Questions about attachment system for new mod...

[mrdummy]

I want make a special mod for my forum, and i 'm busy with examining scripts how it works with attachments upload, verify and adding to database. But you may give some explainations and advices about the system. That saves my examining time more and i can write mod better.

I have some questions:

- how does storage script work, and where in the files can i check/read attachment routines/function?

- In which database fields is attachment data stored if i add some files?

- Are there more database flags placed to know script that attachmant is available by the post? Or is it just checked with SELECT method?

- Which functions are used (and which files) for checking for image view and execute DIV field below the post?
Because i want add special links to attachment div, to open popup window for some extensions, to view or play the file. Where shall i add some code for it?

- If i want add some admin menu option and the new settings page, in which files must i add some codes for it?

- does attachment system checks for existing filename in the attachment folder? It's possible that some user upload same filename as my attachment. Overwrite file is not good.

Are there more points where i must look out for writing mod?
Thank you! The used forum is version 1.0.7, standard package.