Hi Kevin,

Also three tier apps are much more complicated to write, distribute, and maintain, becasue they have many more dependencies that a normal file share app on a local network. Some of the additional complexity of three tier apps is the Firewall, the web server, the need to have detailed expertise in multiple languages like VFP, VB, VBA, perl, MSSQL, postgres, etc. Also, if you plan to run the app on a cost efficient OS like linux, a new OS must be learned. Then there is the difference betweem a local network and a wide area network like the internet which requires a domain name registerred with the InterNIC, etc. If you plan on accepting credit cards or dealing in other sensitive matter, you will need to know something about SSL (e.g. Secure Socket Layer encrytion).

All of the additional complexity make the three tier app much less stable than a normal app, because there are many more points at which a failure could occur. Some users accessing a web app my have to make fifteen to thirty hops through the internet to correspond with the app, and a breakdown at any of these points could cause problems.

LelandJ