Can linux recongnize RAM that BIOS cannot?
 

Hello.

Long time viewer, first time poster.

I finally found a question that I couldn't find an answer for, so hopefully someone here knows.

I have a Fujitsu B2630, which is a small laptop with a Pentium 3 900. I am running openSUSE 10.3/XFCE 4 quite successfully. I use it daily in conjunction with Sprint mobile broadband and it does pretty nicely.

The problem is, it maxes out at 256 MB RAM. It comes with 128 MB that is inside the computer, and then a free slot which supports another 128 MB SODIMM. The BIOS will recognize only 256 MB and no more (according to Fujitsu) and there is no newer BIOS update than the one I have, at least not officially.

Is there any chance that if I put in a (voltage and pin compatible) SODIMM that is 512 MB that SUSE will be able to see it even though the BIOS cannot?

Thanks!

Probably not. That limitation is probably a chipset limitation (so, while the BIOS does not recognise more, it is not an artificial limitation, but the simple fact that there is no point in changing the BIOS to allow a greater amount of memory than the chipset can use).

You could try hacking the bootloader (Grub?), but you'll probably just get a crash, either immediately or a bit later.

I agree, there is no way to trick the BIOS, this is almost always due to hardware limitations.

In that case...
 

Is there any harm that can come to my computer (hardware-wise) if I try it anyways?

Also, is there any chance of being able to use a ReadyBoost flash drive to increase the RAM via USB? I know it might be rather silly... as it would have to go through my USB2 PCMCIA card... but would it potentially work?

Or does someone make a PCMCIA RAM booster of some kind?

Thanks for the replies, much appreciated. Ultimately, it doesn't matter much, because I usually sit around 109 MB used, 141 MB free anyways... but geeky is as geeky does, I guess.

Thanks!

Why put in the effort? Even the latest distros with the latest motherboards can't do what you are hoping to achieve. But well, no, t won't hurt, you'll just see 256MB at best and the rest will be ignored.

Also I do not see the how hacking the bootloader would help.

Like previous have said. You can not because you are limited by the hardware. Though a PCMCIA or Card Bus solid-state drive can be use to add more memory but it will be swappable memory. The throughput of PCMCIA or Card Bus is 133 MB per second or the same bandwidth as PCI cards.

I wouldn't know why the BIOS would limit RAM in a fundamental sense; the address lines for the P-III are 32 bits wide, and given the way most OSs work, including Windows, I don't think a mobo designer could get away with removing some of the address lines, and the paging logic is all handled in standard silicon...

More likely, if you ask me, is the possibility that the limit is set by the memory technology of the day, and the amount of compatible RAM that could be placed on one memory module.

I have a PIII laptop that has 1-128Meg module in it, and I installed another 256 Meg module for a total of 384 Megs. It is an IBM Thinkpad though, not a Fujitsu.

It is not the BIOS. It is the chip set that limits the RAM capacity. Complain to Intel not the computer manufacture.

Actually Vista's ReadyBoost is really designed to improve random I/O performance and not increase virtual RAM size. BTW you can tune both file systems and swap to improve performance with linux.

Look, don't think of it as the BIOS trying to stop you from installing more RAM, think of it as the hardware not capable of supporting more RAM for one or more reasons.

I have a compaq with an opti chipset 160mb ram limit 32 onboard 128mb extra. I put 256mb chip in and it only read 160mb. I dont know if it's hardware or bios personally. but it bites. I like nice even numbers; 64-128-256 etc. wish there was a way to probe...