RE: find file_id or block_id from data block address

Prem

A small correction about my last post...

>IMO in 7.3 the file number part of the DBA is 8 bits (from 8.0 it
>is 10 bits). Therefore the correct file number is 32 (not 128).

7.3 supported 1022 files. Therefore 10 bits are reserved for the file number in the RDBA. \ The difference is the position... In fact the high order bits of the file number are \ stored after the low order bits. The exact number of high/low order bits is platform \ specific, in my previous guess I took 8 for the low order part and, therefore, 2 for the \ high order part, i.e. something like that "LL LL LL LL HH".

E.g. in your case:

Decimal: 537037017
Binary: 0010 0000 0000 0010 1000 1000 1101 1001 File Number: 0010 0000 00 --move high order bits--> 00 0010 0000 --> 32 Block Number: 00 0010 1000 1000 1101 1001 --> 166105

This means that with less than 256 files, the high order byte stores the file number.

HTH
Chris

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