< FVdriver2 is a virtual disk with journalling, like fvdriver.> It differs in one way: the journal labels each write with PID,@ time, lbn, and size of write, so that the PID can be used to sayC in principle one can play back all writes except those done by some < user, or perhaps all except those done in one login session.A    Only the PID is recorded, for reasons of speed and generality. ? It can happen that irp$l_pid is a system address, of course, in @ which case the PID is not readily available and may not exist atA all. for normal use, however, when fvdriver points at a file on a > real disk, the PID will usually be meaningful, with the aid of an accounting record. 