SEQPDL parameter

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Minimum PDL available for sequencer

Summary

Default value
4096
Parameter type
Utable
Where set
On user's parameter line or reset by UTABLE command
Related products
All
Introduced
Model 204 version 7.5

Description

The SEQPDL parameter controls the amount of free space that must be present in the user's Push Down List in order for the SOUL sequencer to proceed with the next quad code.

The minumum and default value of SEQPDL is 4096 bytes.

The maximum value is 8192 bytes.

SEQPDL is a user resettable parameter and can be set on the user's parameter line or reset by the UTABLE command.

Formerly the amount of free space was 1024, which was hardcoded internally in the Model 204 nucleus. With 1024 bytes there were edge cases where abends would break files, resulting in ERROR 2126 USER'S PUSHDOWN LIST OVERFLOWED. SEQPDL is provided to allow enough PDL space so that all of the lower level journaling routines can process error conditions without breaking files. The default value of SEQPDL adds 3072 bytes of free space.

Note: If your applications' actual use of free space in the User Push Down List approaches the limit that you have set in LPDLST, to avoid a PDL overflow you might need to increase the value of LPDLST by up to 3072 bytes (or more if you set a larger value for SEQPDL).