[ILUG] Large amounts of RAM

[Gavin McCullagh]

I remember not that long ago that to get linux to use more than (I
think) 64MB RAM, you had to pass "mem=64M" to the kernel at boot.  My
assumption is that this was the 2.0 kernel or something like that.

This is no longer necessary.  Is it the case that the ceiling was raised
ie if you're above XGB RAM do you now need to pass it to the kernel??  Or,
on the other hand, should Linux now always see all your RAM (in principal
anyway).

I ask because we have a machine here with 3 512MB sticks and top reads:

Mem:   906360K av,  313568K used,  592792K free,   72008K shrd,  133904K 
buff
Swap: 2096440K av,       0K used, 2096440K free                  126188K 
cached


and 


% cat /proc/meminfo 
        total:    used:    free:  shared: buffers:  cached:
Mem:  928112640 361541632 566571008 73945088 137117696 156418048
Swap: 2146754560        0 2146754560
MemTotal:    906360 kB
MemFree:     553292 kB
MemShared:    72212 kB
Buffers:     133904 kB
Cached:      152752 kB
BigTotal:         0 kB
BigFree:          0 kB
SwapTotal:  2096440 kB
SwapFree:   2096440 kB



Is it possible that we've overstepped the new limit??  Do I need to reboot
and pass mem to the kernel??  Does anyone know what the new limit is, if
such a thing exists, other than the kernel's memory support limit??

Thanks in advance

Gavin