________________________________________________________________________ 
   | Table 56. SPIB format                                                  |
   |_______ ________ __________ ____________________________________________|
   | Offset| Length | Label    | Usage                                      |
   | (hex) | (bytes)|          |                                            |
   |_______|________|__________|____________________________________________|
   | 0     | 4      | SPIBHEAD | Spare.  Reserved for the application       |
   |       |        |          | program to use as an eye-catcher.          |
   |_______|________|__________|____________________________________________|
   | 4     | 4      | SPIBLENG | Length of SPIB.                            |
   |_______|________|__________|____________________________________________|
   | 8     | 4      | SPIBUDSL | Length of user default specification list. |
   |_______|________|__________|____________________________________________|
   | C     | 4      | SPIBUDSP | Address of user default specification      |
   |       |        |          | list.                                      |
   |_______|________|__________|____________________________________________|
   | 10    | 4      | SPIBGSXP | Address of application-defined GET STORAGE |
   |       |        |          | exit.                                      |
   |_______|________|__________|____________________________________________|
   | 14    | 4      | SPIBGSXK | User-defined parameter to be passed to the |
   |       |        |          | application program's GET STORAGE exit.    |
   |_______|________|__________|____________________________________________|
   | 18    | 4      | SPIBFSXP | Address of application-defined FREE        |
   |       |        |          | STORAGE exit.                              |
   |_______|________|__________|____________________________________________|
   | 1C    | 4      | SPIBFSXK | User-defined parameter to be passed to the |
   |       |        |          | application program's FREE STORAGE exit.   |
   |_______|________|__________|____________________________________________|