Inter-Process Communication
Processes are isolated by design: each has its own address space, and one cannot read another's variables.
Operating Systems · topic
Concurrency, synchronization and IPC
Inter-process communication by shared memory, message passing and pipes; race conditions and the three critical-section requirements; Peterson, bakery and hardware instructions; semaphores, mutexes and monitors; producer-consumer, readers-writers and dining philosophers.
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The Critical-Section Problem and Software/Hardware Solutions
When two threads update shared data at the same time, the result can depend on the exact order in which their machine instructions interleave. That situation is a race condition.
Semaphores, Mutexes and Monitors
Peterson's algorithm and TestAndSet loops solve mutual exclusion, but they are awkward to use and they busy-wait. Operating systems offer higher-level tools instead.
Classical Synchronization Problems
1) are the standard test bed for any new synchronization primitive. The bounded-buffer (producer-consumer) problem is about counting and waiting for space or data. The readers-writers problem is about letting many readers share while writers get exclusive access, and about who gets starved.
Concurrency, synchronization and IPC cheat sheets
One-page visual sheets for this topic, in the sheet library on the store. Previews are free; the full sheets come with the subject pack.