Lock spaces

Does anyone know where I might find information on how lock spaces
work? According to the help text, ALCOBJ SCOPE(*LCKSPC) will scope the
lock "to the lock space associated with the current thread. If no lock
space is attached, the lock is scoped to the job." I've done some
research and all the references I've found to lock spaces are quite
terse. Technical document 332075326 "Lock Spaces and Job Statuses LSPA
and LSPW" says that "A lock space is an internal object that is used
by other objects to hold object and record locks" and "It is called a
transaction control structure (IBM TCS) at the machine interface.
There is an Attach Transaction Control Structure (ATCHTCS) instruction
that can be used to associate the TCS with the thread." I've also
found a couple APIs that take a lock space identifier and return
information about it, but I can't find anywhere that actually says:

* How and when a lock space is created
* How and when a lock space is attached to a thread (other than that
it's done with the ATCHTCS instruction)
* How I would find a lock space identifier to actually pass to those APIs

I don't need this information for anything in particular, I'm just curious.