[H-GEN] where does linux load first in memory?

[Andrae Muys]

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David Jericho wrote:
> 
> [ Humbug *General* list - semi-serious discussions about Humbug and  ]
> [ Unix-related topics.  Please observe the list's charter.           ]
> [ Worthwhile understanding: http://www.humbug.org.au/netiquette.html ]
> 
> Darrin Mison <staeci at yahoo.com> wrote:
> 
> > Been reading Mueller's Upgrading and Repairing PC's 12ed and discovered
> > that most intel-esque cache controllers can only cache the first 64Meg
> > of RAM.  According to Mueller Win9x and NT load into the top of the
> > memory first (don't know why) so unless you need it you really
> > shouldn't use more than 64Meg in order to maximise performance.
> 
> Slight false hood there. The TX series of chipsets didn't have enough tag
> ram to cache above the first 64MB. Linux users on those systems instead
> would create a ramdisk in the top x meg of ram, and then swap to that.
> 

Be aware that the new 2.4 kernel has a different vm-subsystem which is
particularly lazy about freeing swap (ie. afaik it dosn't).  This
affects your box in two ways that are immediately apparent to me:

1/ You will probably need more swap.

2/ Because you will end up with duplicated swap/mem pages the above
trick no longer works particularly well.

It has been noted on l-k that there are systems using similar tricks, so
the vm-subsystem is going to be changing again to accommidate similar
tricks to the above.

Andrae Muys

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