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Re: 64 bit addressing again

Andreas,
While there is no way for an application to access more than 4 GB of data at one time, there are way to cheat and keep ~8 GB of data live in memory. mmap can be used to map parts of a large file (data set) into an application. The mappings can be changed at any time. The systems buffer cache will keep any part of the file accessed in memory as long as there is room. Multiple processes can also share the data.
If your application is truly random access this will not work. However it will work for access patterns that are more localized. The window(s) into the file can be moved as the progress needs change.
Josh


At 11:57 AM +0100 2/11/04, Andreas Lachner wrote:
On Tuesday, Sep 16, 2003, at 15:50 US/Eastern, Mike Vannorsdel wrote:

Did anyone see the "Optimizing for the PowerMac G5" article today. It
says:

"Today, Mac OS X provides full 64-bit support in the kernel, the
virtual memory subsystem, the file system, and some additional core
components of the OS."

This seems to imply 64-bit addressing is already there. However, from
discussions in here it seems it's not implemented.

My real question is, does anyone know the lowdown on this; does Mac OS
X currently allow 64-bit addressing and if so, where can one find the
documentation to implement it (allocation functions, compiler flags,
ect.)?

There was an answer: no 64-bit addressing support.

Did it change meanwhile?

How can I address 8 GB of ram at all?

Thanks.

CU
Andreas
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References: 
 >64 bit addressing again (From: Andreas Lachner <email@hidden>)



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