Inter-process communication

A grid computing system that connects many personal computers over the Internet via inter-process network communication

In computer science, inter-process communication (IPC), also spelled interprocess communication, are the mechanisms provided by an operating system for processes to manage shared data. Typically, applications can use IPC, categorized as clients and servers, where the client requests data and the server responds to client requests. Many applications are both clients and servers, as commonly seen in distributed computing.

IPC is very important to the design process for microkernels and nanokernels, which reduce the number of functionalities provided by the kernel. Those functionalities are then obtained by communicating with servers via IPC, leading to a large increase in communication when compared to a regular monolithic kernel. IPC interfaces generally encompass variable analytic framework structures. These processes ensure compatibility between the multi-vector protocols upon which IPC models rely.

An IPC mechanism is either synchronous or asynchronous. Synchronization primitives may be used to have synchronous behavior with an asynchronous IPC mechanism.

Approaches

Different approaches to IPC have been tailored to different software requirements, such as performance, modularity, and system circumstances such as network bandwidth and latency.

Method	Short Description	Provided by (operating systems or other environments)
File	A record stored on disk, or a record synthesized on demand by a file server, which can be accessed by multiple processes.	Most operating systems
Communications file	A unique form of IPC in the late-1960s that most closely resembles Plan 9's 9P protocol	Dartmouth Time-Sharing System
Signal; also Asynchronous System Trap	A system message sent from one process to another, not usually used to transfer data but instead used to remotely command the partnered process.	Most operating systems
Socket	Data sent over a network interface, either to a different process on the same computer or to another computer on the network. Stream-oriented (TCP; data written through a socket requires formatting to preserve message boundaries) or more rarely message-oriented (UDP, SCTP).	Most operating systems
Unix domain socket	Similar to an internet socket, but all communication occurs within the kernel. Domain sockets use the file system as their address space. Processes reference a domain socket as an inode, and multiple processes can communicate with one socket	All POSIX operating systems and Windows 10
Message queue	A data stream similar to a socket, but which usually preserves message boundaries. Typically implemented by the operating system, they allow multiple processes to read and write to the message queue without being directly connected to each other.	Most operating systems
Anonymous pipe	A unidirectional data channel using standard input and output. Data written to the write-end of the pipe is buffered by the operating system until it is read from the read-end of the pipe. Two-way communication between processes can be achieved by using two pipes in opposite "directions".	All POSIX systems, Windows
Named pipe	A pipe that is treated like a file. Instead of using standard input and output as with an anonymous pipe, processes write to and read from a named pipe, as if it were a regular file.	All POSIX systems, Windows, AmigaOS 2.0+
Shared memory	Multiple processes are given access to the same block of memory, which creates a shared buffer for the processes to communicate with each other.	All POSIX systems, Windows
Message passing	Allows multiple programs to communicate using message queues and/or non-OS managed channels. Commonly used in concurrency models.	Used in LPC, RPC, RMI, and MPI paradigms, Java RMI, CORBA, COM, DDS, MSMQ, MailSlots, QNX, others
Memory-mapped file	A file mapped to RAM and can be modified by changing memory addresses directly instead of outputting to a stream. This shares the same benefits as a standard file.	All POSIX systems, Windows

Applications

Remote procedure call interfaces

Main article: remote procedure call

• Java's Remote Method Invocation (RMI)
• ONC RPC
• XML-RPC or SOAP
• JSON-RPC
• Message Bus (Mbus) (specified in RFC 3259) (not to be confused with M-Bus)
• .NET Remoting
• gRPC

Platform communication stack

The following are messaging, and information systems that utilize IPC mechanisms but don't implement IPC themselves:

• KDE's Desktop Communications Protocol (DCOP) – deprecated by D-Bus
• D-Bus
• OpenWrt uses ubus micro bus architecture
• MCAPI Multicore Communications API
• SIMPL The Synchronous Interprocess Messaging Project for Linux (SIMPL)
• 9P (Plan 9 Filesystem Protocol)
• Distributed Computing Environment (DCE)
• Thrift
• ZeroC's Internet Communications Engine (ICE)
• ØMQ
• Enduro/X Middleware
• YAMI4
• Enlightenment_(software) E16 uses eesh as an IPC

Operating system communication stack

The following are platform or programming language-specific APIs:

• Apple Computer's Apple events, previously known as Interapplication Communications (IAC)
• ARexx ports
• Enea's LINX for Linux (open source) and various DSP and general-purpose processors under OSE
• The Mach kernel's Mach Ports
• Microsoft's ActiveX, Component Object Model (COM), Microsoft Transaction Server (COM+), Distributed Component Object Model (DCOM), Dynamic Data Exchange (DDE), Object Linking and Embedding (OLE), anonymous pipes, named pipes, Local Procedure Call, MailSlots, Message loop, MSRPC, .NET Remoting, and Windows Communication Foundation (WCF)
• Novell's SPX
• POSIX mmap, message queues, semaphores, and shared memory
• RISC OS's messages
• Solaris Doors
• System V's message queues, semaphores, and shared memory
• Linux Transparent Inter Process Communication (TIPC)
• OpenBinder Open binder
• QNX's PPS (Persistent Publish/Subscribe) service

Distributed object models

The following are platform or programming language specific-APIs that use IPC, but do not themselves implement it:

• Libt2n for C++ under Linux only, handles complex objects and exceptions
• PHP's sessions
• Distributed Ruby
• Common Object Request Broker Architecture (CORBA)
• Electron's asynchronous IPC, shares JSON objects between a main and a renderer process

See also

• Berkeley sockets
• Computer network programming
• Communicating Sequential Processes (CSP paradigm)
• Data Distribution Service
• Database-as-IPC
• Protected procedure call

References

• Stevens, Richard. UNIX Network Programming, Volume 2, Second Edition: Interprocess Communications. Prentice Hall, 1999. ISBN 0-13-081081-9
• U. Ramachandran, M. Solomon, M. Vernon Hardware support for interprocess communication Proceedings of the 14th annual international symposium on Computer architecture. Pittsburgh, Pennsylvania, United States. Pages: 178 - 188. Year of Publication: 1987 ISBN 0-8186-0776-9
• Crovella, M. Bianchini, R. LeBlanc, T. Markatos, E. Wisniewski, R. Using communication-to-computation ratio in parallel program designand performance prediction 1–4 December 1992. pp. 238–245 ISBN 0-8186-3200-3

External links

• Linux ipc(5) man page describing System V IPC
• Windows IPC
• IPC available using Qt
• Unix Network Programming (Vol 2: Interprocess Communications) by W. Richard Stevens
• Interprocess Communication and Pipes in C
• DIPC, Distributed System V IPC