On 7/27/2015 11:31 AM, Ann Harrison wrote:
> >27.07.2015 1:24, Ann Harrison wrote: > Firebird was based on InterBase which was based on Rdb/ELN, an implementation of DEC's [standard(!)] relational > interface. As part of DEC's VAX software empire, DSRI used DEC's error message facility. Every project had a code and > used it as a prefix to its error messages. On Mon, Jul 27, 2015 at 4:14 AM, Vlad Khorsun <hv...@users.sourceforge.net <mailto:hv...@users.sourceforge.net>> wrote: Ann, thanks for explanation. But, it is still not clear why ENCODE_ISC_MSG is more strict than necessary. It limits number of facilities by 31 (bitmask used allows 255) and number of codes per facility by 16383 (instead of 65535). Currently, we have no problem with it, just curious...The high bits in the codes may have been intended for severity ... I really don't remember. The high bits in the facility were to distinguish relational database errors from other DEC product errors. I'd feel free to use any of them.
The only VMS documentation I could find identifies the high order bits as "internal control flags".
A piece of almost forgotten history is that when Interbase first shipped, it had bi-directional interoperability of Rdb/VMS and Rdb/ELN. Something we liked to do was fire up Database on VMS and throw queries at Interbase on an Apollo. Like Firebird, the Rdb y-valve loaded subsystems dynamically, so we could slip our remote (and embedded) subsystems under the DEC y-valve. DEC didn't support TCP/IP ("TCP/IP will blow over before we could do an implementation", which almost turned out to be true), so we had to use a third party TCP/IP.
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