Added April 2013
The /A switch auto-configures the IDX. Instead of prompting for the number of extra empty index blocks to allocate, it prompts for the expected total number of records to configure the index for, and then calculates optimum block size and levels. For example:
ISMBLD TEST/A
Key size: 30
Key position: 1
Size of data record: 64
Number of records to allocate: 1000
Auto-configure index for how many (expected) records: 5000000
79 index blocks will be allocated
IDX Configuration: 5 levels, 2048 byte blocks
Projected IDX blocks by level: 1,3,108,3859,138889
Primary Directory?
Data file device:
Load from file:
Note that the prompt for the number of records to allocate only determines the size of the initial empty file, which is not particularly important since the file will auto-expand as records are added. The only advantage of pre-allocating would be the slight possibility of a more efficient arrangement of disk blocks. The prompt for the expected total is actually more important, as it determines the IDX configuration, which will affect the file performance as it gets larger.
Note also that this version of ISMBLD.LIT is backwards compatible to 6.0.
History
2013 April, A-Shell 6.1.1348: /A switch added to A-Shell
