Computer Science Paper 1 Flashcards
What are peripherals?
Peripherals are external pieces of hardware like a keyboard and mouse
What are embedded systems? (3)
Embedded systems are computers built into other devices.
Generally larger.
They are dedicated to a single task so they are cheap to produce and are efficient.
What does processing power of a CPU depend on ?
1) Clock speed
2) Cores
3) Cache
What are the 3 main parts of a CPU?
1) CU
2) ALU
3) Cache
What is the job of the CU?
It fetches, decodes and executes instructions (FDE Cycle)
Controls flow of data inside and outside CPU
What does the ALU do?
ALU does all the logical calculations.
Stores values in the accumulator
Why is cache useful?
Cache is very fast
Stores regularly used data so it is quick to access
Why is cache not that good?
Cache has a very low capacity and is expensive
How do you find the file size in bits?
File size(bits) = number of bits per character x number of characters
How to find file size in an image ?
File size ( bits) = width x height x colour depth
How to calculate file size in a sound?
File size (bits) = Sample rate (in Hz) x bit depth x length (in seconds)
What are the different levels of cache?
There are different levels of cache:
L1 - quick, low capacity
L2 - slower, holds more
L3 - slower, holds more
What does the Program Counter do?
PC holds the memory address of the instructions on each cycle
What does the MAR hold?
Holds any memory address about to be used by CPU.
What does the MDR hold?
Holds the actual data or instruction, either fetched from memory or waiting to be written to memory
What does the accumulator store?
Stores the results of the calculations of the ALU
What is virtual memory?
Virtual memory is memory in secondary storage if RAM is filled up
Components of a hard disk drive are ?
1)Moving parts
2) store data magnetically on metal disks
3) can be noisy
Components of SSD
- no moving parts
- use flash memory for faster read/write time
- usually quiet
