{}
{   This request is used by Memory Manager to perform an IO transfer.
{}
{       IOP$PAGER_IO (SYSTEM_FILE_ID, JOB_ID, CHAPTER, CHAPTER_OFFSET,
{         BUFFER_DESCRIPTOR, LENGTH, IO_FUNCTION, STATUS);
{}
{ SYSTEM_FILE_ID: (input) This parameter specifies the
{       identity of the file.
{}
{ JOB_ID: (input) This parameter specifies the
{       identity of the job.
{}
{ CHAPTER: (input) This parameter specifies the
{       chapter_number.
{}
{ CHAPTER_OFFSET: (input) This parameter specifies the beginning
{       byte address to/from which data will be transferred from/to the
{       device.  The page frames must already be assigned.
{       There is no requirement on the lock attribute of
{       a page.  This address must be on a mau boundary.
{}
{ BUFFER_DESCRIPTOR: (input) This parameter specifies the
{       buffer_descriptor used to lock pages.
{}
{ LENGTH: (input) This parameter specifies the number of
{       bytes to transfer.  If the request involves more than one
{       allocation unit, the request will be rejected.
{}
{ IO_FUNCTION: (input) This parameter specifies the type of IO
{       function to be performed.
{}
{ STATUS: (output) This parameter specifies the request status.
{}
