Subject Re: [IB-Architect] Database files > 2GB.
Author Charlie Caro
Ann Harrison wrote:
> Understood. I believe that V6 includes a check that keeps you from
> overwriting the beginning of the database when 4GB is exceeded. We
> should check that the change Charlie described is as easy as described.


I can't find my email to you on the code change for NT. If you have it
feel free to circulate it for review and education. Hardly architecture
but the low-level code is a practical and welcome read from the lofty
discourse that goes on here.

Chris Jewell did an exhaustive survey on the Unix variants at one time.
The approaches were fragmented and varied ... like Unix itself.

Some Cognos customer has a VMS V3 kit that allows greater than 2GB
database files. It was a special point release as I recall. The old
jrd/vms.c code was:

LBN = 1 + ((DB page number * DB page size)/ 512);

changed to:

LBN = 1 + ((DB page size/ 512) * DB page number));

Note: LBN stands for 32-bit Logical Block Number (VMS specific)