Synchronization in Interprocess Communication
Synchronization is a phenomenon of coordinating the execution of processes in such a way that two processes cannot have access to the same common data and resources simultaneously. It is a method that is used to maintain the proper sequence of execution of cooperative processes.
Cooperating processes must interact and synchronize in order to cooperate. When processes communicate, synchronization is frequently required. Processes are carried out at unpredictable rates. Interprocess communication requires the use of synchronization. It's either handled by the communication processes or given by the interprocess control mechanism. The following are some of the synchronization methods:
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Semaphore: A semaphore is a variable that regulates how many processes may access a shared resource. Binary and counting semaphores are the two types of semaphores.
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Mutual Exclusion: Only one process thread can access the critical section because mutual exclusion is enforced. This helps with synchronization and avoids race conditions.
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Barrier: A barrier usually prevents an individual process from moving forward until all other processes do not reach it. Many parallel languages employ it, and collective routines create obstacles.
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Spinlock: As the name indicates, a spinlock is a form of lock. While attempting to acquire the spinlock, the processes wait or stay in a loop, verifying whether the lock is accessible or not. The process is characterized as busy waiting because, despite being active, it does not conduct any functional operations (or tasks).
Approaches for Inter-Process Communication
We'll now look at various approaches for processes to communicate with one another.

FIFO
It is the communication between two separate( unrelated) processes. It's a full-duplex approach, which implies that the first process may communicate with the second process and vice versa.
Direct Communication
In this approach, a link is established between one pair of communicating processes, and only one link exists between each pair.
Indirect Communication
Indirect communication occurs when two processes share a shared mailbox, and each pair of processes has many communication links. Many processes can communicate through a connection. The link can be bidirectional or unidirectional.
Shared Memory
Shared memory is a memory that is shared across two or more processes. This permits data to be exchanged inside a specific memory region. Before data may access shared memory, semaphore values must be acquired. By synchronizing access across all processes, this form of memory must be guarded against each other.

It is the fastest way to communicate between processes. The operating system constructs a shared memory segment in RAM so that several processes may read and write to it. The processes share a memory area without using any operating system functions.
Message Passing
It is a communication and synchronization method for a process. The process communicates with each other through message passing rather than shared variables.
IPC mechanism provides two operations:
- Create a communication link(if not already).
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Begin exchanging messages with simple primitives. At the very least, we require two primitives:
- Send (message) - message size variable or fixed.
- Received (message)
The message size might be fixed or variable. If it is constant in size, it is simple for an OS designer but difficult for a programmer. If it is variable in size, it is simple for a programmer but difficult for the OS designer. A typical message may be divided into two parts: the header and the body.
The header section contains information such as the message type, message length, destination id, source id, and control information. The control information includes information such as what to do if the buffer space runs out, the sequence number, and the priority. Messages are often transmitted in a FIFO manner.

When compared to the shared memory technique, message passing is slower. This is due to the fact that it uses system calls to communicate across processes.
Message Queues
In the kernel, a message queue is a linked list of messages. Messages can be sent between processes using a single queue or multiple message queues. The system kernel is in charge of this, and the messages are coordinated through an API. A message queue identifier is used to identify it. This approach allows full-duplex communication between single or many processes.
Pipes
Pipes are commonly used to communicate between two processes that are connected. This only permits data to flow in one direction. Similar to simplex systems (Keyboard). The data from the output is often delayed until it is received by the input process, which must have a shared origin. The first process interacts with the second since this is a half-duplex approach. On the other hand, a full-duplex connection requires the use of another pipe.
Various Other Techniques
Sockets
The socket is the network endpoint for sending and receiving data. This applies to data exchanged between processes on the same computer as well as data sent between various computers on the same network. Sockets are often used for interprocess communication in most operating systems.
This approach is commonly used to communicate between a client and a server via a network. It enables a standard connection that is independent of the machine and operating system.
Signal
They are, as the name suggests, a form of signal that is utilized in interprocess communication in a minimum manner. Typically, they are system messages transmitted from one process to another. As a result, they are not utilized for data transmission but rather for remote instructions between various processes. They are often used to convey remote instructions rather than data between programs.
File
A file is a data record that can be saved on a disk or accessed by a file server on demand. A file can be accessed by several programs as needed. All operating systems use files to store data.
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Frequently Asked Questions
Which type of processes needs Interprocess communication?
In general, there are two types of processes, Independent processes, and Cooperating processes. A process is considered independent if it has no effect on or is impacted by any other process running in the computer system. In contrast, a process is said to be a cooperating process if it can impact or is affected by other processes running in the computer system. The cooperating process needs interprocess communication as every process exchanges data with other processes.
What is the most crucial feature of FIFO?
The first process may communicate with the second process and vice versa. Furthermore, it allows data flow between unrelated processes.
Which IPC mechanism is the fastest?
Shared memory is the fastest approach to interprocess communication. The major advantage of shared memory is that it eliminates message data copying. Semaphores are the most common technique for synchronizing shared memory access.
Conclusion
To summarize the article, we learned how cooperating processes need interprocess communication to communicate. And we also discussed the various approaches to performing interprocess communication and the needs of IPC. Hope you learned something. But the knowledge never stops, so to better understand the operating systems, you can go through many articles on our platform.
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