Operating Systems

The OS is the invisible layer between your code and the hardware. Every file you open, every network packet you send, every millisecond of CPU time — the kernel is making decisions about all of it, constantly, without you ever noticing.

// process lifecycle
NEW
Process created, awaiting admission
READY
Waiting in queue for CPU time
RUNNING
Executing on the CPU right now
BLOCKED
Waiting for I/O or event
TERMINATED
Finished, resources released
// round-robin CPU schedule (q=4ms)
P1
run
run
P2
run
I/O
P3
run