The WBServer.dat file is used by BR32.exe to track whos using which files and which records are currently locked.
This file is used to synchronize reservations associated with workstation IDs. It is not used for file or record reservation, except it does govern which reservation area is assigned to each WSID.
When a file is OPENed a theoretical area way out beyond the end of the file is locked. Depending on what the SHR settings are and which area was assigned to the WSID, a particular set of bytes is locked. Then when the file is OPENed by another user it is easy to see what reservations are in effect.
Record locking occurs in a similar manner by assigning one byte per record way beyond the actual file. This permits unhindered access to data by report writers, and files opened INPUT, etc.
printlocks.exe dumps out this area.