| Parameter | Specify . . . | Minimum | Maximum | Default |
|---|---|---|---|---|
| QBLKSIZE | the block size for sequential datasets used by ADAIOR. | 0 | 262144 | 0 (see text) |
QBLKSIZE specifies the block size, in bytes, for the sequential datasets used by ADAIOR, the Adabas I/O component. Use this parameter to override the default block sizes. For more information about sequential files used by Adabas utilities and their operating system dependencies, read Adabas Sequential Files.
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Warning: If you choose to write tape files with large block sizes, for example for database backups, these files will not be transportable to systems where support for large blocks is not available. This might include a site being used as a backup facility for disaster recovery. |
If QBLKSIZE=0 (the default), the following default block sizes are used:
| Dataset | Block Size |
|---|---|
| Tape | the optimum selected for the device by the operating system |
| CKD-Disk | track-size / k, where k = smallest value such that track-size / k <= 32760 |
| FBA-Disk | 32760 |
Under all operating systems except VSE/ESA, this block size may be provided in the JCL or dataset label.
Under BS2000, disk block sizes are always rounded up to the next integer multiple of 2048 bytes.
During this Adabas session, use a block size of 65,536 bytes for the Adabas sequential data sets used by the ADAULD utility:
ADARUN PROG=ADAULD,QBLKSIZE=65536
During this Adabas session, use a block size of 32,760 bytes for the Adabas sequential data sets used by the ADAORD utility:
ADARUN PROG=ADAORD,QBLKSIZE=32760
