{
{   This request will attempt to locate and reserve an available active
{ volume table entry.  If an entry is reserved, it will be initialized
{ to a default entry value.  The result of the request is returned to
{ the caller.
{
{      DMP$GET_UNUSED_AVT_ENTRY (AVT_INDEX,ABLE_TO_GET_AVT_ENTRY)
{
{ AVT_INDEX: (output) If an active volume table
{      entry is found that satisfies the requirements, the index of the
{      entry will be returned in this parameter.
{
{ ABLE_TO_GET_AVT_ENTRY: (output)  This parameter returns the result of the
{      request.
{
