Quote: Can we make an estimation about the necessary RAM on the Server and on a typical workstation PC?
Yes. The workstation (client) PC would not have to be anything special. Sesame does almost all of the work on the server.
The server, given the numbers you are relaying, would have to have a fair amount of RAM - though not unusually large amounts. It sounds like you have fixed sized records/fields. Sesame will actually shrink this requirement considerably in that we use variable lengths for both records and fields - only using as much space as is actually containing data. With 150 Mb of actual data, I would recommend at least 512 Mb of RAM - and it would only benefit to go for a full gigabyte. It is actually getting pretty hard to find a server configured with less than 512. A reasonably modern harddrive and a > 2 Mhz CPU would complete the picture nicely. Sesame is multithreaded so you might want to look into a multicore or hyperthreading Pentium or AMD.
The next thing to be taken into consideration is the programming requirements. It sounds like your system is a programmed set of a fixed files. Some of that programming may well be unnecessary in that Sesame's engine will take care of much of it automatically. And the clients/form will take care of some of the user interface programming.
Have you looked through the manuals to determine what portions of the requirements would still require SBasic programming, and which portions could be handled by the Sesame engine and client without additional programming?
Quote: During the new design do we have to separate them to 3 files?
No, but you may want to. If the information in the files is closely associated and will be used frequently in concert - then you will want to combine the files into a single application. If the information is used separately, usually - then you may want three (or more) separate applications.