Difference between message queues and mailboxes

Overview :
The task is to learn some differences between message queues and mailboxes in the field of computer science. In computer science, message queues and mailboxes are software-engineering components usually used for inter-machine communique (IPC), or for inter-thread communique withinside the identical machine. They use a queue for messaging – the passing of manipulating or of content. Group conversation structures offer comparable sorts of functionality.

Message queues :

1. Message queuing makes it feasible for programs to talk asynchronously, through sending messages to every different through a queue. A message queue presents brief storage among the sender and the receiver in order that the sender can preserve running without interruption while the vacation spot application is busy or now no longer connected. Asynchronous processing lets in a mission to name a provider, and flow directly to the subsequent mission whilst the provider processes the request at its very own pace.
    
2. A queue is a line of factors ready to be handled — in sequential order beginning at the start of the line. A message queue is a queue of messages sent amongst applications. It consists of a series of labor items that are ready to be processed.
    
3. Data is transferring between sender and receiver application, and this is called a message. And we can say that it is a byte array with some headers on top. 
    
4. The fundamental structure of a message queue is simple: there are purchaser programs known as manufacturers that create messages and supply them to the message queue. Another application, known as a customer, connects to the queue and receives the messages to be processed. Messages positioned onto the queue are saved till the customer retrieves them. The queue can offer safety from carrier outages and failures.
    
5. Some common examples of queues are Kafka, Heron, real-time streaming, Amazon SQS, and RabbitMQ.

Mailboxes :

• The mailbox is an easy mechanism for asynchronous communication. Some architectures outline mailbox registers. These mailboxes have a hard and fast range of bits and may be used for small messages. We also can enforce a mailbox the usage of P() and V() the usage of essential reminiscence for the mailbox storage. A quite simple model of a mailbox, one which holds the simplest one message at a time, illustrates a few crucial standards in interprocess communication.
   
• In order for the mailbox to be maximum useful, we need it to incorporate items: the message itself and a mail prepared flag. The flag is real at the same time as a message has been located in the mailbox and cleared at the same time as the message is removed.

Difference between them :

• A queue in standard has very particular that means in computing as a box facts shape with first-in-first-out (FIFO) get right of entry to semantics. In an RTOS queue specifically, get the right of entry to the queue could be thread-secure and feature blocking off semantics.
   
• A mailbox alternatively has no usually time-honored unique semantics, and I even have visible the time period used to consult very extraordinary RTOS IPC mechanisms. In a few instances, there are in truth queues, however, if the RTOS additionally helps an IPC queue, a mailbox may have someway extraordinary semantics – frequently with appreciation to reminiscence management. In different instances a mailbox may also basically be a queue of period 1 – i.e. it has the blocking off and IPC functionality of a queue, however, and not using a buffering. Such a mechanism lets in synchronous conversation among processes.