Subject: Re: Large Memory Support
To: None <>
From: Thomas T. Thai <>
List: port-i386
Date: 03/23/2004 22:35:57
Thor Lancelot Simon wrote:

>If you want to tackle this, wonderful!  I'm sure a number of people will
>be willing to help you with documentation, advice, and possibly code.
I lack the expertise to back-port Frank's work to i386. However, I can 
test codes and give feedbacks. This PowerEdge 8450 has 32 gig of RAM. 
Only 24 gig is installed right now though.

PAE support may require additional considerations:

1. Device drivers. Hardware would have to support 64-bit addressing or 
use BusDMA to bounce buffers to DMA not accessible by the hardware. One 
would take a performance hit with bounce buffers though.

2. Auto calculation by the kernel for the number of vnodes. With enough 
memory, vnodes could exceed the allowable kernel address space. One 
would have to set this statically or via sysctl.

3. Loadable kernel modules and ACPI.