Computer science - PPE 2
What is a computer?
A computer is a machine that processes data.
What is an embedded system?
They are computers inside a larger system.
What is the CPU, and what does it do?
The (central processing unit) is the brain of the computer system; it processes all of the data and instructions that make the system work.
What are the 3 main components of the CPU?
CU - To manage the FDE cycle
ALU - Does all of the calculations
The Cache - A very fast memory
What is the Fetch instruction of the FDE cycle?
1) Copy the memory address from the PC to the MAR
2) Copy the instruction stored in the MAR address to the MAR
3) Increase the PC to point to the address of the next instruction
What is the Decode instruction of the FDE cycle?
The CU decodes the instruction in the MDR. The CU may then prepare for the next step, e.g by loading values into the MAR or MDR.
What is the Execute instruction of the FDE cycle?
The instruction is performed. This could include loading data from memory, writing data to memory, performing a calculation or logic operation (using the ALU), updating the address in the PC, or halting the program.
What is RAM?
Random access memory is high-speed, volatile (can be lost) memory
What is virtual memory?
It is secondary storage used as extra RAM.
What is ROM?
Read-only memory tells the CPU how to boot up.
What does CPU performance depend on?
Clock speed - This is the number of instructions a single processor core can carry out per second.
Number of Cores - The more cores = the more instructions it can carry ot at once.
Cache size - A larger cache size = Faster access to more data.
What helps CPUs process images?
GPUs (General processing units) are specialised circuits for handling graphics and images.