{
{   The purpose of this procedure is to read from the backup file.  This reads
{ working_storage_length bytes into the area specified by the working  storage
{ area.
{
{       PUP$GET_PART (BACKUP_FILE_ID, WORKING_STORAGE_AREA,
{         WORKING_STORAGE_LENGTH,
{         FILE_POSITION, STATUS)
{
{ BACKUP_FILE_ID:  (input, output) This parameter specifies the identifier for
{       the   backup   file.    This   identifier   was   returned   on    the
{       pup$open_backup_file request.
{
{ WORKING_STORAGE_AREA:  (output)  This  parameter  specifies a pointer to the
{       area where the data is to  be  read  into  (the  destination  for  the
{       data).
{
{ WORKING_STORAGE_LENGTH:  (input)  This parameter specifies how many bytes of
{       data to read from the backup file.
{
{ FILE_POSITION: (output) This parameter returns the permanent file  utilities
{       file position.
{       puc$partition_boundary indicates that all data has  been  gotten  from
{       this logical partition.  puc$eoi indicates that we have read up to the
{       end of the backup file.
{
{ STATUS: (output) This parameter returns the request status.
{
{       CONDITIONS: pue$unusable_restore_file
{                   This indicates that the transfer count returned was
{                   different that working storage length requested.
{
{       IDENTIFIER: puc$pf_utility_id
{
