Need help with memory problem

[Guest sirtaldon]

I have a IBM R50 laptop with 256 MB RAM, dual-boot with XPpro. I installed Mdk 9.2 on it last week. This week I obtained a 1 GB mem module which I added. The BIOS and Windows both see the correct amount of memory at 1280 MB, but Mandrake only sees 883 MB. What can I do to fix this at this point? I have already got most of the stuff I use set up and running fine on the laptop, so a re-install would not be my first choice.

 

Thanks

[Guest sirtaldon]

I just tried something suggested on the Linux-ThinPad.org mailing list archive...

 

Under certain circumstances, Linux may not recognize all of the

RAM that is installed on your ThinkPad (cat /proc/meminfo to see if this applies).

 

To solve this problem, add the line:

append="mem=k"

to the global section (near the top) of /etc/lilo.conf, where is replaced by the number that shows on your monitor when you first boot your ThinkPad.

 

For instance, I have:

append="mem=130496k"

as the first line of my /etc/lilo.conf

 

Well, that doesn't work. My cat /proc/meminfo still shows:

 

total: used: free:

Mem: 925835264 284590080 641245184

(edited for ease of reading)

 

I have so far seen a reference to "recompiling your kernel with highmem support", but I haven't seen any details on how to do this. I have never compiled a kernel, let alone recompiled one, so if this is the only way to do this, I will need some detailed instructions.

 

Thanks.

[fuzzylizard]

You could always try installing the Enterprise kernel from mandrake.

[Qchem]

I agree, it sounds like you don't have highmem in your kernel. Either use the enterprise kernel or go the whole hog and recompile your current kernel with highmem support.

[Gowator]

Yep,

MDK 'vanilla' never include HIMEM support so you have the choices Qchem outlines!

However I dont know what the enterprise kernel is ?

I know it has HIMEM support, what i don't know and have never been able to find out is what else is compiled in/patched etc. in enterprise.

 

My 'interpretation' is that Enterpise would focus on stability at the expense of speed, not necasarily what you want with your laptop.

[Qchem]

Exactly Gowator, it is built more for stability. Myself I would recompile but if that sounds like a scary task use the other kernel.

[phunni]

The easiest thing to do would be to use the config for the default mandrake kernel and use it to recompile your kernel.

 

It would actually be very easy - you'd just have to change one option - support for HighMem. Then you'd have your own normal kernel - not enterprise - and it would support your memory.

 

I think DOlsen had a tutorial for it on his site somehwere

 

I'll see if I can find the link and post back

[Gowator]

Last time i tried this (9,2) i used the .config and ended up with a -custom.

 

I suggest looking vwery carefully at the mandrake sources becuase I dont think they are what Mandrake actually uses itself.

 

This being the case (or not) I prefer like Qchem says to actually compile your own kernel from the official kernel.org.

I couldn't get the mandrake kernel to recompile with HIMEM support and also not give lots of missing symbol errors when I tried to use the nforce drivers.

 

What I know about the enterprise kernel, is lots of stuff wouldn't work with it (although it did give me all my memory back)

The vanilla mandrake source with 4GB HIMEM worked for the HIMEM part but gave the symbol errors. This MIGHT have been an error with a single version ....

OR Mandrake might not provide the same source they compile.

 

IT doesn't actually say its the same does it ? We just presume its the same!

[phunni]

If it doesn't work with Mandrake's .config - then there's a problem, although you could still use that config with a vanilla kernel - you wouldn't have all the options (or supermount), but you could get highmem - and probably never miss the rest.

[coverup]

I use one of the MDK enterprise kernels on T41. Works fine for me except for poweroff does not turn off the laptop all the way. You can install it alongside your current kernel and just add a new stanza to lilo.conf.