Computer Science OCR Flashcards
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bandwidth
The amount of data that can be transmitted over a period of time
What is LAN
Network that is located in a small geographical network. in a LAN you own all the hardware
WAN
The network covers a wider location, a large geographical area, made up of multiple LANs. The hardware is owned by the government.
Types of connection
Copper cable, Wi-fi, fibre-optic cable, Bluetooth. Some are faster than others, and wired is usually faster than wireless.
How does number devices affect a network speed.
The more devices connected means the bandwidth must equally spread amongst each devices, resulting in a lower bandwidth for each device.
interference
Physical walls and additional radio signals can interfere with a with a wireless connection. This slows it down.
Network latency
Measure of how long it takes for a signal to reach its destination. Latency is affected by number of devices on a network.
Concept of layers
Breaking down networking into smaller tasks that work with each other e.g your browser does not care whether you are wired or wireless. Can reduce difficulty as it smaller tasks
Protocols
A set of rules that determine how computers communicate with each other
Standards
a common standard that manufacturers agree on when making things work with each other
Protocols names: TCP/IP (transmission control/internet protocol)
Enables communication over the internet
HTTP(hypertext transfer protocol)
governs communication between a client and webserver, used to send web pages
HTTPS (hypertext transfer protocol secure)
Same as http, but encrypted to provide extra security
FTP (File transfer protocol)
Allows transfer of files between computers
POP (post office protocol)
Governs retrieving emails from email servers, and downloads
IMAP
Internet Message
Access Protocol
IMAP
Internet Message
Access Protocol
SMTP
Simple Mail Transfer
Protocol
Protocol used to send email from a web browser or
client.
Malware
Suspicious software
virus
infects files and needs human to spread
worm
Infects the whole computer and doesnt need as human to spread
trojan horse
appears to be friendly but in the backround does something bad
spyware
controls hardware and utilies it
brute force attack
trying to guess a password
virtual memory
moves data into ssd
optical
uses laser to save as 1s and 0s
magnetic
uses magnets to get binary
solid state
stored on chips electronically
RAM
Very fats storage non volatile
ROM
Used to start up a computer e.g bios
embedded system
a small program that loops commands
von neumann architecture
puts program data and instructions into ram
clock speed
how many fetchb decode execute cyckles can be done in a second
number of cores
each core can be allocated to do something
cache
small and super fast storage that holds previously used program instructions
register
very small but very fast storage, used to hold data or an address
ALU
arithmetic logic unit, performs maths and logic checks
Control Unit (CU)
Directs operation of processer
MAR
memory address register, stores address of next data to be fetched
MDR
memory data register, holds the data that was fetched
Program counter
incremented by one each cycle, holds the new address of what is to be executed next
Accumulator
register that holds values of math equations
