[ale] 64-bit vs 32-bit?

[greg.freemyer at gmail.com (Greg Freemyer)]

On Fri, Apr 1, 2011 at 9:19 AM, Ed Cashin <ecashin at noserose.net> wrote:
> On Thu, Mar 31, 2011 at 10:10 PM, Robert <rs at ale.spam.futz.org> wrote:
>>>The only plus that I have seen it that I can run >4GB RAM. Since I use my
>>>machine for editing and mastering audio I find that to be valuable.
>>
>> I do photo processing. When I had 4gb of ram, I often had to quit my RAW
>> conversion software to free up memory to run the GIMP. I recently upgraded to
>> 8gb, and am still running a 32 bit kernel. Now both apps can use up to 3.5gb
>> of ram each and I can leave them both running. Yay!
>>
>> So, in response to the original poster: I think that unless you *know* you need
>> more than 4gb of ram for a single app/process, you should be fine with a 32 bit
>> kernel, even if you have more than 4gb of ram.
>
> Is your kernel using PAE? ?On the way to the full 64-bit technology,
> there were a lot of stepping-stone technologies, and maybe you're
> being helped by one. ?Just curious.
>

It may not be easy to tell if you have a kernel from the last couple years.

== details
opensuse no longer ships a PAE kernel.  All of their 32-bit kernels
are PAE enabled.

IIRC, it is because the kernel team a year or two ago added some logic
to self-modify the assembly of the kernel on bootup.

IIRC: If PAE capable hardware is found, then the kernel runs as
compiled.  If not, the machine-code is modified to have NOOPs in the
PAE code.

Since then, opensuse no longer ships a pre-compiled non-PAE kernel.

Greg