UNIX AND MICROSOFT

to answer your questions in turn
1. For security reasons it is better to have a web server that the users access then pull the information from a seperate server DB.

2.For this one I believe that it becomes upon more of your prefence. I have seen it done both ways WIN to UNIX/Linux or UNIX/Linux to WIN

Keep to answer 1 for your question 1.

For question 2 it depends on your database. Under Linux (unix) you have the advantage that the Server OS and Database are free, The OS can be made very secure. With PostgreSQL you also have a very powerfull Database under Linux.

There are lots of variables that influence the correct answer to either question. From a technical standpoint, there should be no barrier to having a division of machines and/or operating systems for the app and the database. Sometimes, such a division is required; the app runs on one OS, the Database on another. Or, the combined demands of the app and the database engine are too much for one machine.

However, there may be a requirement to at least use the same OS. For example, if your app only uses Microsoft SQL, then the database server has to run Windows, although it could (and probably should) be on a separate box.

The biggest negatives to a two-machine setup are that you now have two system to administer (users, system os, hardware). There may also be a small performance penalty, since in a one server environment; all data transfers are in memory. Two server means data goes over the network.

Hope this helps.

If you're expecting high usage on your DB or need to separate DB from Apps for security reasons I'd recommend installing DB on its own server. If neither of these is a concern then it shouldn't matter.

If you're comfortable managing multiple platforms then there's no reason why DB and Apps shouldn't be on different platforms.