It was never widely used and essentially disappeared soon after the division was shut down in 1985, possibly because IBM and other companies settled on SQL as the standard.
BS12's lasting contribution to history was the use of a new query language based on ISBL, created at IBM's UK Scientific Centre.
BS12 included a number of interesting features that have yet to appear on most SQL-based systems, some a consequence of following the ISBL precedent, others due to deliberate design.
In addition, BS12 was ahead of SQL in supporting user-defined functions and procedures, using a Turing complete sublanguage, triggers, and a simple "call" interface for use by application programs, all in its very first release in 1982.
Sample query for determining which departments are over their salary budgets:[1] Note the "natural join" on the common column, DEPTNUM.