Difference between the client and server

Hi All ,

I am new to Dynamics 2009 SCM . I am analysing the Purchase order process .While confirming the PO,We are using the Class PurchFormLetter . In that code Two methods are there . 1.Main 2.MainOnserver

In the MainOnSerVer method ,in the Top ,one comments is written like this

// Main method is split to two parts to reduce the interaction between tiers. main method runs on the client. It gets parameters from Args class and passes them to mainOnServer method, which does the main job.

’'Main method runs on the client" --it will work in client (i understand like that )

"mainonserver method runs on the server" --it will work in server(i understand like that )

I have doubt ,what is mean client ,what is mean server . need some explanation on that .

Thanks

md rhiyas .k

X++ can ran on two different tiers: in AX client and in AOS server process.Communication between processes is expensive, especially if they run on different machines, therefore it’s wise to reduce the number of call between client and server.