SUMMARY: Memory addressing

From: Jeff Kennedy (
Date: Wed Jul 19 2000 - 15:51:24 CDT

So, here's how it works.

Solaris can address a boat-load of memory, replies have stated systems
running with up to 64gb and Casper stated that they don't sell systems
with memory that isn't usable. So whatever the max that Sun systems can
hold can be addressed. Swap space is a different story; 2gb for 2.5.1,
4gb for 2.6 and 7 in 32-bit mode, 4+ for 7 in 64-bit mode and 8.

32-bit processes can address not quite 4gb (call it 4 for practical
purposes) and 64-bit processes on a 64-bit OS can address more.

The short answer is; Solaris will address all the memory you can put in
the box, no matter what version. If you're wondering why a 32-bit
process can only address 4gb and a 32-bit OS can address much more than
that it's because of the MMU (memory management unit) that Sun uses. If
you want details on that you'll have to look elsewhere. :-}

Special Thanks goes to Casper Dik (isn't that often the case?) for
explaining in detail how it happens.

Also thanks to:

Chris O'Malley Ravi Channavajhala
Mike DeMarco Nickolai Zeldovich
Paul Yahnig Dave Foster
A.D. Dunham Danny Johnson
Kevin Buterbaugh Frank Smith


Jeff Kennedy wrote:
> A quick question about Solaris 7 and the memory it can address. I was
> asked if Solaris 7 would address 4 gb's RAM and I said yes. Then I
> thought, "I better double check .....".
> I was willing to bet my paycheck on it and still am but I like to cover
> all bases when possible. We have several 420's that are loaded, that's
> what they are wondering about.
> Thanks.


=================== Jeff Kennedy UNIX Administrator AMCC

"One World, One Web, One Program" -> Microsoft Promotional Ad "Ein Volk, Ein Reich, Ein Fuhrer" -> Adolf Hitler

S U BEFORE POSTING please READ the FAQ located at N . and the list POLICY statement located at M A To submit questions/summaries to this list send your email message to: N A To unsubscribe from this list please send an email message to: G E and in the BODY type: R unsubscribe sun-managers S Or . unsubscribe sun-managers original@subscription.address L To view an archive of this list please visit: I S T

This archive was generated by hypermail 2.1.2 : Fri Sep 28 2001 - 23:14:12 CDT