3 pun masih pas. Gimana kalau bilangan binernya, contohnya, 5 bit?” Hehe…Gampang..Contohnya 110012. 5 bit kan? Sebenarnya pemilah2an itu dimulai dari kanan ke kiri. Jadi hasilnya 11 dan 001. Ini kan sebenarnya sudah bisa masing2 diubah ke dalam bentuk desimal. Tapi kalau mau menambah kenyamanan di mata, tambahin aja 1 angka 0 di depannya. Jadi 0110012. Tidak akan merubah hasil perhitungan kok. Tinggal dipilah2 seperti tadi.
konversi bilangan biner ke heksadesimal. sebagai contoh, misalnya saya ingin ubah 111000102 ke bentuk heksadesimal. Proses konversinya juga tidak begitu rumit, hanya tinggal memilahkan bit2 tersebut menjadi kelompok2 4 bit. Pemilahan dimulai dari kanan ke kiri, sehingga hasilnya sbb :
1110 dan 0010
Nah, coba lihat bit2 tersebut. Konversilah bit2 tersebut ke desimal terlebih dahulu satu persatu, sehingga didapat :
1110 = 14 dan 0010 = 2
Nah, ingat kalau 14 itu dilambangkan apa di heksadesimal? Ya, 14 dilambangkan dengan E16.
Dengan demikian, hasil konversinya adalah E216.
Seperti tadi juga, gimana kalau bilangan binernya tidak berjumlah 8 bit? Contohnya 1101012? Yaa…Seperti tadi juga, tambahin aja 0 di depannya. Tidak akan memberi pengaruh apa2 kok ke hasilnya. Jadi setelah ditambah menjadi 001101012. -
Selanjutnya, konversi bilangan oktal ke desimal. Hal ini tidak terlalu sulit. Tinggal kalikan saja setiap bilangan dengan perpangkatan 8. Contoh, bilangan oktal yang akan dikonversi adalah 718. Maka susunannya saya buat menjadi demikian :
1
7
dan proses perkaliannya sbb :
1 x 8o = 1
7 x 81 = 56
Maka hasilnya adalah penjumlahan 1 + 56 = 5710.
oktal ke biner
Langsung ke contoh. Misalkan saya ingin mengubah bilangan oktal 578 ke biner. Maka langkah yang saya lakukan adalah melakukan proses konversi setiap bilangan tersebut masing2 ke 3 bit bilangan biner. Nah, angka 5 jika dikonversi ke biner menjadi….? 1012. Sip. Nah, 7, jika dikonversi ke biner menjadi…? 1112.
berarti…sekarang giliran konversi oktal ke heksadesimal.
Untuk konversi oktal ke heksadesimal, kita akan membutuhkan perantara, yaitu bilangan biner. Maksudnya? Maksudnya adalah kita konversi dulu oktal ke biner, lalu konversikan nilai biner tersebut ke nilai heksadesimalnya. Nah, baik yang konversi oktal ke biner maupun biner ke heksadesimal kan udah dijelaskan. Coba buktikan, bahwa bilangan oktal 728 jika dikonversi ke heksadesimal menjadi 3A16.
konversi bilangan heksadesimal ke desimal Untuk proses konversi ini, caranya sama saja dengan proses konversi biner ke desimal, hanya saja kali ini perpangkatan yang digunakan adalah perpangkatan 16, bukan perpangkatan 2. Sebagai contoh, saya akan melakukan konversi bilangan heksa C816 ke bilangan desimal. Maka saya ubah dulu susunan bilangan heksa tersebut, mulai dari kanan ke kiri, sehingga menjadi sebagai berikut :
8
C
dan kemudian dilakukan proses perkalian dengan perpangkatan 16, sebagai berikut :
8 x 16o = 8
C x 161 = 192 ——> ingat, C16 merupakan lambang dari 1210
Maka diperolehlah hasil konversinya bernilai 8 + 192 = 20010.
konversi dari heksadesimal ke biner.
Dalam proses konversi heksadesimal ke biner, setiap simbol dalam heksadesimal mewakili 4 bit dari biner. Misalnya saya ingin melakukan proses konversi bilangan heksa B716 ke bilangan biner. Maka setiap simbol di bilangan heksa tersebut saya konversi terpisah ke biner. Ingat, B16 merupakan simbol untuk angka desimal 1110. Nah, desimal 1110 jika dikonversi ke biner menjadi 10112, sedangkan desimal 710 jika dikonversi ke biner menjadi 01112. Maka bilangan binernya adalah 101101112, atau kalau dibuat ilustrasinya seperti berikut ini :
B 7 —-> bentuk heksa
11 7 —-> bentuk desimal
1011 0111 —-> bentuk biner
Hasilnya disatukan, sehingga menjadi 101101112.
Yang terakhir adalah konversi heksadesimal ke oktal.
Nah, sama seperti konversi oktal ke heksadesimal, kita membutuhkan bantuan bilangan biner. Lakukan terlebih dahulu konversi heksadesimal ke biner, lalu konversikan nilai biner tersebut ke oktal. Sebagai latihan, buktikan bahwa nilai heksadesimal E716 jika dikonversi ke oktal menjadi 3478. Hehe…Kamu bisa!!!
SEJARAH PERADABAN ISLAM
SEJARAH adalah kejadian masa lalu yang penting dan berpengaruh untuk di
pelajari ,evaluasi ,agama
sejarah berhubungan dengan ilmu objek kajian dan berhubungan dengan peristiwa dan mengunakan metode ilmiah
sumber sejarah bisa lisan /tulisan seperti abstrak prasasti insfrastik
sejarah berhubungan dengan ilmu objek kajian dan berhubungan dengan peristiwa dan mengunakan metode ilmiah
sumber sejarah bisa lisan /tulisan seperti abstrak prasasti insfrastik
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