What is an ICT System? An ICT system is a set-up consisting of hardware, software, data and the people who use them. It commonly includes communications technology, such as the Internet. ICT and computers are not the same thing. Computers are the hardware that is often part of an ICT system. ICT Systems are used in a number of environments, such as: offices, shops, factories, aircraft, ships. They're also used in fields such as: communications, medicine, farming. The importance of ICT systems By using ICT systems we are:  more productive - we can complete a greater number of tasks in the same time at reduced  cost by using computers than we could prior to their invention able to deal with vast amounts of information and process it quickly  able to transmit and receive information rapidly The three main types of ICT systems Information systems (are focused on managing data and information.) Control systems (mainly control machines). Communications systems ( transport data from one place to another). -------------------------------------------------------------------------Input, output and system diagrams What comes out of an ICT system is largely dependant on what you put into the system to begin with. ICT systems work by taking inputs (instructions and data ), processing them and producing outputs that are stored or communicated in some way. An ICT system diagram A system is an assembly of parts that together make a whole. ICT systems are made up of some or all of the parts shown in the diagram. Various devices are used for input, processing, output, and communication. Media integration Methods used for input to and output from ICT systems vary a lot. Input and output formats are the different kinds of media that are used to either gather up and collect data and instructions or to display, present or issue the outputs of processing. Up until recently most media formats required dedicated devices - for example, digital cameras to take digital photographs, scanners to digitise images for use on a computer, or DVD players for video playback - so you needed the correct device in order to work with each media format. There is now a growing tendency for multi-purpose ICT devices or conversion. The driving force is the communication power of the Internet, and the increasing availability of small high-powered electronic technology. This means that you can now get an all-in-one box that can do the same thing as several different ones did before it. Here are some examples: combined printers, scanners and photocopiers, televisions with built-in Internet connections and web browsers, mobile phones that can take photos, record video, access the Internet and play back music Integration of information services Alongside the joining together of technologies, there is also a tendency toward the integration of common public information services. Digital television by satellite, cable or terrestrial aerial now gives access to many channels that have interactive content, which can be used in a similar way to the web. DAB digital radio provides large amounts of text data to be transmitted along with the signal. The Internet now enables broadcasts from radio and TV stations to be 'time-shifted' by the user, who watches or listens to the programme whenever they want to. News services and the mass media such as newspapers, radio, and television are making themselves available so that people can access them when they want and wherever they are. ------------------------------------------------------------------------------------------------------ Implementing a new computer system There are four main stages in setting up a new computer system: Analysis - studying the problem; design - designing a solution; implementation - putting the solution into effect and testing it; evaluation - checking that the solution is working as intended. This process is often called systems analysis. ------------------------------------------------------------------------------------------------------------- All computers are a part of a system made up of hardware, software and the data being used HARDWARE Input devices allow us to enter raw data into a computer. The computer processes the data and then produces outputs that we can understand using an output device. Input devices can be manual or automatic. The processing is mainly handled by the Central Processing Unit (CPU).  Manual input devices The most common manual input devices are the keyboard and mouse. Other manual input devices include: Concept keyboard - Each button on a concept keyboard relates to a particular item or function. Buttons can be labelled with text or a picture. Fast food restaurants often use concept keyboards because very little training is needed to operate them and they're efficient - a single button can order an entire meal. Trackball- Used as an alternative to a mouse. To operate it the user rotates the ball which moves the pointer on screen. They are particularly easy to use for those with limited movement in their hands and are often used in Computer Aided Design (CAD) for their increased precision over a mouse. Joystick- Joysticks used to be popular with gamers but have slowly been replaced by other types of game controller. In construction, joysticks are used to control machinery such as cranes. Digital camera- A digital camera takes pictures and can usually record video too. The pictures it takes and the videos it records are stored in files. These files can be copied to a computer and later edited. Microphone-Microphones are used to input sound. Webcams commonly have microphones built-in. Touch screen- A touch sensitive visual display unit (VDU) or screen has a grid of light beams or fine wires criss-crossing the screen that are used to detect touch. Many mobile phones use touch screens and do away with the keypad entirely. They're often used on cash machines and in shopping centres too. Scanner- A scanner can be used to digitise images. They're similar to a photocopier but they make a digital copy instead of a physical copy. Graphics tablet- A graphics tablet consists of a flat pad (the tablet) on which the user draws with a special pen. As the user draws on the pad the image is created on the screen. Using a graphics tablet a designer can produce very accurate on-screen drawings as if they were drawing on paper.  Automatic input devices Sensors- Sensors are often used as part of a feedback cycle. They collect data continuously and are typically linked to a control program that specifies acceptable levels, eg the minimum and maximum temperature in a green house. Barcode reader- Barcodes are represented by black vertical bars and are read by a barcode reader. Barcodes are printed on nearly every product you buy, each product has a unique code. When read, information stored in the shop's database is recalled, such as the product name and price. This information later appears on your receipt. Magnetic strip (or stripe) reader- Magnetic stripes are built into many plastic cards such as debit or credit cards and personal identity cards. The magnetic strip on the back of the card can hold the personal details of the card owner and, with the necessary PIN, will allow access to secure information, eg bank account details. Data stored on the strip is scanned and input into a computer system by a magnetic stripe reader. Central Processing Unit- The CPU (Central Processing Unit) is the part of a computer system that is commonly referred to as the "brains" of a computer. The CPU is also known as the processor or microprocessor. The CPU is responsible for executing a sequence of stored instructions called a program. This program will take inputs from an input device, process the input in some way and output the results to an output device. CPUs aren’t only found in desktop or laptop computers, many electronic devices now rely on them for their operation. Mobile phones, DVD players and washing machines are examples of equipment that have a CPU. Output devices Common output formats are printed paper, sound, video and on-screen documents. They let the computer communicate with the user. Examples of devices that take advantages of these formats are: Monitor- The most common output device is the monitor. Modern monitors, where the case isn’t more than a few centimetres deep, are usually Liquid Crystal Displays (LCD) or Thin Film Transistors (TFT) monitors. Printers Laser printers are quite expensive to buy and run but produce a high quality output and are quiet and fast Ink-jet printers offer black and white or colour printing with reduced levels of quality and speed. Colour ink jet printers are cheaper to buy than colour laser printers. Plotters- A plotter can be used to produce high quality, accurate, A3 size or bigger drawings. They are usually used for Computer Aided Design (CAD) and Computer Aided Manufacture (CAM) applications, such as printing out plans for houses or car parts. Other output devices Many other types of output device exist including: speakers, projectors, buzzers, motors, lights, mechanical devices, eg a robot arm ----------------------------------------------------------------------------------------------------------------A computer uses two types of storage. A main store consisting of ROM and RAM, and backing stores which can be internal, eg hard disk, or external, eg a CD or USB flash drive. Main store (or computer memory) is divided into Read Only Memory (ROM) and Random Access Memory (RAM). ROM is memory that cannot be changed by a program or user. ROM retains its memory even after the computer is turned off. For example, ROM stores the instructions for the computer to start up when it is turned on again. RAM is a fast temporary type of memory in which programs, applications and data are stored. Here are some examples of what's stored in RAM: the operating system, applications, the graphical user interface (GUI) If a computer loses power, all data stored in its RAM is lost. Storage capacity and file sizes are measured from lowest to highest in: bits, bytes, kilobytes, megabytes, gigabytes, terabytes Size Equal to bits 1 byte 1024 bytes 1 kilobyte 1024 kilobytes 1 megabyte 1024 megabytes 1 gigabyte 1024 gigabytes 1 terabyte Relationship between measurement The size of a file and a storage device's capacity will always be written in its simplest form. For example, an operating system would report a 1 terabyte hard disk's size as 1TB not as 1024GB, although both are correct. The hard disk The main internal backing store is a computer's hard disk. A hard disk stores: the operating system, software @applications or programs, the majority of your data files Hard disks spin at very high speeds (around 7,200 RPM - revolutions per minute) within a sealed unit inside the computer. Hard disks store large amounts of data - 200GB to 1 TB is common in desktop computers. The data stored on a hard disk is retained until deleted, but it needs to be loaded into main store RAM before it can be used. Floppy disks hold very small amounts of data , just 1.44MB and a computer needs a floppy drive to read them. They are used to:  transfer small files of data from one machine to another   backup important small files that are stored on your hard disk store restricted files that you don't want other users of your computer seeing Newer storage mediums such as DVD-RWs and memory sticks have replaced floppy/zip disks. External backing stores: optical discs There are several different types of optical disc, although they all look pretty much the same. CD (Compact Disc) Optical discs that use the same technology as music CDs . They store up to 700MB of data. CDs can be used for multimedia@applications such as encyclopaedias and can store pictures, sounds and video clips or anything else that will fit. There are several formats on the market, such as:   CD-ROM - read only, the data is written to them before they are sold. CD-R - meaning CD-Recordable, the user can write data to the CD once or fill it over time using multi-session (writing to the same disc on separate occasions).  CD-RW - meaning CD-ReWritable, the CD can be written and re-written to. Unlike multisession discs, existing data can be overwritten. DVD (Digital Versatile Disc) DVDs are the same physical size as CDs but hold much more data - a single sided disc can hold up to 4.7 GB. DVDs are commonly used for storing video so you will often see them measured in minutes, eg 4.7GB = 120 minutes. There are several formats on the market, such as:   DVD-ROMs - read only, the data is written to them before they are sold. DVD-R - meaning DVD-Recordable, the user can write data to the DVD once or fill it over time using multi-session.  DVD-RW - meaning DVD-ReWritable, the DVD can be written and re-written to. Unlike multi-session discs, existing data can be overwritten. CD/DVD drives To read from and write data to CDs and DVDs you will need a suitable drive. Today you can buy CD/DVD drives that are able to read all CD and DVD formats and write to CD-R, CD-RW, DVD-R and DVD-RW. Data is written to and read from the discs using a laser. External backing stores Magnetic tape- Principally used for backup of important files from the hard disk and for the long term storage and archiving of data. Advantage- They are small, robust, portable and provide low cost storage per GB . Disadvantages- They are very slow to write to and read from. External hard disks- An external hard disk can store very large amounts of data, eg 1 TB, and can be plugged into your computer via a USB or FireWire port to provide extra storage. They're essentially the same as the hard disk in your computer but due to the casing are usable externally. Advantage- High capacity, eg 1TB or more so they can be used to backup data or move large amounts of data between machines. Disadvantages- They're often quite large and therefore inconvenient to carry around. They have moving parts so are more likely to break, especially if dropped. Memory sticks- A memory stick is 'pen top' sized USB device and can be used in a similar way to a floppy disk but it is inserted into the USB port - it is then seen by the computer as a removable drive. They typically come in sizes from 512 MB to 32GB upwards depending on the price paid. Advantages- Memory sticks can hold large quantities of data. They are extremely portable, so the user can take them wherever they go. They're durable, because they have no moving parts. Disadvantage- Portable storage devices in general are more likely to be lost, stolen or damaged. Backing up and archiving data Data needs to be backed up for many reasons: a user may delete an important file, hard disks can fail, a virus can wipe out data, a fire may destroy the building where the data was being stored (businesses will often store their backups off-site) If the data wasn’t backed up then the consequences could be disastrous depending on what data was lost. If a business lost details of all the payments it had yet to receive the business could go bankrupt as they wouldn’t know what was owed to them or by who. Businesses typically use magnetic tape to backup important data. Your average home user is unlikely to backup their data but those who do will most likely use an external hard disk. Frequency of backups- Some data is more valuable than other data and some data is changed more frequently than other data. These are the kind of issues that must be taken into account when deciding how often to backup data. The value of the data should determine how frequently it is backed up. Archiving- Some data may not be being used very often but it may still be useful or needed in the future. In this case data can be archived. Archived data is copied to a suitable storage medium (perhaps DVDs or magnetic tape) then it is stored safely and securely. The original data is then deleted from the computer system. This is done to free up storage space for new data. ---------------------------------------------------------------------------------------------------------Word processing applications allow users to type and edit text. Desktop publishing (DTP) applications allow users to create page layouts using text and pictures. Word processing Most people are familiar with word processing packages such as Microsoft Word or Writer (part of the Open Office suite). Standard features All word processing applications allow you to: enter and edit text, save, print, cut/copy/paste, check your spelling Text formatting Formatting text makes a document easier to read. You can:  change font type and size change the alignment of text (left, centre, right or justified)  bold text  underline text  italicise text   create bulleted or numbered lists Graphics software The range of pictures, drawings and images which can be produced by a computer are called graphics. The main types of graphics packages are painting, drawing, photo editing and CAD.  A painting application allows freehand drawing and colouring, usually with a mouse. Images made with drawing packages consist of lines, shapes and co-ordinates. Drawing packages are also known as vector drawing packages. Generally a drawing package offers many similar features to a painting. Vector graphics Vector graphics are based on mathematical relationships with control points that make up the image, information is not stored about each pixel. These points are connected by lines and curves called vector paths or vectors. Photo editing Photo editing software allows the user to edit and adjust photographs. Usually these photos come from a digital camera, but they could also be scanned from existing photos. Digital photos are bitmap images. Computer Aided Design (CAD) CAD packages are more sophisticated drawing packages. They are used by engineers, architects and designers to produce detailed design plans and technical drawings. CAD software offers all the features of standard drawing software but in addition may also offer:  greater accuracy (it is possible to work to within 1/72 of an inch)  objects and drawings can be created in 2D, 3D, 2D CAD and 3D CAD  images can be viewed from any angle   powerful scaling, rotation and reflection options libraries of engineering components which can be imported  links to packages to calculate costs Presentation software- is used to create presentations, quizzes, e-learning packages, information points and many other multimedia products. HTML Hyper Text Markup Language (HTML) is a basic programming language for building web pages. It uses a set of predefined tags that the web browser then interprets and renders/displays. HTML is typically written (or generated) in two ways: 1. 2. using a plain text editor, eg Notepad, Notepad++, TextPad etc using a What You See Is What You Get (WYSIWYG) editor, eg Dreamweaver, iWeb, SeaMonkey Composer etc Different types of browser Not all browsers render (display) web pages in the same way. Common browsers include: Internet Explorer, Firefox, Safari, Opera, Chrome ------------------------------------------------------------------------Programming languages A programming language is a specially written code used for writing applications. C++ and Java are examples of programming languages. These are known as high level languages because they have been developed to be a little like a human language. Operating systems An operating system is a system program that controls and organises the general operation of the computer. In any computer, the operating system:  controls the backing store and peripherals such as scanners and printers deals with the transfer of programs in and out of memory  organises the use of memory between programs    organises processing time between programs and users maintains security and access rights of users  deals with errors and user instructions allows the user to save files to a backing store  provides the interface between the user and the computer  In a larger computer such as a main frame the operating system works on the same principles. Computers can operate in many different ways requiring different and complex operating systems. What is a network? A computer network is a number of computers linked together to allow them to share resources. Networked computers can share hardware , software and data. Most computer networks have at least one server. A server is a powerful computer that provides one or more services to a network and its users. For example, file storage and email. There are two main types of network: Local Area Network (LAN) /Wide Area Network (WAN) A LAN covers a small area such as one site or building, eg a school or a college. A WAN covers a large geographical area. Most WANs are made from several LANs connected together. The Internet is a WAN. Viruses can spread to other computers throughout a computer network. There is a danger of hacking, particularly with wide area networks. Security procedures are needed to prevent such abuse, eg a firewall. The Internet is a worldwide system of interconnected computer networks. When you connect your computer to the Internet via your Internet Service Provider (ISP) you become part of the ISPs network, which is connected to other networks that make up the Internet. The World Wide Web The World Wide Web (WWW or Web for short) is the part of the Internet that you can access using a web browser such as Internet Explorer or Firefox . It consists of a large number of web servers that host websites. Each website will normally consist of a number of web pages. A web page can contain text, images, video, animation and sound. Most sites have a page that links the user to the other main areas of the site. This is called the homepage. Web pages are connected by hypertext links. When a link is clicked you will be taken to another page which could be on another server in any part of the world. Connecting to the Internet To connect to the Internet the following are needed: a computer, telephone line (cable being the exception), modem and/or router, an ISP (Internet Service Provider), Web browser, eg Internet Explorer, Firefox, Chrome, Safari, Opera etc. Internet Service Providers (ISPs) ISPs provide access to the Internet. Commonly used ISPs include Sky, Virgin and BT but there are many more. Most offer the same basic package of Internet access, email addresses and web space. You need a web browser to view web pages . The most widely used are Internet Explorer and Firefox. What can you do on the Internet? browse website, send and receive email, download media files, eg Mp3s or video files watch streamed video, eg YouTube, check your bank balance and make payments, buy goods from online shops, create, store, edit and share your documents using web-based applications, eg Google Docs, interact with friends on social networking sites, eg MySpace, Facebook etc, write a blog, signup to forums and discuss topics that interest you with like-minded individuals, game with friends, instant message family and friends, share photos and videos, complete free tutorials covering a wide range of subjects Electronic mail or email is a means of sending messages, text, and computer files between computers via the Internet. VIRUSES A virus is a simple program designed to cause harm to someone else's computer. A virus spreads by duplicating and attaching itself to other files. The extent of the damage depends on the virus. There are tens of thousands of viruses. Some virus damage is insignificant but inconvenient. Some virus damage is disastrous, putting the computer system out of action by erasing files or corrupting data. How do you get a virus? The primary source of infection these days are email@ attachments followed by illegal@ software and infected files from the Internet. If you have up to date anti-virus software installed this will immediately warn you of any infection. If not, there is usually no evidence of the virus and the user is not usually aware.