1.1.1 Architecture of the CPU Flashcards
what is the fetch decode execute cycle
This is where the CPU fetches the next instruction to be processed from the memory (RAM), decodes the instruction and then executes it.
what does a core contain
ALU, control unit and registers
what do cores share
level 3 cache
what are multi core processors
Processors which have more than one core
what is clock speed
the number of fetch-execute cycles that they can carry out per second
what is clock speed measured in
MHz or GHz
what is the ALU
is responsible for all arithmetic operations and all logical operations
What is the control unit
it controls the timing of the units and the flow of data in the CPU.
what is cache
A small amount of high speed memory and is used to temporarily hold instructions and data that the CPU is likely to reuse
what are registers
A small amount of fast memory stored in the CPU
how does cache work in a CPU
Level 1 cache is the fastest but contains the smallest amount of memory and if the CPU needs data that isn’t in level one it will move up the levels until it reaches RAM,
How does the clock speed affect CPU performance?
If you increase the clock speed, you increase the amount of fetch-decode-execute cycles which take place per second meaning that the CPU will be able to process data faster.
How does the cache size affect CPU performance?
If you increase the cache size it means that there is more storage for you to quickly read and write data to. And there is less chance of needing to go to the RAM which is slower
How does the number of cores affect CPU performance?
Because more cores allows multiple cores (ALU, control units,cache, etc) to work simultaneously to complete more fetch-decode-execute cycles at once.
Why does a dual core processor not always operate twice as quick as a single core processor?
Because some codes need to be processed one after the other, so the processors wont be able to work simultaneously.
what other factors affect the speed of the CPU
cooling
age
overclocking
what is cooling
remove the waste heat produced by computer components, to keep components within permissible operating temperature limits
what is age
CPUs get slower over time because of dust build-up on the heatsink
what is overclocking
increasing the multiplier on the CPU, allowing it to run faster.
what is a GPS
a computer system that can be programmed to perform a large number of tasks.
What is an embedded system
systems that have a dedicated function as part of a larger device. They are built to complete a specific set of tasks.
what is the main advantage of embedded systems
general purpose systems are versatile, they aren’t always fully optimised to perform specific tasks. Embedded systems are designed to perform a small number of tasks efficiently.
whats an example of an embedded system
Digital cameras.
Digital wristwatches
why are embedded systems cheap to produce
they require less processing power
what are benefits of embedded systems
They do not need an operating system
They are cheap to produce as they require less processor power
They can be small in size so they can be good for smaller / more compact models
The hardware used to create them is often far more rugged and can be used in a range of scenarios
what are drawbacks of embedded systems
They can only perform a limited number of functions
they are difficult to upgrade due to their limited storage space and processing power
what is the Pc
hold the next address in memory
what is the acc
holds the result of the calculations
what is the mar
hold the address of the current instruction
what is the mdr
hold the data to be fetched from or to be written to the memory
