[erwin1234]

Originally Posted by DoctorOhh

Welocome to Mobileread.

Moved post to its own thread. Please read the "PLEASE READ BEFORE POSTING - The purpose of this subforum" sticky post for guidelines for posting in the development forum.
Here is the current FAQ entry on setting up calibre to run from a network.

Thank you for making this a seperate thread.

The FAQ does not make sense because the answer to the question "on setting up calibre to run from a network" is smiply "Do not put your calibre library on a networked drive". That is not an answer !

The content server solution is not an option. The goal is to have ONE user at the time working with the full calibre software using the DB over the network. So multiple user but NO concurrency - only one user at the time. But from different locations.

Solution 1: All modern network filesystems have a file locking option - if you open a Word file over the network and another user opens the same file you get a dialog box with "file is already open". This could be a simpe check in calibre? http://en.wikipedia.org/wiki/File_locking

Solution 2: Alternatively you could just create a temp filename "metadata.db.locked" at startup and check for the presence of this file at startup and open it for read/write. If you succeed, you can continue. If not, it is already opened in another instance, so inform the user and quit. The normal program exit would remove this .lock file. But in case of a crash it still works because the file will be closed after some time by the OS.