{
{  JOB_ACTIVE_SET_TABLE   (JAST)
{
{  PURPOSE:
{    There is a job active set table for every job who is accessing
{    a set for permanent file usage.  This table serves two
{    functions:
{    -  It allows a means of keeping track of the number of jobs
{       using a set  (by knowing if the job has already accessed
{       the set) .
{    -  It provides a speed up mechanism, so that later accesses
{       to the same set within the job, may access this table and
{       avoid searching the active set table.
{  WHEN ACCESSED:
{    All accessing is done by the set manager.
{    MODIFIED:
{    -  A new entry is created on the first permanent file operation
{       within the job.
{    -  The table is destroyed on job termination.
{    READ:
{    -  The JAST is accessed on all permanent file operations.
{  LAYOUT:
{    The JAST is an adaptable array.
{  PRIMARY KEY:
{    set name
{  RESIDENCY:
{    A pointer to the JAST (stv$p_jast) is a static ring 2 variable.
{    The table is allocated in the job pageable heap.
{    All reading or writing occurs in ring 2.
{  FIELDS:
{    stt$job_active_set_entry = record
{      case entry_type
{      = stc$valid =
{        set_name:  The name of the set that the job is using.
{        unique_set_name
{        ast_index:  The index into the AST for the set.
