📚 Study Docs — Codexion (42 Porto)

This folder contains study notes prepared before tackling Codexion, a POSIX-threads project modeled on the classic dining philosophers problem — coders competing for shared USB dongles instead of philosophers competing for forks.

Each file below covers one concept needed to understand and defend the project.

🗂️ Topics

File	Covers
01-dining-philosophers.md	The classic problem, Coffman's 4 conditions, deadlock vs starvation vs livelock, the N=1 edge case
02-pthreads-sync.md	pthread_mutex_t, pthread_cond_t, wait/signal/broadcast, critical sections
03-scheduling-fifo-edf.md	FIFO vs Earliest Deadline First scheduling, tie-breaking, real-time scheduling basics
04-heap-priority-queue.md	Binary min-heap implemented from scratch, insert/extract-min, use as a scheduler queue
05-timing-precision.md	gettimeofday() vs clock_gettime(), usleep() drift, timedwait vs wait, when a coder notices should_stop, hitting the 10ms burnout window
06-concurrency-debugging.md	Valgrind, Helgrind, ThreadSanitizer — catching leaks, races, and deadlocks

🎯 How this maps to Codexion

Codexion concept	Study topic
Dongles = forks, coders = philosophers	01
Mutex per dongle, cond var for waiting queue	02
scheduler argument (fifo / edf)	03
"You must implement a priority queue (heap)"	04
Burnout log within 10ms, monitor thread	05
Norm + no leaks + no races during defense	06

✅ Suggested study order

1. 01 → understand why the problem is hard
2. 02 → learn the C tools to solve it
3. 03 and 04 → the two mandatory scheduling/data-structure requirements
4. 05 → the precision constraints that make testing tricky
5. 06 → how to verify your own solution before submitting