Lab 2: PIT And Timer IRQs

Generated folder: labs/timer/

Lab 2 introduces periodic hardware events. Instead of asking a high-level OS clock for time, you configure a timer-like device and react to interrupts.

Device Model

Part	Role
Timer 0	periodic interrupt source
Control word	selects timer, access mode, operating mode, BCD/binary
Divisor	converts base clock frequency into requested rate
IRQ line	event path from device to program
Interrupt handler	records that a tick happened

Plan

1. Validate timer number and requested frequency.
2. Compute the PIT divisor.
3. Write low byte and high byte in order.
4. Subscribe to timer interrupts.
5. Keep the interrupt handler small.

Next: implementation tasks.