COMPUTER SKILLSCIS 100

http://www.just.edu.jo/~mqais/CIS%20100.html

1st semester 2013-2014

CH.01INTRODUCTION TO

COMPUTERS

WHAT ARE COMPUTERS? Computers are electronic devices that can

follow instructions to accept input, process the input and then produce information. It is a machine that manipulates data according to a set of instructions.

Computers are machines that perform tasks or calculations according to a set of instructions, or programs.

A computer is a programmable machine designed to sequentially and automatically carry out a sequence of arithmetic or logical operations. The particular sequence of operations can be changed readily, allowing the computer to solve more than one kind of problem. (Wikipedia free encyclopedia)

HARDWARE

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COMPUTERS ARE MADE OF

HARDWARE

SOFTWARE

COMPUTERS ARE MADE OF

• Computers work through an interaction of hardware and software.

• Hardware refers to the parts of a computer that you can see and touch, including the case and everything inside it.

• The most important piece of hardware the central processing unit (CPU), or microprocessor.

COMPUTERS ARE MADE OF

• Software refers to the instructions, or programs, that tell the hardware what to do.

• Ex. operating system (OS), A word-processing program.

HARDWARE

A computer is a system of many parts working together. The physical parts, which you can see and touch, are collectively called hardware. System unit: It is the core of a

computer system. Usually it's a rectangular box. Inside this box are many electronic components that process information.

HARDWARE

The most important of these components is the central processing unit (CPU, or microprocessor) which acts as the "brain" of computer. The CPU has two main components, namely:

Control Unit (CU): controls the fetching of instructions from the main memory and the subsequent execution of these instructions. Among other tasks carried out are the control of input and output devices and the passing of data to the Arithmetic/Logical Unit for computation.

Arithmetic/Logical Unit (ALU): carries out arithmetic operations on integer (whole number) and real (with a decimal point) operands. It can also perform simple logical tests for equality and greater than and less than between operands.

 

RAM

Mother-Board (or Main Board)

CPU

ROM

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PRIMARY MEMORY Memory (fast, expensive, short-term memory):

Enables a computer to store, at least temporarily, data, programs, and intermediate results.

Two general parts:

1. RAM 2. ROM

RAM (MAIN MEMORY)

its a primary storage or random access memory (RAM).

it temporarily holds data and programs for use during processing (volatile: information stored in RAM is lost when the computer is turned off). The more information being processed the more RAM the computer needs.

RAM consists of locations or cells. Each cell has a unique address which distinguishes it from other cells.

MAIN MEMORY

Address Memory locations

1

2

3

n

Memory Cell

MAIN MEMORY

ROM: READ ONLY MEMORY

ROM is part of memory Programmed at manufacturing time

Its contents cannot be changed by users

It is a permanent store

OTHER KIND OF MEMORY

PROM: Programmable Read Only Memory.

EPROM: Erasable Programmable Read Only Memory

Cache Memory Registers: not part of the main

memory.

Input Devices

• Translate data from form that humans understand to one that the computer can work with

• Most common are keyboard and mouse

Selector Buttons

EXAMPLES OF INPUT DEVICES

Keyboard (QWERTY keyboard, ATMs

keyboard)ATM: automatic teller machine

Mouse Scanner Optical mark recognition (Light Pin , Bar code

scanners) Microphone Joystick .

EXAMPLES OF INPUT DEVICES(2)

Point and Draw devices Trackball Touchpad Touch screen Magnetic stripes and smart cars. Digital Cameras

Secondary StorageSecondary Storage

Stores data and programs permanently: its retained after the power is turned off

Examples• Hard Drive (Hard Disk)

Located outside the CPU, but most often contained in the system cabinet

• Floppy Disk• Optical Laser Discs

CD-ROM, CD-RW, and DVD

KINDS OF DISK DRIVESDRIVES

Common Secondary Media

• DiskettesDiskettes– Data represented as magnetic spots on

removable flexible plastic disks– Most common size is 3 1/2 inches, in a rigid

plastic case – Disk drive holds the diskette, reads or

retrieves the data and writes or stores data

Common Secondary MediaCommon Secondary Media• Hard drive

– Data is represented magnetically as with diskettes

– Normally more than one rigid platterplatter in a sealed unit

– These disksdisks are not removablenot removable– Significantly more capacity and faster

operating than diskettes

Hard drive

Common Secondary MediaCommon Secondary Media

OPTICAL LASER DISCS

CD ROM & DVD’s Data is represented as pits and lands

Some kinds are read only (CD-ROM) and some Kinds are rewritable (CD-RW)

Significantly more capacity and faster operating than diskettes

Common Secondary MediaCommon Secondary Media

DVD: Digital Video Disk

Disk size Amount of storageApproximate printed

8.5 x 11 inch pages

5.25 low density 360 Kb 180 pages

3.5 low density 720 Kb 360 pages

5.25 high density 1.2 Mb 600 pages

3.5 high density 1.44 Mb 720 pages

CD 700 MB a small library

DVD 4.7 GB /8.5 GB a feature length movie

Common Secondary MediaCommon Secondary Media

tapes

Panasonic's LS120 3.5 inch diskettes3.5 inch diskettes

Iomega's Zip & Jazz disks

VCR tape (Video Cassette Recorder )

Flash USB disks

MMC (Multi Media Card )

SD

Common Secondary Media

Output Devices

Pieces of equipment that translate the processed information fromfrom the CPU intointo a form that humans can understand.

CPUPr

oces

sed

info

rmat

ion

OUTPUT DEVICES

Monitors Printers

Dot matrix printers Ink jet printers Laser printers

Sound Blasters (Sound Card By Creative Lab)

Controlling other devices

Software

• A collection of computer programs and related data that provide the instructions for telling a computer what to do and how to do it.

TYPES OF SOFTWARE1- System software: helps run the computer

hardware and computer system.

2- Application software: allows end users to accomplish one or more specific (not directly computer development related) tasks.

3- Programming software : usually provides tools to assist a programmer in writing computer programs, and software using different programming languages in a more convenient way.

System Software

• The software that controls everything that happens in a computer.

• Background software, manages the computer’s internal resources

Resources examples : CPU, RAM , I/O devices, …

All hardware and software are under the control of the All hardware and software are under the control of the

operating systemoperating system.

Among other things, the operating systemthe operating system::

1. Determines how valuable RAM is allotted to programs.

2. Performs tasks related to file management.

3. Sets priorities for handling tasks.

4. Manages the flow of instructions, data and information to and from the processor (CPU).

Examples ofExamples of Microcomputer Operating System Software

• DOS - original standard for IBM compatibles

• Windows - a graphical operating environment Windows VISTA, XP, millennium,

2000, 98, and 95

Continue …Continue …

• Windows NT - for powerful workstations & networks

• OS/2 - competitor to Windows 2000• Macintosh Operating System• Unix - originally for minicomputers, now

used on microcomputers and Internet servers

Examples ofExamples of Microcomputer Operating System Software

ContCont..

Application SoftwareApplication Software

• Packaged - “off the shelf”, pre-written programs ( General purpose)

• Custom - written for an organization’s specific purpose (Special purpose)

Packaged Custom

Application Software – Basic ToolsApplication Software – Basic Tools

• Word processors– example: example: Microsoft wordMicrosoft word

• Spreadsheets-- example: example: Microsoft ExcelMicrosoft Excel

• Database managers-- example: example: Microsoft AccessMicrosoft Access

• Graphics-- example: PhotoshopPhotoshop

UNITS OF MEASUREMENTS

Bit (Binary Digit)(takes two values: 1 or 0) Byte = 8 bits

KB (Kilo-byte) = 1024 bytes MB (mega-byte) = 1024 KB GB (giga-byte) = 1024 MB TB (Tera-byte) = 1024 GB

Remark: 1024=210

FOUR KINDS OF COMPUTERS

1. Microcomputers

3. Mainframe computers

2. Minicomputers

4. Supercomputers

ComparisonComparison between the previous kinds of computers may made based on :

Price Processing Speed Storage Capacity Powerful Single-user or Multi-user Supporting hundreds (or thousands) of users

simultaneously Computer Size Companies size …etc.

MICROCOMPUTERS

Microcomputer =>Personal Computer => PC

Personal Computer (PC): A small, single-user computer based on a microprocessor.

DESKTOP COMPUTER

Small enough for a desktop, but not easily portable

Personal computers (PC’s) run general purpose software and are employed by a wide spectrum of users

PORTABLE COMPUTERS

Easily transported from one place to another

PORTABLE COMPUTERS

• Four categories1. Laptops2. Notebooks3. Sub-notebooks4. Personal Digital

Assistants (PDA)

PDA

MINICOMPUTERS

A multi-user computer capable of supporting up to hundredshundreds of users simultaneouslysimultaneously.

Desk-sized More processing speed and storage

capacity than microcomputers General data processing needs at small

companies Larger companies use them for specific

purposes

MAINFRAME COMPUTERS

A powerful multi-user computer capable of supporting many hundredshundreds oror thousandsthousands of users simultaneouslysimultaneously.

Larger machines with special wiring and environmental controls

Faster processing and greater storage than minicomputers

Typical machine in large organizations

SUPERCOMPUTERS

An extremely fast computerextremely fast computer that can perform hundreds of millions of instructions per second.

The most powerful of the four categories

Used by very large organizations, particularly for very math-intensive types of tasks

1- Store a large amount of data and information for a long period of time.

2- process data and information in high accuracy level .

3- Speed in processing data information.

4- Sharing of information / network.

Characteristics of Computers

UnderstandingUnderstanding the difference between Data, Information and Knowledge:

ComputerComputerData

Knowledge

Information

DataData: is the name given to basic facts such as names and numbers.

InformationInformation: is data that has been converted into a more useful or intelligible form.

KnowledgeKnowledge: arrangement of information and classifying information of the same type or the same topic.

e. g.

-2 4 0 -3 10 (datadata) | | sort \ / -3 -2 0 4 10 (informationinformation)

Data

• Document files

• Worksheet files

• Database files

Processing data produces information, and processing information produces knowledge.

COMPUTER VIRUSESCOMPUTER VIRUSES

COMPUTER VIRUSES

A computer virus are small software programs that are designed to spread from one computer to another and to interfere with computer operation.

A virus might corrupt or delete data on your computer, use your e-mail program to spread itself to other computers, or even erase everything on your hard disk.

TYPES OF COMPUTER VIRUSES

Macro Viruses Network Viruses

•Trojan Horses Logic Bombs

Companion Viruses Boot Sector Viruses

Multipartite Viruses

SOURCES OF COMPUTER VIRUSES

Three primary sources The Internet

Via downloads and exchanges

Diskettes

Exchanging disks

Computer networks

Can spread from one network to another

HOW DO YOU KNOW IF YOU HAVE A

VIRUS? Lack of storage capability

Decrease in the speed of executing programs

Unexpected error messages

Halting the system

VIRUS PROTECTION

•The software package distributed with new PCs always includes an antiviral program. The best way to cope with viruses is to recognize their existence and use an antiviral, or antivirus program.

Some tips that will help minimize your Some tips that will help minimize your vulnerability to viruses:vulnerability to viruses:

1. Delete e-mails from unknown or suspicious, untrustworthy (unreliable) sources, especially those with files attached to an e-mail.

2. Never open a file attached to an e-mail unless you know what it is, even if it appears to come from a friend.

3. Download files from the Internet only from legitimate and reputable sources.

1. Update your antivirus software at least every two weeks as over 200 viruses are discovered each month.

2. Backup your files periodically3. Traditionally virus protection has

been at the PC or client level. However, this may change as companies look to network and Internet service providers for more services.