Please enable JavaScript.
Coggle requires JavaScript to display documents.
Y11 Jan mock 2022 - Coggle Diagram
Y11 Jan mock 2022
Threats and prevention
-
-
Access levels, read/write/execute
-
-
Physical security - locks, security guard, CCTV
-
-
-
Image representation
-
-
-
-
Metadata - data about data! E.g. date created, author, device image taken on
CPU
-
FDE
- Address from PC is copied to MAR
- Data or instruction from the memory location identified in the MAR is copied to the MDR
- Instruction is decoded by the CU
If it is a calculation, performed by the ALU, results of calculations are stored in the accumulator
- Program counter contains address of next instruction
Registers
MAR, MDR, accumulator, program counter, current instruction register
Performance
Cache size, clock speed, number of cores
Other factors affecting performance - RAM size, graphics card, type of hard drive - magnetic HDD or SSD
Networks
Topologies
Star
Central switch, if a device fails the rest of the network is unaffected, easy to add more devices, good performance. If there is a problem with the switch or the server the whole network is affected
Mesh
Fully connected - all devices are connected to one another, takes away the need for a central switch, if one node fails (NO SINGLE POINT OF FAILURE), there are alternative routes for data. Expensive because it requires a lot of cables, complicated to set up
-
Protocols
-
-
HTTPs - secure websites, encrypted
Email protocols
-
IMAP - I for incoming, you download a copy, email stays on server, once you delete it, it is deleted from server
POP3 - Post office protocol - POSTMAN PUTS LETTERS 'IN' YOUR LETTERBOX (incoming). Server holds email UNTIL you download it, at this point it is deleted from the server
-
Character sets
-
ASCII
7 bits for standard, 128 characters, 8 bits for extended, 256 characters
Unicode
16 bits, 65 thousand+ characters
Used to represent all of the languages of the world. ASCII was not big enough for languages like Chinese which uses lots of characters
Errors, testing, maintainability
-
Iterative and final
Iterative, test as you develop, final test once development is complete
Comments, indentation, sensible variable names
Primary storage
RAM
-
-
-
When RAM is full, a section of the hard drive can be used as RAM, this is called virtual memory
-
-
Search algs
Binary - midpoint, discards left/right, must be in order, good for large lists
Linear - checks one at a time, good for small lists
Data types
Integer (whole number), string, boolean (true or false), character, float/real (with decimal)