Inter-Process Communication (IPC): Techniques, Advantages, Disadvantages & Applications

Introduction

Inter-process communication (IPC) refers to the mechanisms provided by an operating system that allow processes to exchange data and coordinate their actions. Applications typically use IPC by functioning as clients (requesting data) and servers (responding to requests). In distributed computing, many processes act as both clients and servers.

IPC plays a critical role in microkernels and nanokernels, which minimize kernel functionality. These systems rely heavily on IPC to communicate with external servers, significantly increasing message exchanges compared to monolithic kernels. IPC interfaces typically include analytical frameworks and structured communication procedures to ensure compatibility across multi-vector protocols.

IPC can be synchronous or asynchronous. Synchronization primitives can be used to create synchronous behavior even when an asynchronous IPC mechanism is used.

Inter-Process Communication Techniques

Pipes

Pipes provide a half-duplex (one-way) communication channel between two related processes. One process writes data into the pipe, and another process reads from it—similar to filling and emptying a bucket.

Shared Memory

Shared memory allows multiple processes to access a common memory region. Communication occurs when one process updates the shared memory and other processes read the changes.

The classic example is the Producer–Consumer problem:

The Producer generates items.
The Consumer consumes items.
A shared buffer holds the items.

The problem may be:

Unbounded buffer – unlimited buffer size.
Bounded buffer – buffer has a fixed capacity.

In the bounded buffer case, the producer must stop when the buffer is full, and the consumer must wait when it is empty.

Message Passing

Message passing allows processes to communicate without shared memory. Two processes create a communication link and exchange messages using primitives such as:

send(message, destination)
receive(message, source)

Messages may be fixed-size or variable-size. Each message typically consists of a header (containing type, source, destination, length, and control information) and a body. Messages are usually delivered in FIFO order.

Message Queues

Message queues store messages in a linked list inside the kernel. Each queue is identified using a unique message queue identifier.

Direct Communication

In direct communication, processes explicitly name each other. A link must exist between communicating processes, and every pair of processes must establish a (usually bidirectional) communication link.

Indirect Communication

Processes communicate via mailboxes or ports. The sender places a message in a mailbox, and the receiver retrieves it. Links may be uni- or bi-directional.

FIFO

FIFO (named pipes) allow full-duplex communication between two unrelated processes. Process P1 can communicate with P2 and vice versa.

Reasons to Use Inter-Process Communication

Improves modularity and system organization
Supports computational efficiency
Allows separation of privileges
Enhances communication and synchronization between applications
Enables multiple operating system components to coordinate their actions

Advantages of IPC

Enables one application to control or communicate with another
Supports shared data exchange through semaphores, memory segments, and other mechanisms
Efficient message transfer between processes
Reduces blocking issues found in other communication methods
Enables parallel execution of tasks by dividing programmes into independent modules
Makes maintenance and debugging easier due to modular design
Supports multitasking such as editing, compiling, and audio playback simultaneously

Disadvantages of IPC

Pipe communication may have a fixed data size limit
Message queues have an upper limit on total data size
Shared memory requires processes to avoid writing to the same location simultaneously
Synchronization and memory protection issues may arise
Slower than direct function calls
Risk of data corruption if memory access is not properly managed