When a connection wants to lock an object, it gets a lock request block which specifies the object and the lock level requested. Eack locked object has a lock block. Request blocks are connected to those lock blocks either as requests that have been granted, or as pending requests.
The settings:
1 means locks are granted first come, first served.
0 means emulate InterBase v3.3 behavior, where locks are granted as soon as they are available; can result in lock request starvation.
FbServerConfig Class | FirebirdSql.Data.Firebird.Services Namespace