Control Unit - decodesinstructions.Co-ordinates the execution of instructions.Directs the fetch, decode, executecycle.
Clock - Sends a regularelectricalpulse which synchronises the components.Influences the number of instructions carried out eachsecond
Cache - Makes retrieving data from the computer'smemory more efficient.Storesdata for fasteraccess, and also storesfrequentlyuseddata.
To increase a computer's performance
Increase the clock speed
Increase the numberofprocessor core
Increase the cache size
HLL VS LLL
HLL has higherlevel of abstraction
HLL runsacrossdifferentCPUfamilies.
HLL usesEnglish-likelanguage so it is easier to understand and learn
Programs written in LLL areusuallymoreefficient
Programs written in LLL usually uselessmemory
Programs written in LLL can directlyaccesshardwarecomponents.
Compiler vs Interpreter
Translates the whole program in one go(C)
Standaloneprogram does not require the compileroncomputertorun(C)
Produces a list of errorsaftertranslation(C)
Translatescodeonelineatatime(I)
Program requiresinterpreter to be present to run the code(I)
Stopsexecution as soon as an error is encountered(I)
Computer Network
A group of computers that are linked together
Encryption
Encryption scrambles the data before transmission and changes plaintext into ciphertext so it cannot be read by unauthorisedusers.
EMBEDDED SYSTEMS VS NON-EMBEDDED
An embedded system is a computersystem with a dedicated function, inside a largermechanicalunit, e.g. trafficlights, washing machines, dishwashers and coffee machines.
A non-embedded system is a computersystem with multiple functions, referred to a general-purpose machine
An embedded system compared to a non-embedded system is typically: