ISDD Flashcards
Describe the structure of a database?
Databases contain tables, these tables contain records which is all the data stored about one object, the records contain fields which is a single piece of information on the object.
What are the advantages of a relational database?
avoid unnecessary duplication of data
tables are linked so data only needs to be changed once
What are the purpose of primary, surrogate, foreign and compound keys?
Primary key is a unique identifier for a record
A surrogate key is a field in a table which has been created to ensure a unique field exists
A foreign key is used to link fields together in different databases
A compound key combines more than one field in order to make a unique value
What are the purpose of tables, forms and reports?
tables display large amounts of data on the one screen
A form is graphical and displays one record at a time
A report is used to arrange data into an easy to read or print format
What is meant by a relationship in a database?
a relationship is when one or more entity is associated with each other
What is a calculated field?
A calculated field is one which is created using a query which calculates a result from one or more existing fields
How can websites be structured?
Websites can be structured in a linear format or in a hierarchical format
What will all websites contain?
Head, title and body
What do style sheets allow us to do?
Style sheets allow us to separate the look and feel of a web page from its content and structure.
Make sure pages on a web page are consistent in appearance
How can web pages be structured into different sections?
Using , and
What does CSS stand for and what is it used for?
Cascading style sheets
is a standard way of implementing style sheets
What does CSS consist of?
Consists of rules they are made up of a selector and a group of attributes called the declaration
Where is metadata found?
Metadata is found in the head section of a webpage
What is Metadata used for?
Metadata is used to give information about a webpage
What are static web pages and what is a dynamic web page?
A static web page does not change every time they are viewed
A dynamic web page contains information which will change each time the page is loaded
What is an interactive web page?
An interactive web page is one that requires the user to click on buttons or other elements in order to interact
What is a database driven website?
A database driven website is a dynamic web page which allows users to search through stored information.
What is a standard file format?
A standard file format is one which will open and display correctly on all platforms?
Why is compression necessary and what its advantages?
Media files can be very large.
allows more files to be stored on to backing storage
files will be faster to transmit and download over the internet
What is compressions job?
Compression is used to reduce the size of files
Explain the difference between lossless and lossy compression?
lossless reduces file size but does not lose any information. lossy reduces file size but loses information
How can the size of sound files be reduced?
Croppping
Lowering sampling depth
lowering sampling frequency
How can the size of graphics files be reduced?
Cropping
lowering resolution
changing colour depth
How can the size of video files be reduced?
Shorten length
altering resolution
reducing the frame rate
What is the two types of video compression and explain them?
Inter-frame and intra-frame compression.
Inter-frame stores the information which changes between each frame after storing a reference frame.
Intra frame treats each frame as a bitmapped graphic and uses graphic compression techniques
What can a scripting language be used for?
A scripting language can be used to automate a complicated process, automate a repetitive action, create macros or to add functionality to an application
can also be used to add interactive features to a web page
What is a script and what does it provide?
A script is code for a website that allows changes every rime the web page is visited.
A script also provides interactivity
What is client side scripting?
Client side scripting is where the code for the scripts are executed on the users computer
What is server side scripting?
Server side scripting is where the code for the scripts is executed on the server
How does server side scripting allow for more security?
User is unable to view or access scripts
What is search engine optimisation?
Trying to achieve a high ranking for a website within a search engine.
How to websites reduce loading time?
Websites will have their code and media files optimised to reduce load times.
Why is testing a website essential?
Ensure all hyperlinks work correctly, pictures display clearly and that there are no spelling or grammar errors.
What is beta testing?
Beta testing is when users outside of the design process use real world test data in order to test the software
How would a website have good usability?
If it contains clear information and can be easily accessed by a range of users
what does usability depend on?
Target audience, type of user, navigation, screen layout and accessibility
How may different devices not be able to display a website?
not enough RAM, hard drive space or correct browser
Modern websites make use of responsive design which is what?
Where the style sheets rules will differ for different platforms.
Describe data?
Data is unprocessed and has no meaning
Describe information?
Information has been processed and has a meaning
What is an information system?
An information system is where data can be collected, processed and stored on a computer
How can information on the web be hidden?
giving instructions to search engine web crawlers
What are the purpose of input and output devices?
input devices are used to put data into a computer. Output devices are used to display processed data.
How can digital cameras be compared?
resolution
zoom capabilities
battery life
extra features
How are touchscreens used?
a monitor you can touch, touch controls a mouse
What are the different types of scanning?
OCR - optical character recognition, saves parts as ASCII file
OMR - Optical Mark Reading, inputs large amounts of data
How can barcode scanning be linked to database inputs?
Each barcode acts as a record in the database
What are the different types of monitor available?
LCD - Liquid crystal display
Touchscreen
OLED- Organic Light Emitting Displays
LCD Projectors
How can printers be compared?
Resolution of printout
Print speed
How can processors be compared?
Type of Processor
Number of Processors
Speed of Processor
Amount of Cache memory
What is the difference between main memory and backing storage?
Main memory stores programs and data when they are being used
Backing storage stores programs and dat when the computer is off
What are the differences between ROM and RAM?
ROM - Read only memory
RAM-Random Access memory
What is cache memory and how can it improve a computers performance?
Faster memory
located on or near the processor which reduces time for fetch execute cycle
What is the operating system responsible for?
The responsible for interpreting user commands, file management, memory management, input/output management, error reporting and resource allocation
All software should come with what?
A licence
What are the different types of licence available?
Single use or site use
Explain freeware?
Freeware is software which is free but cannot be edited
Explain shareware?
Shareware may be free for a trial but then the user is expected to pay to use the program or access full functions
Explain proprietary software?
Known as closed source, source code is not available and cannot be modified
Explain open source software?
Software can be modified to suit user
What is commercial software?
Commercial software is software that is sold for a profit
What is portability?
Portability is if the software can run on more than one platform or device
Different hardware devices require different types of what?
Operating system
Explain distributed storage?
Several computers are used to store all the information in a network
Why is offline storage very secure?
it cannot be accessed electronically
What is a backup?
A backup is a second copy of information
how may backups be stored?
using separate backing storage devices or cloud computing
What is a backup strategy?
A backup strategy is a plan of how an organisation is going to manage its backups, what information will be backed up how often backups are made and where they will be stored
What is meant by data transfer speed?
Data transfer speed is the rate at which information can be transferred between devices
How does Magnetic storage work?
Magnetic storage uses magnetic charges stored on metal oxide to represent data
How does optical storage work?
Optical storage uses the reflection of light from a surface or lands and pits to represent data
What is a network?
A network is two or more computers connected together
What is meant by connectivity?
Connectivity is how the computers are connected together
Explain a cloud system?
A cloud system allows information to be stored on servers provided by a company and the information can then be accessed from anywhere
Cloud systems reduce what?
Cloud systems reduce the hardware and software demands placed on a company’s network
Why is cloud based computing so secure?
Regular backups are taken constantly
explain private public and hybrid clouds?
A private cloud is limited to one company or person, a public cloud is open to any user, a hybrid cloud is a combination of both
What is web hosting?
Web hosting is where a company provides space on a web server to save pages so they can be accessed over the internet
What are switches used for?
Switches are used to speed up communication between devices within Local area networks
What are routers used for?
Routers are used to send packets between networks over the internet
What is phising?
Phishing is an attempt to get users to pass on sensitive information to criminals using fake communications
What are viruses?
Viruses are malicious programs that can replicate by copying their code into other programs
What are worms?
Worms are malicious programs that replicate across network connections
What is a Trojan horse?
A program which appears to be legitimate but hides a malicious action
What is spyware?
Spyware is used to spy on you whilst you are using the computer?
What is keylogging?
Keylogging keeps track of each key which is pressed on a keyboard.
Describe a DOS attack?
A DOS attack aims to bring down a server or a network so that it is not available to use
What is Ransomware?
Ransomware is software which encrypts the files on a network so that they can only be accessed when the decryption key is purchased
Explain a DDOS attack?
A DDOS attack aims to bring down a network by swarming it with requests from many computers.
What are two methods of protecting a computer system from security risks?
Anti virus and firewalls
Explain encryption and decryption?
Encryption is using a key to turn data into seemingly meaningless content.
Decryption is reversing the original process using the key
What is meant by symmetric key encryption?
The same key is used for both encryption and decryption
Explain public and private key?
Public key encryption means the encryption key is available to anyone to use to encrypt data. only the private key can be used to decrypt data and is kept to one person
what is a digital certificate?
A digital certificate is an electronic document that contains an electronic signature which is used to identify an organisation or individual
What is a digital signature?
A digital signature is an electronic signature that can be used to authenticate the identity of someone sending you information
What is validation?
Validation is used to check information which is being entered into a website or program/information system
The regulation of Investigatory Powers Act gives the government the power to do what?
Intercept and acquire data on communications from service providers
Set up surveillance on individuals or organisations
Access encrypted data
In modern/recent years computers have become what?
More affordable, portable and run faster
What is an intelligent system?
An intelligent system is a machine that has the ability to perform a task that would require intelligence if they were performed by a human.
The use or creation of a computer system creates a what?
A carbon footprint.
