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Computer Science (ATAR Year 12 - All Topics)

Ronan Kavanagh Computer Science Year 11 Englisch 192 Karten

Karten in diesem Stapel (192)

  1. 1ProgramAn organised list of instructions that when executed by a computer causes it to perform a specific task.
  2. 2PrototypeA scaled down, working version of the final product meant to:
    - Test design aspects and features
    - Illustrate ideas
    - Get user feedback
  3. 3SDLC StepsPreliminary Analysis
    Analysis
    Design
    Develop
    Implementation
    Evaluation and Maintenance
  4. 4Preliminary Analysis + ExampleThe project is analysed to see if it is economically viable.
    Ex: Feasibility study, problem defintion
  5. 5Analysis + ExampleThe cost and resources of the current system and the ones to be used are analysed
    Ex: Model of current system, requirements of system
  6. 6Design + ExampleThe system is designed using charts, diagrams and prototypes.
    Ex: Creating a GANTT chart, creating a prototype, logical/physical design
  7. 7Develop + ExampleThe system is developed using the hardware and software required.
    Ex: Hardware/Software acquisition, construction + testing
  8. 8Implementation + ExampleIt is decided how the new system will take over the old system
    Ex: Phased, Pilot, Parallel, Direct Cut
  9. 9Evaluation and Maintenance + ExampleCheck if the system meets the requirements of the project, preventative maintenance and troubleshooting
    Ex: Performance evaluation, fault finding + correction
  10. 10Network Topology TypesStar
    Bus
    Ring
    Extended Star
  11. 11Star Network Topology 1 AdvantageAll computers connected to a central computer or database.
    Adv.: If noncentral computer has problems, rest of network still functions
  12. 12Star Network Topology 1 DisadvantageAll computers connected to a central computer or database.
    Disadv.: If central computer fails, the whole network ceases to function
  13. 13PAN + ExamplePersonal Area Network: Several different devices connected to a person's personal computer
    Example: Bluetooth devices connected to laptop
  14. 14LAN + ExampleLocal Area Network: A network that spans a geographically small area.
    Example: A group of computers and a server in one room connected in a star topology
  15. 15WiMAX vs WiFiWorldwide Interoperability for Microwave Access X:
    . Nodes can cover wider range than WiFi
  16. 16HTTP + How it sends textHyper Text Transfer Protocol: Defines how messages are formatted and transmitted and what actions web servers and browsers should take in response to them.
    Sends in plain text
  17. 17HTTPS + How it sends textHyper Text Transfer Protocol: Defines how messages are formatted and transmitted and what actions web servers and browsers should take in response to them.
    Sends in cipher text
  18. 18Communication ProtocolsFTP: File Transfer Protocol
    HTTP: Hyper Text Transfer Protocol
    HTTPS: Hyper Text Transfer Protocol Secure
    SMTP: Simple Mail Transfer Protocol
    WAP: Wireless Application Protocol
    TCP: Transmission Control Protocol
  19. 19FTP DefinitionFile Transfer Protocol: Promotes sharing of files via remote computers with reliable/efficient data transfer.
  20. 20How Does FTP Work? (Hint: 3 points)- FTP requires user + pass
    - User computer = Local Host Machine (retrieving files) connects to remote host
    - Files can be transferred between both hosts
  21. 21Basic Components of a Data Communications System (5 Marks)Sending device
    Message (signal)
    Protocols
    Receiving device
    Transmission medium
  22. 22Protocol (2 marks)- Collection of steps required for two entities to communicate
    - Separated into logical layers
  23. 23Digital Signal (3 marks)Distinct on or off pulses.
    Not continuous
    Specific values to represent information
  24. 24Analogue Signal (2 marks)Continual electrical signal in a carrier wave with specific AMPLITUDE and FREQUENCY
  25. 25Ethernet Cable (2 Marks)Network protocol that accesses the network by first listening to see if the cable is free.
    Two nodes transmitting at same time is called a collision
  26. 26BandwidthThe amount of data, instructions and information that can travel over a communication channel
  27. 27Twisted PairTwo insulated wires twisted around each other to create interference protecting magnetic field
  28. 28Unshielded Twisted Pair + 2 UsesTwisted core is covered with plastic material without cladding material.
    LAN network use
    Low cost
  29. 29Fibre OpticMade up of one or more thin strands of glass or plastic tubules
    Uses light signals
  30. 30Benchmark TestingPerformance test of hardware and/or software that uses specific measured indicators
    (ex: time to render 3D graphics)
  31. 31Rapid Application Developement (RAD) [5 marks]- Increased speed and quality
    - Relies on high user involvement
    - Prototyping
    - Integrated CASE (computer aided software engineering) tools
    - Code generators
  32. 32RAD StepsInitiate: Project setup + preliminary interviews
    Develop: Develop + Evaluate iterations #
    Deploy: Review, rebuild and implement
  33. 33JAD- Users, analysts and managers work together
    - Specifies and reviews system requirements through intensive meetings
  34. 34Project ManagementThe set of procedures, rules, technologies and practices that managers use to organise, staff, direct and control a project or system can be delivered ON TIME, IN BUDGET, MEETING REQUIREMENTS of user
  35. 35What is MRIBOT in project management?Meeting Requirements, In Budget, On Time
  36. 36Insert AnomalyData added to poorly constructed table results in data repetition
    Effect: Increases input error and null value chance
  37. 37Update AnomalySame piece of data appears multiple times = Multiple changes needed when updating
    Effect: If all changes not made, data becomes inconsistent
  38. 38Delete Anomaly- When an unnormalised table has records holding data on mult. entities
    - Deleting one record can unintentionally delete other entity information if appears only once
  39. 39Flat FileSingle relation
    Cannot be cross-referenced
    Cannot be linked
  40. 40Waterfall/Linear SDLCEach stage occurs serially
  41. 41Linear/Waterfall Pros/ConsPros: Not many unforeseen costs, time limits can be achieved, large projects
    Cons: Difficult to make changes later, if logical/physical flaw found late = costly, takes long time to implement
  42. 42Prototype Pros/ConsPros: Allows analyst achieve user requirements better, involves user sooner, reduces user training, cost effective
    Cons: Unpredictable time/costs
  43. 43Iterative - RADRapid Application Development
    Gathers system requirements using JAD
    Constant feedback from users/customers
    Any quick method
  44. 44JADJoint Application Development
    Intense workshops + focus groups
    Prototyping + User feedback
    Re-use of software components (CASE)
  45. 45RAD Pros / ConsPros: Faster than SDLC, short dev cycles, flexible to change, meet users need better, feel more comfortable
    Cons: Lower testing level may be carried out, may be difficult to involve important users
  46. 46OS DefinitionSoftware that makes computer work
    Co-ordinates all aspects on computer
    Controls CPU
    Manages software
    Can access memory and other devices
  47. 47Role of OSScheduling tasks: Task priority and resource allocation
    Managing concurrency: Simultaneous running decisions
    Managing memory and addresses
    Manage devices
  48. 48Types of OSEmbedded
    Standalone
    Server
  49. 49Embedded OS [3 Marks]-Built in to specific hardware config
    -Designed to be compact and resource efficient + lightweight
    -Designed to run particular task efficiently
  50. 50Standalone OS [4 Marks]Works on device by itself
    Does not require any other library or another OS to boot
    OS never exits, begins own execution, never fully hands over execution
    Loads into memory
  51. 51Server OS [2 Marks]Designed for specific task (usually over network)
    Has special features required by client-server architecture
  52. 52Role of File Systems [3 Marks]- Space management
    - File naming
    - File directory creation
  53. 53File Names- Used to identify where specific set of information stored in file system
    - File name is identifier given to computer file
  54. 54Directories- Folders = Directories
    - Capable of grouping specific files to centralised place
  55. 55Database Normalisation Definition + 3 RolesBreaks down and splits table into smaller ones to:
    - Implement into relational database
    - Eliminate redundancy
    - Organise data efficiently
    - Reduce potential for data anomalies
    - Reduce file size (data stored only once)
  56. 561st Normal Form Requirements [3 Marks]- Each table has PK
    - Each field has atomic value
    - All repeated fields removed
  57. 572nd Normal Form Requirements [4 Marks]- All 1NF requirements met
    - Redundant data and separate entities moved to new table
    - Create/Identify primary keys for new relations
    - Resulting tables related by foreign key
  58. 583rd Normal Form- Each non-key field functionally dependent on primary key
  59. 59Router- Communication device that forwards packets from one network to another
    - Can be used to create subnetworks to balance traffic
  60. 60Gateway- Entrance to another network
    - Can be hardware or software
    - Can translate different protocols (even different types of network can communicate)
  61. 61Firewall- Filters data coming thru internet connection
    - Prevents unauthorised user access to private networks
    - Each message examined and those not meeting criteria blocked
  62. 62Modem- Converts digital and analogue signals
    - Can then be transmitted over a telephone line or digitally
  63. 63Repeater- Extends a network reach
    - Regenerates signal received
  64. 64Switch- Connects network segments and devices
    - Uses MAC addresses to filter/forward traffic to designated device
  65. 65What is Twisted Pair Used For?Telephone + LAN
  66. 66What is the range of UTP and STP and what is the bitrate?- 100 metres
    - 1 Gbps
  67. 67Single Mode vs Multi-Mode Fibre OpticSingle Mode: Single light wave, 3 km
    Multi-mode: Multiple light waves, 2 km
  68. 68Broadcast Radio Advantages/Disadvantages- Slower and susceptible to noise than wired
    + Flexability and portability
  69. 69Microwave Advantages/Disadvantages+ Can have thousands of individual channels
    - "Line of sight", meaning it relies on repeaters every 30-50 km
  70. 70Satellite Advantages/Disadvantages+ Long distance
    - Long delay (about 500 ms)
  71. 71Cellular Transmission Def + Advantages/DisadvantagesNetwork area divided into cells, closest station picks up signal and passes to destination device or station
    - Radio waves can be intercepted
    + Low cost, portability
  72. 72CSMA/CD LAN Process (4 marks)1. Node "listens" to medium to detect idle state
    2. If has data to transmit, transmits to idle medium
    3. Stop and wait occurs if collision
    4. Random transmission before retransmission
  73. 73CSMA/CA1. Node wanting to transmit sends RTS (request to sent) frame
    2. If receiving node permits, it sends CTS (clear to send)
    3. After CTS received by transmitting node it transmits. Other device sense CTS and do not contest.
  74. 74Point-To-Point Networks- Dedicated link between two devices
    - Typically use wired connection
    example: Two computers communicating via modems
  75. 75Why IPV4 to IPV6- Number of addresses possible with 4 octets running out
    - IPV6 has 6 octets
  76. 76IEEE 802.3- Ethernet
    - Uses wired CSMA/CD
    - Can be implemented
    - Divides all data being transmitted into variable length frames
  77. 77IEEE 802.5Token passing
  78. 78IEEE 802.3 vs 803.3u vs 803.3z802.3 = Ethernet (CSMA/CD) access method
    802.3u = Fast ethernet
    802.3z = Gigabit ethernet
  79. 79IEEE 802.15Bluetooth (point-to-point)
  80. 80SMTPSimple mail transfer protocol stores and forwards email messages.
    Messages encrypted using Pretty Good Privacy and Secure Locket Layer.
  81. 81Proxy Server- Intercepts all requests to a webs server to see if it can fulfil the requests itself (ex. present cached pages)
    - Forwards to web server if unable to
    - Saves time + traffic
  82. 82Web Server- Stores web pages that can be requested by client
    - Uses HTML and HTTP to format webpages and transfer to client
  83. 83Applications Server- Holds programs and data that adds functionality to webpages
    - Example: Feedback forms + database data
  84. 84SAN (4 marks)- Block based storage area network
    - Appears as a local disk to client OS
    - High end servers, disk arrays and mediums
    - Each server has specific, dedicated access to disk arrays
  85. 85NAS (3 marks)- Provides file level storage when NAS device installed via TCP/IP
    - Appears as file server to client OS
    - Files on NAS can be accessed by workstations and servers
  86. 86Layers of TCP/IP ModelApplication
    Transport
    Internet
    Link
  87. 87Application Layer of TCP/IP + Protocols- Defines protocols that allow user to interact w/ network
    - Ensures: Data representation, encoding + dialog control
    - Protocols: HTTP, SMTP, HTTP, FTP, DNS
  88. 88Transport Layer of TCP/IP + Protocols- Defines how data flows between hosts
    - Ensures: Reliability, flow control and retransmission
    Protocols: TCP, UDP
  89. 89Internet Layer of TCP/IP + Protocols- Defines routing of source packets in internetwork to destination
    - Ensures: Packet path independent of path and networks taken to get there
    - Protocols: IPv4, IPv6, ICMP
  90. 90Link Layer of TCP/IP + Protocols- Defines issues IP packet requires to cross physical link between two devices
    - Protocols: MAC, PPP, ARP
  91. 91TCP/IP Role- TCP: Terminating, establishing and maintaining connection
    - IP: Data transfer, packet addressing, packet routing and fragmentation
  92. 92Parity Checking vs Checksum ByteParity Checking: Parity bit added to each coded character
    Checksum Byte: Checksum byte added to a block transmission (around 500 characters). Uses NACK/ACK.
  93. 93Client Computer- Communicates with a server computer to access their data and resources
  94. 94Server Computer- Manages network resources (example: hard disk storage, printer + internet access)
  95. 95"The Internet is decentralised" What does this mean?- Each host/network connected to the internet is independent
  96. 96Local Carrier- Provides the "backbone" of the Internet between cities/countries
  97. 97ISP Definition- Host the servers (Points of Presence) that allow users to connect to the Internet infrastructure placed by local carrier
  98. 98SDLC Data Gathering TechniquesObservation
    Questionaire
    Interview
    Sample forms
    Sampling volume of work processed by system
  99. 99Standard Operating Environment- Set of selected software
    - Installed on all computers on a network within an organisation
    - All machines have same hardware architecture
  100. 100SOE Pros- Cost effective and efficient in purchasing and maintaining hardware/software
    - Network service tasks can be automated, standardised and regulated
  101. 101SOE Cons- Users may need to adjust to an operating system or software not familiar with
    - Specialist software sometimes unavailable
    - Network admin may be needed
  102. 102Role of Drivers- Software that gives directions to a computer on how to operate a device
    Example: Installing printer drivers to use printer hardware
  103. 103Virtualisation- Simulated version of something
    Example: OS, server, storage device, network resources
  104. 104Platform Virtualisation (2 marks)- Virtual machine as compact, isolated software container simulating an OS
    - Other devices, including the VM, sees it as a real computer
  105. 105Virtualisation benefits (4 marks)- Cost efficient (less hardware, energy efficient)
    - Faster application/service delivery
    - VM can be moved to other hardware
    - Easier backup + better disaster recovery
  106. 106CPU Components- ALU
    - Control unit
    - Registers
    - Program counter
    - System Clock
    - Data, address and control bus
  107. 107ALU- Performs all arithmetic operations of a CPU such as +, -, multiplication and logic operations (comparisons, <, >)
    - Used during "Execute"
  108. 108CU- Control unit extracts instructions from registers and decodes them
    - Instructs other parts of CPU such as ALU by ensuring decoded instructions are run
    - Used for "Decode" in Fetch-Execute cycle
  109. 109Registers + Types- Fastest memory type in a CPU
    - Instructions called from registers during "Fetch"
    Instruction
    Address (Program Counter)
    Status
    General
  110. 110Program Counter- Type of register that contains address for instruction currently being executed
    - Also counts the sequence of instructions
  111. 111System Clock- Regulates timing and speed of computer instructions
    - Uses a vibrating quartz crystal, each pulse a clock cycle
    - Controls operation of various system buses in computer
  112. 112Fetch-Execute Cycle Steps1. Fetch
    2. Decode
    3. Execute
    4. Store
  113. 113Control Bus- Bus lines used within CPU that allows communication between components
    - Indicates whether operation is read or write
  114. 114Data Bus- Two way (read/write) bus lines used by CPU to communicate with other devices
    - Transfers program instructions to CPU
  115. 115Address Bus- Specifies the memory address in the device CPU is communicating with
  116. 116Fetch (Fetch-Execute Cycle)1. The CU gets address from program counter
    Instruction fetched from address and stored in instruction register
  117. 117Decode (Fetch-Execute Cycle)2. The instruction set is decoded by the control unit so it can be processed (executed)
  118. 118Execute (Fetch-Execute Cycle)3. Control unit moves data into ALU registers where arithmetic and logical instructions executed
  119. 119Store (Fetch-Execute Cycle)4. The results are written back into primary memory or register by the CU
  120. 120Multi-Processor System- Computer with multiple processors allowing simultaneous instruction processing
    - Faster data processing
  121. 121Processing TypesSequential
    Parallel
    Distributed
  122. 122Sequential Processing- Single task run until completion on single processor
    - Tasks only completed one at a time
  123. 123Parallel Processing- Multiple processors w/ program tasks broken up and shared amongst them
    - CU reassembles results afterwards
  124. 124Distributed Processing- Multiple processors w/ task broken up and shared amongst them
    - Uses different types of components (e.g. graphics card)
    - May be "farmed out" to CPUs in other computers
  125. 125Benchmarking- Testing the performance of hardware or software by using specific, measured indicators
    - Enables comparison between similar parts (e.g. processing speed of CPUs)
  126. 126Disaster Recovery Purpose- Plan that details how to protect computer system during/after a disaster
    - Specifies how to minimise downtime and data loss
  127. 127Disaster Recovery ToolsRedundant Array of Independent Disks (RAID)
    Tape Backup (magnetic tape cartridge)
    CD-RW, DVD-RAM, Blu-Ray
  128. 128Backup Procedures + ExplanationsIncremental (Archival): Only files changed since last backup saved
    Full: Copies and backs up all files in a computer
  129. 129Incremental Backup Pros/ConsPros: Fastest method, requires minimal storage space, only most recent changes saved
    Cons: Recovery time consuming (all incremental backups and last full backup needed)
  130. 130Full Backup Pros/ConsPros: Fastest recovery method, All files saved
    Cons: Longest backup time
  131. 131RAID 0- "Striping" is used: Data broken up and spread across disks
    - One disk used to keep track of data locations (increased speed)
    - No redundancy (no backup)
  132. 132RAID 1- Data duplicated into separate hard disk drive
    - 100% redundancy
    - Can survive one disk failure
  133. 133RAID 10- Nested/Hybrid RAID
    - Multiple level one RAIDs in "pairs"
    Visual:
    | 1 | 1 | | 2 | 2 |
    | 3 | 3 | | 4 | 4 |
    | 5 | 5 | | 6 | 6 |
  134. 134Uninterruptable Power Supply- Provides emergency power to a comp. system in case of power failure
    - Gives time for main power source to be activated or for a proper shutdown
  135. 135Desktop Virtualisation- Servers host entire desktop environment and its' applications specific to each user
  136. 136Personal Computer Virtualisation- Physical computer runs multiple virtual PCs (with their own OS and applications)
    - Switching can be done without needing to reboot
  137. 137Server Virtualisation- Multiple logical servers hosted on one physical computer
    - Can be used to have many low-power servers on one device (e.g. email, file storage, print)
  138. 138Storage Virtualisation- Many physical storage devices appear as single logical storage device
    - Makes it easier to manage data
  139. 139Platform with application virtualisation purpose- Virtualised applications bring down their own environment on demand, isolated from OS
  140. 140Software License Requirements TypesNetwork
    Enterprise
    Commercial/Proprietary
    End User License Agreement (EULA)
  141. 141Network- Can only be installed on certain # of devices
    - License purchased for every device ("per seat")
  142. 142Enterprise- Agreement between software dev and organisation
    - Allows all users to install software on any device unrestricted
  143. 143Commercial/Proprietary- Licensed under exclusive legal right of copyright holder
    - Can only be used under certain conditions (cannot modify, further distribute or reverse engineer)
  144. 144EULA- End user license agreement
    - Legal contract between manufacturer or author of software and end user
    - Aims to protect both parties from liability if software is used in unintended way
    - Details how software can/cannot be used
  145. 145Cloud Computing- A network of remote servers hosted on Internet rather than local server/personal computer
    - Can store, manage and process data
  146. 146Distributed Database- Data broken up + stored across multiple computers across network
    - Each sites is independent, but sites work together as though combined
  147. 147Centralised Database- Database and DBMS at same site (all processing done at site)
    - Can be accessed by terminals connected to site
  148. 148Distributed Database Pros- Local control over database (e.g. security, hardware)
    - Not reliant on central site (reduced vulnerability + bottlenecks)
    - Easy to add other sites
    - Query processing faster
  149. 149Distributed Database Cons- Requires complex software/high costs
    - Harder to manage (more complex)
    - More processing power used for queries
  150. 150Centralised Database Pros- Only requires simple DBMS
    - Easier to manage security + integrity
  151. 151Centralised Database Cons- Susceptible to bottlenecks
    - If central database fails, cannot be used
    - May be difficult to expand
  152. 152Data Warehouse- Huge database system
    - Stores and manages data about past and present transactions of an entire business
  153. 153Data Mining- Using data from a data warehouse to make predictions that may be useful
    - Finds pattern/relationships amongst data
  154. 154Centralised Database- DBMS and database at single site (all processing done there)
    - Data can be accessed remotely via connected terminals
  155. 155Centralised Database Pros- Only requires simple DBMS
    - Easier to manage security and integrity (one location)
  156. 156Centralised Database Cons- If central database fails, cannot be used
    - Bottlenecks may occur
    - May be difficult to expand on
  157. 157Distributed Database Pros- Avoids bottlenecks
    - Faster query processing
    - Easy to add different sites
  158. 158Distributed Database Cons- Requires complex DBMS/Software
    - Higher cost to run
    - More difficult to manage
    - Requires more processing power and maintenance
  159. 159Data Warehouse- Huge database system
    - Has data of an entire businesses' past and present transactions
    - Data can be used for data mining
  160. 160Data Mart- Subsection of a data warehouse
    - Relates to specific category of a business (e.g. marketing, sales)
    - Easy access to frequently needed data
  161. 161Ethical Issues Using Data WarehousesPrivacy Control: Makes it possible to analyse routine of buyers
    Misinterpretation of Data: Data quality may not be high, correlation vs causation
  162. 1623 things users tracked by a Data Warehouse should know:- The purpose of the data collection
    - How it will be used
    - Who will be able to mine it and see it
    - What limits are on the data mining
    - What securities protect their data
    - How their data can be collected
    - Laws that permit government to access it
  163. 163Domain Name System- Distributed database
    - Can resolve a hostname (translate domain name into IP address), and if can't asks other DN server
  164. 164Interpreter vs CompilerInterpreter: Translates source code into machine code line by line as the program runs
    Compiler: Translates source code in one go before the program runs
  165. 165Syntax Error- Code syntax is not followed correctly leading to it unable to be executed
  166. 166Logic Error- Program runs but an error in the algorithm causes an unexpected result to occur
  167. 167Run-Time Error- While program is running, error causes program to terminate or fail unexpectedly
    - e.g. trying to divide by 0, datatype mismatch
  168. 168Internal Documentation Examples- Documentation that makes the program easier to understand for programmers
    - Example: Comments
  169. 169Modem- Converts signals between digital and analogue
  170. 170Bridge- Connects two similar network segments + translates protocols allowing communication
  171. 171Gateway- Entrance to another network
    - Can translate protocols allowing different network types to communicate
  172. 172TCP/IP LayersApplication
    Transport
    Internet
    Network
  173. 173Application Layer- Has protocols that allow user to interact with network
    Example: Dialog control, data representation
  174. 174Transport Layer- Has protocols that controls how data flows between hosts
    Example: Ensures reliability, flow control, retransmission
  175. 175Internet- Defines the routing packets take to the correct destination
  176. 176Link Layer- Defines the issues an IP packet requires to cross a physical link between two devices
  177. 177Methods Used to Compromise Network SecurityDenial of Service (DoS)
    Back Doors
    IP Spoofing
    Phishing
  178. 178Denial of Service- Attack tries to consume network/website resources such as CPU, memory, disk space etc.
    - Continually sending page or login requests can cause this
  179. 179Back Door- "Back door" created by programmer or hacker is used to bypass security measures
  180. 180IP Spoofing- Hacker changes the IP address on packet headers to a trusted host
    - Can be used to gain unauthorised access to a network and can be used for DoS
  181. 181Phishing- E-mail fraud method where hacker pretends to be legitimate entity
    - Can be used to extract personal and financial information
  182. 182Cloud Computing Disadvantages- Cloud servers do not have redundancy and are not backed up
    - May be bandwidth issues (must be enough servers for devices)
  183. 183Cloud Computing Advantages- No hardware required (no physical store centre)
    - Easily accessible (from anywhere)
  184. 184Factors Influencing Performance of NetworkBandwidth
    Network Design
    Data Collisions
    Excess Broadband Traffic
  185. 185Bandwidth effect on Network Performance- Amount of data that can be transmitted can decreased if network enabling devices fail
    - Fast or gigabit internet can increase performance
  186. 186Network Design- Schematic method of showing physical devices/communication lines present
    When creating networks:
    - Ability to fulfil required functions (ex: running applications, compatibility)
    - LAN protocols
    - Security and cost
    - Expansion potential
  187. 187Data Collisions- When two nodes in same network transmit at same time
    - Packets collide and are fragmented and must be retransmitted
    - Network segmentation reduces data collisions (using switch or router)
  188. 188Excess Broadcast Traffic- Causes a slowdown in accessing network services/resources
    - Consumes bandwidth unnecessarily
  189. 189Referential Integrity- Ensures foreign keys in one table match primary key in another table
    - Ensures the link created is active
  190. 190Domain Integrity + Example- Ensures fields store values of correct type, format and range
    Data Types: Ensures data is stored in consistent types
    Field Sizes: Data is stored in most useful and economical way
    Default Values: Specifies a value that is entered when no explicit value entered
  191. 191Passing Parameters by Value- The function/module calls a copy of a variable from another function/module
    - Changing the variable will not change it in its' origin function/module due to it being a copy
  192. 192Passing Parameters by Reference- Sends a memory reference to the function/module
    - Ehen it changes it, it changes in the original function/module it was declared in

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Beschreibung
Year 12 ATAR Computer Science terms and definitions, made using the Year 12 2020 ATAR syllabus.
Erstellt von
Ronan Kavanagh
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101
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