Pertemuan ke-5

Computer and Information Processing

Learning Objectives

Untuk memahami bagaimana data dan program direpresentasikan ke dalam komputer Apakah Sistem Komputer itu?

The CPU & Storage Input Output Devices Trend IT Menjelaskan tentang konsep komunikasi data

dan sistem jaringan komputer

Digital Data Representation

Computers today are mostly digital computers—devices that can only understand two states.

The two states of a digital computer are typically represented by 0s and 1s.

Natural-language messages are translated to the computer into binary form.

The Binary Numbering System

The binary numbering system represents all numbers using just two symbols (0 and 1).

Coding Systems for Text-Based Data

ASCII and EBCDIC Fixed-length codes that can represent any

single character of data as a string of eight bits

Unicode A 16-bit code that can be used to represent

text-based data in virtually any written language

Byte Terminology

Byte - a string of eight bits

kilobytes (KB) thousands of bytesmegabytes (MB) millions of bytesgigabytes (GB) billions of bytesterabytes (TB) trillions of bytes

petabyte (PB) about 1 quadrillion bytesexabyte (EB) about 1 quintillion bytes

Parity Bit

In fixed-length coding systems a parity bit is often automatically added at the end of each character to enable computer systems to check for transmission errors.

In odd-parity systems, the parity bit makes the number of 1-bits in a byte to be an odd number; using even parity, the number of 1-bits is an even number.

Coding Systems for Other Types of Data

Graphics data

Audio data

Video data

Machine Language

Machine language is the binary-based code used to represent program instructions.

The basic set of machine-language instructions that a CPU can understand is that CPU’s instruction set.

Most programmers rely on language translators to translate their programs into machine language for them.

Inside the System Unit

The system unit of a PC is the case that houses processing hardware and other hardware.

All of the hardware contained within the system unit is connected to the system board or motherboard.

CPU

The microprocessor (CPU chip) contains a variety of circuitry and components and is connected to the motherboard.

CPU, cont’d.

Processing speed is measured in megahertz (MHz) or gigahertz (GHz).

A computer word is a group of bits or bytes that may be manipulated and stored as a unit.

Other factors that affect the speed of the computer include RAM, cache memory, bus width, and bus speed.

Memori : ROM (Read Only Memory)

Jenis memori yang hanya bisa dibaca (read only) oleh komputer.

Keperluan utama ROM adalah untuk menempatkan program yang disebut BIOS (Basic Input Output System).

BIOS adalah program yang mengendalikan komputer pertama kali sebelum dikendalikan oleh sisrem operasi.

ROM ini ditulis oleh perusahaan yang memproduksi sebuah komputer.

Memori : RAM (Random Access Memory) RAM dapat ditulis, dibaca dan mudah menguap (volatile).

Sifat penulisan dan pembacaan datanya adalah secara random.

Data yang ditulis dalam RAM dapat dihapus atau diganti dengan yang lain.

Disebut juga Read-Write Memory

Memori : RAM (Random Access Memory)

Jenis-jenis RAM

•DRAM (Dynamic RAM)

•SRAM (Static RAM)

•NVRAM

•FRAM (Ferroelectric RAM)

Memory: RAM

RAM is volatile

Types of RAM

DRAMSRAM

SDRAMDDR SDRAM

RDRAMPC133 SRAM

Memory

Cache memory

Registers

ROM

Flash memory

Buses

Buses are electronic paths that data travels around on a computer system.

Internal buses move data around within the CPU.

Expansion buses establish links with peripheral devices.

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System Expansion

Expansion cards for desktop PCs Video-graphics board, fax/modem board, or

sound card

PC cards: expansion for notebook & other portables

Expansion for handhelds and mobile devices USB port, SD cards, MM cards, and

Springboard modules

Ports

Common ports:

SerialParallelSCSIUSB

FirewireNetworkMIDIIrDA

Typical CPU Components

Arithmetic/logic unit

Control unit

Registers

Decode unit

Prefetch unit

Internal cache

Bus interface unit

Storage

Magnetic Disk Systems Magnetic disks are the most important storage

medium in computers today.

Two popular types: floppy disks hard disks tape disk flash disk

Data is written by magnetizing particles on the disks in a certain way to represent 1s and 0s.

Floppy Disks, cont’d.

Tracks, sectors, and clusters The disk’s file directory keeps track of the

contents of the disk.

Hard Disks, cont’d.

Hard disk systems for notebooks Can use either internal or removable hard

drives

Hard Disks, cont’d.

Hard disk systems for large computer systems May use a system consisting of multiple

hard drives; RAID is a recent trend

Optical Discs

Laser beams write and read data packed at very tight storage densities, several times finer than that of a typical magnetic disk.

CDs

CDs are permanently etched when data is stored on the disc.

Recordable (CD-R) discs can be written to, but not erased and rewritten.

Rewritable (CD-RW) CDs can be used in the same way as magnetic disks—data can be stored and erased as needed.

DVDs

DVDs are read-only and may replace VHS as the movie media of choice.

Rewritable DVDs (DVD-RAM or DVD+RW) allow users to record on DVD discs.

Magneto-Optical Discs

M-O discs use a combination of magnetic and optical technologies.

Can store up to 5.2 GB per disc.

Smart Cards

Smart card: credit-card-sized piece of plastic that contains some type of computer circuitry. Holds less than a few megabytes Commonly used to store prepaid amounts of

digital cash, or personal information

Smart card readers are attached to a PC or built into a cell phone, keyboard, or other device.

Flash Memory Devices

Flash memory sticks Size of a stick of gum; hold from 4 to 64 MB

each Flash memory cards

Standards include CompactFlash, SmartMedia, Secure Digital (SD), and MultiMedia Card (MMC)

Flash memory drives Have no moving parts—are more shock-

proof and portable than conventional drives

Input and OutputDevices

Input and Output

Input devices convert data and programs that people can understand into a form comprehensible to the CPU.

Output devices convert the strings of bits used by the computer back into a form that people can understand.

Pointing Devices: Mouse

Pointing Devices: Electronic Pens

Electronic pen: an alternative to the mouse to select objects or to write or draw on the screen

Devices that use pen input: Graphics tablets Signature capture devices Pen-based computers

Pointing Devices: Touch Screens

Touch screens are used:

When other input

devices are impractical

When consumer input is required, as in consumer kiosks

Other Pointing Devices

Joystick Trackball Pointing stick Touch pad

Scanners and Related Devices

Source data automation involves collecting data in machine-readable form as soon as it is generated.

Source data automation is used to convert source documents into digital form and commonly utilizes some type of scanner.

Optical Scanners Optical scanner: converts hard-copy images

of text pages, photographs, and drawings into digital form

Types of image scanners: Flatbed Sheet-fed Hand-held Drum Three-dimensional

Optical Readers

Optical marks

Optical characters

Optical codes

Magnetic Ink Character Recognition Reader

Magnetic ink character recognition is used primarily with processing checks.

Readers can read the special magnetic characters, as well as sort documents by their codes.

Multimedia Output Devices

Speakers

Data and multimedia projectors

Voice-output systems

Multifunction Devices A multifunction device offers some combination

of:

Printing

Copying

Scanning

Faxing