Difference between revisions of "Interprocess Communication (IPC)"

Revision as of 20:23, 11 November 2021

Official Definition: Interprocess communication (IPC) is used for programs to communicate data to each other and to synchronize their activities. Semaphores, shared memory, and internal message queues are common methods of interprocess communication.

What it means:
IPC is a method for two or more separate programs or processes to communicate with each other. This avoids using real disk-based files and the associated I/O overhead to pass information. Like a file, you must first create or open the resource, use it and close it. Like real files, the resources have an owner, a group, and permissions. Until you remove the resource it continues to exist. Unlike real disk-based files, semaphores, message queues and shared memory do not persist across reboots.^[1]

Approaches to Interprocess Communication^[2]
The different approaches to implement interprocess communication are given as follows − Pipes: Pipe is widely used for communication between two related processes. This is a half-duplex method, so the first process communicates with the second process. However, in order to achieve a full-duplex, another pipe is needed.

Message Passing: It is a mechanism for a process to communicate and synchronize. Using message passing, the process communicates with each other without resorting to shared variables. IPC mechanism provides two operations:
- Send (message)- message size fixed or variable
- Received (message)
Message Queues: A message queue is a linked list of messages stored within the kernel. It is identified by a message queue identifier. This method offers communication between single or multiple processes with full-duplex capacity.
Direct Communication: In this type of inter-process communication process, should name each other explicitly. In this method, a link is established between one pair of communicating processes, and between each pair, only one link exists.
Indirect Communication: Indirect communication establishes like only when processes share a common mailbox each pair of processes sharing several communication links. A link can communicate with many processes. The link may be bi-directional or unidirectional.
Shared Memory: Shared memory is a memory shared between two or more processes that are established using shared memory between all the processes. This type of memory requires to protected from each other by synchronizing access across all the processes.
FIFO: Communication between two unrelated processes. It is a full-duplex method, which means that the first process can communicate with the second process, and the opposite can also happen.

↑ What is Interprocess Communication (IPC)? IBM
↑ Approaches to Interprocess Communication Guru99

[1] What is Interprocess Communication (IPC)? IBM

[2] Approaches to Interprocess Communication Guru99

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-'''Interprocess communication (IPC)''' is used for exchanging [[Data|data]] between multiple threads in one or more processes or programs. The Processes may be running on single or multiple computers connected by a network. It is a set of programming interface which allow a programmer to coordinate activities among various program processes which can run concurrently in an operating system. This allows a specific program to handle many user requests at the same time. Since every single user request may result in multiple processes running in the operating system, the process may require to communicate with each other. Each IPC protocol approach has its own advantage and limitation, so it is not unusual for a single program to use all of the IPC methods.<ref>What is Interprocess Communication (IPC)? [https://www.guru99.com/inter-process-communication-ipc.html Guru99]</ref>
+Official Definition: '''Interprocess communication (IPC)''' is used for programs to communicate data to each other and to synchronize their activities. Semaphores, shared memory, and internal message queues are common methods of interprocess communication.
+What it means:<br />
+IPC is a method for two or more separate programs or processes to communicate with each other. This avoids using real disk-based files and the associated I/O overhead to pass information. Like a file, you must first create or open the resource, use it and close it. Like real files, the resources have an owner, a group, and permissions. Until you remove the resource it continues to exist. Unlike real disk-based files, semaphores, message queues and shared memory do not persist across reboots.<ref>What is Interprocess Communication (IPC)? [https://www.ibm.com/support/pages/interprocess-communication-ipc-overview#1.3 IBM]</ref>
-'''Approaches to Interprocess Communication<ref>Approaches to Interprocess Communication [https://www.tutorialspoint.com/what-is-interprocess-communication Tutorials Point]</ref>'''<br />
+'''Approaches to Interprocess Communication<ref>Approaches to Interprocess Communication [https://www.guru99.com/inter-process-communication-ipc.html Guru99]</ref>'''<br />
 The different approaches to implement interprocess communication are given as follows −
-*Pipe: A pipe is a data channel that is unidirectional. Two pipes can be used to create a two-way data channel between two processes. This uses standard input and output methods. Pipes are used in all POSIX systems as well as Windows operating systems.
+Pipes: Pipe is widely used for communication between two related processes. This is a half-duplex method, so the first process communicates with the second process. However, in order to achieve a full-duplex, another pipe is needed.
-*Socket: The socket is the endpoint for sending or receiving data in a network. This is true for data sent between processes on the same computer or data sent between different computers on the same network. Most of the operating systems use sockets for interprocess communication.
+*Message Passing: It is a mechanism for a process to communicate and synchronize. Using message passing, the process communicates with each other without resorting to shared variables. IPC mechanism provides two operations:
-*File: A file is a data record that may be stored on a disk or acquired on demand by a file server. Multiple processes can access a file as required. All operating systems use files for data storage.
+**Send (message)- message size fixed or variable
-*Signal: Signals are useful in interprocess communication in a limited way. They are system messages that are sent from one process to another. Normally, signals are not used to transfer data but are used for remote commands between processes.
+**Received (message)
-*Shared Memory: Shared memory is the memory that can be simultaneously accessed by multiple processes. This is done so that the processes can communicate with each other. All POSIX systems, as well as Windows operating systems use shared memory.
+*Message Queues: A message queue is a linked list of messages stored within the kernel. It is identified by a message queue identifier. This method offers communication between single or multiple processes with full-duplex capacity.
-*Message Queue: Multiple processes can read and write data to the message queue without being connected to each other. Messages are stored in the queue until their recipient retrieves them. Message queues are quite useful for interprocess communication and are used by most operating systems.
+*Direct Communication: In this type of inter-process communication process, should name each other explicitly. In this method, a link is established between one pair of communicating processes, and between each pair, only one link exists.
+*Indirect Communication: Indirect communication establishes like only when processes share a common mailbox each pair of processes sharing several communication links. A link can communicate with many processes. The link may be bi-directional or unidirectional.
+*Shared Memory: Shared memory is a memory shared between two or more processes that are established using shared memory between all the processes. This type of memory requires to protected from each other by synchronizing access across all the processes.
+*FIFO: Communication between two unrelated processes. It is a full-duplex method, which means that the first process can communicate with the second process, and the opposite can also happen.