AWE and SQL 2000

Win 2000 server, SQL 2000

What exactly does the /3GB do?

We have added 4GB of RAM to an existing 4, but have not yet added the switch, although /PAE has been in the boot.ini file for some time. (why would that be? THat switch is for the os, isn't it? Does win 2000 not handle the 4GB of RAM?)

In my research, it says that SQL Server will only be able to access 2GB of memory without it, however, there is 4GB on the server now, so won't it continue to use the 4? SHould the switch be different?

Should the switch ever be different? Once you get to 36GB aren't you supposed to leave the switch off, and why?

We are going to upgrade to Win 2003 - is there anything different we will need to do in order to use the full 8GB? It is not planned to enable AWE until we go to Win 2003, although I can't get an answer on why that would be from our server people - is there a known issue on upgrade?

/3GB allows Windows applications that are marked LargeAddressAware (which SS 2000 is) to have 3GB of user virtual address space instead of the usual 2GB. For SQL Server, this is usually a good idea because it greatly reduces problems related to address space management in 32-bits.

If you do not have AWE enabled, the size of the user virtual address space also forms an upper limit on how much physical memory SQL Server can use; if AWE is enabled, then SQL Server can use up to 64GB of physical memory, but still within the confines of either a 2GB or 3GB address space.

I'm not sure why one would only enable AWE for SS 2000 on Win 2003 and not Win 2000. The amount of physical memory used would be fixed in size, and allocated at server startup. Things are different for SS 2005, but that's another story.