Interrupts

Generated by devices to signal they need attention

Example

  • Input is ready
  • packet arrived from internet

Interrupt Handler

Function in the kernel that services a device request
Interrupt process:

  1. Device signals the processor through a physical pin or bus message
  2. Processor interrupts the execution of current running program
  3. Begins executing interrupt handler in Kernel mode
Most interrupts can be disabled

Non-maskable interrupts are for urgent system requests

  • Overheating

Configuration

  1. The OS initializes the IDT with entry points for up to 256 interrupts
  2. OS initializes IDT base address and length
  3. OS executes lidt instruction to load the IDT Register
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Hardware Interrupt Handling Process