Use for questions related to interrupt signals and interrupt handling.
In computing, an interrupt is an asynchronous signal indicating the need for attention or a synchronous event in software indicating the need for a change in execution.
A hardware interrupt happens in response to some hardware event (say mouse movement) and causes the processor to save its state of execution and begin execution of an interrupt handler. At the same time, the possibility for this interrupt is disabled (to prevent it happening repeatedly) and must be re-enabled by software after the current interrupt has been serviced.
Interrupts are usually identified by number, and normally there is a system table somewhere in the OS that maps this number to the address of function that must service the interrupt.
Software interrupts as seen by the programmer do not differ much from the usual function calls. However they are usually implemented as specific instructions in the instruction set so may require less code to be called. Software interrupts are processed in a very similar way to the way hardware interrupts are processed, often using similar context switching and a shared interrupt table for both.
