COMPUTER ESSENTIAL

MM BUKAR29-10-2014

Computers, data and information

A computer is an information processing machine. Computers process data to produce information. The sets of instructions that humans give computers are called programs or software. Software that carries out a particular type of task for a user is often called applications software.

The three stages of computing are input, processing and output.A computer works through these stages by ‘running’ a program.

A program is a set of step-by-step instructions which tells the computer exactly what to do with input in order to produce the required output.

Computers can work much faster than humans;Computers never get tired or need a rest;Computers can do jobs that it would be dangerous for a human to do;Computers can store large amounts of information in a very small space;Computers can find information very quickly;Computers never lose or misplace information.

Information and Communication Technology (ICT)

Information and Communication Technology (ICT) is the technology required for information processing. In particular, it relates to the use of electronic computers to convert, store, process, transmit, and retrieve information. It is an all-encompassing term that refers to the devices used for creating, storing, using, or exchanging information electronically.

DIFFERENT TYPES OF ICT SERVICES/USERS

Internet services:…..shopping, office services are becoming available online.

E-commerce:…This is the ability to purchase goods and services online

E-banking:…online banking enable customer to access their account via the internet.

E-government:…this is the means by which local and national government services are being made available online..e.g. revenue tax collection, electronic voting and public record systems

Computer Systems

Hardware is the name that is given to any part

of a computer

that you can actually touch.

An individual piece of

hardware is called a device.

The basic hardware of any

computer consists of a central

processing unit (CPU) along with input, output and backing

storage devices.

The system unit is the main box containing the essential electronic parts such as motherboard, processor, hard drive, RAM

Peripherals are all the devices that plug into the system unit. Peripherals can be input or output devices

Computer Systems

Manual Input Methods

Manual input devices are used by people to enter

data by hand.

Pointing devices

Digital camera

Touch screenScanner

Graphics tablet

Microphone

Input and output devices are attached to computers via ports. Each port is a socket into which a plug can be inserted. Two of the most commonly used areUSB stands for Universal Serial Bus. Printers, keyboard and other accessories can be attached easily to your computer via USB port, as well as items such a Smartphone, digital cameras and storage devices.HDMI stands for High-Definition Multimedia interface HDMI ports are found on digital audio devices, such as high definition digital television, video projectors. They connect to HDMI complaint audio and video devices, to transmit High-definition uncompressed video and multi-channel audio through a single cable.

INPUT/OUTPUT PORTS

SOME OTHER PORTS YOU MAY ALSO USE ARE

•Serial port

•Parallel port

•Network

•Firewire port

Storing

data

Data storage devices can be divided into 2 main categories:

Backing storage is used to store programs and data when they are not being used or when a computer is switched off. When programs and data are needed they are copied into main memory but also still remain on backing storage. Magnetic tape drives, floppy disk drives and hard disk drives are all examples of backing storage devices.The Main Memory contains two types of memory chip called ROM and RAM which hold program instructions and data.

BITS and BYTESComputers store and process data using binary numbers. A single unit in binary is called a bit which stands for binary digit. Computer memory is measured in bytes.One byte is made up of eight bits. One byte can store one character.

1 0 0 0 0 0 1 0 The eight bit binary code in this byte represents the letter A

The size of a computer’s memory is normally measured in kilobytes (Kb), megabytes (Mb) or gigabytes (Gb). The table below shows some of the main units of size that we use to measure computer memory.

Random Access Memory (RAM)

RAM is the computer’s ‘working memory’.

RAM temporarily stores programs and data that are being used at a given time.

The contents of RAM can be changed and are lost when the computer is turned off.

Memory which is wiped clean when the computer is turned off is called volatile memory.

Read Only Memory (ROM)

The main use of ROM memory chips in a computer is to store the program that runs when the computer is turned on which loads the operating system (e.g. Windows 7) from disk.

The contents of ROM can’t be changed and aren’t lost when the computer is switched off.

Memory which isn't wiped clean when the computer is turned off is called non-volatile memory.

PROM and EPROM

PROM and EPROM are both special types of programmable read only memory.

PROM stands for Programmable Read Only Memory. This type of memory can be programmed once but can’t be changed again afterwards.

EPROM stands for Erasable Programmable Read Only Memory. This type of memory can be programmed and then changed whenever necessary.

Output Methods

Before any output can be produced by a computer it must have an output device connected to it.

The output devices that you are probably most used to will be the screen, or monitor, and the printer.

Another sort of output that you will have experienced when using a computer is sound, which is output through a speaker.

Monitor

The quality of the output on a monitor depends on its resolution.

The resolution of a monitor depends on the number of pixels that it can display.

A monitor or screen is an output device that can display graphics and text and video. The picture on a monitor is made up of thousands of tiny coloured dots called pixels.

Dot matrix printers

A dot matrix printer forms characters and graphics on the paper by producing patterns of dots. If you look closely at a print-out from a dot matrix printer you will see the tiny dots which make up the printout.

The part of the printer which forms the patterns of dots is called the print head. The print head is made up from pins which are pushed out in different arrangements to form the various patterns of dots needed.

Inkjet printers

Inkjet printers work like dot matrix printers because the printouts that they produce are made up of patterns of very small dots but the print head has a set of tiny holes rather than pins. As the print head moves across the paper ink is forced out through the holes to form the image. Inkjet printers are very quiet to operate and can produce good-quality printouts of both graphics and text. Relatively cheap colour graphics can be printed using a colour inkjet.

Laser printers

Laser printers give very high-quality printed output of both text and graphics very quickly and quietly. They are generally more expensive to buy than inkjet printers and the toner cartridges are more expensive.They are very suitable for large volume printouts because of their speed.

Speakers

Computers can output music, voices and many other complicated sounds using speakers. To be able to output sound a computer needs to have a special circuit board inside it called a sound card. Plotters

The main difference between a plotter and a printer is that a plotter uses a pen to draw the computer output onto the paper. Some plotters use a set of coloured pens to produce colour output. Plotters produce very accurate drawings and are often used in computer aided design or CAD.

Browsers•To browse or ‘surf’ the Internet a browser program is required•Microsoft Internet Explorer, Firefox , Opera, chrome and Netscape Navigator use search engines to search for information by entering keywords

URLs

•Uniform Resource Locator•These give the location of individual sites on the World Wide Web•Most start with http//:www.•They often reveal the country of origin such as .uk for the United Kingdom. They also indicate whether the site is commercial with either .co or .com, a government organisation with .gov, or an academic organisation with .ac

Hyperlinks

•A piece of text or a graphic that contains the address of another location on the Web

•Creation of hyperlinks is a basic feature of any Web design packageHot spots

•Area on an object that contains a hyperlink•To create a hot spot an active area must be defined on an object and a hyperlink associated with it

Modems•A modem converts a digital signal to an equivalent analogue signal so that it can be sent down a telephone line.

telephone line

analogue signal

Modem ModemComputer

digital signal

01001

Computer

01001

digital signal

Faxes•A fax machine scans paper documents and converts them into digital format. •The digital version is then converted into analogue format and sent over an ordinary telephone line to another fax machine. •The fax machine at the receiving end converts the analogue information back into digital format and reproduces an exact hard copy of the original document. •Faxes are particularly useful for transferring images such as plans, drawings or documents with signatures between remote locations when it is important that an identical copy of the original is received at the other end.

File compressionFile compression software can be used to make files smaller so that more data can be stored in the same amount of space on backing store.

When a compressed file on backing store needs to be used it must be decompressed.

This can be done using decompression software or by setting files up to be self-extracting which means that they can automatically decompress themselves.

Winzip is an example of software that can be used to compress and decompress files.

TeleworkingTelecommuting is when people work from home instead of travelling to work and use methods of electronic communication such as the telephone, fax machine, e-mail, the Internet and videoconferencing to communicate with the outside world. Advantages:

Time isn’t wasted travelling to and from work;Cars are kept off the roads which helps the environment;Working at home is less stressful and it is much easier to

concentrate;Working hours are more flexible and can be fitted around other

things that need doing such as collecting children from school;People who live large distances away from each other can work

together without having to meet in person;Businesses need smaller offices and spend less on light and

heating.

Disadvantages of teleworking

Workers may miss the company of their co-workers and feel isolated Having your workplace at home might mean that you end up doing too much work and not having enough time off It is more difficult for mangers to monitor and control the workforce

Health and Safety

•Working with computers for long periods of time can cause:

• Stress• Eyestrain• Wrist injuries• Neck and back problems

•Employers can be sued if they do not take steps to protect employees

Repetitive strain injury•Repeating the same physical movements over and over again can cause a condition known as RSI•Repeated presses on the keyboard and long periods of holding and moving a mouse cause a build up of damage to the hands arms and shoulders

•Spending long periods of time in front of a computer screen can cause eyestrain•This can be avoided by:

• Ensuring there is enough light• Reducing the amount of glare• Ensuring workers wear correct prescription glasses if

needed

Eyestrain

TYPES OF COMPUTERS

A personal computer is also known as a “PC”.

It is an affordable, stand-alone computer designed for use by

one person at a time. PCs come in several types. Each types is suitable for different users. The main type

are listed below.

Desktops A PC that

usually sits on, or under, user’s desk and is not mobile.

Laptops Portable (PC) that is smaller than a

desktop but larger than a tablet PC. You

can work with it on your lap. Good

for user who travel frequently.

TYPES OF DEVICES

With advances in technology, many handheld, portable, digital devices are available-Smartphone Is a mobile phone with additional features. The extra features can include such things s PC functionality, Internet access and multimedia capabilities.Media players can play text, audio, photos, video and graphics in a variety of formats.Digital cameras These take digital pictures-images which are stored in binary form, usually on a memory card within the camera. The images can be downloaded to a PC via for example a USB or firewire port.

There are two main types of software that are used on personal computers and devices

Operating System softwareOperating System (OS) software is the master control program that keeps everything flowing smoothly inside your computer or device. It acts as the host for the application software on your device.The operating system starts-up your device. It controls and launches software applications, schedule tasks, allocates storage, handles the interface to peripheral hardware.

THREE POPULAR OPERATING SYSTEMS FOR COMPUTERS ARE:

•Microsoft window (with version such as window 7, window vista and window 8)•Apple Mac OS•LinuxPopular Operating systems for devices are:•Android•Window phone•iOS•Blackberry

There are two main types of software that are used on personal

computers and devices

Application softwareApplications software enable users to accomplish specific task on the computer. Programs are available to create files such as document, spreadsheet, presentations and databases; in addition to task such as communicating via the internet and playing games. It is important to pick the right application software for the job in hand

Specialist application software

Specialist application software performs a single very specific type of task.

Programs to work out driving routes are one common example of specialist application software. Other examples

include programs to work out payroll, calculate accounts, deal with stock control and handle appointments.

Example of applications software

Word processor•Letter, Long report and project planSpreadsheet•Collect data, Collate and chart social club information and compare forecast and actual resultsDatabase•Records of employees’ details, Client contact list and Resource databasePresentation•Introduce an idea, Present result of a project and Give details of a forthcoming product launchCommunications (e-mail)•Correspond with clients, Communicate with friendsWeb browsing•Search for cost-effective resources, review client websites

SOFTWARE CAN BE ACCESSED IN A VARIETY OF WAYS:

A program can be

installed locally

A program can be

installed on a network

A program can be made available

online. This enable users to

access their programs from

a variety of devices, at any time when they have access to the internet.

SOCIAL NETWORKING

Social network via the internet allows groups of people to share information and experiences that are of interest to all the people in each group….Below are some examples of social networking sites.•Facebook•Twitter•Google+•MySpace•Bebo•Friend Reunited

Network Concepts

A network is a collection of several computers connected together, so they can securely share and access files (documents and applications), data and resources ( for example printer), as well as being able to communicate electronically.A client/server network is the most efficient way to connect multiple computers to share information• The server is the central computer that stores everyone’s files.• A client is any computer that can access the information stored on the server.

TYPES OF COMPUTER NETWORKSLocal Area Network (LAN) LANs are usually confined to a small geographic area, such as an office or building.Wireless Local Area Network (WLAN) is a LAN where the computers and equipment are connected wirelessly-using a router to transmit data between equipmentWide Area Network (WAN) A WAN connects computers across a large geographic area. Such as a city or country. The internet is an example of WAN

INTERNET

The word internet comes from the phrase “ Interconnection of networks”. It is the biggest computer network in the world, reaching millions of people, on thousand of interconnected networks. No one person or group controls the internet, so finding a particular piece of information can be challenging.World Wide Web (WWW) can be used to access the information that sits on the internet. You can use the communication structure of cables and satellites that makes up the internet globally, to access the web via a browser.

An intranet is a computer network used within one company or organisation. It has limited access and usually provides a similar look and feel to the Internet. It is a private network. Virtual Private Network (VPN) A VPN is a network that allows users who are not connected directly to their organisation’s network ( for example through a LAN or WAN) to connect to that network and access the computers, drives and folders to which they have logon rights. The data sent and received via this connection will be encrypted, so it cannot be read by anyone who attempts to intercept it.

It is possible to connect to the internet via a variety of options.•Phone line this can give you access to ADSL broadband.•Mobile phone can use mobile phone network to connect to the internet•Cable – cable operator offer broadband service via their high speed fibre-optic cables.•Wi-fi – wi-fi uses radio frequencies, rather than cable & telephone line. •Wi-max – is a wireless broadband tech that has a much greater range that wi-fi -…its range may be as much as 25 mile•Satellite-for home or businesses located in remote areas.

Questions