CXC Information Technology Section One Revision Does not include binary arithmetic & Information Processing (Unit 5) What you’ll need Past paper questions: 2010 – 2014 Mr. Alleyne website: www.it.anthonyalleyne.com Constant revision is critical

Unit One - Basic components CPU: ALU and control unit Primary Storage: RAM, ROM etc. Secondary Storage: diskettes, CDs etc. Input devices: mouse etc. Output devices: monitor etc.

Primary Memory Bistable device: Only has two states, on and off (1 and 0) Read Only Memory: boots up the PC. Non volatile Random Access Memory: used while PC is working. Volatile (needs power) PROM: Programmable ROM EPROM: Erasable programmable ROM

Secondary memory Magnetic tape: uses sequential access. Good for backing up Floppy disk: uses direct access. Hard disk (drive): fixed or moving head Optical disk: CD / DVD Memory cards: Cameras, phones etc. USB (flash) drives: Portable USB – Universal Serial Bus

Other terms Track: Circles around disk’s surface Sector: One part of the circle Cluster: Adjacent sectors Buffer: extra memory space when copying data Sequential access: data stored in the order it’s received Direct access: data stored in any order Hard drive interfaces SCSI, IDE, SATA and USB (external hard drive)

Units of storage Bit: smallest unit of storage Byte: 8 bits Kilobyte: 1024 bytes Megabyte: 1024 kilobytes Gigabyte: 1024 megabytes Terabyte: 1024 gigabytes Word / Word size: size of a single instruction. (i.e. How much data a CPU can handle at one time.)

Input Devices Mouse Keyboard Joystick Microphone Scanner Webcam Graphics pad/tablet Barcode reader Light Pen Touch terminal Optical Mark Reader Optical Character Reader Magnetic Ink Character Reader Biometric System Sensor

Output Devices Monitor Projector Speakers Headphones Printers Plotter Microfilm

Output terms Resolution Pixel Quality Hard copy Soft copy Human readable Machine readable

Printers Dot matrix Line IMPACT Daisy Wheel Inkjet Laserjet Thermal NON -IMPACT

Software Application Software Systems software Custom written (for one purpose only) Specialised (for a group/category: ACCPAC) General purpose (for everyone: Word, etc.) Integrated (more than one programme: Office) Systems software Operating system (Windows, Linux, Unix, OSX)

Operating System functions File management Resource management User management Input – Output management Security Memory Maintenance (defrag, format, cleanup)

Interfaces and terms Command line interface: command must be typed. Difficult to use Menu driven interface: command selected from a menu: Options limited Graphical user interface: Like Windows Pop up and pull down menus Icons Taskbar

Processing – how does the CPU do it? Batch: collect in groups, then process Online: processed once CPU is on Real-time: processed immediately Timesharing: processes many jobs, a piece at a time

Computer specifications CPU: 2.4 Ghz 64-bit Pentium 4 Hard drive: 1TB 7200 rpm SATA Memory: 1GB DDR-RAM OS: Windows 7 Home edition Ports: 6 USB ports, 1 firewire port Optical drive: 54X DVD/RW drive Slots: 1 AGP slot Video: Radeon 64MB video card

Extranet: private with some outside access Networks Local area network: small area Metropolitan area network: medium sized area Wide area network: large area (e.g. continent) Internet: public Intranet: private Extranet: private with some outside access

Networking terms Coaxial cable (antenna) Bandwidth (how much) Twisted pair (phone/ADSL) Fiber optic cable (light) Infrared Bluetooth Wi-fi Hotspot Bandwidth (how much) Speed / Rate (how fast) Voiceband (phone line) Broadband (ADSL) Wireless Simplex (1 way only) Half duplex (1 way at a time) Full duplex (both ways)

The internet & terms WWW Web page, site, browser HTTP, HTML FTP URL Upload vs. download Search engine IRC E-mail Bulletin board Newsgroup Blogging E-commerce E- learning VoIP

Data Security Passwords Encryption Access restrictions Firewalls Virus protection Backup & recovery Archiving Locks Security guards Fireproof cabinets Waterproof cabinets Biometric systems

Data misuse Information Theft Copyright infringement Eavesdropping Invasion of privacy Computer fraud Propaganda

Current trends Expert Systems Computer Aided Manufacturing (and Design) Teleconferencing Telemarketing Robots Laser technology

Jobs Technician Software / computer engineer Database / Network administrator File librarian Web master / web developer Software trainer (teacher) Systems analyst Programmers

Information Processing Anyone can use computers for the following Communication Research Publishing and Printing Storage Data processing and analysis