Distributed computing generics

Generics are defined as a pattern example or model. Today and everyone to learn about distributed computing generics, distributed computing generics can be divided into five categories of a total of nine common generics, the next one.

first, the message related

Message-related generics include message-passing generics and message system generics.

1. Message-Passing generics

Messaging is the basic way that processes communicate with each other. Two interprocess messages, one for the sender and one for the receiver. The sender sends a request message that is sent to the receiver and returns a reply message after processing is received.

2. Message system generics

Message system generics or object-oriented middleware (MOM) are extended on the basis of basic messaging generics. The message system can be understood as an intermediary between independent and process, so that there is no coupling between the two processes that communicate with each other. Sent by the sender of a message, the message is stored in the message system, and then forwarded by the message system of the corresponding recipient, the sender once the message sent out, you can perform other tasks, the rest of the forwarding work has a message system to complete.

Message system generics can be further divided into two seed types: Point-to-point message generics and publish/Subscribe message generics.

1) Point-to-point message generics

This generic type is the sender and receiver of the corresponding generic, sent by the sender of a message to the message system, the message system is forwarded to the receiver's message queue, the message system can provide a staging mechanism to separate the sending and receiving of messages. The recipient extracts the message from its own message queue and then processes it.

2) Publish/Subscribe message generics

The generics are many-to-many generics, multiple subscribers can have multiple subscriptions, a message is sent by the sender to the messaging system, and the message system forwards the message to each Subscriber subscribing to that type of message based on the subscriber's subscription type and message type. This generic type can provide a process multicast message to a set of processes.

second, server-related

Server-related generics include the client/server generics and the-to-peer generics.

3. Client/server generics

Client/server generics are composed of clients and servers that assign asymmetric roles to each of the two collaboration processes, the client process initiates a request to the server, and waits for the server to respond, and the server waits for a request from the customer to process and respond.

4.p2p generics

A peer to peer is derived from a peer network (also known as Peers computer network). This is a non-central server, relying on the user group exchange of the Internet system, each user is both a node, and serve as a server responsibility. It can be said that there is no server, it can be said that each client side is a server.

third, remote call related

Remote invocation-related generics include remote procedure call generics, distributed object Generics, and network Service generics.

5. Remote Procedure Call generics

Provides a generic type that enables developers to write distributed software systems just like traditional applications that run on a single processor. You can use ideas and concepts similar to local procedure calls for interprocess communication.

6. Distributed-Object generics

Distributed object generics apply object-oriented to distributed system, which is the natural extension of object-oriented software development technology. You can enable applications to access individual objects that are distributed across the network, and by invoking the object's methods, the application sequence can gain access to the service.

1) Remote method invocation

Remote Method Invocation (RMI) is an object-oriented version of RPC. A process can call an object method that can reside on a remote host.

2) Object Request Agent

The object request agent generic has an object requester, an object provider, and an object request agent. The process makes a request to the object request agent, which forwards the request to the object that can provide the expected service.

7. Network SERVICE generics

A network service generic consists of a service requester, a service provider (object), and a directory service. First, the service provider registers itself on a directory server on the network, and when the service requester needs to access the service, contact the server directory directly, and if the requested service is available, the directory server returns a reference or address for the service, which the process uses to interact with the required service.

Four, mobile agent8. Mobile Agent Generics

A mobile agent generic is a movable program or object. An agent starts from the source host and then automatically moves between the web hosts according to the execution route it carries. Delegate access to the required resources or services on each host and perform the necessary tasks to complete the mission.

Five, cloud services9. Cloud-based services generics

The National Institute of Standards and Technology defines three service models for cloud computing: IaaS, PAAs, and SaaS.

1) Basic implementation-as-a-service (IaaS)

In the form of services to provide virtual hardware resources, users do not need to purchase servers, network equipment, storage equipment, only through the Internet rental can build their own application system.

2) Platform as a service (PaaS)

Provide application service engine, such as Internet application programming interface, running platform, etc. Based on the app service engine, the user can build such an app.

3) Software as a service (SaaS)

Users use the software over the Internet, and users do not have to buy software, just rent the software on demand.

Distributed computing generics