End-of-Extent Appendage

If an end-of-cylinder or file-protect condition occurs, the system updates the seek address to the next higher cylinder or track address and retries the request. If the new seek address is within the current extent for the data set, the request is executed; if the new seek address is not within the current extent for the data set, the EOE appendage is entered. To try the request in the next extent, move the new seek address to the location pointed to by register 6.

If a file protect is caused by a full seek (command code=07) embedded within a channel program, the request is flagged as a permanent error, and the ABE appendage is entered.

The end-of-extent (EOE) appendage is entered when the seek address specified in the input/output block is outside the allocated extent limits indicated in the data extent block.

The simplest way to compare two track or block addresses to see their relative positions on the volume is to use the CLC instruction; however that technique works only if both addresses (CCHH or CCHHR) contain cylinder numbers of less than 65536. To handle any addresses that are more or less than cylinder 65536, use the TRKADDR macro with the COMPARE option. See Compare two track addresses (TRKADDR COMPARE).

You can use the following optional return addresses:

Contents of register 14 to return control to the system, causes the ABE appendage to be entered. The system places an end-of-extent error code (X'42') in the ECB code field of the input/output block for subsequent posting in the ECB.
Contents of register 14 plus 4: The channel program is posted complete with X'42'. The ABE appendage is not reentered for this request.
Contents of register 14 plus 8: The request is tried again.

Registers 10 through 13 in an EOE appendage can be used without saving and restoring their contents.