Re: Using >1GB RAM

Xintian Wu (xintian@cse.ogi.edu)
Tue, 13 Jan 1998 12:21:10 -0800 (PST)


May I ask if what I shall do with the 2GB 4 CPU machine?
If I can live with 2GB user space and 2GB kernel space, is it
worth modifying the kernel? Please give me a rough estimate
of the workload.

I know that SunOS OpenServer can support up to 4GB memory though
it is very expensive. How do they manage to do that?

thanks very much

xintian

On Tue, 13 Jan 1998, MOLNAR Ingo wrote:

>
> On Tue, 13 Jan 1998, Albert D. Cahalan wrote:
>
> > Perhaps a new architecture, p6big. Mostly it would have symbolic
> > links into the i386 code. The page tables would use the weird
> > 36-bit Pentium Pro features (64 GB physical memory). Segments
> > would be used everywhere. All the old segment registers get used
> > as originally intended, but to go past 4 GB in 1998.
> >
> > For really big processes, gcc needs to learn about 48-bit far pointers.
>
> no, the PPro 'bigphys' feature extends physical memory space to 64G
> (actually extends it to 64 bits, but i guess the CPU itself is 64G
> limited), but logical address space will stay pure 32 bits.
>
> hm, is such 'above 4G' memory PCI DMA-able? it's pretty much useless if it
> doesnt integrate well into PCI.
>
> -- mingo
>