GCSE ICT Full Course - Computer Components

• CPU - contains all instructions required by computer to function and perform operations (like a 'brain')
• Main/internal memory - two types (ROM and RAM)
• Motherboard - ain circuit board with slots to plug in other boards; contains built-in sound and video controllers
• Sound card/video card - controls sound/video execution in computers; default in motherboard can be replaced for better quality
• Backing storage - storage holding data and programs when computer is switched off; examples include hard drives (main backing storage on desktop computer), memory stick (small stores to transfer data between computers), DVDs/CDs (for permanent storage of data such as music/video)
• Wireless card - allows computer to connect to any other wireless device to share/transfer files or connect to the internet
• Dongle - device that is connected to a computer to allow access to wireless broadband or use of protected software

• Software freeze - system stops responding to software commands; likely if computer is low on RAM/hard disk space or many packages open simultaneously; press Ctrl + Alt + Del to shut package down safely
• Error dialogue - frequent software freezes/error dialogues may need to be shown to technician; if specific software package consistently displays error messages uninstall and reinstall it
• Full storage - full storage space causes computer to slow down and freeze often; delete unwanted files; archive those which are rarely needed but do not want to delete (copying to removable memory e.g. USB)
• Paper jam - caused if paper incorrectly loaded; switch off printer before removing jam, reload with new paper

• Uninstalling software - uninstall software which freezes/causes problem/unnecessarily uses RAM space

  è Registry

  File on computer storing important information about how it is set up, must only be altered by experts

• OMR - reads data from a sheet (e.g. pencil marks on a sheet as used in 11+ examinations)
• OCR - scans documents/PDF files and converts to text
• RFID - uses electromagnetic waves to track tags attached to devices

Consider entry of data in ways which are:

• User-friendly
• Efficient
• Securely
• In large volumes
• Efficiently

Actuator - device used to move/control mechanism/computer system

Plotter - device plotting an image based on commands from a computer

• Internal - ROM (Read Only Memory) contains instructions which are loaded during boot up, but computer cannot write data to it; RAM (Random Access Memory) used whilst computer is operating holding programs and data whilst computer is switched on, when power is switched off data held in RAM is lost, increasing size of RAM improves computer performance; ROM is permanent and RAM is temporary
• Printer buffer - stores 'jobs' sent to printer until it is ready to execute

• CD-ROM and DVD-ROM
• CD-R and DVD-R
• CD-RW and DVD-RW
• BD-R
• Hard disks (fixed and removable)
• Magnetic cartridges
• Flash memory (cameras and MP3 players)
• Solid state disks

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.

Carried out by the use of interviews, questionnaires and observation in the analysis of new or existing systems to determine whether or not the proposed system is suitable

• Feasibility study
• Analysis
• Design
• Implementation
• Testing
• User training and documentation
• Evaluation and monitoring
• Maintenance
• This is an iterative process (for arriving at a decision or a desired result by repeating rounds of analysis or a cycle of operations)

• Input - input of data via an input device
• Processing - input data manipulated to produce meaningful information
• Storage - information is stored in the system to be used at a later date
• Output - output of information (sorted data) via an output device
• Feedback - output of a system fed back into system to influence input

• Visual checks - "proof-reading"
• Double entry - data entered twice (possibly by different operators) and compared, a warning sign given if they do not match
• Range check - entered data must fall within a specified range
• Type check - ensures correct type of data is entered (e.g. numerical, text, etc.)
• Presence check - self explanatory
• Length check - self explanatory
• Look-up list - self explanatory
• Check digit - uses algorithms (e.g. the ISBN-10 numbering system for books makes use of 'Modulo-11' division. In modulo division, the answer is the remainder of the division. For example 8 Mod 3 = 2 i.e. the remainder of dividing 8 by 3 is 2.)

Identification of humans by fingerprints/patterns on the retina, for instance

Files transferred using file-sharing websites and VLEs e.g. importation, exportation, file attachments and photo sharin websites

Compression techniques: zip and unzip

Consider effectiveness of:

• Time constraints
• Convenience
• Quality of presentation
• Range of facilities
• Versatility
• Transferability of information into other formats
• Cost
• Internet speed

• Operating systems - control file operations (e.g. save, load, delete, copy and rename)

Types of operating systems

• Interactive - allows user to interact directly with OS whilst one or more programs are running(either GUI or command-line e.g. MSDOS)
• Multi-tasking - allows several tasks to be performed simultaneously
• Real time - designed to handle input data within a guaranteed time (latency) (e.g. micro-seconds for applications such as real-time speech processing or it slower for less time intensive tasks)
• Multi-user - several users can access simultaneously

• Applications software - carries out user-related tasks to solve problems

Advantages

• High budgets
• Restriction of sharing of code (as this is considered theft)

Disadvantages

• Vendor lock-in of code
• Requirement to upgrade
• Restriction of user freedom (i.e. cannot be used commercially)
• Users cannot manipulate code

Advantages

• Low cost
• Software can be shared freely by users
• Security problems detected by other users through forums etc.

Disadvantages

• Insecure - hackers have access to source code to alter illegally
• Breach of patents as anyone can access source code
• Unreliable/poorer quality

• Applications hosted on internet rather than downloaded to hard drives or RAM

Advantages

• Reduced admin costs as there is no need to install and maintain
• Instantly available - no download required
• Improved access - can be accessed wherever internet is available
• No need to download upgrades/newer versions

Disadvantages

• Security issues - hackers may be able to access
• Risk of host corrupting/malfunctioning
• May become expensive due to monthly subscriptions

Essentially word processors deal with text documents whereas DTP deals with text and graphic publications

Word processing software: letters, essays, memos and reports

DTP: posters, leaflets, flyers, brochures, catalogues, magazines and business cards

• Hotspots - image/piece of text with a link (image map contains more than one hotspot)
• Marquee - allows you to select rectangles, ellipses, lines and columns
• Flash tools - allows you to integrate interactive features and animations
• RSS feed - used to publish frequently-updated works such as news, radio programmes and video
• HTML - text file containing tags providing information regarding how information is to be displayed

User can get answers to such questions so that they can better consider altenatives

• Database - collection of stored data organised into files or data tables
• Flat file - only one table of data
• Relational - data stored within several tables with necessary links within them present
• Relational databases reduce data redundancy (the need for duplicate data in the table so time is wasted retyping the same data so more data is stored than needs be making database larger)
• Data can be extracted from a database to produce many different types of reports and data from different files in a database can be used to produce a single report

a website that brings information together from diverse sources in a uniform way which apart from search engines offer other services such as e-mail, news, stock prices, information, databases and entertainment, for instance Yahoo and iGoogle

• Provide internet access
• Offer storage on their server where you can store your website
• Offer email facilities
• Instant messaging where you can send messages to others whilst they are online
• Access to online shopping
• Access to new, sport, weather, financial pages etc.

POP (Post Office Protocol) - used when you want to store email on your own computer

SMTP (Simple Mail Transfer Protocol) - used when outgoing mail is transmitted across internet

Advantages

• Helps build online communities especially if lonely/disabled
• Allows you to befriend friends of your friends
• Useful for expressing opinions on matters
• Allows you to find out what people and organisations you care about are doing realtime
• Used to exchange photographs with friends and family

Disadvantages

• Images may be posted on inappropriate sites
• Stalkers can identify you or find out your details
• Addiction may result
• Image may be edited and spread without consent
• Employers may find information about you
• Rumours can spread quickly

• Readings taken regularly over a period of time using sensors

Types of sensors

• Temperature/heat (in school experiments or in domestic central heating systems)
• Light (automatic lighting/investigating how light levels affect plant growth)
• Sound (noise disputes)
• Pressure (air pressure/depth of liquid/hydraulic systems)
• Humidity (meteorology)
• PIRs (Passive Infrared Sensors) (detect movement in air fresheners/burglar alarms)

Advantages

• Readings can be taken 24/7
• Readings taken at exactly the right time
• Sensors can be situated in inhospitable areas
• Cheaper in terms of no employees required to take readings
• No human error - more accurate

Disadvantages

• Equipment error/malfunction can cause incorrect readings
• Possibility of zero error
• Equipment is expensive

• Input (sensors)
• Process (computer deciding which action to taje when receiving data from sensors, sending signals to output)
• Output (e.g. lights, controlled by control signals)
• In a control-feedback loop output from the system directly affects the input; used to keep conditions steady or customise output according to circumstances

• Concerns personal data (alive, more personal than name/address e.g. medical records, criminal history etc.)
• Purpose: to protect individuals against misuse of data

Rights and responsibilities of the data subject and holder: 

• Anyone handling personal data must register with the Information Commissioner and state what they intend to do with the data
• Anyone can apply to see the personal data held about them
• Data must be kept secure and up-to-date
• If data is processed unlawfully the data subject may claim compensation

Exemptions (free from obligation) from the DPA:

• When data is being held for personal, family, household affairs or recreational use
• Where data is used for producing accounts, wages and pensions
• Where data is used for prevention or detection of crimes
• Where data is held by a sports or recreation club that is not a limited company
• Where data is used for medical records or social worker reports

• Accountability (clear management responsibility of data)
• Visibility (of data subject to data held about them)
• Consent (of data subject)
• Access (of data subject to data held about them)
• Stewardship (protection of data by organisations through its life span)
• Responsibility (of data handling)

Personal data should be:

• Processed fairly and lawfully
• Obtained only for specified purposes
• Adequate, relevant and and not excessive
• Accurate and kept up-to-date
• Not kept for longer than is necessary
• Processed in accordance with the rights of the data subject
• Kept secure
• Not transferred to a country outside the EU unless they have comparable data laws

Software:

• Creating user accounts
• Use of authentication/log on details (user IDs and appropriate passwords)
• Keeping passwords/PINs secure
• Regular changing of passwords
• Levels of access
• Security questions
• Image/code recognition
• Selective drop-down menus

Physical

• Locks
• Clamps
• Alarms/surveillance
• Location of equipment

• Purpose - prevention of hacking
• Hacking - when unauthorised access is gained to a system
• Anti-hacking measures - firewall, intrustion detection (monitors network/system activities for malicious activity)
• Virus - a relatively simple programme written with the intent to cause nuisance/inconvenience
• Anti-virus measures: anti-virus and anti-spyware software; treating files from unknown sources with caution

• Law where if copyright is held by the owner copying of their work is illegal; avoid plaigarism

Moral/ethical implications of file sharing:

• Artists can go bust if work is illegally downloaded
• Young children can access unsuitable material
• It is unfair on the owner

• An ISP can deny services in specific circumstances

Issues

• Excessive heat/temperature
• Management of electrical systems/computers
• Hygiene

Preventative measures

• Air conditioning
• Not overloading electrical sockets
• No trailing wires
• Checking and mending/replacing malfunctioning equipment
• Blinds to block out direct sunlight
• Use of fire extinguishers

• Automated production lines with fewer workers and more standard products
• Automated stock control ensuring stock is kept at correct levels
• Internet shopping reducing need for 'high street' premises
• Creation of new industries
• Globalisation

• Size of business/workforce
• Location of offices/manufacturing plant
• Different ways of working
• Different capabilities of people and computers
• Homeworking/teleworking
• Hot desking (involves multiple workers using a single physical work station or surface during different time periods)
• Mobile computing
• Flexible hours
• Job satisfaction
• Increased unemployment
• Monitoring of employees at work

• Email-flaming/spam
• Intentional theft
• Plagiarism
• Information corruption

• Screen filters
• Ergonomic keyboards
• Screen magnifiers
• Voice recoders
• Spoken text
• Adjustable-height desk

• Collaboration - recursive (repeated) process where two or more parties (people, organisations or countries) work together towards meeting common targets

Collaborative working processes

• Checking against agreed group plans/organising work schedules
• Identifying issues/risks
• Ensuring consistent layout (house style)
• This is an iterative process to ensure fitness for purpose
• Communicating with others
• Project management: each worker plays a key role in completing work to a deadline

Video/teleconferencing

• Based on two or more locations being able to interact with others via multi-way video/tele and audio transmissions simultaneously

Collaborative software tools

• Share workspaces; communications tools; project management and workflow tools

Measures ensuring secure data transfer:

• File naming conventions and version control
• Read/write file permissions

Safeguards:

• Encryption
• Firewalls
• Back-ups
• Secure sites

Advantages

• Working from home (allowing for:)
• More time spent on tasks
• Reduced travelling costs
• Protection of the environment (reducing carbon emissions)
• Tailored working conditions
• Does not prevent distractions from affecting work
• Removes regular social interaction with work colleagues

Disadvantages

• Limits face-to-face contact with colleagues for reduced interaction regarding work
• May lead to isolation

Main circuit board with slots to plug in other boards; contains built-in sound and video controllers

Controls sound/video execution in computers; default in motherboard can be replaced for better quality

Storage holding data and programs when computer is switched off; examples include hard drives (main backing storage on desktop computer), memory stick (small stores to transfer data between computers), DVDs/CDs (for permanent storage of data such as music/video)

Allows computer to connect to any other wireless device to share/transfer files or connect to the internet

A device that is connected to a computer to allow access to wireless broadband or use of protected software

Frequent software freezes/error dialogues may need to be shown to technician; if specific software package consistently displays error messages uninstall and reinstall it

Full storage space causes computer to slow down and freeze often; delete unwanted files; archive those which are rarely needed but do not want to delete (copying to removable memory e.g. USB)

Caused if paper incorrectly loaded; switch off printer before removing jam, reload with new paper

Advantages

• Reduced admin costs as there is no need to install and maintain
• Instantly available - no download required
• Improved access - can be accessed wherever internet is available
• No need to download upgrades/newer versions

Disadvantages

• Security issues - hackers may be able to access
• Risk of host corrupting/malfunctioning
• May become expensive due to monthly subscriptions

Uninstall software which freezes/causes problem/unnecessarily uses RAM space

è Registry

File on computer storing important information about how it is set up, must only be altered by experts

Advantages

• Readings can be taken 24/7
• Readings taken at exactly the right time
• Sensors can be situated in inhospitable areas
• Cheaper in terms of no employees required to take readings
• No human error - more accurate

Disadvantages

• Equipment error/malfunction can cause incorrect readings
• Possibility of zero error
• Equipment is expensive

Radio frequency identification - uses electromagnetic waves to track tags attached to devices

• Excessive heat/temperature
• Management of electrical systems/computers
• Hygeine

Scans documents/PDF files and converts to text

Data can be extracted from a database to produce many different types of reports and data from different files in a database can be used to produce a single report

Device used to move/control mechanism/computer system

• Images may be posted on inappropriate sites
• Stalkers can identify you or find out your details
• Addiction may result
• Image may be edited and spread without consent
• Employers may find information about you
• Rumours can spread quickly

Stores 'jobs' sent to printer until it is ready to execute

Readings taken regularly over a period of time using sensors

• Interactive - allows user to interact directly with OS whilst one or more programs are running (either GUI or command-line e.g. MSDOS)
• Multi-tasking - allows several tasks to be performed simultaneously
• Real time - designed to handle input data within a guaranteed time (latency) (e.g. micro-seconds for applications such as real-time speech processing or it slower for less time intensive tasks)
• Multi-user - several users can access simultaneously

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