The predecessor of App Server is MiddleWare (middleware), history is much longer. As early as the last 1960s, it has been widely used in the IBM mainframe system, called TP Monitor, more famous is the BEA's Tuxedo and IBM CICS, running in the Terminal / Server mode Server, which is mainly It is separated by commercial logic, which can be used to automatically manage transactions, resources, and fault tolerance. Because the development is very long, the technology is very mature. MiddleWare was first written in Cobol, and now you can still see the old system of COBOL's middleware, and then MiddleWare is re-implemented with C , and the famous middleware has IBM CICS, BEA's Tuexdo, still extensive application at high end. In the system, especially banking systems.
However, after the appearance and extensive application of object-oriented techniques, TP Monitor is not object-oriented, but the business logic of TP Monitor does not have the scalability of commercial components in the distributed object system. , Reusability, exhibit a lot of limitations.
However, like PHP is mainly a functionally-oriented functional language, TP Monitor can still support very perfect, because of the support of TP Monitor, PHP can also be applied in the enterprise environment.
The EachNet I know is:
Code: Linux Apache PHP Tuxedo Oracle
EachNet puts a server in Shanghai several ISPs to ensure that the service is not accessible due to an ISP problem. I have seen EachNet servers in Shanghai hotline machine room, saying that everyone may not believe that Eachnet actually uses itself compatible machine, the chassis of the century star, is estimated to be stronger than us. There are about six or seven machines to load balance.
Object Request Brokers is another middleware that supports distributed object calls. However, its problem is just a proxy (Broker), system-level features require yourself, including management concurrency, transaction, resource management, and fault tolerance mechanisms, etc., and there are also mutual interactions between different manufacturers. The compatibility problem of operation.
A new server that integrates TP Monitor and ORB is called, called the CTM (Component Transaction Monitor) Component Transaction Monitor. APP Server is used in our specific management applications.
In 1997, the CTM market has undergone tremendous changes, as the Sun's J2EE standard is officially released, from this year, all CTM manufacturers use Java to rewrite their own products, such as Sybase originally called Jagus CTS's things, now it has become a pure Java implemented Easerver, Borland's company App Server is also like this. In this way, in addition to Microsoft, there is still a Java-based App Server.
App Server can automatically manage concurrency, transaction, object distribution, load balancing, security, and resource management, etc. Simply, App Server is a management server component, which provides a full-featured running environment for server components.
For example, the database system is managed, which also provides data with a monitoring and managing operating environment, providing transaction, security, load balancing, concurrency, etc. System-level feature, for users Say, you don't need to handle the concurrent lock problem of the database table, handle the resolution of the SQL statement, handle the index optimization, etc., the same for the caller of the server components, do not need to handle concurrency requests, Object creation, destruction, cache, control component transaction, etc. System-level feature. The relationship between the App Server to the server component is the relationship between the database system on the data. App Server is completely a very complex server software similar to the database system, where the database system (RDBMS) is managed, and App Server is the management object. This is also my feelings after I study WebLogic Server.
Microsoft is the earliest manufacturer of App Server, called Microsoft Transaction Server (MTS). Others have many different technology-based App Server, but with the release of the EJB specification, mainstream App Server is basically J2EE. At present, the App Server market is mainly the mainstream of Java application servers and Microsoft's .NET application servers for J5EE specifications.
Tuxedo, etc. Based on process traditional intermediates will continue to play a huge role in specific occasions, such as those that require extremely high response performance and based on specific platform C / C , or have an irreplaceable role.
The server component model provided by the App Server does not solve all problems, and the data sharing cannot be called and data sharing based on the server components implemented by different technologies, such as the SOAP protocol, based on the SOAP protocol. Web Services tries to solve this problem and wants to unify all different technical components on the Internet into a single Web Services. This is also one of the hot reasons for Web Services, and the standard unity is good for everyone.
