{
{  VOLUME_SET_TABLE   (VST)
{
{  PURPOSE:
{    The volume set table preserves information about a set, and the
{    volumes in a set.  This information is maintained on the volume,
{    and is recoverable.
{  WHEN ACCEDDED.
{    All accessing of the VST is done by the set manager.
{    MODIFIED:
{    -  When volumes are added to a set, or a new set created a
{       volume set table is created on the volume.
{    -  When member volumes are added to a set, the volume is
{       listed in the master volume set table.
{    -  When a pf root is created it is stored in the master
{       volume set table.
{    READ:
{    -  When a volume becomes active, the VST is read to determine
{       what set the volume belongs to, and whether the volume is
{       a member or a master.
{       The information is transfered to the active set table.
{  RESIDENCY:
{    The volume set table is a device file on each volume.
{    Its ring attributes are 3, 3.
{    The device file name is STF$VOLUME_SET_TABLE CAT RECORDED_VSN.
{    The volume set table is read/written in ring 2, on a create_set,
{          or add_member_to_set.
{    The vst is read/written from ring 1 on a volume_active.
{  FIELDS:
{    stt$vol_set_table = record
{       data_being_modified:  This field is used for device file integrity
{             checking.  This string should be initialized to 'TRUE ' at
{             the start of a open for modify, and set to 'FALSE' at the
{             end of the operation.
{      version_name:
{      vsn:
{      internal_vsn:
{      case entry_type: Is the volume in a set? (should always be )
{      = stc$valid =
{        set_name:
{        unique_set_name:
{        case vol_status_in_set: Member or Master?
{        = stc$member_vol =
{          master_vsn: The name of the master volume
{                that this member belongs to.
{          master_internal_vsn:
{        = stc$master_vol =
{          set_owner:
{          master_dm_packet_storage:
{          member_vsn_list_locator: A "pointer" to the list of members
{          pf_root_storage: Indicates if the PF root has been stored.
{          vst_heap: ALIGNED [0 MOD 32] ost$heap,
{    stt$member_vsn_entry = record
{      case entry_type: stt$entry_type of
{      = stc$valid =
{        member_vsn:
{        member_internal_vsn:
{        member_dm_packet_storage:
