A2 CCEA ICT Revision Cards

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Flashcards on A2 CCEA ICT Revision Cards, created by Aidan Magee on 23/05/2016.
Aidan Magee
Flashcards by Aidan Magee, updated more than 1 year ago
Aidan Magee
Created by Aidan Magee almost 8 years ago
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Question Answer
Main features of a relational database • Data is stored in tables • Tables are linked together through key fields • Avoids data duplication • Easier to change data as changes are implemented throughout
Data consistency An attribute has only one value at a particular time A change to the data value is implemented throughout the database.
Data inconsistency A particular attribute is stored more than once in a database and has different values
Data independence Stored data is separate from the programs which accesses it
Data integrity The accuracy, reliability or completeness of the data this can be affected by input errors and processing errors minimised by data verification/validation
Data redundancy This refers to the duplication of data. The same data is stored more than once thus taking up unnecessary space and can lead to data inconsistency
Flat file A database system in which each database contains a single file which is not linked to any other file.
Disadvantages of flat file Some non-key attributes will be stored more than once • This can lead to increased storage requirements and to data inconsistency where an attribute may have more than one value
Purpose of normalisation The purpose of normalisation is to organise data efficiently, eliminate redundant data and ensure that only related data is stored in a table.
Normalisation 1NF – remove repeating groups 2NF – Remove non-key dependencies, after 1NF has been reached 3NF – Remove fields that depend on other non-key fields for each of three stages, after 2NF has been reached
Advantages of normalisation • Data redundancy is eliminated as each non-key attribute for an entity occurrence is only stored once in the database. This minimises the storage requirements • Data consistency is ensured, as an attribute for an entity occurrence will have only one value so there will only be one current value for an attribute • Improved data integrity • Improved data independence
Primary Key / Key attribute A primary key uniquely identifies a record
A composite key A composite key consists of two or more keys fields, each of which may be a primary key in another table which together uniquely identify a record
A foreign key • A foreign key is a link between two tables • A foreign key is an attribute in one table, but is a primary key attribute in another table
Entity A person, place, thing, or concept about which data can be collected
ER Model • Graphical representation of a system’s requirements • Identifies the entities about which data is stored and the relationship between them • Identifies entity attributes including primary keys
DBMS • Facilitates the definition, construction, update and sharing of data among users. • ·Enables protection of data by password and levels of access· • Facilitates the maintenance of a data dictionary • Facilitates backup and recovery
Role of the database administrator (DBA); • Installing and upgrading the DBMS software • Monitoring the performance of the database • Making optimum use of storage • Establishing backup and recovery duties • Setting access rights
Facilities provided by a DBMS for end users • End users will be able to run queries • End users will be able to produce reports (Information retrieval) • End users will be able to run macros • Maintain data - Users will be able to input and edit data
How does the DBMS improve the quality of the organisation’s information • Due to no data inconsistency data should be more accurate. • Due to no data redundancy data retrieval should be more efficient
Strategic Decision Making • Decisions made by directors for; • Long-term planning decisions and setting organisation objectives
Tactical Decision Making • Decisions made by middle management for; • Medium term planning decisions
Operational Decision Making • Decisions made by supervisors or shop-floor workers for; • Day to day decisions
Internal sources of information • Data collected within the organisation • For example current stock levels, past orders (historical sales), running costs (wages)
External sources of information • Data collected external to the organisation • For example information about competitors (prices, different products), Info on customers (location, age, tastes), Economics factors (future costs of labour, energy so that financial plan can be made.
Purpose of MIS To help an organisation to achieve its goals by providing managers with an insight into the regular operations of the organisation to enable them to plan more effectively
Features of MIS • Provides the management reports required to manage an organisation efficiently • It aggregates data from a range of sources both internal and external • Example: data processing systems • Performs financial analysis
Advantages of MIS • Facilitates planning - Improves the quality of planning as it provides relevant information for good decision making • Minimises information overload - Changes larger amounts of data in to summarised form making it easier to understand
Disadvantages of MIS • Cost - The development cost can exceed the budget as it is expensive • Time - May not be ready on time as it can take a long time to develop
Expert System The user interface • The user answers questions about the problem and receives a solution to the problem The knowledge base • This contains information about the problem domain and rules about the problem domain • Represents the knowledge of human experts The inference engine • Applies the rules and draws conclusions • It may apply fuzzy logic
How is Expert System constructed • Human experts will be questioned by the expert system's designer • The human experts will explain how they make decisions about (topic) They will explain the information, rules, and intuition they use
Expert system Advantages • Will always produce consistent results • Will always be available • Can contain the knowledge of the global body of human specialists, not just a single human • Can be cost effective as consultants can be used for less routine work • May be more user friendly as people may be less intimidated by a computer
Expert system Disadvantages • May be too rigid and not benefit from human intuition or learn from experience • May be difficult to update the knowledge base to reflect changing market conditions • Can lead to an over reliance and in a decline in human experts
Decision Support System (DSS) Definition A decision support system is software which analyses large volumes of data to identify trends to enable managers to select business strategies
Decision Support System (DSS) Features • Assists management in solving complex business problems • Applies various business models to large amounts of data • ‘What if’ analysis can be performed • Assists organisations with strategic, tactical, and operational decision making
Decision Support Systems Advantages • Time saving - Reduces decision cycle time which increases employee productivity • Cost saving - Reduces labour costs due to less time spent making decisions
Decision Support Systems Disadvantages • The data used by the DSS may be incorrect as the algorithms used may be incorrect • The DSS may fail and so the decisions will be unavailable • The DSS may be inflexible and unable to compete with human intuition
Potential threats to the security of data • Unauthorised access - through bypassing the username and password system • Physical threat - someone may bypass the door • Insecure communications as someone may intercept data while it is being transferred electronically • Viruses - Malicious software may compromise data’s integrity
Disaster Recovery Planning • It describes how critical operations will be restored after a natural or human induced disaster It ensures: • Critical data has been identified • Key processes are identified • Key personnel have been identified and will continue to have access to the organisation • Identifies alternative location where the computer system can operate until the threat is over
Backup and Recovery strategies Real time Real time: • A mirror copy of the data should be kept on a separate computer system. RAID is used. • If the live system fails the organisation can switch automatically to the mirror system
Backup and Recovery strategies Every month / Batch: • Only data which has changed since the last backup needs backing up (Incremental backup) • A complete backup can be performed (Complete backup) • The backup should be performed at regular intervals • The backup should be stored away from the computer system • In the event of data loss, the backup copy can be retrieved • Recovery - The master data should be restored from the backup copy. The batch of transactions should be processed again.
Client server • There is a controlling network server • The server services requests made by clients • Clients have minimal resources • There is central control of security
Client server Advantages • Software can be shared • Hardware can be shared • Communication between users is possible • Users are not restricted to a specific computer • Security can be controlled centrally
Client server Disadvantages • The server is expensive to purchase • Specialist staff such as a network manager is needed • If any part of the network fails a lot of disruption can occur
Peer to peer network • There is no server/controlling computer • All nodes/stations/computers are of equal status • Nodes are both suppliers and consumers of resources • Each node makes some of its resources available to the other nodes
Peer to peer network Advantages • Low installation costs as there is no need to resource a dedicated server • No need for a sophisticated operating system • If one computer fails it will not disrupt any other part of the network
Peer to peer network Disadvantages • Low level of security as security cannot be controlled centrally • Because each computer might be being accessed by others it can slow down the performance for the user • Files and folders cannot be centrally backed up
Distributed database Features • Portions of the database are stored at a number of different locations within the network Each location stores that portion of the database they need to access frequently • The DBMS synchronises the database at regular intervals
Advantages of distributed database • Increased security as staff access can be limited to only their portion of the database • Local database still works even if the company network is temporarily down • Reduction of the effect of errors as they will be local rather than the entire organisation being effected
Disadvantages of distributed database • Each shop is responsible for its own security • Each shop must be resourced with HW and SW to store and access its data • Each shop must have the appropriate IT personnel • Local data may be unavailable during regular synchronisation with HQ
Centralised database Features • The single copy of the database is stored in a single location where all database maintenance takes place • Users access the database remotely • Users can make changes to the data remotely
Centralised database Advantages • There is only a single copy of the database so synchronisation is more efficient • The database is at a single location so security can be managed more effectively
Centralised database Disadvantages • Synchronisation of changes to the centralised database is complicated, so there may be various copies with different data • If the centralised server fails, no data is available to the user which causes large amounts of disruption • Multi-user access depends on communication link, if there are high levels of traffic there will be slower access
Wireless Communication Advantages • Devices do not have to be physically connected together so devices can connect to the network anywhere there is a signal • Additional devices can be connected to the network using a wireless card/portable devices such as notebooks can be added
Wireless Communication Disadvantages • Security can be a risk unless access to the network is password protected • Once a virus infects one network terminal or a particular file it can spread rapidly to other terminals because they are all connected whereas a standalone computer is not connected to other computers
Mobile technology • Radio frequency waves are used for communication information • When a mobile phone connects to a network it communicates with the nearest base station • The area covered by a base station is known as a cell • Each cell is usually split into three sectors which overlap with the sectors of neighbouring cells to create an uninterrupted network • When people travel, the signal is passed from one base station to the next and usually never has to travel further than the nearest base station • A mobile phone contains a Subscriber Identity Module (SIM) which is a smart card that gives the user access to a range of subscriber services. The SIM card identifies the subscriber to the network system
Need for communication standards • To ensure that when a message is transmitted between two network nodes the message follows agreed rules • Different technologies may be used • Example – different transmission speeds
Open Systems Interconnection (OSI) • The OSI model consists of an abstract model of networking and a set of specific protocols • It defines a layered protocol, and there are seven layers • Each layer deals with specific functionality and is independent of the others • Control is passed from one layer to the next • Each layer interacts directly only with the layer immediately beneath it and provides facilities for use by the layer above it • An example is the application layer which interacts with software applications that implement a communicating component.
Checksum • A checksum function is applied to a number of bytes/a block of data • The check sum is sent as part of the data • It is recalculated after data transmission • If the checksum is incorrect, there is an error in the data • The data can be retransmitted • Some types of checksum may automatically correct the error
Echo checking • The receiving device sends the received data back to the transmitting device • The transmitting device can compare this data with the original and retransmit the data if there was an error
Parity bits • An additional bit is calculated from other bits in a byte of data set to make the total number of bits either even or odd • The parity bit is checked after data transmission • If the parity bit is incorrect, a transmission error has occurred (Learn digit sequence in notes)
Firewall • This monitors traffic into the network • Traffic must comply with the security policy • Different levels of security can be set • If the policy is not met, access is denied
Access rights • Each user is allocated an access level which controls the access they have to specific data files, for example Read Only • The access levels are maintained in an electronic table… and automatically checked when a user tries to access a datafile
Username and password • Each authorised user is allocated a unique UserID and a default password which can be changed by the user • A valid UserID and password is required to log on
Data encryption • Data is encoded before transmission using a special key • On receipt, the data is converted back to its original form • Intercepted data is meaningless without the key
Accounting software • Concerned with reporting networkusage • Gathers details about user activity including the number of log ons and the resources used • Used to charge different users or groups of users for the resources that they may have used, eg printer charges • Used to identify unusual patterns of network usage that may be suspicious
Auditing software • It records which users have logged on and for how long to identify which user might have done something unauthorised or for accounting purposes • It records what software has been accessed to monitor the usage of each software package • It records unsuccessful attempts at log on to detect hacking
RAD Rapid Application Development • It is an iterative development process • Users and developers take part in regular workshops • A preliminary data model is developed along with a user interface • This helps verify the requirements • There are strict deadlines set for each refinement (check if I mean requirement) • Requirements are categorised as essential and non essential
Waterfall life cycle method • Consists of a number of distinct stages • Example – Analysis • Each stage has a deliverables e.g. requirements specification • Each stage may be repeated
Role of the end user in waterfall method • The end user is involved in the analysis stage during fact finding • The end user is next involved during acceptance testing to agree the system meets its specification
Prototyping • A first-cut model is developed and evaluated by the users who provide feedback to the developer • There are two types – evolutionary and throwaway
Role of the ICT developer in system development • To write program code to meet system specification • To plan testing of code • To test code • To document code • To maintain code.
Role of the End User in system development • Will assist the systems analyst in identifying the system requirements during the analysis stage by taking part in interviews. • Will be involved in using the system during acceptance testing and will provide feedback to the systems analyst • Limited involvement once the specifications have been drawn up until presented with the finished product, when it is generally too difficult to make changes or constantly involved with evolutionary prototyping or RAD, if this approach to systems development is used. • Signs the contract.
Need for documentation • During System maintenance (System undergoes Corrective, Adaptive, Perfective maintenance) • During the development of system, so that programmers and testers know what expected.
Technical Documentation - contents • System specification • HW & SW specifications • Data dictionaries • Data models, e.g ERDs • Test schedule/datas
User Documentation- contents • Contains installation instructions • HW/SW configuration • User guide • Help / FAQ • Security and Backup procedures
CASE Tools Graphics / modelling tool • It creates a model of the new system including DFDs and ERDs • Templates of standard modelling shapes can be used to improve productivity/quality • Designs can be validated automatically so accuracy can be ensured
CASE Tools Project management tool • Assists planning of the project schedule • Assists calculating and monitoring the project budget • Assists the creation of Gantt charts, PERT chart, and critical path • Assists the identification of tasks
CASE Tools Code generator • Assists the production of program code from form program specifications or form designs • Code will be optimised
CASE Tools Data dictionary generator • Automatically produces code from interface design or module specifications • Code will be optimised
CASE Tools Interface generating tool • Assists the production of code for the user interface from design of IO objects (buttons/ text boxes etc.)
Custom built / in house development • The system will be tailored to meet the exact user requirements instead of being a general solution to suit many different types of user • The development team will be available for training/maintenance
Custom built / in house development Advantages • Should meet the user requirements exactly as the development team will work with the end users • Team available to help users resolve problems so support is available
Custom built / in house development Disadvantages • Expensive as the full development costs must be met by the client • Takes a relatively long time as all stages of the life cycle must be completed
Off the shelf The software could be purchased ready made “off the shelf” from a computer store
Off the shelf Advantages • Lower cost as it is spread over a number of users, rather than just one • Available immediately as it is already developed
Off the shelf Disadvantages • The user may be paying for functionality they do not require • The software may not be completely satisfy their requirements as it was not developed uniquely for them
Outsourcing The software would be developed by specialist software developers external to the business
Outsourcing Advantages • Should meet the user requirements exactly as the development team will work with the end users • Team available to help users resolve problems so support is available
Outsourcing Disadvantages • Expensive as team of external consultants has to be hired which means the full development costs must be met by the client • Takes a relatively long time as all stages of the life cycle must be completed
Alpha testing • This is carried out by the developer • Module testing against module specifications • Integration testing using the system module architecture • System testing against the system specifications • Test schedule/test data used
Beta testing • Performed by representative end users using real data and real volumes of data • This is pre-release testing
Acceptance testing • This is carried out by the eventual end users • They use the software using real data in realistic conditions and provide feedback to the developers • It is the final stage before the software goes live
Processes of review and software maintenance Corrective: Errors will be detected and corrected. For example an incorrect formula has been used Adaptive: Additional functionality will be added. For example a new report is required by the user Perfective: The performance of the system will be improved. For example a faster processor to decrease response times
Features of a well designed HCI (human computer interaction) • Provision for support • Provision for shortcuts for more experienced users • Consistency throughout the interface to reinforce long term memory • Uncluttered screens that can be customised, for example the addition of toolbars
Purpose of user interface • To accept input from the user and to provide output for the user
Command line • There is a prescribed list of command words • Each command has its own syntax including a short word, e.g. COPY • The user inputs the specific command at a prompt • Some commands require parameters or switches
Command line Key Terms Key terms Prompt: A message which indicates the purpose of input Parameter: Refers to additional information required for a command
Form driven • The screen layouts reflect existing data entry forms • Data input boxes in the same positions • Screens displaying the same text • The user may be able to tick boxes • The order in which the user completes the form may be controlled
Natural language • Allows user to interact using written or spoken ‘human’ language • Verbs or phrases are used to instigate functionality • Example: creating, selecting, modifying data • The user’s commands are compared with a database of sounds using speech recognition software • Speech Recognition software is used
GUI It uses windows • Each window represents a different application • These can be opened and closed by the user It uses icons • An icon is an image which suggests an application • The user clicks on the icon to start the application It uses menus • Each menu presents a series of options • The user selects the required option It uses a pointer Which the user moves using a mouse to select an option
How a GUI assists experienced users The interface could include short cuts - a combination of two or more keys pressed at the same time, such as Ctrl + S for Save
Dialogue • A special window used in user interfaces to display information to the user, or to get a response if needed • A dialog is formed between the computer and the user • For example an alert which displays a message and requires only an acknowledgement
Psychological factors which influence human interaction with a computer system Perception • Past experiences or intuition can influence how users perceive objects, for example green for go, red for stop Memory • How humans retain and recall information including long-term and short-term memory, for example using a standard interface Ergonomic (physical) • Hardware factors such as the seating position • Health factors such as using an ergonomic keyboard • Environment factors such as the lighting in the room
Support available to the user of an information system: User guides • This will be designed for the end user • It will describe the overall purpose of the software • It will describe the interface • It will describe menu options • It will describe how to perform common tasks
Advantages of electronic user guide over printed manual • It can incorporate multimedia elements, for example video clips • The user can click hyperlinks to navigate through the guide or link to external resources
User guide - Contents • System configuration - Specifies the minimum hardware and software required Installation guide - • Implementation instructions - Describes how to install the software • Trouble shooting - Describes common problems and how to fix them using step by step examples
Help Desk • A dedicated telephone number through which the user can communicate directly with a person trained in support • They may be able to control the user’s computer remotely • They will talk the user through the system
User group • A dedicated body of end users of a particular system who communicate via an electronic forum • The user can post their problem, or start a thread and get a response from users with the same problems
The use of ICT based resources for training and re- skilling of employees Online course • The course is delivered over the Internet • Each trainee can train at convenient times and set their own pace • The course content is presented using multimedia • Participants may communicate with the instructor and other trainees via email, forum or user groups
The use of ICT based resources for training and re- skilling of employees Interactive DVD • The content can include multimedia components such as images to show the user how to perform task, for example by showing screenshots of the user interface • The user can select menu options and use hyperlinks to choose a personal path through the material • In-built assessment may be included and the trainee's progress stored
Video conferencing Hardware needed: • Video camera • Webcam • Microphone • Speakers • Monitor Software needed: • Communication software • Compression / decompression software
Advantages of Video conferencing • Travelling is reduced in terms of cost and time as trainees can participate from their normal work places • It supports multimedia as trainees can observe what the tutor is doing • The training session can be recorded and repeated later
Computer Misuse Act • Unauthorised access to computer material • Unauthorised access with intent to commit or facilitate commission of further offences • Unauthorised modification of computer material
Data Protection Act • The Act applies to any computerised or manual records containing personal information about people • Organisations using personal data must: • Register and comply with the DPA’s 8 principles • Appoint a Data Protection officer • Identify what data will be stored and the purpose for which it is being processed
Limitations of the Data Protection Act • Some data is excluded, for example data processed for the purpose of safeguarding national security or for the prevention or detection of crime • It can be difficult and time consuming to enforce the legislation for a data subject to find out what data is being held about them
Role of Data Controller • This is the person within the organisation responsible for ensuring compliance with the legislation • They determine the purposes for which the data is processed, the way in which the data is processed and monitors how data is processed
Rights of the Data Subject • Can view the data an organisation holds on them for a small fee • Can request that incorrect information be corrected • Can be compensated if their request is ignored, the request or the data concerned can be destroyed by court order • Can require that their data is not used for direct marketing
Copyright, Designs and Patents Act • Applies the concept of intellectual property/ownership to software • A licence is required for copyrighted software • It is illegal to copy unlicensed software • It is illegal to distribute unlicensed software
The Health and Safety at Work Act • Defines legal standards for computer equipment and identifies the steps employers must take to minimise risks • The Act places most responsibilities firmly with the employer • The employee may receive damages for injuries if the employer could have foreseen the risk and ignored it
Implications of ICT legislation for an organisation, its employees and members of the public
Eyestrain Can be minimised by: • Exercising the eyes by focusing on objects at varying distances • Blinking regularly • Keeping the air moist • Adjusting the screen height and seating
Repetitive Strain Injury (RSI) This can occur in the upper back, wrists, neck, causing a numbness. Can be minimised by: • Take regular breaks every half hour from working at your computer • Regularly stretch to relax the body • Use footrests, wrist rests and document holders • Use an ergonomically-designed keyboard
Carpal tunnel syndrome This occurs when a nerve is pinched causing numbness or pain Can be minimised by: • Wearing a wrist brace • Have a cortisone injection
Backache This affects the muscles in the back causing pain Can be minimised by: • Maintain a natural posture while using the computer • Have adequate lower back support and footrests
social, moral and ethical issues from the point of view of the professional arising from the use of ICT • Social: Refers to how someone gets along with people • Moral: What someone thinks is the best and right thing to do • Ethical: How someone perceives the world around them • Possible issues involve hacking, unlicensed software, privacy of data, security, property and copyright
Acceptable use policy • A rationale for the policy • The employer’s rights and the employee’s responsibilities regarding the use of ICT, for example the internet and email • Security procedures such as secure logging on and off • Prohibited actions which will compromise data security, e.g. the use of storage devices not checked for viruses • Management and employees responsibilities relating to legislation • The disciplinary process and the penalties for non-compliance
moral and ethical implications of ICT in relation to professional bodies British Computer Society (BCS) • Chartered institute for IT and computing specialists • Promotes wider social, economic progress through advancement of IT science and practice • Brings together academics to share knowledge and promote new thinking
Benefits of BCS • The BCS delivers a range of IT courses and training for beginners, home users, and professionals • Members can continue their professional development and get widely recognised qualifications or training
moral and ethical implications of ICT in relation to professional bodies Association for Computing Machinery (ACM) • Has a set of general moral imperatives which employees must abide by including trustworthiness, being fair, avoiding harm, and respecting privacy and confidentiality • More specific responsibilities are expected of members including maintaining professional competence, reviewing professional practice, honouring contracts, and only accessing information they are authorised to access • Members are expected to uphold and promote the principles of the code and violations of the code can mean members are removed from membership
Benefits of ACM • Access to a wide range of resources, such as publications or on-line books • Access to special interest groups which allow access to specialist publications or activities • Access to professional development courses and career advice • Contact with online forum groups communicating with fellow professionals throughout the world
Disadvantages of belonging to a professional body • Cost of membership • Abiding by code of conduct could lead to a competitive disadvantage • Extra responsibilities due to code of conduct which could incur costs
Impact of the increasing use of ICT in the Service sector • Primarily made up of insurance, tourism, banking, retail, and education • Information systems allows for analysis of trends and forward planning • In banks can use the internet to check the credit rating of any customers and contact their head branch to download details of the latest loan and investment products • In retail, management can use ICT to predict future sales and target specific segments of their market to promote certain products • In an insurance company, details about the client can be held
Impact of the increasing use of ICT in the Manufacturing sector Information systems assist manufacturing in the following ways: • Planning for the future is much easier today because historic and current trends in the marketplace can be accessed with great ease • The difficulty in assessing quantities of raw material is removed. Historical data of exactly how much raw material is consumed on each product, including wastage can be analysed • If a new product is to be made, CAD and CAM systems can be used to make production more efficient and accurate • A warehouse system could transmit orders for raw materials without humans even having to notice that stock levels are falling, or a courier could be automatically informed that goods are ready to be picked up
Use of ICT on the employee: Teleworking Teleworking is the use of ICT to enable people to work at a considerable distance from their conventional place of work
Use of ICT on the employee: Teleworking advantages for employees Advantages for employees • Reduced travel time, costs and stress • Less disruption to family life since the teleworker is at home more often and there is a reduced need to move house when relocated by work • Flexible hours suiting a person's preference rather than traditional 9 - 5
Use of ICT on the employee: Teleworking advantages Advantages for employers • Cost savings in term of premises and labour • Increased productivity due to reduced travel time and stress, and fewer interruptions • Improved motivation as employees respond well to the signal of trust that being allowed to telework gives them
Disadvantages of teleworking • An organisation may have less control over their employees. Management may find it more difficult to monitor the work rate of employees • Some people lack the motivation to work along, and need the discipline provided by set hours and a managed environment • The teleworker may find it difficult to concentrate in their home environment due to distractions De-skilling - Employees tasks may be taken over by a computer system that is more efficient. This has the risk of redundancy. Re-skilling - Employees may need to be trained to use new equipment which costs the organisation is terms of time and money
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