December 11, 2019
Amitraj
Interprocess communication (IPC)
-> Interprocess communication (IPC) is a set of programming interfaces that allow a programmer to coordinate activities among different program processes that can run concurrently in an operating system. This allows a program to handle many user requests at the same time. Since even a single user request may result in multiple processes running in the operating system on the user's behalf, the processes need to communicate with each other. The IPC interfaces make this possible. Each IPC method has its own advantages and limitations so it is not unusual for a single program to use all of the IPC methods.
-> IPC methods include pipes and named pipes; message queueing;semaphores; shared memory; and sockets.
Pipes −
Communication between two related processes. The mechanism is half duplex meaning the first process communicates with the second process. To achieve a full duplex i.e., for the second process to communicate with the first process another pipe is required.
named pipe
In computer programming, a named pipe is a method for passing information from one computer process to other processes using a pipe or message holding place that is given a specific name. Unlike a regular pipe, a named pipe can be used by processes that do not have to share a common process origin and the message sent to the named pipe can be read by any authorized process that knows the name of the named pipe.
A named pipe is sometimes called a "FIFO" (first in, first out) because the first data written to the pipe is the first data that is read from it.
network socket
A network socket is one endpoint in a communication flow between two programs running over a network.
Sockets are created and used with a set of programming requests or "function calls" sometimes called the sockets application programming interface (API). The most common sockets API is the Berkeley UNIX C interface for sockets. Sockets can also be used for communication between processes within the same computer.
This is the typical sequence of sockets requests from a server application in the connectionless context of the Internet in which a server handles many client requests and does not maintain a connection longer than the serving of the immediate request:
socket()
|
bind()
|
recvfrom()
|
(wait for a sendto request from some client)
|
(process the sendto request)
|
sendto (in reply to the request from the client...for example, send an HTML file)
A corresponding client sequence of sockets requests would be:
socket()
|
bind()
|
sendto()
|
recvfrom()
Sockets can also be used for "connection-oriented" transactions with a somewhat different sequence of C language system calls or functions.
The Secure Sockets Layer (SSL) is a computer networking protocol that manages server authentication, client authentication and encrypted communication between servers and clients.
Message Queues −
Communication between two or more processes with full duplex capacity. The processes will communicate with each other by posting a message and retrieving it out of the queue. Once retrieved, the message is no longer available in the queue.
Shared Memory −
Communication between two or more processes is achieved through a shared piece of memory among all processes. The shared memory needs to be protected from each other by synchronizing access to all the processes.
Semaphores −
Semaphores are meant for synchronizing access to multiple processes. When one process wants to access the memory (for reading or writing), it needs to be locked (or protected) and released when the access is removed. This needs to be repeated by all the processes to secure data.
-> Interprocess communication (IPC) is a set of programming interfaces that allow a programmer to coordinate activities among different program processes that can run concurrently in an operating system. This allows a program to handle many user requests at the same time. Since even a single user request may result in multiple processes running in the operating system on the user's behalf, the processes need to communicate with each other. The IPC interfaces make this possible. Each IPC method has its own advantages and limitations so it is not unusual for a single program to use all of the IPC methods.
-> IPC methods include pipes and named pipes; message queueing;semaphores; shared memory; and sockets.
Pipes −
Communication between two related processes. The mechanism is half duplex meaning the first process communicates with the second process. To achieve a full duplex i.e., for the second process to communicate with the first process another pipe is required.
named pipe
In computer programming, a named pipe is a method for passing information from one computer process to other processes using a pipe or message holding place that is given a specific name. Unlike a regular pipe, a named pipe can be used by processes that do not have to share a common process origin and the message sent to the named pipe can be read by any authorized process that knows the name of the named pipe.
A named pipe is sometimes called a "FIFO" (first in, first out) because the first data written to the pipe is the first data that is read from it.
network socket
A network socket is one endpoint in a communication flow between two programs running over a network.
Sockets are created and used with a set of programming requests or "function calls" sometimes called the sockets application programming interface (API). The most common sockets API is the Berkeley UNIX C interface for sockets. Sockets can also be used for communication between processes within the same computer.
This is the typical sequence of sockets requests from a server application in the connectionless context of the Internet in which a server handles many client requests and does not maintain a connection longer than the serving of the immediate request:
socket()
|
bind()
|
recvfrom()
|
(wait for a sendto request from some client)
|
(process the sendto request)
|
sendto (in reply to the request from the client...for example, send an HTML file)
A corresponding client sequence of sockets requests would be:
socket()
|
bind()
|
sendto()
|
recvfrom()
Sockets can also be used for "connection-oriented" transactions with a somewhat different sequence of C language system calls or functions.
The Secure Sockets Layer (SSL) is a computer networking protocol that manages server authentication, client authentication and encrypted communication between servers and clients.
Message Queues −
Communication between two or more processes with full duplex capacity. The processes will communicate with each other by posting a message and retrieving it out of the queue. Once retrieved, the message is no longer available in the queue.
Shared Memory −
Communication between two or more processes is achieved through a shared piece of memory among all processes. The shared memory needs to be protected from each other by synchronizing access to all the processes.
Semaphores −
Semaphores are meant for synchronizing access to multiple processes. When one process wants to access the memory (for reading or writing), it needs to be locked (or protected) and released when the access is removed. This needs to be repeated by all the processes to secure data.
