Post by notbob
I gotta Vaio (Asus m/b) P4 box (2001?). All on-board (board mounted)
grapics/video and no wifi or other IDE cards (I use 'CAT-5').
BTW: how much memory (RAM)?
If you got 3 GB or less, PAE in the kernel isn't needed which makes
the machine a bit faster (no need to change mappings whenever you go
to the screen memory, that can then be mapped within the last 1GB of
address space, where you don't have any RAM anyway).
With 4 GB, of course, you DO need PAE (Physical Address Extensions) as
you want your programs to be able to use all of that RAM (and 4 GB is
the 32-bit address space limit, so you do not want video memory to
overmap part OF that RAM).
See the HIGHMEM options in the kernel's config file:
# CONFIG_NOHIGHMEM is not set
# CONFIG_HIGHMEM4G is not set
# CONFIG_DEBUG_HIGHMEM is not set
(these are mine, _with_ PAE).
HIGHMEM4G is the one to set for a single 4GB address space, so when
your RAM is less then that. Then both the kernel and your programs
will get the video memory mapped into the last GB of that address
PS: NOHIGHMEM is for a machine with 1 GB or less, then both kernel and
user space will be mapped at the same time.
If you are compiling a kernel that will never run on a machine with
more than 1 Gigabyte total physical RAM, answer off here (the default
choice, and suitable for most users). This will result in a 3GB/1GB
split: 3GB are mapped so that each process sees a 3GB virtual memory
space and the remaining part of the 4GB virtual memory space is used
by the kernel to permanently map as much physical memory as possible.
If the machine has between 1 and 4 Gigabytes physical RAM, then
answer 4GB here.
(actually, with modern screen adaptors, 3 GB is the limit here)
If more than 4 Gigabytes is used, answer 64GB here. This selection
turns Intel PAE (Physical Address Extension) mode on. PAE implements
3-level paging on IA32 processors. PAE is fully supported by Linux,
and PAE mode is implemented on all recent Intel processors (Pentium
Pro and better).
But not all versions of the Pentium M seem to support it (or at least
do not show THAT they support it).