Subject Re: [firebird-support] FB2.5 and Multicore
Author Michael Ludwig
Dimitry Sibiryakov schrieb am 11.06.2010 um 20:42 (+0200):
> 11.06.2010 20:15, Michael Ludwig wrote:
> > Don't get it. You're saying you would use SuperClassic on a
> > 32 bit server with less than 4GB RAM (so 2GB or 3GB), but not
> > with the maximum of 4GB?
> Right. In this case SC won't be able to use whole RAM. (BTW,
> maximum available RAM for 32 bits system is much more than 4Gb. Even
> Windows can handle up to 16 Gb in Standard edition and 64 Gb in Data
> Center edition. Windows XP memory limit is artificial.)

Thanks, this is news to me! This page has some answers and pointers as
to the how and why of that being so:

32-bit Windows Server address > 4GB RAM - How?

It seems that (a) hardware and (b) the OS has to supplement the
straightforward single-32-bit integer addressing scheme in some
way. In addition, drivers have to support it, which may make it
impractical for desktop operating systems with myriads of drivers
outside any form of centralized control and hardcoded assumptions
as to the 4GB limit.

> > I'm probably misunderstanding, but if not, what is the reason
> > for those indications for running SuperClassic?
> RAM usage. 32 bits Classic Server can use more that 2-4Gb RAM. 32
> bits Super Classic (or Super Server) - can't (unless you run some of
> them).

Probably because the former runs as multiple processes each going up to
some given max of 2-4 GB, while the latter are single-process models
which only go as far as one process can go?

Michael Ludwig