system calls

Question 1

why do we use system calls

Answer 1

they stop applications from directly manipulating the hardware etc and makes them go through the os

Question 2

what are system calls

Answer 2

defined api to the kernel then provides access control

Question 3

how do software interrupt work

Answer 3

parameters are stored in known registers
calls the software interrupt which invokes the kernel which calls the interrupt service routine and finds all registers in the stack which hold parameters