HOW ICT WORKS

Unit 6

What is a Computer? a computer can be

defined as a machine for processing and storing information electronically

it must have a way for us to get information into the machine, and some way to get it out afterwards so we can see it

Anatomy of a Computer Computers have evolved from

massive ones that used to occupy a room to ones that fit into a purses.

As advanced as today’s computers are, they are still only capable of completing tasks assigned to them by users.

They work by carrying out four functions: input, storage, processing, and output.

In order for a computer to perform these functions, it must have hardware and software.

Functions of Computers Input:

The computer collects data or instructions from you. (getting information (also called data) into a computer

system) Examples of input:

keying using a keyboard pointing and clicking a mouse or touchpad pointing a stylus touching a screen speaking into a microphone

NOTE: the difference between data and information Data is raw, unprocessed numbers, characters, or

symbols. Information is data that has been processed so that it

can be understood and used in decision making.

Functions of Computers Storage:

The computer saves, or stores, data or instructions in its memory for use during processing.

Information is stored in a computer in two main ways: RAM (Random Access Memory) and hard drive (hard disk)

RAM: Random Access Memory, for information being used at the moment. This information is lost when powering off the computer.

Hard Drive: Stores information for future retrieval (even when power is turned off). The hard drive stores large amounts of information (typical drives today hold in excess of 200 gigabytes).

Functions of Computers Storage (continued)

Other type of drives: H: Drive – The hard drive on the

Burnhamthorpe Adult Learning Centre network C: Drive – The hard drive on the computer you

sit in front DVD/CD Drive (usually identified by another

letter) CD-R (recordable compact disc) and CD-RW

(rewritable compact disc), and DVD+/–R USB/Jump Drives – Portable storage External Hard Drives – For extra storage

Functions of Computers Processing:

The computer interprets and processes the data you input.

It adds, multiplies, divides, finds, or manipulates data (numbers, text, or symbols) to complete a task you have given it.

Takes place in the processor, or Central Processing Unit (CPU).

Functions of Computers Output:

The computer displays or produces information from the data that it processed. The different ways to get data/information out from the

computer The output might be:

Monitors: something you see on the screen (such as an answer to a mathematical problem),

Speakers: something you hear (such as a ding when you have made an error), or

Printers: something you command the printer to print. Internet connections/modem: both input and output

Computer Hardware What Is Hardware?

Hardware is any part of a computer you can touch.

There are two categories of hardware:

internal—the components of the computer system contained inside the computer case

external or peripheral devices—those components that are attached to the computer through cables or wireless technology

Computer Hardware

Computer Hardware 1st-Power

the computer needs a power supply.

Electricity is brought into the computer via a power cord.

2nd-Motherboard Once inside the computer,

electricity travels through metal tracks on the motherboard, which is the main circuit board of the computer.

All components inside the computer are attached to the motherboard, as are external devices.

Computer Hardware 3rd-CPU

Electricity quickly makes its way to the CPU, which is attached to the motherboard.

Transistors then control the flow of electricity. The CPU (central processing unit), also called the

microprocessor, is the main computer chip that manages information flow in the computer, as well as processing instructions and data.

AMD and Intel are both makers (manufacturers) of computer processors

Intel: Centrino, Pentium, Celeron, etc. Dual Core, Quad Core AMD: Turion, Anthlon

Computer Hardware 4th-ROM + RAM

Memory chips are also attached to the motherboard. One type of memory is ROM (read-only memory).

It is also called the system BIOS, where information, including instructions for start-up, is stored at the time of manufacture.

There will be one or more ROM chips.

RAM (random access memory) is also called user memory. RAM memory is installed on little circuit boards called modules

that plug into the motherboard. RAM is temporary memory that stores information for the

length of time a computer is left on or a program is left running. The data you see on your monitor while using your computer is stored in RAM. Once the computer is turned off or your program crashes, any information in RAM is lost unless you saved it to another location (e.g., hard drive, USB flash drive).

Add more memory by plugging in another module. The amount of memory is always is some multiple of two bytes.

The most common values are, 128, 256, 512 and 1024 megabytes.

Computer Hardware Video:

Computer Hardware Information: What makes a Computer Work? http://www.youtube.com/watch?v=EvIZWKh0KbY

Computer Hardware-How CPUs Work? Think of the CPU as the brain of the computer. Without it,

the computer would not function. Every time you input data into your computer, the CPU

processes those instructions using four tasks: 1. Fetch—The CPU fetches, or gathers, the code for an

instruction. Then, it places the code in the temporary memory where the instructions are stored, known as the instruction cache.

2. Decode—The CPU decodes, or interprets, the instruction in an area of the CPU chip called the decode cache. It determines which functions are to be performed.

3. Execute—The CPU processes, or executes, the instructions and sends the results to their proper destinations.

4. Store—The CPU sends the results of the instructions to the proper memory location to be retained, or stored, for further instructions.

Computer Hardware-How CPUs Work? Video:

Computer Hardware Information: How Do Processors Work? http://www.youtube.com/watch?v

=0mvKz_tmcmU&feature=relmfu

Check Your Understanding Computer Hardware Questions:

What is input? What is output? What is processing? What is hardware? How are the tasks a CPU performs like those of the

human brain?

Peripheral Devices Peripheral devices can be attached by cable

or wireless technology to the computer to perform specific functions.

Peripherals are plugged into special sockets on your computer, called ports, using appropriate cables, or they are connected wirelessly.

Some examples: Monitors Modems Expansion cards (graphics card or a sound card) Printers Pointing devices (mouse)

Peripheral Devices Examples (continued)

Graphic tablets Gamepads Keyboards Speakers Microphones Scanners Webcams

Computer Software Computers will not serve you if they consist

only of hardware—no matter how efficient, fast, or sophisticated the hardware is.

To carry out the four functions of the computer, computers must also include software. Without software, you can turn your computer on,

but it will do nothing.

Computer Software So if the physical parts of a computer are

called hardware (you can touch) Software is the electronic instructions that

tell the hardware what to do Organized into sets called programs

Send e-mail, need an e-mail program Surf the net: need an internet browser (program) Microsoft Word and PowerPoint are software we’ve

used

Computer Software There are two types of software:

operating-system software, and application software.

Operating-system software, (O/S)-controls the overall activity of a computer, sometimes called platforms This program takes care of the basic computer functions In our case, Windows XP from Microsoft Windows 7 is the newer Operating System software from

Microsoft Previous Microsoft Operating Systems:

Windows 95, Windows 98, Windows ME, Microsoft Vista

Computer Software Operating-system software (continued) Example:

O/S is similar to school office staff . The role of the operating system is to recognize data

coming in from a keyboard or mouse (similar to the school office staff’s role of greeting

new students and finding out where they need to be placed in the school),

send information to the screen or printer (ensure the new students get to their classrooms),

keep track of directories and files on disks (monitor where all students are placed), and

control all peripherals.

Computer Software Operating-system software (continued) The operating system is responsible for

running software and for security. It ensures that unauthorized users do not enter

the system. This role makes the operating system the most

important piece of software on a computer.

Computer Software Operating-system

software (continued) Different operating

systems may have different sets of rules. As a result, software

created for one operating system will rarely work on another.

Many different operating systems exist: the five most common

are:

Computer Software Application software- designed to allow

users to perform—to apply—a specific task, such as calculate numbers, enter text, or play a game. Also called software, application, or a program. This type of software is often categorized by its

function. Some common application-software packages:

Utility software is used to maintain your computer and make sure it runs efficiently. Examples of utility software are McAfee VirusScan and Norton Utilities.

Computer Software Some common application-software packages:

Productivity suites are all-in-one business-software packages that usually contain a word processor, spreadsheet, and database. Some also include presentation software. Examples of productivity suites are Microsoft Office, Corel WordPerfect Office, Apple iWork, and OpenOffice.org.

Computer games include Solitaire, Minesweeper, NBA LIVE, FIFA Soccer, Madden NFL, and The Sims.

Other programs: Word-processing software (Microsoft Word and Corel WordPerfect), Spreadsheet software (Microsoft Excel, IBM Lotus 1-2-3, and Corel Quattro

Pro), Database software (Microsoft Access, FileMaker Pro, and Corel Paradox), Presentation software (Microsoft PowerPoint and Corel Presentations), Desktop-publishing software (Microsoft Publisher, Adobe InDesign, and

QuarkXPress), Graphics software (Corel Draw, Adobe Photoshop, and Macromedia Fireworks), Web-development software (Macromedia Dreamweaver, Adobe GoLive, and

Microsoft FrontPage), Internet-browser software (Microsoft Internet Explorer and Mozilla Firefox),

and Communication software (Microsoft Outlook and Mozilla Thunderbird).

Components of the Computer

Check Your Understanding Computer Hardware and Software Questions:1. What are peripherals? Give three examples.2. What is software? What are the two main

types of software? Give one example for each.3. In your own words, describe what an

operating system is.4. How is operating-system software different

from application software?5. Explain why a particular piece of software will

not run on all computers.

Computer Communication How Do Computers Communicate with One

Another? In order for computers to share information directly,

they must be linked to one another through a network. When two or more computers are connected by

cables or radio signals, they form a network. When a computer is not connected to a network,

it is called a stand-alone. There are two advantages to networking

computers: access to information, and access to equipment.

Computer Communication- Access to Information By networking computers, information can be

transmitted directly from one computer to another.

Networking allows many people to share files and software in several ways: All users on a network can access software from a

central location. All users on a network can access shared files. A user can connect to a network from another

location, and then access all of his or her files and shared software.

Computer Communication-Access to Equipment Computers on a network can share hardware.

For example: If one or more printers are added to a network, then all

the computers on that network can share those printers.

Networks also allow computers to share other hardware, such as modems and projection devices.

Computer Communication There are two main types of networks:

LAN and WAN

LAN (local area network) consists of a group of networked computers that are

all located in one building. Example: a school, a classroom, or even your home (two

computers networked in order to share a printer) Some networks consist of entire office building with

hundreds of computers networked together so that users can share software, hardware, peripherals, and information.

When a LAN is constructed using wireless technology, it is called a WLAN, or wireless local area network.

Computer Communication WAN (wide area network)

is a group of networked computers located in a variety of locations in a large geographic area.

Example: some school boards have all the computers from each school in an entire city networked together through a WAN.

WANs can be set up to transmit information between computers using a variety of media including telephone line, cable, and satellite.

Computer Communication This figure shows two LANs within a WAN.

Computer Communication Though there are many advantages of having

a network, there are also some disadvantages: Security issues

System open to hackers Expensive to install Experience network downtime

Fileserver may fail causing network to go down Proper administration time

Requires considerable time and expertise Cables may break

Connection fails

Computer Communication Whether you are setting up a LAN or a WAN,

there are different ways of setting up communication. Networks are typically set up in one of two ways:

client/server network peer-to-peer network

Computer Communication In a client/server network, one (or more)

computer becomes the leader of the other computers in the network.

The leader is called the server. The server is generally bigger, faster, and more

powerful than the other computers. It can run the network operating-system software.

Computer Communication The other computers in the network are called

the clients, or nodes. They connect to the server through a switch or hub.

The switch or hub is a central device that connects several computers together or several networks together. allows the computers to share the server’s processing

power and store information. Each client must have a NIC (network interface card) to be

a part of the network. The NIC is an expansion card that allows the computer

to act as a client or node in the network. Usually, any network that has more than a dozen

computers uses this type of arrangement.

Computer Communication The peer-to-peer network arrangement

allows computers to share resources and files, as well as access resources and files. Means: individual nodes act simultaneously as

clients and servers. The peer-to-peer arrangement requires a hub

or switch, as well as a NIC for each node. Similar to the client/server arrangement

The major advantage of peer-to-peer networks is that they are inexpensive to set up; however, they tend to burden nodes because they have to play the server’s role.

Computer Communication

This figure shows how a client/server network is set up.

Computer Communication-How Networks are Arranged How Networks are Arranged Physically

All networks consist of two or more pieces of hardware connected together by cables or wireless technology.

The network topology is the physical layout of the cables that connect the nodes and peripherals of the network.

There are two basic network topologies: bus topology and star topology.

Computer Communication-How Networks are Arranged Bus topology

all nodes and peripherals are attached to one main cable.

One broken connection will bring down part or all of the network.

Star topology all nodes and peripherals are connected to one

hub, or switch, at the centre of the network with separate cables.

One broken connection will not affect the rest of the network.

Computer Communication Cables connect

the nodes and peripherals of the network in two basic arrangements.

Computer Communication Video:

What is a Network Attached Storage (NAS) and how can it help me? - Courtesy of Netgear Media http://www.youtube.com/watch?v=r3hn4dcxDSs

Computer Networking Tutorial http://www.youtube.com/watch?v=TVvEheZVwdg http://www.youtube.com/watch?v

=GyTLPl5t-0Q&feature=relmfu http://www.youtube.com/watch?v

=kfEDPQAYH4k&feature=relmfu

Check Your Understanding Computer Communication Questions

1. What are the advantages of networking computers together?

2. Identify one disadvantage of networking computers together.

3. What technology allows computer networks without wires?4. Describe the difference between a LAN and a WAN.5. Name and describe two ways that computers communicate

with one another.6. Name the two main network topologies.7. Sketch the arrangement of the two network topologies.

Explain how each works.8. Which network topology would you choose if you were

responsible for creating your own network? Why?