I have acquired a subversion repository. The problem with it is that everything is in the root (apparently nothing fancy like branching was ever done).
Now I want to reconfigure it to follow standard convention:
/svnpath/repo
/trunk
/branches
/tags
How do I do it and still keep the old history?
Well Option 1 would be to check it out, create the new directories for trunk and what not and move the files into where they need to be then commit. Then blow away your working copy and checkout only trunk to a working copy.
Option 2, and probably the more appropriate or "correct" way would be to do a dump of the repo. Then create another one with the classic structure and import the dump file to trunk. See Migrating a Repository