Covers reader-writer problem enabling multiple concurrent readers while enforcing exclusive writer access. Uses lightswitch pattern where first reader locks resource and last reader unlocks, preventing deadlock while allowing categorical mutual exclusion.
Addresses reusable barriers for iterative thread synchronization. Introduces two-phase barrier using dual turnstiles to prevent threads from lapping each other, maintaining state reset for repeated synchronization cycles in loop-based thread cooperation.
Details barrier implementation challenges and deadlock avoidance. Discusses turnstile pattern for sequential thread passage and demonstrates deadlock scenarios when barriers are placed inside mutexes, requiring careful synchronization design.
Presents multiplex pattern allowing limited concurrent threads and barrier synchronization for n threads. Shows how semaphores initialized to n control simultaneous access and how barriers force threads to wait until all arrive at checkpoint.
Explores mutual exclusion using semaphores to protect shared variables. Introduces the mutex pattern where semaphores initialized to 1 enforce exclusive access to critical sections, preventing concurrent access to shared resources through wait/signal mechanisms.