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GCSE ICT. For those that don’t know? My Name is Mr Hall I am Director of Learning for: ICT,(GCSE/OCR Nationals/Cambridge Nationals) Computer Science Business.

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Presentation on theme: "GCSE ICT. For those that don’t know? My Name is Mr Hall I am Director of Learning for: ICT,(GCSE/OCR Nationals/Cambridge Nationals) Computer Science Business."— Presentation transcript:


2 For those that don’t know? My Name is Mr Hall I am Director of Learning for: ICT,(GCSE/OCR Nationals/Cambridge Nationals) Computer Science Business Studies

3 What is the course made up of? B061-theory leading to external exam B062 –practical task-controlled assessment B063-theory leading to external exam B064-practical task controlled assessment

4 B061-theory leading to external exam Today we will be starting the theory associated with B061 ICT in today’s world

5 What you will learn The different types of ICT system and their uses The difference between hardware and software The hardware components of ICT systems The software used in ICT systems

6 The different types of ICT system and their uses ACTIVITY 1 Make a list of three items that you own or use regularly ( apart from your laptop or PC) – that use ICT and that you think you could not do without, and then write down what your life would be like without them.

7 ICT systems What is a computer? A computer is a programmable machine that follows a set of instructions. Early computers were mechanical with levers and cogs such as Charles Babbage’s Difference Engine which was an automated, mechanical calculator, large enough to fill a small room! Charles Babbage’s Difference Engine

8 ICT systems Babbage’s Analytical Engine was designed to be a general purpose computer but was never built, some believe, because the technology of the day was either not good enough or too expensive. Babbage was still working on the design when he died in 1871. A working model was built in 1992 and can be seen in the Science Museum in London. Watch video on this now

9 Digital computers Modern computers are not mechanical but are electronic and, while some analogue computers are used in universities for research, most computers now are digital. Computers can follow or execute a set of prewritten or recorded instruct ions, called a program, and respond to commands entered by a user. All computers used today have the same basic structure, although the way the components are arranged in the structure differs depending on the use to which the computer will be put. The photos show some examples of modern computers: Show brief history of computers video

10 Keywords Write out in the back of your GCSE text books the following keywords and their definitions Analogue Analogue signals are continually variable and even small fluctuations in the signal are important. Analogue systems use continuous ranges of values to represent information. Digital Digital signals have discrete values such as on/off, 1 or 0. Inbetween values are not used.

11 Personal computers Used in schools at home- you use for tasks such as writing reports or letters in a word- processor, doing calculations or data modelling in spreadsheets, photo and video editing or playing games. Often connected together on a network. The internet which also allows PC’s to be used for searching the World Wide Web, sending and receiving email messages, accessing chat rooms or instant messaging, writing blogs and using social networking sites. PC’s include netbooks, laptops, notebook computers, palmtops, desktop computers, tablet computers, PDAs and handheld computers. Smart phones can also carry out many of the tasks normally associated with personal computers with the added advantages of being able to keep in contact with friends by text message or telephone, having an inbuilt camera and playing music or video files or using applications when out and about away from home. Pc’s are often found in businesses and are used for general tasks such as running database management systems, business spreadsheets and for specialised business purposes such as computer-aided design and computer-aided manufacture such as making cars or televisions. Also, PC’s can be used for capturing and monitoring data received from sensors such as for recording temperatures and pressures of the weather.

12 Types of computer -Activity 2 For each of the different types of computer shown, write down some typical tasks that it would be most suitable for.

13 Other types of computer system Supercomputers and mainframes Embedded computers

14 Supercomputers Show titan super computer video

15 Mainframes Show mainframe video

16 Embedded computers

17 Activity 3 Use the internet to find out what is meant by ‘microcomputer’ and write down the names of two famous makes of microcomputer. http:// These provide explanations and descriptions of different types of computers.

18 More GCSE ICT Keywords… Write out the following keywords in the back of your text book. NB:You will need to learn these for revision for your exam Personal computer These include netbooks, laptops, notebook computers, palmtops, desktop computers, tablet computers, PDAs and handheld computers. Used for web searching, email, running applications, e.g. word-processing, spreadsheets, databases, and many other software applications in homes and offices Mainframe computer Large computers used in banks, insurance firms where very large amounts of data have to be processed quickly Supercomputer Very fast computers used in universities and other areas where complex calculations are needed and speed of calculation is important

19 Student task:gcse ict keywords Input Entering data into a computer system is input. Processing Data is converted it from one form to another. This is done by following a set of instructions and commands. Output When the results of processing are shown, this is output. Storage Data is kept or recorded while waiting to be used or for future use. Write out the following keywords in the back of your text book. NB:You will need to learn these for revision for your exam

20 Hardware Whatever the type of computer, it will always have the same basic hardware structure. There will also be all the components, nuts, bolts, screws, wiring and connectors, etc. to allow all the other components to work together but essentially a computer system consists of INPUTS, OUTPUTS, PROCESSING and STORAGE devices and data flows around the computer system from one to another as shown in the following diagram Nb copy this diagram into the front of your gcse ict text books

21 computer systems

22 A computer system input processing output Main or internal memory Backing storage Nb copy this diagram into the front of your gcse ict text books

23 Activity 4 Imagine that you have a list of your friends and want to keep it on your laptop. You carry out three tasks: 1.typing in the list, 2.sorting the list into alphabetical order of name 3.printing yourself a list to keep at home. Identify which of the three tasks is input, output and processing.

24 More components in a computer system.. A “NIC” A router Usb pen drive processor Mouse other devices will be present : components needed to connect the computer systems to others on a network.(nic) communication devices such as modems, network interface cards, routers and hubs. Other connection systems may also be present, e.g. USB interfaces. A hub

25 Student task Find out how a Network interface card works Find out how a router works Find out how a processor works Nb :Do not copy and paste and write out in your text books please so that you have a bank of notes to revise from

26 Keywords to write out… Network When computers are connected together so that they can share data and devices such as printers, they are said to be in a computer network. Interface This is where data is transferred between computer devices or between people and computers. USB interface The Universal Serial Bus interface was designed for use on personal computers to connect peripheral devices such as printers, keyboards and flash drives. It is now commonly used to connect other devices such as cameras. USB connections are also now found on many other devices such as PDAs, mobile phones and can also be used to charge batteries. Peripheral device Any device that is not actually part of the computer but is attached to a computer is called a peripheral device. Peripheral devices are seen as expanding the system and include scanners and printers. Nb Write out in the back of your gcse it text book

27 Activity 5 Find out what a ‘user interface’ is and what it is for. Write out the answer in the front of your book

28 Communication devices Modem This device encodes digital information on to an analogue signal. Often used to send digital data along ordinary telephone lines Network interface cards This device is often just called a network card or NIC; these provide the electronic circuitry for computers to communicate on a network Hub This device connects different networks sections Routers and switches These devices connect different networks and can be used to control where the data is sent. They are often found in homes and used for connecting to the internet USB interface This is used to connect a computer with another device such as a flash memory device Nb:Write the following notes into the front of your GCSE ICT text book Neatly-You will need to revise these

29 Processing data(1) Processing in computer systems is carried out by the Central Processing Unit(CPU). The CPU is a collection of electronic circuits that carry out, or execute, instructions either in a program or which are entered by the user and which make decisions using the instructions. The instructions have to be entered into the computer, stored in the computer’s main memory, or in some special memory actually inside the CPU itself, and the results output from the computer for every task that the computer is asked to perform. If the computer is switched off, then the data that users need to carry on with their work when it is switched back on and all the instructions needed to start and operate the computer have to be kept on a storage device. Nb:Please write out the above notes in your text books neatly

30 Processing data (2) If this data was not stored safely, the users would have to redo all of their work every time they switched off and restarted the computer; if the instructions to start the computer were not stored, then it wouldn’t restart! The components used for input include not only the familiar devices such as the mouse and keyboard found in personal computer systems but also more specialised input devices such as microphones designed to capture sounds, suck and puff switches used by those people unable to use their hands to manipulate a keyboard or mouse and the input devices used in computer games (such as wireless games controllers) and at supermarket terminals. Nb:Please write out the above notes in your text books neatly

31 Input devices Mouse Keyboard Microphone Barcode reader Chip and pin reader Web cam Sensor Remote control Nb:Write out the above outputs from a computer as they will come up in an exam

32 Student activity 6 Persons with physical disabilities often have difficulties using computers in schools to do their work. Find out about the specialised equipment and software that can help those people to use computers WEBLINK:

33 Output devices Speaker: produce sounds Monitor : This is the ‘screen’ or ‘display’ found on most computer systems and used to see the results of processing.Monitors are now nearly all LCD with flat screens, and the older-style ‘vacuum tube’ displays are no longer used. They are found in all shapes and sizes but ‘widescreen’ monitors are best for viewing movies Printer: Printers produce copies of the results on paper – this is ‘hardcopy’ Nb:Write out the above outputs from a computer as they will come up in an exam

34 Storage devices The storage of data and instructions is important because the CPU needs to be able to access the data or instructions quickly and easily and a user needs to be able to store their work for future use. A computer system has two types of storage for its data: 1.the main memory (also called internal memory(Ram and Rom),where the data that is being used, is about to be used or has just been used by the CPU is kept. 2. backing storage for longer-term storage of data. Nb:Write out the above outputs from a computer as they will come up in an exam

35 Activity 7 The size or capacity of storage devices is measured in bytes. (a) Find out what is meant by a ‘byte’. (b) Find out how many bytes make up a kilobyte (Kb), a megabyte (Mb) and a gigabyte (Gb). Nb:Write out the above outputs from a computer as they will come up in an exam

36 Rom memory used to store data or instructions that do not need to be changed ie the instructions needed when the computer is first switched on.(bootstraploader for example) When a computer is first switched on, the CPU does not know what to do so there are a few instructions stored in ROM that tell it where and how to find the instructions to get started. ROM is a type of memory from which data can be read but which cannot usually be changed or erased such as the data that a computer needs when starting up or the instructions in a washing machine. users must not be able, or have any need, to alter these instructions because if they do then the machines would not work. Also, ROM does not lose its data when the electrical power is switched off. It is said to be nonvolatile, i.e. keeps its data without the need for electrical power. Special types of ROM can have the data changed, e.g. an EEPROM (Electrically Erasable Programmable Read Only Memory) can be erased and reprogrammed and there are other types that are used for specialised purposes such as storing the configuration details of a router. Sometimes, the initial startup instructions of a computer (called the BIOS) are stored in EEPROMs so that they can be updated in the future. Write out the following notes in your GCSE Text books

37 memory

38 Ram memory Show how ram memory works video RAM does not keep any data if its power supply is switched off (it is said to be volatile). Data in RAM can be accessed much faster than in ROM. More importantly, the data in RAM can be accessed quickly wherever it happens to be stored. RAM is used to store the data and instructions such as the operating system that the CPU is currently using, and the data and software applications being used by the user. When switched on, the instructions stored in its ROM will be used to start it(bootstraploader) and load the operating system from the hard disk into its RAM. When it is ready for use, a user may start an application like a web browser and this will also be loaded from the hard disk into RAM ready for use. Write out the following notes in your GCSE Text books

39 Ram memory

40 Memory keywords ROM Read Only Memory is a permanent storage area of memory that does not lose its data when power is turned off – it is said to be nonvolatile. Data can only be read from ROM, not written to it. RAM Random Access Memory loses its data when power is turned off – it is said to be volatile – but can be written to as well as read from. BIOS The Basic In Out System that is needed to tell the computer what to do on startup Write out the following notes in your GCSE Text books

41 Different types of memory storage Flash memory Removable storage media(cd/cdrw/dvdr/dvdrw/blueray etc)

42 ©2003 The McGraw-Hill Companies 5.3 Storage Devices Storage device stores information to be recalled and used at a later time Storage device consists of: Storage medium Storage device Three major technology types for information storage: Magnetic Optical or laser Flash memory  SimNet Concepts Support CD: “Storage Concepts”

43 ©2003 The McGraw-Hill Companies Storage Medium Terms – Byte – Kilobyte (KB) – Megabytes (MB) – Gigabytes (GB) – Terabytes (TB) – Petabyte (PB) – Exabyte (EB) = 8 bits ≈ 1 Thousand Bytes ≈ 1 Million Bytes ≈ 1 Billion Bytes ≈ 1 Trillion Bytes ≈ 1 quadrillion Bytes ≈ 1 quintillion Bytes

44 ©2003 The McGraw-Hill Companies Magnetic and Optical Storage p. 5.142 & 5.144 Fig. 5.13 & 5.16

45 ©2003 The McGraw-Hill Companies Magnetic Storage Devices: Internal Magnetic Hard Disk Magnetic storage devices can be either internal or external Internal magnetic hard disks are fixed inside the system unit External magnetic hard disks are portable  SimNet Concepts Support CD: “Removable Disks”

46 ©2003 The McGraw-Hill Companies Magnetic Storage Devices: Internal Magnetic Hard Disk Internal hard disk is a magnetic storage device with One or more thin platters that store information sealed inside the disk drive. Read/write heads access the information on surface Heads read information while copying it from disk to RAM Heads write information when copying it from RAM to disk

47 ©2003 The McGraw-Hill Companies Magnetic Storage Devices: External Magnetic Hard Disk External hard disks are magnetic storage media which are portable storage units that you can connect to your computer as necessary Great for backup storage devices Ability to transport your hard disk from one computer to another

48 ©2003 The McGraw-Hill Companies Hard Drives Long term storage system and application software Operating system and application software are copied from the hard disk to memory Capacity measured in gigabytes

49 ©2003 The McGraw-Hill Companies Floppy Disks and Zip Disks Removable magnetic storage media come in two basic types: – Traditional floppy disks – Zip disks These storage media are useful for: – Storing files for backup or security purposes – Transferring files from one computer to another

50 ©2003 The McGraw-Hill Companies Removable Magnetic Storage: Floppy Disk Floppy Mylar disk – Housed inside a hard plastic casing – Thin, flexible plastic disk 3.5 inch floppy disks – also called floppies, diskettes, floppy disks – Holds about 1.44 megabytes of information High-capacity disks – Zip® disk p. 5.144 Fig. 5.15

51 ©2003 The McGraw-Hill Companies Removable Magnetic Storage: Zip Disk High capacity plastic platter disk – Called removable hard disks – Provide a higher storage capacity than Mylar disks Example - Zip® disk with capacity of 100MB, 250MB, and 750MB

52 ©2003 The McGraw-Hill Companies Optical Storage CDs DVDs Both are optical storage and have three formats: – Read-only – Write-once – Read-and-write

53 ©2003 The McGraw-Hill Companies Optical Storage Media Read-Only  CD-ROM  DVD-ROM One-Time Writable  CD-R  DVD-R  DVD+R Fully Read-and-Write  CD-RW  DVD-RW or DVD+RW or DVD-RAM  SimNet Concepts Support CD: “CDs and DVDs”

54 ©2003 The McGraw-Hill Companies Flash Memory Cards Flash memory cards have high- capacity storage laminated inside a small piece of plastic Flash flash memory cards do not need a drive with moving parts to operate

55 ©2003 The McGraw-Hill Companies Flash Memory Talk CompactFlash (CF) xD-Picture Card (xD) SmartMedia (SM) Card SecureDigital (SD) card and MultiMediaCards (MMC) Memory Stick Media

56 ©2003 The McGraw-Hill Companies Flash Memory Card Readers Some devices have flash memory slots into which you slide your flash memory card Other devices can use an external flash memory card reader in order to transfer information A flash memory drive is a flash memory storage medium for a computer that is small enough to fit in your pocket and usually plugs directly into a USB port

57 15-57 Networking Computer network A collection of computing devices that are connected in various ways in order to communicate and share resources Usually, the connections between computers in a network are made using physical wires or cables However, some connections are wireless, using radio waves or infrared signals

58 15-58 Networking The generic term node or host refers to any device on a network Data transfer rate The speed with which data is moved from one place on a network to another Data transfer rate is a key issue in computer networks

59 15-59 Networking Computer networks have opened up an entire frontier in the world of computing called the client/server model Figure 15.1 Client/Server interaction

60 15-60 Networking File server A computer that stores and manages files for multiple users on a network Web server A computer dedicated to responding to requests (from the browser client) for web pages

61 15-61 Types of Networks Local-area network (LAN) A network that connects a relatively small number of machines in a relatively close geographical area

62 15-62 Types of Networks Various configurations, called topologies, have been used to administer LANs – Ring topology A configuration that connects all nodes in a closed loop on which messages travel in one direction – Star topology A configuration that centers around one node to which all others are connected and through which all messages are sent – Bus topology All nodes are connected to a single communication line that carries messages in both directions

63 Types of Networks A bus technology called Ethernet has become the industry standard for local-area networks Figure 15.2 Various network topologies 15-10

64 15-64 Types of Networks Wide-area network (WAN) A network that connects two or more local-area networks over a potentially large geographic distance Often one particular node on a LAN is set up to serve as a gateway to handle all communication going between that LAN and other networks Communication between networks is called internetworking The Internet, as we know it today, is essentially the ultimate wide-area network, spanning the entire globe

65 15-65 Types of Networks Metropolitan-area network (MAN) The communication infrastructures that have been developed in and around large cities

66 15-66 So, who owns the Internet? Well, nobody does. No single person or company owns the Internet or even controls it entirely. As a wide-area network, it is made up of many smaller networks. These smaller networks are often owned and managed by a person or organization. The Internet, then, is really defined by how connections can be made between these networks.

67 15-67 Types of Networks Figure 15.1 Local-area networks connected across a distance to create a wide-area network

68 15-68 Internet Connections Internet backbone A set of high-speed networks that carry Internet traffic These networks are provided by companies such as AT&T, GTE, and IBM Internet service provider (ISP) A company that provides other companies or individuals with access to the Internet

69 15-69 Internet Connections There are various technologies available that you can use to connect a home computer to the Internet – A phone modem converts computer data into an analog audio signal for transfer over a telephone line, and then a modem at the destination converts it back again into data – A digital subscriber line (DSL) uses regular copper phone lines to transfer digital data to and from the phone company’s central office – A cable modem uses the same line that your cable TV signals come in on to transfer the data back and forth

70 15-70 Internet Connections Broadband A connection in which transfer speeds are faster than 128 bits per second – DSL connections and cable modems are broadband connections – The speed for downloads (getting data from the Internet to your home computer) may not be the same as uploads (sending data from your home computer to the Internet)

71 Packet Switching To improve the efficiency of transferring information over a shared communication line, messages are divided into fixed- sized, numbered packets Network devices called routers are used to direct packets between networks Figure 15.4 Messages sent by packet switching 15-18

72 15-72 Open Systems Proprietary system A system that uses technologies kept private by a particular commercial vendor One system couldn’t communicate with another, leading to the need for Interoperability The ability of software and hardware on multiple machines and from multiple commercial vendors to communicate Leading to Open systems Systems based on a common model of network architecture and a suite of protocols used in its implementation

73 15-73 Open Systems The International Organization for Standardization (ISO) established the Open Systems Interconnection (OSI) Reference Model Each layer deals with a particular aspect of network communication Figure 15.5 The layers of the OSI Reference Model

74 15-74 Network Protocols Network protocols are layered such that each one relies on the protocols that underlie it Sometimes referred to as a protocol stack Figure 15.6 Layering of key network protocols

75 15-75 TCP/IP TCP stands for Transmission Control Protocol TCP software breaks messages into packets, hands them off to the IP software for delivery, and then orders and reassembles the packets at their destination IP stands for Internet Protocol IP software deals with the routing of packets through the maze of interconnected networks to their final destination

76 15-76 TCP/IP (cont.) UDP stands for User Datagram Protocol – It is an alternative to TCP – The main difference is that TCP is highly reliable, at the cost of decreased performance, while UDP is less reliable, but generally faster

77 15-77 High-Level Protocols Other protocols build on the foundation established by the TCP/IP protocol suite – Simple Mail Transfer Protocol (SMTP) – File Transfer Protocol (FTP) – Telnet – Hyper Text Transfer Protocol (http)

78 15-78 MIME Types Related to the idea of network protocols and standardization is the concept of a file’s MIME type – MIME stands for Multipurpose Internet Mail Extension – Based on a document’s MIME type, an application program can decide how to deal with the data it is given

79 15-79 MIME Types Figure 15.7 Some protocols and the ports they use

80 15-80 Firewalls Firewall A machine and its software that serve as a special gateway to a network, protecting it from inappropriate access – Filters the network traffic that comes in, checking the validity of the messages as much as possible and perhaps denying some messages altogether – Enforces an organization’s access control policy

81 15-81 Firewalls Figure 15.8 A firewall protecting a LAN

82 15-82 Network Addresses Hostname A unique identification that specifies a particular computer on the Internet For example

83 15-83 Network Addresses Network software translates a hostname into its corresponding IP address For example

84 15-84 Network Addresses An IP address can be split into – network address, which specifies a specific network – host number, which specifies a particular machine in that network Figure 15.9 An IP address is stored in four bytes

85 15-85 Domain Name System A hostname consists of the computer name followed by the domain name is the domain name – A domain name is separated into two or more sections that specify the organization, and possibly a subset of an organization, of which the computer is a part – Two organizations can have a computer named the same thing because the domain name makes it clear which one is being referred to

86 15-86 Domain Name System The very last section of the domain is called its top- level domain (TLD) name Figure 15.10 Top-level domains, including some relatively new ones

87 15-87 Domain Name System Organizations based in countries other than the United States use a top-level domain that corresponds to their two-letter country codes Figure 15.11 Some of the top-level domain names based on country codes

88 15-88 Domain Name System The domain name system (DNS) is chiefly used to translate hostnames into numeric IP addresses – DNS is an example of a distributed database – If that server can resolve the hostname, it does so – If not, that server asks another domain name server



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