possible defective ram module in t23

[l.butler]

Hi,
I recently picked up a 512mb ram module for my t23. I installed it in slot 1, with a 256mb module in slot 2, then ran pc doctor memory check on it; then I swapped it into slot 2 and repeated. In both cases, each module was recognised; however, in both cases the new ram was diagnosed to have a fault in it. The two 256mb modules tested fine and I have never had any memory issues, that I can remember. (no pun intended )

I would like to return/exchange the module, but a question niggles at the back of my mind: could this diagnosis be caused by a not up-to-date bios and ec?
At present I have bios v1.13 and ec v1.04 on this t23.

Thanks,
Leo Butler
-------------------------
t22 - 20gb hdd/384mb ram/debian etch-ubuntu 8.04-tinyme pclinuxos
t23 - 120gb hdd/2x256mb ram/wg511t pcmcia wifi card/debian lenny

http://www.maths.ed.ac.uk/~lbutler

[RealBlackStuff]

No, the RAM either works or not.
It won't hurt your laptop though to update BIOS to 1.20 and ECP to 1.06a.
http://www-307.ibm.com/pc/support/site. ... MIGR-57669
There are a few issues that have been solved since your BIOS version came out.

Get your money back or swap for another module.

[l.butler]

Thank you.

[rkawakami]

As a secondary check, you could also run a dedicated memory diagnostic such as memtest86+:

http://www.memtest.org/#downiso

[czukuczuku]

about updating bios, there's line; "You need an AC adapter and a charged battery pack to update the BIOS.", and if i dont have battery at all, can i run update? atm i have 1.18, is there really need to go for 1.20?

[rkawakami]

I seem to recall that there might be a way to update the T23 BIOS without a working battery, but I can't seem to find it here in the archives. I did find one for an A30 but I'm not sure if it can be applied to the T23:

http://forum.thinkpads.com/viewtopic.php?t=1363

In any event, updating the BIOS (or Embedded Controller) can have disastrous results if you lose AC power during the update. I would not recommend it. As far as having the latest BIOS and EC updates, I generally don't bother if the system is otherwise operating fine. As an example, the T23 (2647-5NU) I'm on right now has BIOS 1.09. You can read the update notes for a brief description on what was changed and what bug(s) were supposedly fixed.

[l.butler]

Ray, thanks for the advice. Memtest should be available in all majour linux repositories; it is certainly in debian's.

The thinkwiki has an excellent guide to upgrading the bios/ec. I followed the advice there and installed the most recent bios/ec for the t23. As rbs said, this didn't affect the diagnosis.

There is a software-only way to remedy some defects in ram. While looking for memtest, I came across a patch to the linux kernel called kernel-patch-badram. According to the documentation, it allocates all the bad memory (identified by memtest) to the kernel, and the kernel ring-fences that bad memory.

If the distributor gives too much hassle in returning the defective module, I'll give it a try and report back.

[RealBlackStuff]

Your laptop's health depends on reliable RAM.
I wouldn't even consider your mentioned software option!
Give that distributor hell


On a different note:
Heard this definition of a haggis:
A sheep with its two legs on one side shorter than the two on the other side.
That way it can walk around the mountain in only one direction, and never fall off.

[l.butler]

Ahh, you must read Burns' ode to haggis. It'll moisten your eyes, if not whet your appetite.

I should tell you that a football presenter here has mentioned more than once that guinness drinkers ought to be banned from pubs. It takes soooo long to pour.

-----
I'll keep your advice about ram in mind.

[l.butler]

This is a rather long post, but I wanted to report back on the badram patch.

I decided to go ahead and investigate the badram patch to the linux kernel.

I ran memtest86+ over my bad memory. It can display errors in a form suitable for badram. I ran it for about an hour, and it stabilised after about 15minutes; I went to work and let it work away for another 9 hours. It didn't discover more errors, so I felt pretty confident.

I built the linux kernel (v2.6.26) with the badram patch applied on a machine with good memory, installed the kernel, added to the bootloader (grub) command-line the stanza `badram=0x... , 0x...' which identifies a block of memory containing all defects identified by memtest.

I booted up successfully. In fact, I realised I'd not built the wireless modules when I built the badram-patched kernel, so I built and installed the wireless modules on the `new' machine and rebooted. I'm writing this post over my wireless connection with the patched kernel and newly-built wireless modules.

In all, I would say that this patch is very promising. I would want to stress test it more and feel out the limits, but already it has exceeded expectations.

Here is some information:
# dmesg | grep RAM
[ 0.000000] BadRAM option is =0x0d812000,0xff80e000
[ 0.004000] Memory: 767612k/785856k available (1715k kernel code, 16156k reserved, 724k data, 324k init, 0k highmem, 1024k BadRAM)

You can see that only a small bit of memory is defective -- less than 0.2%.

Leo

[rkawakami]

Interesting solution to a "bad memory" problem. Sort of like when a disk drive has some bad sectors and they get mapped out. That said, I'm with RBS in not using that solution . Depending upon the nature of the memory defect, it can either be limited to a few cells and not affect any other cells for the rest of the life of the memory. Or, the defect may spread out over time and result in additional memory cells going bad. In which case your system may encounter random failures until you patch out the new errors.

[RealBlackStuff]

I should tell you that a football presenter here has mentioned more than once that guinness drinkers ought to be banned from pubs. It takes soooo long to pour.

That presenter probably likes his pint of bitter (cats p!ss) lukewarm (Yukkg!)

That's why we order a pint of lager first, while we wait for the first Guinness.
Then, as soon as we get our pint of Guinness, we ask the bartender to "put the next one on".
We'll be in Guinness for the duration.
And you'll hardly find better customers than Guinness drinkers! We never, EVER, dawdle over a pint!
Slainte!