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Components of a computer system.

• CPU; (central processing unit). Modern computers often have multiple-core (e.g. dual/quad) processors, allowing the computer to work faster.
• Microprocessor; to perform all the instructions and calculations required for the computer to function. It comes in the form of a silicon chip.
• Motherboard; is a PCB (printed circuit board) which holds many of the system’s vital components, including the CPU and dedicated sound cards and video cards.

Internal Memory.

• ROM; (read-only) contains the commands that are designed to be read only, such as the system’s boot-up instructions.
• RAM; (random-access) holds the data needed by the programs currently in use.
  The data is stored in the memory temporarily and lost when the PC is switched off.

Input and Output Devices.

• Input devices allow users to enter data into a system. Examples include keyboards and scanners.
•  Output devices allow the system to transfer, or display (output) data. Examples include printers and monitors

Types of Computer.

• Personal Computer; these are general-purpose computers and include desktop computers, laptops, netbooks, notebooks, tablets, PDAs, smartphones and other handheld devices. Typical software applications include word processing, spreadsheets, databases, e-mail clients, playback and gaming.
• Mainframe; these are power computers mostly used by large organisations for processing and storing large amounts of information. Commonly used for financial transaction processing.
• Supercomputer; these perform calculations faster than any other type of computer. For this reason they are best suited to perform complex calculations for simulation and modelling, often in the field of scientific research.  

Hardware and Software.

• Hardware refers to the actual parts of a computer system. These include processing, input, output and storage devices as mentioned above.
• Software provides the instructions that the system needs in order to carry out tasks required by the user.
• Hardware is physical (it can be touched), whereas software isn’t (it consists of program code and data files)
• Hardware and software work together. Hardware needs software to translate the user’s actions into instructions that it can understand and execute. Without hardware, this software cannot be used at all.

User Interfaces.

These provide a platform for interaction between humans and computer systems.

Types

• Graaphical user interface (GUI)
• Command Line
• Direct Neural

Graphical user interface.

WIMP; means Windows, Icons, Menus and Pointers

Advantages

• Easy to use
• Look good

Disadvantages

• Use alot of computer power

Command Line Interface

This involves the user entering text commands.

 Advantages.

• They are quick.
• They don't need much memory or power to run.

Disadvantages.

• The user has to know the commands to be able to use these interfaces

Direct Neural Interface.

A direct communication pathway between the brain and an external device.

Direct-neural interfaces are often aimed at assisting, combining or repairing human cognitive or sensory-motor functions.

Embedded Systems.

these are computer microchips found in electrical applicances, such as washing machines, microwaves or DVD players.

Advantages.

• they can make the appliance easier to use
• They often help to save energy
• can be programmed to perform repetitive tasks automatically

Disadvantages.

• they can make appliances more expensive
• can be difficult to repair
• sometimes using their advanced features can be too complicated for the average user.

Input devices.

•  Mouse ;Pointing device allowing movement of a cursor on a computer screen.
• Joystick; Stick device for rotation movement, designed for gaming use.
• Interactive Whiteboard; Similar to a large touch screen, used in education and within business as a presentation tool, using your finger or light pen to view or input data.
• Barcode Scanners; Electronic device for scanning printed barcodes which contain information about goods.
• OMR – Optical Mark Recognition; Fast data entry for high volume data. Widely used for marking multiple choice exams, market research questionnaires and the National Lottery where answer/choice is indicated by black pencil mark against choice.
• Light Pen; Light sensitive device for touching on a screen to select an instruction

Output devices

• Speakers; Outputs sound waves that are heard by the user.
• MP3 player / iPod; Portable digital device which outputs audio, usually via headphones although some have built-in speakers.
• Sound and Video card ; Both connected to the motherboard to enable output of audio and video. Many of today’s sound and graphics cards are capable of outputting High Definition audio and video.
• Actuators / Robotic Arms; An actuator is the moving part of an item such as a robot. Using the controls from a computer the actuator responds accordingly, e.g. raises the robotic arm in a car manufacturing plant.
• Computerised Motors; These are motors controlled by a computer, e.g. if a computer server room is getting too hot the computer would instruct the air conditioning motor to turn on, therefore giving an output of cold air.

Inkjet Printers.

for Printing your schoolwork at home.

Advantage.

• Cheap and good quality printing

Disasdvantage.

• Cartridges can be expensive

Laser Printer.

Printing large quantities of work at one time.   Advantages.

• Printing large quantities of work at one time

  Disadvantages.

• Can be expensive to buy and run

Plotter.

Printing large road maps. Advantages.

• Good at printing in colour and in detail

Disadvantages.

• Can be expensive to buy

Dot Metrix

Multiple printed pages such as an invoice. Advantages.

• Can print multiple copies at one time

Disadvantages

• Can be very noisy  

Hard drive

Stores the operating system software, application software and the user’s documents and data files.

Advantages.

• Relatively cheap, large capacity storage
• Fixed inside the system, so not easily misplaced
• Stores and retrieves data faster than some mediums, e.g. CD-ROMS

Disadvantages.

• They can fail and are prone to damage upon impact, leading to lost or corrupt data
• Not as portable as other storage mediums, due to size, weight and internal location

Optical Storage.

Optical disc storage mediums, read and written to by a laser.

Advantages.

• Faster access than a floppy disk
• Lightweight and easy to carry around
• Cheap to produce and buy in bulk
• Widespread compatibility

Disadbantages.

• slower than a hard drive
• Easily scratched/damaged, potentially making them unusable
• Limited storage capacity, particularly CDs

Memory Sticks and Cards

used for storing and transferring files, and come in many different sizes. They are usually connected to computers and devices via USB.

Advantages.

• Small, light and easy to carry around
• Large storage capacity for their size

Disadvantages;

• Very easy to break
• Data can be lost if you do not properly remove the device from the computer after saving

Memory units

• Bit;  the smallest amount of data that can be stored (on or off, 1 or 0)
• Byte;  = 8 bits - used to store 1 letter
• Kilobyte; 1024 bytes
• Megabyte; 1024KB
• Gigabyte; 1024 MB
• Terabyte;  1024 GB

Communication Devices

• Modem; These are used to encode digital computer signals into analogue signals (and vice versa) to allow computers to communicate over a phone/cable line.
• Router; Routers are used to identify an efficient route for data transfer across a network. They are commonly used in homes to allow the Internet connection to be shared and distributed between multiple computers. Routers enable both wired (using Ethernet) and wireless network connections.
• Hub; a simple piece of hardware that has a number of devices connected to it. It receives data from one port and sends it via other ports. 
• Network interface card (NIC); Often referred to simply as network cards/adaptors, these allow users to connect to networks via Ethernet cables or Wi-Fi.

Types of operating system

• Interactive;  Controls the actions of a computer where processing is instant
• Multitasking; The majority of OS systems are multi-tasking allowing many processes to be performed at the same time.
• Real-time; Controls the actions of a computer where processing is almost instant or at least within a set time frame

Utillity software

Software used to analyse, configure, optimise and maintain a computer system.
Examples include disk defragmentators, registry cleaners and anti-virus software.

Drivers

Software supporting specific hardware devices such as video cards to ensure they communicate effectively with the operating system.

Application software

This is designed to enable users to perform specific tasks, and includes applications for creating and managing information, data and media content, and communicating with others.

• Word-processors – e.g. to write letters and reports
• Spreadsheet software – e.g. to model financial data
• Database management software – e.g. to store customer and product details
• Desktop publishing software – e.g. for producing brochures and leaflets
• Presentation – e.g. for creating slide shows using text and multimedia 
• Web authoring software – for creating and editing web pages
• Multimedia software – e.g. to create an interactive quiz using
• Graphics-editing software – e.g. to edit photographs or create web graphic 
• Video-editing software – for editing video files
• Communications software – e.g. social networking, chat, instant messaging, web browsers and email clients

Programming software

• Compiler; Converts high level programming code such as C++ into code that the computer can execute.
• Interpreter; Similar to a compiler, however it converts each line of code sequentially, rather than the entire code at once.
• Debugger; Helps a programmer to identify ‘bugs’ in their code.
• Linker;  A programme that takes one or more objects generated by a compiler and combines them into a single executable program.
• Editor;  Used to edit source code using only text. Also has tools such as syntax highlighting to aid developers.    

File Types.

This refers to the way that information is encoded for storage in a computer file. There are different file types used for different purposes, for example to save images, documents and to store executable programs.

Images: JPEG (Joint Photographic Experts Group,    GIF (Graphics Interchange Format), TIFF (Tagged Image File Format) Audio: WAV (Waveform Audio File Format,  MP3 (MPEG 1 Audio Layer 3), AAC (Advanced Audio Coding) Video:  MPEG2 (Motion Picture Experts Group 2),       MPEG4 (Motion Picture Experts Group 4), AVI (Audio Video Interleaved) Document: DOC (Word Document),   XLS (Excel Spreadsheet), PDF (Portable Document Format)

Word processing and DTP

WP is predominantly used for working with text documents whereas DTP is capable of more accurate manipulation and used for text and images.

Word-processing DTP Letters Posters Business cards Essays Leaflets Magazines Memorandums Flyers Catalogues Reports Brochures  

Presentation software

In addition to generic software features, some typical features of slideshow software include: · Insert slide · Presentation timing · Slide layouts · Colour schemes · Hyperlinks/buttons · Slide transitions · Sound effects · View slide show · Animation · Print handouts  

Multimedia software

This includes software for audio, DVD/Blu-ray and video players. Some typical features include:

· Volume adjustment · Start · Mute · Stop · Play · Playlist · Pause · Subtitles · Forward/fast forward · Downloads · Backward/reverse · Streaming

Web Authoring software

In addition to generic software features, some typical features of web authoring

Master pages · Forms · Navigation bar · Flash tools · Animations · Counters · RSS feeds · Hotspots · Hyperlinks · Conversion to HTML

Data types

• Integer – positive or negative whole numbers (no decimal places), e.g. 1, 2, 3
• Currency – Usually displayed using two decimal places with a currency symbol, e.g. £150.00 
•  Percentage – Displays the value as a percentage, e.g. 20% 
•  Fraction – Displays the value as a fraction, e.g. ¼
•  Decimals – Displays the value as a decimal; the number of decimal places used can be set, e.g. 1.66

Other formats

Text, Date, Time, Limited-choice option and Boolean.

Encoding

During data entry, data may be encoded. A number of different codes are defined for the data. For example a gender field may be stored as codes (e.g. 'M' for Male, 'F' for Female).

The benefits of doing this are:

• Speeds up data entry as the data is often a single letter
•  Less data, requiring less storage space to save, resulting in faster retrieval of information
• Easy to validate, and less prone to human error during data entry

Data capture form

Where information is entered directly into a form by the person completing it or a third-party, then typed into a computer system by the organisation issuing it, e.g. bank application form.

Advantages;

• Answers to specific questions are collected
• Fast to complete by hand

Disadvantages;

•  Possible copying errors when inputting data
• Poor handwriting on the form can lead to incorrect data inputting

Questionnaire

Where the user enters their own information following the format of a laid-out questionnaire that is asking either open or closed questions.

Advantages.

•    User will give accurate answers
•   If using a coded questionnaire, answers can be turned into results instantly

Disadvantages.

•    User may misinterpret a question
• Poor handwriting on the form can lead to incorrect data inputting

Chip and Pin

A chip in one device, usually a credit card and a PIN number known by the user and acknowledged by the device as correct identification.

Advantages.

•  PIN numbers are usually four digits and easy for the user to remember
•   Secure as long as the chip is embedded into the device and the PIN number is kept confidential

Disadvantages.

•   Chips can become easily damaged
• PINs can be forgotten deeming the device unusable until the PIN number has been remembered or reset

Biometrics

Methods for recognising a person by their physical attributes or behaviour, used for identification or verification, e.g. finger recognition when entering a building, or face recognition to eliminate you from a criminal list.

Advantages.

• High accuracy and reliability
• You carry it with you all the time

Disadvantages.

• Some methods are very intrusive
• Some methods are expensive to implement

RFID

Uses RFID tags applied to products, animals, or people for the purpose of identification and tracking using radio waves. Everyday uses include tagging animals (tracking) and goods in a retail store (security).

Advantages

•  Can communicate through objects
•  Chips when secured are difficult to remove

Disadvantages.

• More expensive than barcodes
• Vulnerable to damage, e.g. by water or static discharge

OMR

Fast data entry for high volume data. Widely used for marking multiple-choice exams, market research questionnaires and the National Lottery where answer/choice is indicated by a black pencil mark against choice.

Advantages.

•     Simple to use
•   Quick to be read by a computer

Disadvantages.

•   May not work properly if paper is torn or crumpled
• Cannot be read if markings are off line

Barcode scanner

Horizontal lines that represent numbers that convert into information about a product such as: country of origin, manufacturer code, product details and a check digit, uses include: supermarket – pricing an item; libraries – book loan control; local government – census form counting.

Advantages.

• Instant identification of an item
• Faster than typing in a product code

Disadvantages.

•   If the code is damaged it cannot be read
• The stock database must be kept up to date otherwise the barcode is obsolete

key words

• Columns;  run horizontally and are labelled by capital letters like A, B, C, etc.
• Rows; run vertically and are labelled by numbers 1, 2, 3, etc.
• Cells; are identified by which column and row they are positioned on, e.g. A2 or C7.
• Cell Reference; identifies a cell (eg B6 or G9). It is made up of the column and row.
• Cell Range; refers to a series of cells. It is written like this B6:G9. This represents all the cells between B6 and G9.

Formulas

Formulas can be entered into cells to do calculations. They always start with an "=" sign. They can include numbers or cell references as part of the calculation.

=B6 * 50 --> multiplies the contents of cell B6 by 50

=G9 + B6 --> adds the contents of G9 to B6 Formulas are good because they do calculations quickly and easily and automatically recalculate if the data changes.

Automatic Recalculation

Where data is used in a formula, if any of this data is changed, the formula updates its calculations accordingly and outputs the updated value. This is the key purpose of spreadsheet software.

Sorting data

Data can be sorted on a single column, or multiple columns (by establishing an order of sorting). Text is usually sorted A-Z (and vice versa), and numeric data is usually sorted Smallest to Largest (and vice versa).

Graphs

Spreadsheets allows for numerical information to be displayed into a graphical format using graphs and charts.There are variety of graphs and charts, each for different purposes. These include:

• Bar chart
• Column chart
• Pie chart
• Line graph
• Scatter graph

These are usually created by selecting the data to be used, before using a wizard to customise, preview and output the chart/graph. This may include adding things such as chart and axis titles, legends, data values, etc. Bar and column charts are best for comparing data. Pie charts are mostly used for showing proportions of data, for example percentages.

Functions

• SUM;  =SUM(A1:A3), Add all values between A1 and A3
• AVERAGE; =AVERAGE(A1:A3), Take the average between A1 and a3
• MAX; =MAX(A1:A3), What is the largest number between A1 and A3
• MIN; =MIN(A1:A3), What is the smallest number between A1 and A3
• ROUND; =ROUND(C4,2), Rounds the number in C4 to 2 decimal places
• ROUNDUP; =ROUNDUP(C4,2), Rounds up the number in C4 away from 0 to 2 decimal places
• IF; =IF(C4>20,YES,NO), If the value in C4 is greater than 20 then put the answer YES otherwise put the answer NO
• RANK; =RANK(C4,A1:A3,0), Take the value in C4 against the list in A1:A3 and descending order 0
• COUNT; =COUNT(A1:A4), How many values are there between A1 and A4
• LOOKUP; =LOOKUP(C4,A1:B4) , Look up the value in C4, within the area of A1 to B4 and give the value in the corresponding cell

Data modelling

A model is software which is designed to copy the way something works in real life. It makes calculations using formulas and functions to predict what is likely to happen based on data recorded about what actually did happen in the past or is predicted to happen.The way it works is to ask ‘what if...’ in a situation and the computer will respond with appropriate answers.

For example, if you have an egg in a frying pan on a low heat (it will not cook), what if... the heat was turned up to medium (it will start to cook), what if... the heat was turned up to full power (it will definitely cook). When using the ‘what if’ scenario in a computer model it will be mathematical (figures only) or simulation-based (actual equipment).

Features

• Field (column)
• Record (row)
• Field names 
•  Insert and delete fields/records
• Enter and edit fields
• Organise/select record
• Queries
• Reports
• Primary key (unique identifier)

Mail merge

This is used for extracting data from databases so that it can be used in documents. Common applications of mail merge include letters, invoices, pay slips, membership cards, etc.

Before you can produce a mail merge you need to have a list of contacts, in a database or spreadsheet file. You can then use this file to insert the fields that you need to produce your mail merge in a Word document.

Flat file databases

All data is stored in one place/table. Flat file databases can be created in spreadsheets, word processors and databases software.

Advantages;

• Simplicity – ideal for very basic data structures, easy to implement
• Can be in a variety of formats, e.g. spreadsheet, database or document

Disadvantages;

•    Data redundancy – data is often duplicated because of layout
•  Data may become inconsistent – the same items of data have to be entered/updated several times

Relational databases

Data is stored in different tables which are linked together using relationships using unique identifiers (primary/foreign keys).

Advantages;

•  Reduced input effort – data only keyed in once
•  Data is only stored once, avoiding data redundancy

Disadvantages;

• Complexity – require technically skilled personal to create and manage them, e.g. database administrators

Backups and archiving

The process of backing-up refers to making copies of a person or organisation’s files, which can be restored at a later date if the original files are lost or become corrupted. Files are backed up to a removable device and at least one backup should be kept off-site, in case of a fire or other natural disaster. An archive is a location where files that no longer in use are kept for reference.

The backup and archiving policy used depends on the following:

• Content / Backup Type – which data needs to be backed up? Is a full or partial backup required?
• Frequency / Timing – how regular should the data be backed up?
• Backup Media – how is the backup data going to be stored? 
•  Location – where will the backup will be stored?

Physical methods of protecting data

• Keep ICT equipment in areas that only authorised people can enter
• Use surveillance methods (e.g. security guards / alarm systems / CCTV)
• Keep removable media (e.g. USB memory sticks) safe and secure
• Use security locks and clamps to secure equipment
• Biometric scans (e.g. fingerprint / retina)

Software methods of protecting data

• Assign each user their own unique login details for identification purposes
• Using strong passwords and security questions
• Access rights to specify which files each user can access
• Encrypt files so that they cannot be understood if intercepted
• Selective drop-down lists – prevents unauthorised access through key logging software

Data encryption

Encryption is the most effective way to achieve data security. When data is transmitted, it can be scrambled into a code so that if it is intercepted during transmission, it cannot be used. To read an encrypted file, you must have access to a secret key or password that enables you to decrypt it.      

Types of malware

• Viruses; A virus is a malware program designed to cause damage to a computer system. They are particularly harmful to individuals and organisations as they can corrupt or damage files as they duplicate and spread throughout the system.
•  Worms; A worm is a program that replicates itself in order to spread across a computer network such as the Internet. The most significant difference between a worm and a virus is that a worm is a complete program on its own. Worms can disrupt network traffic and damage data.
• Trojans; A Trojan is software that appears to function in a certain way (for example, as anti-viruses software), but actually performs a completely different action. This may not damage the computer system directly, but it can allow unauthorised access (hackers) into the system.
• Spyware; Spyware is a type of malware which is installed on a computer system and collects user information, both without the user’s knowledge. Spyware often ends up on your computer after downloading and installing free software.
• Adware; Like spyware, adware installs itself on another computer without the owner's knowledge, and often places advertisements on the screen. Although a nuisance, adware on its own is not considered to be harmful. 

Preventing Malware

• Treating files from unknown sources with caution, or better still, avoiding them totally
• Installing dedicated anti-virus/spy-ware/ad-ware software to monitor incoming files and run system scans
• It is important that the software is updated regularly as threats are constantly evolving

Hacking

Hacking is the process of accessing, or attempting to access, a computer system without authorisation.

Hackers often use key logging software; this is software which records key strokes by a computer user without their knowledge or permission. This information is then used to gain access the system.

Prevent hacking

The most common technique of preventing unauthorised access is to use a working firewall. These prevent unauthorised access to computer systems and can be either hardware or software-based.

Intrusion detection systems (IDS) may also be used to monitor the network or computer system for malicious activities.

Communication services

Facsimile (Fax)

• Recipient does not have to be there to receive the document
• Not confidential

Telephone

• Service depends upon size of bandwidth (the channel for data to pass through)
• Telephone, only for speech, time wasted in connecting
• Telephone tag: phoning and leaving messages
• Time zone differences affect immediate calls
• Automated switchboards, Digital Dorothy (voice activated)

VoIP (Voice Over Internet Protocol)

• Uses a PC (with microphone and speakers) to send audio in real time via the Internet
• Much cheaper than normal phone calls (especially international calls)
• Multi-way talking possible, i.e. more than two people at once

Sharing files

When files are shared and used between different people, it is important to consider the following:

• File naming conventions – using a consistent method to clearly describe file contents
• Use of version control – for example, appending the filename with v1, v2, etc. to indicate a chronological order of file updates
• Use of file permissions – used to allow different levels of access to a file in a shared location, depending upon the role of the person/group. These include:
•  No Access
• Read-Only
• Read/Write 
•  Read/Write/Delete
• Full Access

Key terms

• Web browser; An Internet Service Provider (ISP) supplies a connection to the Internet, e.g. Sky Broadband.
• IP Address; used to identify individual devices on a computer network.
  An IP address consists of four numbers, each of which contains one to three digits, with a single dot (.) separating each number or set of digits, e.g. 10.0.40.105
• Email; widely used method of communication, mainly for businesses but also for social purposes. Email software can be web-based, i.e. Hotmail or installed software such as MS Outlook.

Social networking

Blogs are usually maintained by an individual with regular entries of commentary, descriptions of events, or other material such as graphics or video. Most blogs are interactive, allowing visitors to leave comments and even message each other via widgets on the blogs and it is this interactivity that distinguishes them from other static websites. As of February 2011, there were over 156 million public blogs in existence.

Advantages;

•   As a viewer you can read other people’s opinions about the topic you are passionate about
•  As a blogger you can get your opinion across without having to acknowledge the viewer

Disadvantages;

• The information posted may not be accurate but just a blogger’s opinion
• With so much information it may be difficult to distinguish the truth from the garbage

Monitoring and tracking

ICT is used for monitoring and tracking in a number of ways, including the following:

• RFID – Uses RFID tags for the purpose of identification and tracking using radio waves. Everyday uses include tagging animals (tracking) and goods in a retail store (security).
• Cookies – small text files created upon website visits and stored on your computer 
• Key logging – software or hardware-based method of tracking keyboard key stokes, usually to gain confidential information without the user’s permission
•  Mobile phone tracking – uses a process called triangulation to calculate the position of mobile phones based on the strength of roaming signals to nearby antennas.
• Automatic number plate recognition – used for enforcing tolls/congestion charges and road offences – the image is captured using a camera and processed by OCR to output the vehicle registration number.

WiFi

• Wireless connectivity; does not need cables to connect devices
• Requires an access point, e.g. a wireless router
• Can transmit through objects, but there is a limit to how far the device can be from the access point, and interference can be a problem
• Popular in business and homes
• Good security options, e.g. WEP, WPA

Bluetooth

• Wireless connectivity; does not need cables to connect devices
• Transmits data at a fast rate over a short distance
• Widespread application of technology, e.g. headsets
• Popular in business and homes

Geographical Inforation system

• Combines mapping services with database facilities
• Used in many industries such as environmental, criminology, weather prediction
• From one location data can be captured, stored, analysed and presented in an appropriate output

Types of network

• Local Area Networks (LAN): are networks that connect computers and devices (printers, scanners, etc.) over a limited geographical area such as a building or school.
• Wide Area Networks (WAN): A collection of computers spread over a wide geographical area, may make use of microwaves, satellites or telephone lines.

Networks

Advantages

• Sharing of software and data between users
• Centrally controlled security both in terms of access to and backup of data

Disadvantages

•   If the central file server fails network users cannot access files stored on it
• Viruses can spread easily around a network 

Common Problems

Software Freeze; This can be very damaging and proves that you should regularly save your work. If this does happen you can select ‘Ctrl Alt Del’ and open the Task Manager, then select ‘End Task’. If this works this will save the current file then stop the program from running and when you restart the program, your file should be restored by the computer’s automatic backup facility.

Error Dialogues; When a dialogue box appears the computer is trying to tell you that you have made a mistake. You need to follow the instructions on the screen and usually answer ‘OK’, ‘Retry’, or ‘Cancel’.

Storage Full;Your memory space is limited and when you have saved too much work it will become full. If this happens you need to save some work onto an external storage device and delete it or just delete some files to release some spare space.

Printer Paper Jam; The paper in your printer will pass from the holding bay to the finishing tray; along the way there will be certain parts of the printer that will open to allow you access should a piece of paper get stuck. If this happens you can gently pull out the paper in the direction of the printer rollers and avoid tearing it. 

Hardware and Software Problems

Hardware;

• Computer usually taking too much memory or CPU power and running very slowly
• Incompatible software (including drivers)
• Blue Screen of Death (possibly related to hardware failure)

Software

• Computer's display is distorted (video card)
• Computer’s ports don’t work (e.g. DVI, USB)
• Failure to load the operating system (hard-drive)
• Network Interface Card not responding

Troubleshooting

Software problems can be resolved by:

• Uninstalling/repairing software or updating drivers
• Restoring the system to an earlier point in time

True hardware problems can only be resolved by repairing or more commonly, by replacing the faulty hardware.  Computer components are much cheaper nowadays and most components can be installed with relative ease.

Computer misuse act

Computer Misuse Act of 1990 was passed to deal with the problems of hacking, viruses and other nuisances. Level 1​ Unauthorised access to computer programs or data as a nuisance. Example: Cause damage to a computer/data just to prove you can, break the password code into the Bank of England to brag to your mates. Level 2​
Unauthorised access with a further criminal intent.
Example: Cause damage to a computer/data for malicious reasons, ex-employee planting a virus.
   Level 3​ Unauthorised modification of computer data. Example: Hack into a computer system to commit a crime, break the password code into the Bank of England to steal money.  

Computer misuse act 2

The law consists of: ·         Deliberately planting a virus in a computer with the intention to cause damage ·         Using computers in work time to carry out unauthorised work ·         Copying computer programs illegally ·         Hacking into someone else’s system to view or change information ·         Using computers for fraud, e.g. fictitious employee’s on pay roll   Offences covered by the Act: 1.      To impair the operation of any computer 2.      To prevent or hinder access to any program or data 3.      To impair the operation of any program or reliability of any data   On looking at whether an offence under this act has taken place, it is necessary to prove intent.  The court then has to prove that the person who did the act knew they were doing it. Very few cases under the act have ever come to court. 

Data protection act

The act was updated in 1998 to cater for the growing use of computers both at home and in the office.

Data Subjects; The individuals who have personal data held about them on a computer system. The Data Protection Act allows individuals to have access to information held about them on a computer and where appropriate to have it corrected or deleted.

The Rights of Data Subjects

• To compensation for unauthorised disclosure / inaccurate data
• To access the data held about them and to have it rectified or deleted if inaccurate

When Can Personal Data Be Processed?

Personal data can be processed if one or more of the following conditions have been met:

• The data subject has given their consent
•  It is a legal obligation

data protection act 2

Information That Must Be Provided By the Data User about the Data That Is to Be Stored

 Reason why data is to be stored   

• Type of data to be stored
• Who will have access to the data (recipients)
•  Any organisations to whom data will be passed on (transfers) 
•  How the data will be collected

The Data Protection Registrar

• Administers a public register of all data controllers (those organisations holding personal data)
•  Investigates complaints and initiates prosecutions for breaches of the act

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Eight Principles of the Data Protection Act (www.dataprotection.gov.uk)

• Data processed lawfully
• Held for a specific purpose only
• Data shall be adequate, relevant and not excessive
• Data shall be accurate and up to date
•  Data should not be kept longer than necessary
•  Data shall be processed in accordance with the data subject
•   Data shall be held securely
• Data shall not be transferred outside of Europe

Who is Exempt from the Data Protection Act?

•  Payroll, pensions, tax and accounts data
• Data used for household and recreational use (in some cases)
• Statistical or research purposes, e.g. census
•  Crime and National Security

personal data guardianship code

This is not a legal requirement but a social awareness guidance of how organisations should look after personal data, to keep up to date with this you can visit the British Computer Society website at: http://www.bcs.org/. The principles of the code cover:

• Accountability: be responsible for the manner in which the personal data is collected, used and stored to remain safe and secure.
• Visibility: have the personal data accessible at all times for the data subject to review and amend if necessary, charging for this service is acceptable.
• Consent: data subjects should be given as much control as possible over how their data is collected, stored and used.
• Access: data subjects should be informed who else within the organisation will have access to their personal data.
• Stewardship: those that collect the personal data must understand they are responsible for its well-being while it is in their possession and during any transfer to a third-party.
•  Responsibility: the organisation should have a policy detailing how it adheres to the personal data guardianship code and the Data Protection Act.  

Copyright law

Copyright is the set of exclusive rights granted to the author or creator of an original work, including the right to copy, distribute and adapt the work.  The Copyright Design and Patents Act 1988 was introduced to protect the intellectual property of individuals and organisations.  The act covers a wide range of materials such as music, films, literature and software.

Illegal Media Download and File Sharing

Illegal downloads and file sharing has a significant impact for the producers of the materials. It also has serious consequences for those who legally sell and distribute the media legally, for example high street stores, as less and less people are now buying the media and are turning to illegal downloads. 

increasing numbers of computer users are facing legal action for their downloading activities as copyright owners increase efforts to protect their work.  All Internet Service Providers have the right to deny users Internet access, where they are caught persistently downloading media illegally from the Internet. 

Potential health problems

Potential health problems associated with computer use are:

Stress; This is a major factor in work-related illness. Symptoms can include headache and loss of sleep and appetite.

Computer systems put additional pressure on workers:

• They may be used to monitor performance
• Technologies such as smartphones and teleworking makes it difficult to employees to ‘switch’ off when not at work
• They can induce fear and panic particularly in older people
•  Software can be difficult to use
• Constantly bring about the need to perform new tasks that you may not be able to cope with

potential haealth problems 2

RSI (Repetitive Strain Injury);Caused by excess use of a keyboard and can usually affect the hands, wrists, elbows, arms, shoulders and/or neck. Can be very painful and debilitating. Once it develops it tends to recur.

Eyestrain; Brought on by long hours spent in front of a screen, although there is no evidence that computers cause permanent damage!

Factors that could contribute to eyestrain are:

• Glare from monitors
• Improper lighting

ELF (Extremely Low Frequency) radiation;Exposure to ELF is an everyday occurrence as it can occur naturally – sun, fire, magnetic effects.

Backache/neck strain;Often caused by improper seating and posture position of human and keyboard/screen.

potential health problems 3

The Ergonomic Environment;The design and functionality of the office environment. This includes:

• Lighting: well lit, with blinds. Computers shouldn’t face windows or back on to a window.
• Furniture: chairs of adjustable height, with tilting backrest, swivelling on five-point base.
• Work space: combination of chair, desk, computer, accessories, lighting, heating and ventilation all contribute to overall well-being.
• Hardware: screen must tilt and swivel and be flicker-free, the keyboard separately attached.

Measures to prevent poor health when working with computers include:

• Take regular breaks
•  Have regular eye tests
• Use a wrist rest and foot stool
•  Use adjustable furniture: seat, desk, monitor
•  Don’t overload power sockets, use surge protectors
• Control the room temperature 

Accesibillity

A range of features (software and hardware) have been developed to aid people with disabilities, including:

• Screen filters and magnifiers
• Customised desktop environments
•  Braille keyboards
• Specialist input devices (sip-and-puff, etc)
• Voice recognition
• Use of captions and sub-titles for visually impaired people
• Software accessibility options

Technology can be used generally to make disabled people's lives better, helping them to stay in touch when they are unable to get around (social networking, email, web cams, etc), use household appliances that contain embedded systems to help them control the device, provide entertainment (games, DVDs, etc) and help them with education (internet, collaborative learning, etc).

sensors

A key element of data logging and control systems is the measurement of physical quantities, achieved using sensors. Sensors are used to measure things such as light, pressure, temperature and movement.The output from the sensor can be converted into an electrical signal for use in controlling a process or in displaying a physical quantity.  An analogue to digital converter (ADC) is needed to converted analogue signals (the amount of light, temperature, etc) into a digital signal that can be understood by a computer.

Commonly used sensors and examples of use:

•   Temperature – measures how hot or cold an environment is, e.g. in vehicle engines
• Light    – measures levels of light, e.g. to trigger security lighting, or to detect when an car is close to a wall
• Humidity – measures the amount of moisture in the air, e.g. for weather reporting
• Pressure – measures pressure; used in a range of applications, e.g. fluid/gas flow and altitude. 
• Motion – detects when something is moving.
• Tilt / Rotation– detects when something is falling over or in a phone/tablet to detect if it is turned round.

Data logging

Data logging is when a computer is attached to a sensor that is responsible for collecting data over a period of time. The system generally runs automatically with little or no human intervention. Remote data logging is when a sensor is responsible for collecting data and is then returned to the computer in another location to download the data collected, where possible with little human intervention.

device control

Control software is responsible for managing a device and making it follow instructions, this is often used for moving an object such as: electronic toys and games, greenhouse windows, actuators (robots) and traffic control. 

Whereas monitoring just involves recording information, control involves making something happen, or responding to inputs.

Control Instructions

In schools control programming is normally taught using LOGO. The main commands used in LOGO are:

•   FD or Forward (e.g. FD 10 means move forward 10 units)
• BK or Backward (e.g. BK 10 means move backward 10 units)
•  Home 
•  RT or Right (e.g. RT 90 – means right turn 90 degrees)
• LT or Left (e.g. LT 90 – means left turn 90 degrees)
• PU or Pen Up
• PD or Pen down

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Control Devices 

The following are the most commonly used control devices:

• Actuator – this is the motor and related hardware that is used in a control system. They may be used to lift a car park barrier or open a lift door.
•  Lights – these can be the output from a control system; they can be used in traffic lights or as warning lights on a control panel.
• Buzzers – these are used to output sounds, a common example is in alarm systems.
• Robotic arm – computer-controlled devices that can be moved to a certain location using position sensors as part of a feedback loop.

Feedback loop

The data is collected, FEEDBACK and INPUT to the computer, which is PROCESSED and OUTPUT back to the device.

The sensors involved in control software collect the data first and pass it to the computer which then sends a message to react if appropriate.  For example, opening electric garage doors:

 The driver presses the hand control sensor (infrared) to hit the sensor pad on the garage door. The sensor pad on the garage door sends a message to the computer control software, which gives an instruction to the garage door arms (actuators) to swing open.

online banking and shopping

The massive growth of the Internet has resulted in more and more online services for e-Commerce.  This includes retail services such as banking and shopping.

Online Banking and Financial Services

• 24/7 access to online banking and financial services
•  Can send and receive money electronically
• Customer can check their account balance, transfer funds between accounts, pay credit card and utility bills, apply for loans, open new accounts and view standing orders and direct debits
•  Large amount of information readily available for customers to read and compare
• Convenient for the customers as they can manage finances without having to leave their home

online banking and shopping 2

Online Shopping

• Small businesses can thrive due to significantly reduced overheads (e.g. no premises / less staff)
• This results in generally lower prices for consumers than high street stores
• Consumers can shop around to find the best deals
• Convenient for the consumer as they can shop any time without having to leave their home, and also get items delivered to them

Online shopping websites have a range of features that enable shoppers to easily buy goods:

• Electronic "basket" - stores items people want to buy
• Online catalogue of items - shows what goods are available, gives pictures, etc
• Search box - allows user to find an item to buy easily
• Payment system - user can pay for goods online using PayPal or credit card

Changing patterns of employment

  There have been many changes in the pattern of employment due to the increased use of ICT, for example:   •   Type of workforce – fewer jobs in manufacturing as a result of automation, but more skilled jobs in ICT development and support. •   Location of offices / manufacturing plant – due to globalisation, lots of manufacturing is now outsourced abroad, to China for example. •   Different capabilities of people and computers – general increase in levels of skills as ICT is increasingly used.  The need for skilled workers to implement and maintain systems and train users has increased.   Other changes include: •   Increased homeworking / teleworking due to advances in communications technology •   Roles with flexible hours now more common •   Ease of tasks – ICT has made many tasks to be carried out faster and more effectively •   Increased unemployment – many jobs have been significantly or even disappeared in recent years due to the increased use of ICT in the workplace, especially in the manufacturing industry   

collaberation

Collaboration is where two or more people or organisations work together for a common goal, also known as project management.

Features of working collaboratively:

•  Draw up and regularly check against group plans
•  Discuss all issues and risks as a group
• Have a consistent layout of the project
•  Ensure your project is ‘fit for purpose’ for all included parties
• Produce a group work schedule including meetings and communicating channels 

teleconferencing / videoconferencing

Teleconferencing

A communication system that allows people in different physical locations to exchange ideas and information interactively with the use of telephones, known as a conference call.A number of people in different locations around the world can have a multi-way conversation via the telephone. Some telephones have the facility to set this up or it can be done by all participants dialling in to a central conference call number.

Videoconferencing

This is similar to teleconferencing but done with the use of video cameras, microphones, large monitors and computers. It requires a broadband internet.

teleconferencing / videoconferencing

Advantages;

• No need to travel to meetings
•  Meetings can be arranged with little notice and can be conducted at any time, anywhere
• Organisations save on money due to reduced costs e.g. travel and accommodation
• You can see body language when using video

Disadvantages;

• Different time zones need to be taken into account when dealing with people in different areas of the world
• Reliance on fast broadband connection may lead to disruptions due to technical difficulties
• All participants require the technology to attend the meeting

the internet

Advantages;

•  Vast amount of information at your fingertips 24/7
•  Access to organisations that you may not otherwise find out about, e.g. disability support groups

Disadvantages;

• Lack of central control / censorship
• Cannot guarantee whether a website and it’s information is genuine or not

online hazards

• Phishing scams; Don’t open or respond to un-trusted emails with any personal information
• Spam;Use a spam filter to help prevent spam emails reaching the inbox
• Viruses; Install and maintain updateable anti-virus software
• Spyware; Install and maintain reliable anti-spyware software