Essential Computing Concepts

Computer Department Foundation Program

Fall 2009

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• People: the most important part

• Hardware: consists of the equipment: keyboard, monitor, etc…

• Software: refers to the programs and its purpose is to convert data into information

• Data: unprocessed facts, and once processed, it becomes information.

• Procedures: guidelines for people to follow when using software, hardware, and data

Information SystemInformation SystemAn Information System has the following parts:

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What is a Computer System?

Hardware Software

Equipment Programs

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Supercomputer: The fastest and most expensive high-capacity computers used by very large organizations

Mainframe: Large computers, capable of great processing speeds and data storage

Minicomputer: midrange computers used by medium-sized companies

Microcomputer: Least powerful, small computers, but most widely used (desktop, Notebook or laptop, and Personal Digital Assistants)

Types of ComputersTypes of Computers

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SupercomputerMainframe

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Microcomputer

Desktop

Laptop

PDA(Personal Digital

Assistant)

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Supercomputer

Mainframe

Minicomputer

Microcomputer

More

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Any Computer System

Memory

Central processing unit(CPU)

Input

Hard Disk

Output

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Processing Cycle2. Central processing unit

(CPU)

3. Output

1. Input

Memory

4. Storage

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Main Parts of a PC include:

The System UnitCPUMemories (Temporary or Permanent)

Input Devices Output Devices Secondary storage Devices Communication Devices

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The System Unit The Motherboard, RAM, ROM, Hard Drive,

Video Card and Power Supply are all inside the System Unit.

Ports and buses are used to connect Input, Output, Secondary Storage and Communication devices to the System Unit.

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Picture of a Motherboard

Slots

RAM

CPU

Ports

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The Motherboard

Everything inside the system unit is connected to the motherboard.

Cards are plugged into slots on the Motherboard Example: Graphics Card, Sound Card, Network

Card. Hard drive is connected by cables.

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The CPU

Central Processing Unit (or Processor) The brain of the computer Does all the Calculation and Processing Contains:

Control Unit (CU): translates instructions from: Users language to the machine’s language (0s and 1s). From machine’s language to users language.

Arithmetic Logic Unit (ALU): does the logical & arithmetic operations.

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The speed of the CPU CPU is Measured in HertzHertz

1 Hertz = 1 cycle/second 1 cycle = 1 addition

Conversion table: 1 Kilohertz (KHz)=1000 Hz 1 Megahertz (MHz)= 1000 KHz=1,000,000 Hz 1 Gigahertz (GHz)= 1000 MHz=1,000,000,000 Hz

Typical speed of modern CPU is 3 GHz.

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Random Access Memory(RAM)

Electronic Components that temporarily store data (numbers, text, graphics, etc) being processed

All programs and data are loaded into RAM

Temporary/Volatile – is deleted when the computer is switched off

Measured in BytesBytes.

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Read Only Memory(ROM)

A set of chips containing permanent (non-changeable) instructions to make the computer start working.

Can be read but cannot be written to

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Ports and Buses

Located on the system unit Used to connect peripherals (any outside

device you can attach to your computer) Types:

Serial PortParallel PortUniversal Serial Bus (USB)

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Serial Ports data transferred bit by bit Normally two: COM1 and COM2 Used to connect devices such as modems

Parallel Ports Transfer more than one bit in one read/write Usually two: LPT1 and LPT2 Used to connect devices such as printers

Universal Serial Bus (USB) Serial – one bit in one read/write Used for devices like scanners, digital cameras and

flash drives

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Input Devices Mouse Keyboard Scanner Microphone video camera light pen joystick

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Output Devices

Monitor/Screen

Printers Laser printers Inkjet printers

Plotters: To print maps, floor plans and big designs.

Speakers

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Secondary Memory/Storage (Permanent)Magnetic Disk Hard/Fixed Disk (HD) Floppy Disk (FD)

Optical Disk Compact Disk (CD) Digital Versatile Disk (DVD)

Flash Memory

•Disks must be formattedformatted before use•Format draws tracks on the disk•Tracks is divided into sectors

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Formatting a diskTrack

Sector

Preparing a disk for reading and

writing

Disks will be divided into tracks and

sectors

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Magnetic Disks

Floppy Disk Most common is 1.44MB Consists of thin, circular, flexible

plastic disk with magnetic coating.

Hard Disk Consists of 1 or more rigid metal

platters coated with a metal oxide material for recording.

Common size 10GB to 75GB.

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CD (Compact Disc) Flat, round, portable, metal storage. In variety

formats: CD-ROM (CD-Read Only Memory)

Capacity: 650MB-800MB CD-R (CD-Recordable)

Write on disc one time only CD-RW (CD-Rewritable)

Write many times (similar to floppy)

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Same size as a CD but stores seven times CD capacity on a single side.

DVDs can also be double-sided or dual layer.

Today most DVDs are used to display full-length commercial motion pictures.

Capacity: 4.7GB to 17GB

DVD (Digital Video Disc)

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Flash Memory

Also known as flash drive, pen drive, jump drive, thumb drive, key drive, or memory stick.

Removable data storage device that uses flash memory (Electro-Magnetic memory) and a USB connector

Attached via computer USB ports. Capacity up to 16GB(as in 2006).*

*Inside the Flash Memory

*Refer to: http://en.wikipedia.org/wiki/USB_flash_drive

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Storage Devices Capacities

Storage Device Capacity

Floppy Disk 1.44 MB

CD 650-800 MB

DVD 4.7 to 17 GB

Flash Up to 16 GB

Hard Disk 10GB to 75GB

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Peripherals

Type of computer hardware that is added to a computer.

Typical examples: Camera, Scanner, Joystick, Printers, Flash Memories.

* From: http://en.wikipedia.org/wiki/Peripherals

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Computer = Hardware + Software

Hardware : refers to the Equipment

Software : refers to the ProgramsA program is a set of instructions which tells

the computer how to do its work

Types of Software

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Types of Software

System Software : Programs to control the operation of the computer E.g. Operating System (Windows, Unix, Linux etc)

Application Software : Programs for various applications E.g. Programs for word processing, business, scientific

and other applications such as Microsoft Office which consists of MS Word, MS Excel, etc.

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Machine’s Language

All data entered to the computer must be represented by series of 0s and 1s (i.e. by Bits).

A Bit (short for Binary digit) is the smallest unit of storage in the computer.

It consists of two numbers 0 or 1. This representation is called:

Binary System.

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Binary Numbering System

Base 2

Consists of only two digits: 0 and 1 Data is represented in Bytes. One character requires 1 Byte for

storage. 1 Byte = 8 Bits. Example: 100000001

000000000

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Storing Data

Storage capacity: The amount of information that can be stored in a secondary storage device or in a memory.

Storage Capacity is measured in Bytes and its Multiples: (B, KB, MB, GB)

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Representing Data

The ASCII code (American Standard Code for Information Interchange) is used for letters and symbols.

There are 256 character in the ASCII Coding.

“A” 65 (01000001) “?” 63 (00111111) “£” 163 (10100011)