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Parallelism, IPC deadlock and OS role

Short answer

Parallelism means executing multiple tasks simultaneously for speedup. Deadlock in IPC arises when two processes each hold a resource and wait for the other's resource. The OS prevents it via ordered resource requests, avoids it with Banker's algorithm, detects cycles in wait-for graphs, and recovers by killing processes or preempting resources.

What do you mean by parallelism? Explain the case of deadlock that may arise during inter process communication. What role does the operating system play in handling such deadlocks?

Parallelism

Parallelism means doing more than one task or operation at the same time to increase throughput and speed. It can be at instruction level (pipelining, superscalar), thread level, or process level (multiprocessors, multicomputers).

Deadlock during inter-process communication

Processes that communicate or share resources (through semaphores, messages or shared memory) may wait for each other.

  • Example 1: P1 has locked resource R1 and requests R2; P2 has locked R2 and requests R1. Neither can continue.
  • Example 2: P1 does receive(P2) and P2 does receive(P1), each waiting for a message the other never sends.

All four conditions hold: mutual exclusion, hold and wait, no preemption and circular wait.

Role of the operating system

The OS handles deadlock with these methods.

  1. Prevention: it makes sure one condition cannot hold (e.g. ordered resource requests, or requesting all resources at once).
  2. Avoidance: it examines each request using Banker's algorithm and grants it only if the system remains in a safe state.
  3. Detection: it periodically builds a resource-allocation (wait-for) graph and looks for cycles.
  4. Recovery: it ends one or more deadlocked processes, or preempts resources from some and rolls them back.
  5. It also provides synchronisation tools (semaphores, monitors, time-outs) so programmers can avoid deadlock.

✓ Answer checked by Claude Opus 5.5 (high effort)

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