Re: Memory upgrade

On 10/11/24 15:05, Claudio Jeker wrote:
> On Fri, Oct 11, 2024 at 03:00:23PM +0200, Christian Schulte wrote:
>> On 10/11/24 13:57, Stuart Henderson wrote:
>>> On 2024-10-09, obsdml@loopw.com <obsdml@loopw.com> wrote:
>>>>> In a second server I have upgraded from 7.5 i386 to 7.6 i386 but server sees only 4GB of RAM
>>>>
>>>>> Is anybody with similar experiences? Any ideas how to fix RAM?
>>>>
>>>> run 64bit OpenBSD
>>>>
>>>> 32bit address space is limited to a max of 4GB**, and some of that is eaten up by PCI devices, etc.
>>>> ** PAE can work around this, but I'm not sure if OpenBSD supports PAE at all (and theres other issues/caveats with using PAE of course, including speed and security)
>>>
>>> OpenBSD does support PAE on i386, but not for increasing address space,
>>> just for W^X. See /sys/arch/i386/i386/pmapae.c r1.28.
>>>
>>>
>>
>> Hmm. Why not give up on i386 and make that i686 instead (Pentium Pro)?
>> What I mean by this. Rename the current i386 to i686 by compiling it for
>> i686 and update the pmap to support more than 4GB physical RAM (PAE).
>> Supporting i386 is like supporting 68030.
>
> That's such a trivial task you should be able to finish it over the
> weekend. We all wait for your diff on Monday.
>

Is this irony, or would someone really wait for a diff from me and use
it? Take i386. Compile it with something -march=i686 or pentiumpro by
default. That's it. Add support for the various PAE MMU options. You get
a 32 bit OS supporting more than 4GB of physical RAM. I have so many
older laptops/servers/whatever lying around I could (re)start using with
this. My current daily is a Lenovo x240 with 8GB of RAM running amd64
and this thing is swapping like mad. Throw a 32 bit OS at it supporting
those 8GB of RAM and go for it. Why would anyone throw away such a
machine, just because a 64 bit OS hits its boundaries, when a 32 bit OS
would not?

--
Christian