The following chart gives a brief description of the Exec functions that
control device I/O.  See the Amiga ROM Kernel Reference Manual: Includes
and Autodocs for details about each call.


                  Table 19-4: Exec Device I/O Functions
  ______________________________________________________________________
 |                                                                      |
 |     Exec Device                                                      |
 |     I/O Function                  Description                        |
 |======================================================================|
 |  createiorequest()  create an iorequest structure (v36).             |
 |  deleteiorequest()  delete an iorequest created by createiorequest() |
 |                     (V36).                                           |
 |       opendevice()  gain access to an exec device.                   |
 |      closedevice()  close exec device opened with opendevice().      |
 |             doio()  perform a device i/o command and wait for        |
 |                     completion.                                      |
 |           sendio()  initiate an i/o command.  do not wait for it to  |
 |                     complete.                                        |
 |          checkio()  get the status of an iorequest.                  |
 |           waitio()  wait for completion of an i/o request.           |
 |          abortio()  attempt to abort an i/o request that is in       |
 |                     progress.                                        |
 |______________________________________________________________________|


             Table 19-5: Exec Support Functions in amiga.lib
  ______________________________________________________________________
 |                                                                      |
 |        Function                   Description                        |
 |======================================================================|
 |          beginio()  initiate an asynchronous device i/o request.     |
 |      createextio()  create an iorequest data structure.              |
 |      deleteextio()  free an iorequest structure allocated by         |
 |                     CreateExtIO().                                   |
 |______________________________________________________________________|