Note f4 Computer System

7/31/2019 Note f4 Computer System

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COMPUTER SYSTEM

Definition

A computer system is defined as an electronic device with a combination of components

designed to accept(input) and process data according to specific rules(process) to produce

results(output) which can be stored for future use(storage). A computer system consists of

four major hardware components; input devices, output devices, processor and storage

devices. A computer system requires hardware, software and a user to fully function.

Input - Input is any data or instructions that we enter into the computer system for

processing. There are four types of input: which are text, graphic, audio and video. Example of

input devices are keyboard, light pen, joystick, microphone, mouse, video & digital camera.

Process - The processing unit controls all activities within the system. The CPU is an example

of a processor. It has the same important as the brain to human being. The processor

interprets and carries out the basic instructions that operate the computer. Example of

processors or CPU are Pentium IV, AMD Athlon, G4.

Storage - Storage is a location which data, instruction and information are held for future use.

It is the physical material that keeps data, instruction and information. There are two types of

storage. They are the primary storage and secondary storage. The example of storage devices

are RAM and ROM(primary storage), hardisk, Floppy Disk, diskette, CD ROM and DVD

ROM(secondary storage).

Output - Output is data that has been processed into a useful form, called information. There

are four types of output, which are texts, graphics, audio and video. Example of output

devices are monitor, printer, speaker and plotter.

The information processing cycle

Input - Users input data or instruction into the computer system to be process. Input could

be either text, graphic, audio or video. Input devices are used by users to input data. Input

devices are any electronic device connected to a computer and produces input signals.

Process - Data or instruction being input into the computer system is then processed by the

CPU which controls all activities within the system. The results of the processed data are then

sent to an output device as usable data. Examples of CPU or processors are Intel Pentium 4,

AMD K6 Athlon, Win Chip 2, Cyrix 686, Intel Celeron.

A CPU interprets the data and carries out the instructions by processing data and controlling

the rest of the computers components. A CPU consists of two subcomponents; the ControlUnit (CU) and the Arithmetic Logic Unit (ALU).

Input Process Output

Storage


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CU or Control Unit main functionis to direct the CPU to process data byextracting instructions from memory and decodes and executes them. It tells the rest

of the computer system how to carry out the programs instructions. It directs the

movement of the electronic signals between the memory, which holds data,

instructions and processed information, and the arithmetic logic unit. It also directs

these control signals between the CPU and the I/O devices. The ALU or arithmetic-logic unit performs two types of operations: arithmeticand logic. Arithmetic operations are fundamental mathematical operations: addition,

subtraction, multiplication and division. Logical operation consists of comparisons.

That is two pieces of information or data are compared to see whether the result is

equal, less than or greater than.

The CPU manages a four-step basic operation which is called a machine cycle.The steps are Fetching, Decoding, Executing & Storing.

The Machine Cycle

Storage - Computer storage is important to help users store programs and data to be used at

a later time. It is also useful to keep current data while being processed by the processor until

the information is saved in a storage media such as a hard disk or a diskette. Computer

storage also stores instructions from a computer program. There are two type of computerstorage; primary storage and secondary storage.

Primary storage is known as the main memory of a computer, including RAM(Random-Access Memory) and ROM (Read-Only Memory). It is an internal memory

(inside the CPU) that can be accessed directly by the processor.

Secondary storage an external storage that refers to various ways a computer canstore program and data. Many complex functions, such as translators for high-level

languages and operating systems are placed in primary storage. Secondary storage is

an alternative storage. It is very useful to store programs and data for future use.

Decode

Memory

Arithmetic-Logic Unit Control Unit

F

e

t

c

h

x

e

c

ut

e

2

3

4 12 x 3

010011001101

36

1

Decodes

Store

12 x 3= 36


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Output - Output is the result of data processing activity when it is presented external to the

system. The output from a computer can be in a form for use by people, for example, printed

or displayed. There are four types of output, which are texts, graphics, audio and video.

The relationship of data representation

Bit - A bit is the smallest unit of data that the computer can process. Bit is a short for binary

digit. A bit is represented by the numbers 1 and 0. These numbers represent the binary

system. They correspond to the states of on and off, true and false, or yes and no. All digital

data use the binary system to process the information. This information includes letters,

digits or special character.

Byte - Byte is a unit of information built from bits. One byte is equals to 8 bits. Eight bits that

are grouped together as a unit. A byte provides enough different combinations of 0s and 1s to

represent 256 individual characters. One byte represents a single character such as the

number 3, letter b or a $ symbol. Bits and bytes are the basis for representing all meaningful

information and programs on computers.

Character - Computers does not understand letters, numbers, pictures or symbols. Computers

uses binary system to count only as it only recognizes two states that are 0 and 1. A byte

represents a single character in the computer. One character such as A, 7, 9 and + is eight bits

that are grouped together. A byte provides enough different combinations of 0s and 1s to

represent 256 individual characters. For example, the capital letter F is represented by the

binary code 01000110 that can be understood by the computer system.

Coding Scheme

The combinations of 0s and 1s are defined by patterns. These patterns are called codingsystem or schemes. There are three character codes or coding schemes to represent

characters which are ASCII,EBCDIC and Unicode. ASCII is most widely used for personal

computers. EBCDIC was developed by IBM and is used primarily for large computers like

mainframes and high end servers.

The 256 character capability of ASCII and EBCDIC is to small to handle characters that are used

by other languages such as Arabic, Japanese and Chinese. The Unicode coding system are

designed to solve this problem. It uses two bytes (16bits) combination to represent one

character. This gives it capability to represent 65,536 different characters. This can cover all

the worlds languages. Unicode is downward-compatible with ASCII meaning that Unicode can

recognize ASCII

ASCII (American Standard Code for Information Interchange) was established to:

To make it possible for humans to interact with a digital computer that processes onlybits.

achieve compatibility between various types of data processing equipment making itpossible for the components to communicate with each other successfully.

enables manufacturers to produce components that are assured to operate correctlyin a computer.

make it possible for humans to interact with a computer. It also enables users topurchase components that are compatible with their computer configurations.


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Complete the table below

ASCIICode

Symbol ASCII Code Symbol ASCII Code Symbol

00110000 0(48) 01000001 A(65) 00100001 !(33)

1(49) 01000010 B(66) ?(63)

2(50) C(67) @(64)

3( ) D(68) $(36)

4( ) E(69) %(37)

5( ) F(70) &(38)

6( ) 01000111 G(71) *(42)

Units of data measurement

Bit - A bit is represented by the numbers 1 and 0. They correspond to the states of on and off,

true and false, or yes and no.

Unit

Hierachy

Byte - 1 byte = 8 bit

Kilobyte (KB) - 1 KB = 1024 bytes or 1 KB = 210 bytes

Megabyte (MB) - 1 MB = 1 048 576 bytes or 1 MB = 220 bytes

Gigabyte (GB) - 1 GB = 1 073 741 824 bytes 1 GB = 230 bytesTerabyte (TB) - 1 TB = 1 099 511 627 776 bytes or 1 TB = 240 bytes

Note:

1 KB = 1 024 byte

1 MB = 1 024 KB = 1 048 576 byte

1 GB = 1 024 MB = 1 048 576 KB = 1 073 741 824 byte

1 TB = 1 024 GB = 1 048 576 MB = 1 073 741 824 KB = 1 099 511 627 776 byte

Units of clock speed measurement

Clock speed or computer speed means how fast a computer can process data. In other words,this means the speed the computer can turn data into information. It is measured by a system

clock that is situated in the microprocessor.

The clock speed is measured in hertz which means once machine cycle per second. The speed

of the system clock has no effect on the speed of printers or disk drives.

The combination of speed and number of paths determines the total processing speed or

channel bandwidth as it is sometimes referred to. This is because different processors use

different architecture.

For example:-

1.4 GHz Pentium 3 1.4 GHz Pentium 4 1.4 GHz Power PC G4

Bit Byte KiloByte Megabyte Gigabyte Terabyte ??


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Hertz & Seconds

A hertz is one cycle per second. Megahertz (MHz) 1 Megahertz (MHz) equals to one million cycles of the system clock.

(Mega is a prefix that stands for million. A computer that operates at 933 MHz has 933

million clock cycles in one second.)

Gigahertz (GHz) -1 Gigahertz (GHz) equals to one billion cycles of the system clock. Inrelation with megahertz, 1.0GHz is equivalent to 1000 MHz. Giga is a prefix that stands

for billion. GHz is most often used as a measurement of a PC processor chip and power,

with bigger numbers meaning more speed and higher price. A microprocessor that runs at

200 GHz executes 200 billion cycles per second. For a 2.4 GHz machine . Its clock rate is

2.4 billion cycles per second.)

Input devices used for text, graphic, audio and video

Input devices are any hardware components that allow user to enter data and instructions

into a computer.

Input Devices For Texts - Keyboard, virtual keyboard (on the screen) & an optical reader (uses

a light source to read characters, marks and codes and then converts them into digital data

that a computer can process e.g. barcode reader.

Input Devices For Graphics - Scanner is a device that captures images from photographicprints, posters, magazine pages and similar sources for computer editing and display. Digital

camera allows you to take pictures and store the photographed images digitally.

Input Devices For Audio - Audio input can be speech, music or sound effects. Audio input

devices are such microphone( to record or give command to the computer) and digital musical

instruments like the Musical Instrument Digital Interface (MIDI) keyboard ( to play and record

music ).

Input Devices For Video - Video input can be from a digital camera, webcam or Closed-Circuit

Television (CCTV). CCTV video camera is a type of digital video camera that enables a home or

small business user to capture video and still images. A webcam is any video camera thatdisplays its output on a web page. A digital video camera allows you to record full motion and

store the captured motion digitally.

Pointing Devices - A pointing device is another form of input device that enables the user to

freely move an on-screen pointer to select text, menu options, icons, and other on-screen

objects. Pointing devices such as a mouse (has buttons, a rolling ball or an optical reader),

trackball ( a stationary device with a ball on top or at the side), joystick ( a vertical lever for

control), gamepad (game controller held in both hands with thumbs and fingers to control),

graphics tablet and touch screen ( used to input spatial data into the computer. Spatial data

refers to data that is continuous and multi-dimensional).


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Output devices used for text, graphic, audio and video

Output device is any device that is capable of delivering or showing information to one or

more user. An output device shows prints and present the results of a computers work e.g.

speaker, monitor, LCD projector, Printer, Plotter.

A monitor is an example of an output device that can be used to display text. It can also

display graphics and video. It accepts video signals from a computer and displays information

on its screen.

A printer is another example of an output device that can be used to print text, apart from

graphics, on mediums such as paper, transparency film or even cloths. A photo printer is a

colour printer that produces photo-lab-quality pictures.

An image setter produces high quality output compared to an ordinary laser printer. An image

setter is a high resolution output device that can transfer electronic text and graphics directly

to film, plates, or photo-sensitive paper.

A pair of speakers is an audio output device that generates sound. The headphone is a pair of

small speakers placed over the ears and plugged into a port on the sound card. A woofer or

subwoofer is used to boost the low bass sound and is connected to the port on the sound

card.

A Liquid Crystal Display (LCD) projector uses its own light source to project what is displayed

on the computer on a wall or projection screen. A digital light processing (DLP) projector usestiny mirrors to reflect light which can be seen clearly in a well-lit room.

MotherBoard

Motherboard is the main

circuit board which has some

electronic components

attached to it and others built

into it. CPU, expansion slots,

expansion cards, RAM slots,

ports and connectors are the

components on the

motherboard.

The location of the slots for

central processing unit (CPU),

expansion slots, expansion

cards, RAM slots, ports and

connectors


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DIAGRAM FOR COMPONENTS OF A MOTHERBOARD AND LOCATION OF EXPANSIONSLOTS AND PORTS

PCI slots or expansion slot is a where expansion cards are attached to themotherboard. Examples of expansion cards are

o Video Graphic Accelerator Cards(VGA),o Network Inteface Cards(NIC),o TV Card or Audio Card

Dimm Memory Channel or Ram slots is connector where RAM is inserted CPU Socket is where the CPU is housed ( on the diagram its labeled as mPGA 476

Socket)

IDE connectors are for connecting hard disk or CDrom


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Ports and connectors


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USB

PS/2

Serial (DB-9)

ADB

Examples of Ports

Abbreviation for Universal Serial Bus, and becoming the most common port for

connecting device peripherals to personal computers.

A mini DIN plug containing 6 pins. Developed by IBM for connecting the

keyboard and mouse.

A 9-pin D-type connector meeting EIA-232 standard. Possibly used to

connect some trackballs, mice, modems and monitors

Abbreviation for Apple Desktop Bus, and used by Apple Computers before the

iMac. Apple computer now use the USB port.

Storage

Primary Storage (RAM, ROM) - Primary storage is the main memory in a computer. It stores

data and programs that can be accessed directly by the processor. There are two types of

primary storage which are RAM (Random-Access Memory) and ROM (Read-Only Memory).

RAM is installed inside computers. RAM is also known as a working memory.

Random-Access-Memory (RAM )- The data in RAM can be read (retrieved) or written(stored). RAM is volatile which means the programs and data in RAM are lost when

the computer is powered off. Computer uses RAM to hold temporary instructions and

data needed to complete tasks. This enables CPU to access instructions and data

stored in the memory very quickly. RAM stores data during and after processing.

Read-Only-Memory (ROM) - ROM is another type of memory permanently storedinside the computer. ROM is non-volatile. It holds the programs and data when thecomputer is powered off. Programs in ROM have been pre-recorded. It can only be

stored by the manufacturer; once it is done, it cannot be changed. Many complex

functions, such as start up operating instructions, translators for high-level languages

& operating systems are placed in ROM memory. All the contents in ROM can be

accessed and read but cannot be changed.

Differences Between RAM and ROM

RAM ASPECT ROM

Stores during and after processing Data and program Stored by manufacturer

Stores information temporarily Content Stores instructions(Information) permanently


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Secondary Storage (magnetic medium optical medium, flash memory)

Secondary Storage is another alternative storage device to keep your work and documents. Itis very useful to store programs and data for future use. It is installed externally. It is non-

volatile, which means that it does not need power to maintain the information stored in it. It

will store the information until it is erased.

Secondary storage can be divided into magnetic medium, optical medium and flash memory.

Magnetic Medium - Magnetic medium is a non-volatile storage medium. It can beany type of storage medium that utilizes magnetic patterns to represent information.

The devices use disks that are coated with magnetically sensitive material. The

examples of magnetic storage are magnetic disk ( floppy disk, used for off-line

storage, hard disk, used for secondary storage), magnetic tape ( video cassette, audiostorage reel-to-reel tape & others)

Optical Medium - Optical medium is a non-volatile storage media that holds contentin digital form that are written and read by a laser. These media is usually a flat,

circular portable disc which include various types of CDs and DVDs. These following

forms are often commonly used:

o CD, CD-ROM, and DVD are a read-only storage, used for distribution of digitalinformation such as music, video and computer programs.

o CD-R is a type of optical storage where it can be written once and cannot beerased or written over once it is saved.

o CD-RW, DVD-RW, and DVD-RAM allow data that have been saved to beerased and rewritten It is however slow to write but fast reading type ofstorage.

The disk capacity of optical media is more compared to magnetic media. Durability is

another feature of optical media; they are able to last for up to seven times as long as

traditional storage media.

Flash Memory - 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 when the power is turned off, the data remains in the memory.Flash memory cards and flash memory sticks are examples of flash memory.

Flash memory cards are also used with digital cellular phones, MP3 players, digital

video cameras and other portable digital devices. Flash memory is also called USB

drives, thumb drives, pen drives or flash drives, are the up-and-coming players in the

portable storage market.

The advantages of flash memory are, it offers faster reading or access time compared

to other secondary storage devices, (though not as fast as RAM) it is durable and

requires low voltage. It is also light and small. The disadvantage is it is more expensive

than the magnetic disk of the same capacity.

Very fast, but uses a lot of power Processing time Fast, but uses very little power

Volatile Volatility Non-volatile


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Types of Operating System (OS)

Operating system is a set of programs containing instructions that coordinate all the activities

among the computer hardware resources. Most operating system performs similar functions

that include starting booting a computer, managing memory and configuring devices. Some

operating system also allow user to control a network and administer security measures.

Stand-alone OS WinXP, Windows Vista, Mac OS, Linux, Dos Networking Operating System (NOS) Windows NT, Windows Server 2000, Linux,

Unix, Solaris

Embedded Operating System Windows CE, Palm OS, Symbian OS, Embedded Linux.

Platforms For Operating System

PC Platform Operating Systems - The examples of operating systems used on PC platforms or

IBM compatible computers are DOS used a command line interface when Microsoft first

developed it. Microsoft Windows XPs operating environment is a Graphical User Interface

(GUI). Both are closed source software.

Apple Platform Operating Systems - The operating systems used on Apple platforms are Mac

OS & Mac OS X. Mac OS was the first commercially successful graphical user interface. It is a

closed source software and are targeted for use with home desktops and workstations. Mac

OS X is a multitasking operating system and targeted for use with home desktops,

workstations and servers. It also has better security protection compared to Mac OS, for

example the integrated firewall utility.

Cross-Platform Operating Systems - Cross-platforms operating systems are UNIX and LINUX.

UNIX is a multitasking operating system. Some versions of UNIX have a command line

interface but most versions of UNIX offer a graphical user interface. Linux is a popular, free,

UNIX-like graphical user interface operating system. It is an open source software. Linux

provides a great deal of liberty to those that interact with Linux technology. Although Linuxruns on many kinds of equipment, it is best known for its support of IBM-Intel PC-based

hardware.

The Main Functions Of OS

starting a computer providing a user interface managing data & program managing memory configuring devices

Platform Opens Source Proprietary

PC and IBM compatible Linux (Ubuntu, KDE, Redhat,

Open Suse), FreeBSD, TinyOS

Ms Dos, Ms Windows XP, MS

Windows Vista

Mac- Macintosh (Apple) - Mac OS, Mac OS X


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Starting the Computer - The first function of an operating system is to start the computer.

This process is called booting. Booting means to load & initialize the operating system. It can

happen in two ways: warm boot or cold boot.

A warm boot means restarting a computer that is already on. It normally happensafter installing a new software or hardware or after an application crashes or stops

working. A cold boot means starting a computer that is already off. It happens when we turn on

a computer that has been completely powered off.

Providing a User Interface - This function controls how the user enters data and instruction

and how information is displayed. The three type of user interface are Command-Line, Menu-

Driven and Graphical User Interface . The user interface typically enables users:

to start an application program to manage disks and files such as formatting, copying and renaming to shut down the computer safely by following the correct procedures

Managing Data & Programs - When we start an application, the CPU loads the applicationfrom storage into memory. In the early days, single-tasking operating systems could run only

one application at a time. Multitasking operating systems enable users to work with two or

more application programs at the same time.

Managing Memory - The computer's operating system is responsible for managing memory

such as:

optimizing the use of RAM allocating data & instruction to an area of memory while being processed monitoring the contents of memory releasing data & instructions from being monitored in memory when the process is

done

Configuring Devices - Another function of an operating system is handling input and output,

as well as enabling communication with input and output devices. Most operating systems

come with drivers for popular input and output devices. These drivers install new devices and

check whenever there is conflict with these devices.

Operating System Interface

The three type of user interface are Command-Line, Menu-Driven and Graphical User

Interface.

Command-Line User InterfaceThe command-line user interface requires a user to type

commands or press special keys on the keyboard to

enter data and instructions that instruct the operating

system what to do. It has to be typed one line at a time.

It is difficult to use because it requires exact spelling,

syntax or a set of rules of entering commands and

punctuation. Complicated rules of syntax that specify

exactly what you can type in a given place require

memorization. It is also easy to make a typing mistake.

The advantage of command-line interface is, it helps theuser to operate the computer quickly after memorizing the keywords and syntax.


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Menu Driven Interface

Menu-driven user interface

enables the user to avoidmemorizing keywords such as

copy, paste and syntax. On-

screen, menu-driven interface

provide menus as means of entering

commands. It shows all the options

available at a given point in a form of text-based

menu. Menu-driven user interfaces are easy to

learn.

Graphical User Interface (GUI) - GUI makes use of the computers graphics capabilities to

make the operating system and programs easier to use, which is also called user-friendly.Today GUIs are used to create the desktop that appears after the operating system finishes

loading into memory.

GUI is commonly used and has become a standard.

It is easy to differentiate the interfaces between

Mac OS, Windows XP or Linux by looking at their

desktops. GUI with menus and visual images such

as buttons, icons and other graphical objects to

issue commands where many actions can be

initiated by clicking icons that represent computer

resources such as files, programs and networkconnections. On the desktop, we can initiate

many actions by clicking the icons that represent

the computer resources such as files, programs and

network connections.

Differences Between Command-line Interface and Graphical User Interface

The Types Of Application Software

Application software is a computer program or a suite of computer programs that performs a

particular function. Application software includes all programs that perform specific tasks such

as word processing, spreadsheet, database, presentation, e-mail and web browsing.

Command-line Interface ( Dos) Graphical User Interface ( Windows/Linux)

User has to memorise all the syntax

to issue command

User does not need to memorise all the

syntax to issue command

Difficult to use ( Not user friendly) Easy to use (User friendly)Takes a long time to learn Relatively shorter time to learn


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The uses of application software

Word Processing Software - A word processing software allows users to create and

manipulate documents containing mostly text and sometimes graphics. The software can be

used to produce documents such as letters, memos, reports, fax cover sheets, mailing labels,

newsletters, and web pages. Examples of word processing software are Microsoft Word,

StarOffice Writer, TexMaker and Corel WordPerfect.

Functions:

creating and editing documents defining the size of paper on which to print and specifying the margin changing the shape and size of characters organizing text e.g. columns or newsletter style incorporating many types of graphical images Typing words in a paragraph continually without having to press the enter key at the end

of every line

Spelling checks according to existing thesaurus Inserting header and footer Drawing different types of table Record macros. A macro is a set of keystrokes and instruction recorded and saved under a

short key code or macro name

Mailmerge is a method of taking data from a database and inserting it into a documentsuch as letter, mailing labels, envelops and name tags. It usually requires two files, one

that stores the data to be used and the other is the document which the information on

how to format the data.

Spreadsheet Software

Spreadsheet software is an application that allows users to organise and manipulate data in

rows and columns. It produces worksheets that require repetitive calculations budgeting,

maintaining a grade book, balancing accounts, tracking investment, calculating loan payments,

estimating project costs and preparing financial statements.

Examples of spreadsheet software are Microsoft Excel, Corel Quattro Pro and Sun Staroffice

Calc.

Types Of

Software

Examples

Proprietary Open Source

Word

Processing

MS Word, Corel Word Perfect, Easy

Word, Ceframe Word

KWord, OpenOffice Write, AbiWord

Spreadsheet Ms Excel, Corel Quattro Pro, Easy

Spreadsheet, Celframe, Spreadsheet

Kspread, OpenOffice calc,

GNumeric,

Presentation Ms Powerpoint, Corel Presntations,

easyPresentation, Celframe

Powerpresentation

KPresenter, OpenOffice Impress,

Agnubis

Graphic Editor Adobe Photoshop, Adobe Illustrator,

Corel Draw, Jasc Paintshop Pro,

Ulead Photoimpact

GIMP, Inskscape, Photoscape,

Paint.Net, CinePaint


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Function:

Creating editing, formatting worksheets in rows and column Utilize formulas which can perform calculations on the data in the worksheet Create different types of charts to graphically depict data Has the ability to recalculate using the what-if analysis there updating any changes in

data automatically Can create a query to retrieve specific data

Presentation Software

Presentation software is an application that allows users to create visual aids for

presentations to communicate ideas, messages and other information to an audience.

Examples of presentation software are Microsoft PowerPoint, StarOffice Impress and

CorelDraw.

Funtions

Provides a variety of predefined presentation formats with complimentary colours andbackgrounds, text and graphical accents to the slides

Provides a selection of layouts for every presentation such as title slide, two column slide,or slides for graphic, chart of graphs layout.

Can enhance texts, charts or graphics with special effects such as shading, shadows,textures. Slide transitions and custom animation too can help to produce an effective

presentation

For automatic display of presentation slide timing can be set Can insert images, videos, and audio clipsGraphics Software

Graphics software is an application that allows users to work with drawings, photos and

pictures. It provides the users the ability of creating, manipulating and printing graphics.

Examples of graphics software are Microsoft Paint, Adobe Photoshop, Adobe Illustrator, Corel

Painter and Macromedia Fireworks.

Can draw pictures, shapes and other graphical images with various on-screen tools such aspen, brush, eyedropper and paint bucket

Modify, and adjust contrast and brightness Cropping of images Removing the red-eye effect Adding special effects like shadows and glows.Differences between word processor and spreadsheet

Word Processor Differences Spreadsheet

Replaced typewriter for producing

documents

Main usage Used for projects that require

repetitive calculations

Letters, memos, reports, mailing

labels, newletter

Document

types

Accounts, gradebooks

Very limited functionality Calculations Wide range of function available for

calculation

Types and usage of utility programmes

Utility programs, also known as service programs, perform maintenance-type tasks related to

the managing of a computer, its devices, or its programs. They provide services not supplied

by other system software programs. Most computers come with built-in utilities as part of the


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system software. However they may also be bought separately as external utility programs

such as Norton SystemWorks and McAfee Utilities.

File Manager - File manager is the software used to manage files on a disk. It provides

functions to delete, copy, move, rename and view files as well as create and manage folders

(directories). File manager performs tasks of formatting and copying disks, displaying a list of

files on a storage medium, checking the amount of used or free space on a storage medium,organising, copying, renaming, deleting, moving and sorting files and also creating

shortcuts.Example of a file manager utility program is Windows Explorer

Diagnostic Utility - A diagnostic utility compiles technical information about a computer's

hardware and certain system software programs and then prepares a report outlining any

identified problems. Information in the report assists technical support staff in remedying any

problems. Example: Norton Utilities

Disk Defragmenter - When an operating system stores data on a disk, it places the data in the

first available sector on the disk. The process of defragmentation is the reorganising of the

disk so the files are stored in contiguous sectors. A fragmented disk has many files stored innon-contiguous sectors. Defragmenting reorganises the files so they are located in contiguous

sectors, which speeds access time. Example Norton Speed Disk, Windows Disk defragmenter

File or Data Compression - Data compression is a utility that removes redundant elements,

gaps and unnecessary data from a computers storage space so that less space is required to

store or transmit data. With the increasing use of large graphics, sound, and video files, data

compression is necessary to reduce the time required to transmit such large files over a

network. Compressed files are sometimes called zipped files and it must be unzipped to its

original form before being used. Example WinZip, WinRar, PKZip

Disk Scanner - Disk scanner is a utility program that detects and corrects both physical andlogical problem on a hardisk and searches for and remove unnecessary software or file.

Antivirus, AntiSpyware - These are programs that protect a computer against malicious

softwares or codes by identifying and removing viruses or spywares found in memory, storage

media or incoming files. Examples Norton Antivirus, Lavasoft Adware.

Proprietary and open source software

Proprietary Software - Proprietary software is also called closed source software. This means

that the company that developed the software owns the software, and no one may duplicate

it or distribute it without the companys permission. Users have to pay for the use of th

software. The closed source software or proprietary software offers a stable system with

support if the software fails or malfunctions. Examples of Proprietary Software are Ms-Dos,

Mac OS, UNIX & Solaris.

Open Source Software - Open source software is not a closed software. It is provided for use,

modification and redistribution. Any programmer can make improvements which can result in

better quality software. A programmer can download from the Internet for free and modify

with suggested improvements. The only qualification is that changes can't be copyrighted.

Linux is an example of Open Source Software. Linux is the popular multi-tasking UNIX type

operating system. Some version of Linux are command line. Others are GUI. The two most

popular GUIs available for Linux are GNOME and KDE. Many application programs, utilities

and plug-ins have Linux versions including OpenOffice.org, PHP-Nuke, The GIMP, Mozilla,


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ClamAV, OpenLDAP, Audacity and RedHat. Users can obtain Linux in a variety of ways. Some

download it for free from the web. Others purchase it from vendors.

Differences between proprietary and open source software

Open Source (Linux,Ubuntu, OpenOffice.Org,

Write, GIMP)

Proprietary (Windows Vista, MS Office 2007,

Adobe Photoshop CS4)

Can be purchased with its source code Source code not for saleUser can get for free of charge User must pay to get the software

User canmodify source code User cannot modify

User is free to install to any computer User must have a license from vendor before

installing

No absolute ownership and so no party is

responsible for technical support

Full support given from vendor if problems arises

from the use of the software

Pros and Cons of proprietary and open source software

SOFTWARE PROS CONS

Windows XP

(Propriety Software)

runs on a wide range of hardware,

has largest market share, has manybuilt-in utility

security problems, not efficient as a

server OS, have to reboot everytime a network configuration is

changed

Mac OS X (Propriety

Software)

easy to install, best Graphical User

Interface (GUI), secure and stable

supports only Apple computers,

base hardware more expensive than

other platforms, fewer utilities

available, fewer games than

Windows, many applications still

being updated to run with OS X

Linux (Open Source

Software)

runs on a wide range of hardware,

has largest number of user interface

types, can be used as desktop PC OSor server

limited support for games, limited

commercial application available,

can be difficult to learn

Pervasive Computing

Pervasive computing means the technology that is gracefully integrated in our everyday life.

The user is no longer aware of this embedded technology. Pervasive computing uses web

technology, portable devices, wireless communications and nomadic or ubiquitous computing

systems. Other terms for pervasive computing are Ubiquitous Computing, Calm Technology,

and Things That Think.

Pervasive computing devices are not personal computers, but very tiny - even invisible -devices, either mobile or embedded in almost any type of object imaginable, including cars,

tools, appliances, clothing and various consumer goods - all communicating through

interconnected networks. Thee examples of pervasive computing in our daily lives are which is

the automatic Touch 'n Go, SmartTAG toll gate & the 3G technology video phone.

Documents

Note f4 Computer System