Introduction
When several processes run on the same computer and share resources — memory, files, printers, database records — they can step on each other's toes. Two processes updating the same bank balance at the same time can silently lose money. One process waiting for a resource held by another, while that other waits in return, can freeze the whole system forever. Process synchronization is the set of techniques that make concurrent processes cooperate correctly, and deadlock is the situation where a group of processes is stuck waiting on each other permanently.
For BCS, Bank IT, and IT-officer exams this topic is a favourite: expect definitions (critical section, mutex, semaphore, deadlock), the four Coffman conditions, the Banker's algorithm (with numbers to compute), and comparison questions (semaphore vs mutex, deadlock vs starvation). This lesson builds the ideas from first principles and drills the exact things examiners ask.
Learning objectives
- Explain race conditions and why concurrent access to shared data is dangerous.
- Define the critical-section problem and its three required properties.
- Understand hardware and software solutions: Peterson's algorithm, locks, semaphores, mutexes, monitors.
- Solve the classic synchronization problems (producer–consumer, readers–writers, dining philosophers) conceptually.
- State the four necessary conditions for deadlock and the four strategies to handle it.
- Compute safe sequences and grant decisions using the Banker's algorithm.
- Distinguish deadlock, starvation, and livelock, and answer comparison MCQs quickly.