Making this conversion
The process known descriptors associated with the tube because he inherited these descriptors. This shows that only the process of the offspring of the creator of the tube whose ancestors know the descriptors themselves are entitled to use the tube. An anonymous tube allows communication between father-son process same parentage or brothers running on the same machine. It queue management system should also be noted that the tubes do not preserve the limit of posts in the tube.
The creation of the tube takes place before the creation of the son process so that it can inherit the descriptors of the tube and therefore use it to communicate with queue management system his father. Each process, father and son, closes the descriptor that it is useless and the farm father pip, the descriptor is read as a writer on the tube. Conversely, the son closes pip, the descriptor write since it is reading on the active queue management tube. UNIX message queues is another communication mechanism placed on the same machine UNIX process.
First queue management system approach
Unlike the mechanism of the tubes, the mechanism of message queues is external to the system of the UNIX file management system. The system handles a specific table for this tool, which is identified by a key kind. This key is a numeric value and all processes with knowledge of the key can use the message queue to send or receive messages. We see therefore that unlike tubes, the message queue can be used by processes not necessarily affiliated with one another. The message queue is the UNIX implementation of the concept of mailboxes.
It has two properties: the preservation of the message limit that is different tubes, and the possibility of multiplexing that is to say only one queue can be used for active queue management multiple recipients. Posts in a message queue are necessarily consist of two parts: primitive can receive a message from a message queue. It is at this level comes multiplexing we talked about earlier, that is to say, the receiver may designate any messages in the queue, a message he wants to get more specific.
We need to know
Write a program where a father creates a son. The father and son communicate via two PIP and queue management system PIP tubes. Written in PIP father, who is played by his son, the message hello and waiting on a response from PIP son. The son reads the message of PIP father and active queue management he returns the string Hello in PIP. We begin with a brief review of the concept of memory in hardware.
The physical memory consists of a set of contiguous memory words appointed by each physical address. The processor accesses the words of main memory through two queue management system registers, the register address and the register RAD Data RDO. RAD register contains the address of the word to be read or the word address where to write while the RDO register contains either the data to be written or read the data.
