Chapter 2 - Ict

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CHAPTER 2

COMPUTER SYSTEM

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System Concept

Computer system

- Defined as combination ofcomponents design to process data

and store files- A computer system is a complete,

working computer that combines

components designed to processdata, retrieve and store files in ameaningful way

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State the meaning of input,process, output and storage1. Input any information that is fed

(given) to the computer for process2. Process- is a program that is running

on your computer or manipulates data

in the computer-2 major processes:

Arithmetic process that is anyaffirmative function

Logical process- that is comparisons likeEqual to, less than or grater than, true orfalse etc

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3. Output - is the useful informationthat the computer produced afterprocessing the data according to our

instructions4. Storage- A location which data,

instruction and information are held

for future use. Every computer usesstorage to hold system software andapplication software

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Processing cycle

input process Output

storage

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Data Representation

State the relationship of datarepresentation:

BIT smallest unit of data that the

computer can process. Short forbinary digit. A bit is represented bythe number 1 and 0. They correspond

to the states of on and off or yesand no

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BYTE a unit of information built frombits. 1 byte = 8 bits. 8 bits that aregrouped together as a unit. A bit

provide enough different combinationof 0s and 1s to represent 256individual characters

CHARACTER 8 bits grouped

together as a unit are called byte. Abyte represents a single character inthe computer

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-there are three codes to represent asingle characters which are ASCII,EBCDIC and Unicode

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Introduction to binary coding

Function of ASCII

-ASCII was established to achievecompatibility various types of data

processing equipment making itpossible for the components tocommunicate with each other

successfully-ASCII enables manufacturers to

produce components that are assured

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-ASCII makes it possible for humans tointeract with a computer. It alsoenables users to purchase

components that are compatible withtheir computer configurations

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Data measurement

Bit

Byte

Kilobyte(KB)

Megabyte (MB)

Gigabyte(GB)

Terabyte (TB)

Sila lihat cara pengiraan pada nota NokA dan sila salin

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Basic terminology8bits=1 byte

1,024 byte=1 KB

1,024 KB=1MB1,024 MB=1 GB1,073,741,824

bytes=1GB


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Data Measurement ChartData Measurement SizeBit Single Binary Digit (1 or 0)Byte 8 bitsKilobyte (KB) 1,024 BytesMegabyte (MB) 1,024 KilobytesGigabyte (GB) 1,024 MegabytesTerabyte (TB) 1,024 GigabytesPetabyte (PB) 1,024 TerabytesExabyte (EB) 1,024 Petabytes


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Clock Speed Measurement

Evolution of communication

-every microprocessor contains systemclock. The system clock control speed

of all the operations within a computer-the speed of the clock is measured by

how many cycles per second the clock

makes

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Hertz and Seconds-the clock speed unit is measured in

hertz. A hertz is one cycle per second.

1 hertz = 1 cycle1 second

Megahertz (MHz)

-mega is a prefix that stands for miliion.1 MHz = 1,000,000 cycles

1 second

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Gigahertz (GHz)-Gigahertz (Ghz) equals to one billion

cycles of the system clock. In relationwith megahertz, 1.0 Ghz is equavalent to

1000 MHz.-for example, a microprosessor that runs

at 200 Ghz executes 200 billion cyclesper second. This is what they are talking

about they say computer is a 2.4 GHzmachine. Its clock rate is 2.4 billioncycles per second

1GHz=1,000,000,000 cycles

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Processing speed

A CPU with a higher clock speed canprocess more instructions per secondthan a CPU with a lower clock speed.

-for example:a 1GHz CPU is faster than aCPUoperating at 800MHz. The speed of

the system clock affects only the CPU.

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Microprocessor speed

Microprocessor speeds aredetermined by their clock speed andare usually expressed in

gigahertz(Ghz), billion of machinecycles per second

for example, a personal computer that

is listed at 2.2 GHz had a processorcapable of handling 2,2 billionmachine cycles per second.

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Speed and path

The combination of speed and numberof paths determines the totalprocessing speed or channel

bandwidth. This is because differentprocessor often use differentarchitectures.

For this reason, a 1.4 GHz Pentium 4performs better than a 1.4 GHzPentium 3, but it is not as fast as a 1.4GHz Power PC G4 processor

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Hardware

Input device is any peripheral (piece ofcomputer hardware equipment) usedto provide data and control signals to

an information processing systemsuch as a computer or otherinformation appliance

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Input devices for text

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Keyboard-you can enter data such astext and command into acomputer by pressing thekeys on the keyboard

Virtual keyboard- You can press the keys of avirtual on the screenkeyboard

Optical reader- A devices that uses a light toread characters, marks and thenconverts them into digital datathat a computer can process


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Input devices for graphics A devices that captures

images fromphotographic prints,poster, magazine pagesand similar sources forcomputer editing anddisplay

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A digital camera allows youto take pictures and store thephotographed images digitally


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Input devices for Audio

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Microphone

Audio input is the speech, music and sound effectsentered into the computer.

Midi keyboard


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Input devices for video

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CCTV CAMERA WEBCAM DIGITAL VIDEOCAMERA

Video input is input of motion images captured into the computerby speed input devices


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Pointing devices

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MOUSE TRACKBALL GRAPHIC TABLET TOUCH SCREEN

A pointing devices is another form of input devices. Pointing devicessuch as mouce, trackball, graphic tablet and touch screen are user

to input spatial data into the comnputer


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OUTPUT DEVICES

Output devices is the result of dataprocessing activity when it ispresented external to the system. The

output from a computer can be in aform for use by people, for example,printed or displayed

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Types of output devices

Monitor

- A monitor is an example of an outputdevices that can be used to display

text. It can also graphic and video. Printer

- It can be used to print text, apart from

graphics on mediums such as paper,transparency film even cloths

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Speaker- A pair of speakers is an audio output

devices that generates sounds. The

headphone is a pair of small speakersplaced over the ears and plugged aport on the sound card

LCD (Liquid Crystal Display)

- Uses its own light source to projectwhat is displayed on the computer ona wall or projection screen

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MOTHERBOARD

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This is a motherboard and its components.Motherboard is the main circuit board of the systemunit, which has some electronic components attachedto it and others built into it.


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This is the location of the Central processing Unit

(CPU)

This is where the expansion slots are located


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These are Peripheral Component Interconnected (PCI) expansionslots. A personal computer local bus which runs at MHz and

supports plug and play

The Industry standard Architecture (ISA) expansion slots arealso the components of the motherboard. A PC expansion busused for modem ,video displays, speaker and others

peripheral


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This is the expansion card. It is slotted in the expansion slot

This is call RAM (Random Acces Memory). RAM is

the memory pf the computer


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This is location of the ports. Connectors are pluggedinto these ports. Port is point at which peripheralattaches to a system unit so it can send data to orreceive information from the computer


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Components of the motherboard

Central Processing Unit (CPU)

-CPU control the operation of thecomputer. It interprets and carries out thebasic instructions that operate a

computer.- The processor significantly impacts

overall computing power and managesmost of a computers operations

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Expansion slot

- Expansion slot are the socket where thecircuit boards or the adapter cards can beinserted into the motherboard

- A Peripheral Component Interconnect (PCI)bus is a high speed bus that connects high

speed devices- An Industry-Standard Architecture (ISA)expansion slot in a computer where ISAaccessories can be added to.

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Expansion card

- It is plugged into an expansion slot. It isused to add new devices or capabilities

to a computer.- It is design to provide expanded

capability to a computer. It also providedon the surface of standard-size rigidmaterial (fiberboard) and then pluggedinto one of the computers expansion slotin its motherboard (backplane)

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RAM slot

-the slot where the computer memory,also called is RAM is placed on thecomputers motherboard.

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Ports and connectors


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- A port is the point at which a peripheral

attaches to a system unit so that theperipherals can send data to receiveinformation from the computer.

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There are the different kinds of port ina system unit. The ports are:SERIAL PORT

PARALLEL PORTUNIVERSAL SERIAL BUS(USB) PORT

FIREWIRE PORT

SPECIAL PURPOSE PORTS

MIDI PortCSI Port

IrDA Port

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Serial Port

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A serial port is a socket on a computer used to connect amodem, data acquisition terminal or the system otherserial devices via a slow-speed serial interface.

A serial port is used to connect a device to the system unitby transmitting data one bit at a time


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Parallel port

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A parallel port is a socket on a computer used to connect a printeror other parallel devices via the computers parallel interface.


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USB Port

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A USB port is socket on a computer or peripheral devices into which u USB cablPlugged in. Its used to connect all kinds of external devices, such as external h

Drives, printers, mouse and scanner. It can transfer data to a speed of 12 megaPer second


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FireWire port

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-Firewire is similar to a USB port in that it can connectmultiple types of devices that require faster datatransmission speeds.- Previously the Firewire port is called IEEE 1934 port,a personal computer serial bus interface standard

-usually camcorders and other video equipment use thisport to transmit data on a computer.


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Special Purpose Port

MIDI port

- It is designed to connect the system

unit to a musical instrument, such asan electronic keyboard

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SCSI Port

- It is special high-speed parallel port

used to attach peripheral devices suchas hard disk and printers

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IrDA Port

- Some devices transmit data viainfrared light waves. For this wireless

devices to transmit signals to acomputer, both the computer and thedevices must have an IrDA port

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CENTRAL PROCESSING UNIT


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CENTRAL PROCESSING UNIT(CPU)

A central processing unit or CPU is amicroprocessor (or processor for short).It is an integrated circuit chip thatcapable of processing electronic signals.

The CPU is the most important elementin a computer system.

A CPU interprets instructions given by

the software and carries out thoseinstructions by processing data andcontrolling the rest of the computerscomponents

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Control Unit (CU)

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Basically the control units mainfunction is to direct the CPU toprocess data. The control Unit

extracts instructions from memory anddecodes and executes them

ARITHMENTIC LOGIC UNIT


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ARITHMENTIC LOGIC UNIT(ALU) ALU as its name implies can perform all

arithmetic and logical operations.Arithmetic operation is an operation thatforms a function of two numbers.

This function is usually on the classoperation: add, subtract, multiply anddivide

Logic operation is an operation on logicalvalues, producing a Boolean result. Theyincluded AND, OR, NOT, NAND, Nor,XOR, and XOR and equavalence.

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STORAGE

Computer storage is the holding of datain an electromagnetic form for access bya computer processor.

Function of computer storage

- Computer storage is important to helpusers store programs and data be at alater time

- It is also useful to keep current data

while being processed by the processoruntil the computer is saved in a storagemedia such as a hard disk or a diskette

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Types of computer storage

Primary storage is known as themain memory of a computer, includingRAM (Random Access Memory) andROM (Read Only Memory). It is aninternal memory (inside the CPU) thatcan be accessed directly by thecomputer

Secondary storage is the alternativestorage in a computer. It is anexternal storage that refers to variousways a computer can store program

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Primary Storage

It is installed internally. 2 main types ofprimary storage are RAM and ROM Data from RAM can be read or retrieved

and written or stored during processing

whereas data from ROM can just beread only RAM is volatile, means the program and

data will be lost when the computer is

turned off ROM is non-volatile, means it holds the

program and data even when thecomputer is turned off

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Secondary Storage

Secondary storage is an alternativestorage. It is very useful to storeprograms and data for future use. It isrequired for two reasons:

1. The working memory of the CPU islimited in size and cannot alwayshold the amount of data required

2. Data and programs in secondarystorage do not disappear when thepower is turn off

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Primary Storage

Types of primary storage-RAM is acronym for Random-Access

Memory which means the data and

program in RAM can be read andwritten.

-ROM is acronym for Read-Only

Memory. The data or program inROM can just be read but cannot bewritten at all

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RAM(RANDOM ACCESS


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RAM(RANDOM ACCESSMEMORY) RAM is installed inside computers.

RAM is also known as a workingmemory

The data in RAM can be read(retrieved) or written (stored)

A computer uses RAM to hold

temporary instructions and dataneeded to complete tasks

RAM stores data during and after

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ROM(READ ONLY


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ROM(READ ONLYMEMORY) ROM is another type of memory

permanently stored inside thecomputer.

Program in ROM have been pre-recorded. It can only be stored by themanufacturer; once it is done, it

cannot be changed. Many complex functions, such start up

operating instructions, translator forhigh level languages and operating

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Partitioning the hard disk

Step by step how to use a windowsXP CD to partition a hard disk

1. Insert the Windows XP Installation

CD and restart the computer2. Press the key stated on the screen toenter the BIOS setup.

3. Set the CDROM drives at the first

booting device in the boot sequence4. Follow the instruction, when you get

the message press any key to boot

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5. Once the boot from CD-ROM hasstarted it will display at the top of thescreen: setup inspecting yourcomputers hardware configuration.

6. Then after that the screen displayedsetup is loading files7. Finally, setup is starting windows and

will display after a short delay the

Windows XP professional Setupscreen.8. Select to set up Windows XP now and

press the ENTER key

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Differences between RAM and


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Differences between RAM andROM

RAM ROM

DATA ANDPROGRAM

Stores during andafter processing

Stored bymanufacturer

CONTENT Stores informationtemporarily

Stores instruction(information)permanently

PROCESSING TIME Very fast, but uses alot of power

Fast. But uses verylittle power

VOLITALITY Volatile Non-volatile

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Secondary storage

Secondary storage is alternativestorage to keep your work anddocuments

It is very useful to store programs anddata for future use

It is non-volatile, which means that is

does not need power to maintain theinformation stored in it. It will storedthe information until it is erased.

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Types of secondary storage

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MAGNETIC MEDIUM-Non volatile. It can be any type ofstorage medium that utilizesmagnetic pattern to representinformation-Magnetic disk such as ; a floppydisk and hard disk-Magnetic tape including videocassette, audio storage reel to reeltape and others

OPTICAL MEDIUM- Non volatile storage media thathold content in digital form thatare written and read by laser.These media included varioustypes of CDs and DVDs


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Flash memory is a solid-state, non-volatile, rewritable memory thatfunctions like RAM and a hard disk drive combined. Flash memory

store bits of electronic data in memory cells just like DRAM(Dynamic RAM), but it also works like a hard disk drive that whenthe power is turned off, the data remains in the memory


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Software

Operating system (OS)PC platform OS Apple platform OS

Documents

Chapter 2 - Ict