What is difference between Middleware and MiddleTier From an IBM tutorial
The n-tier model has a client tier, atleast one server tier and atleast one middle layer.
I guess by middle layer it means middle tier.
Also in the same tutorial
Because middle tiers are typically implemented using Web Servers - using JSPs and Servlets...
That means middle tier consists of Servlets and JSP. What does server tier consist of ? EJBs and Database? Also i read somewhere that middleware consists of Servlets, JSPs and EJBs. So does that mean part of middleware is in middletier and part in server tier (provided my above assumption about server tier is right). Also if there is something called middleware there must be something called frontware(?) and endware(?). Does such a thing exist? All these names are really confusing me. Can someone please help. Thanks
Architectural layers like presentation, business logic and persistence and patterns like model view controller are technology independent. We could have those three layers or components in a stand-alone desktop application, or spread them across multiple network nodes.
Tiers usually refer to physical machines. 2-tier is commonly a desktop client and database server. Three tiers is usually a client, some kind of application server and a database server. More tiers usually arise from breaking up the middle one.
I like a definition of server as a process that waits for connections and processes requests from clients. So an HTTP server, a servlet container, an EJB container, a CORBA orb, a Tuxedo TPM or a database all meet the definition.
You could map layers or components one-to-one to your tiers, or you could find some layers split across tiers or two or more on one tier.
Now to your question, what is middleware? I'm not sure there is a solid definition. In my shop it's the glue that connects the nodes, things like MQ-Series. IBM seems to include servers and databases in there some times. Some might consider any "black box" framework stuff as middleware.
Bottom line: There are zillions of choices in architecture. You might find common usage for terms and architectural structures, but don't assume that everybody means the same thing when they use the same words. Ask and make sure
A good question is never answered. It is not a bolt to be tightened into place but a seed to be planted and to bear more seed toward the hope of greening the landscape of the idea. John Ciardi