generally i know my stuff

[kurabii]

working on Servers i usually accumulate memory, wheather it be pc2700/2100 memory modules, but this time i ended up getting 133mhz and for my mod thats listed in the chopshop i cant seem to get it to recognize the memory...
well 32mb(s) is detected out of 2 slots both having 256mb sticks in.

dell 2300. Used for mod. detects 32mb of ram out of two sticks filled, i put in some other memory pc100 and the computer just beeps. (meaning bad memory, or just straight not usable.)

never really ever asked this question but does server memory not work with regular computers? i mean it is about 2 or 3 times the size of regular dimms...
if this is a stupid question im sorry i just wanna get my mod working. and if i am left with 32mb then itll just be for linux...

but id like to get winblows on it.

thinking...hmmmmm.

thanks for listening to me.
ESA

[bobvillain]

sounds like it might be ECC, and most desktop mobos don't do it ECC style. but thats just a guess. have you looked up the model numbers? how many chips are on the sticks?

[kurabii]

yut two bits of errors...
well the 128 acting like 32mb through memtest actually tested good....
4 passes like a friggen champ. right now im running a hdd test for kicks...

ill just install Damn small linux...its prolly because its server memory prolly. i have extra 133 at work. i called and they have extra so ill bring the mod to work and test it there...

ECC = error code correction.
its in all mobos isnt it. thats y it has a system speaker.

dang...
any ideas bobcillain? thanks tho. no worries ill just not throw a fit hahaha.

ESA

[wizkid]

It might have something to do with the banks on the mem chips. Some motherboards have limitations and will automatically cap the sticks if they are dual bank for example. Check the motherboard manual if you have it. Might also be like bob said, ECC sticks being incompatible with a desktop board. ECC = error check and correction and it is not in all motherboards, the system speaker is for p.o.s.t./hardware status beeps etc.

[kurabii]

no manual. but easily downloadable from dell.
i happened to get Damn small linux all up and lookin hot. :).

now im just gonna format the drive. install music and boot it up again and try and access my music.

thanks guys. ill try and find it. love this forum

ESA

[Starbuck3733T]

I have it's rackmount brother in my basement now - 2x550 Xeon 2GB DDR ECC.

Not all mobos can handle ECC, most crap out in fact. You're correct about the definition, though. The way it works is that ECC is able to handle and correct ("scrub") 1-bit errors on the fly. This works by a series of logical operation on the 8-bits (IIRC) in the memory that works out the ECC value. If it's 0 and the parity value works out to 0, the READ() is good. If it doesn't match (1 where it's supposed to be a 0 or vice versa) then the read is bad - either the data is bad or the ECC flag wasn't read correctly. Most of the time that this happens, the READ() is re-executed a few times until it comes back good.. and if not, IIRC an NMI is fired.

Also, it may seem like 1-bit error correction is no big deal, but IIRC from my coursework back in EE land, 80-85% of memory read errors are only 1 bad bit.

[bobvillain]

from google:
http://www.pcguide.com/ref/ram/errECC-c.html
http://cr.yp.to/hardware/ecc.html

while i've never used it, i believe ecc ram has an extra chip on it. and maybe for some reason when you use it in a mobo that doesn't support ecc, it only sees that extra chip for some reason. just an idea; i'm sure someone else has dealt with these types of things.

edit: star beat me to it :)

[jaguarking11]

Its an older mobo and older sdr memory had issues with compatibility,

I would see if there is a bios upgrade for the mobo. However it sounds like your mobo isnt recognising them simply because those dims are probably dual sided and the older mobos cant recognise more than one side or more than a certain amount of memory per side.

[kurabii]

nice. u guys are friggen kick a$$.
im painting my peref(s) i paint taped the contacts and am painting everything now. ribbon cables, psu cover, and hdd hahahaha
this is my first mod and i wanna try everything.
the psu is actually wayyy too big for everything to fit.
im in a squirrel... was actually thinking of taking it apart and mounting but as i started it i realized i dont know anything about what can kill me about the psu hahaha and was like well i know one thing... the ground is right there and uhhh ... nah i wont do so.

lol
this thing is gonna be nice :)
just need mesh. been trying to find it locally. dont wanna wait too long with shipping and if id a started this mod when i ordered from mnpctech i would have bought some sheets.

stupid me.
thanks guys i really appreciate the feedback and schooling guys.

ESA

[CandyKid]

Lots of good information, but lets put it all together.

First off, ECC memory needs to be separated from parity memory. In parity memory, each 8-bit dword is protected by a ninth parity bit. The problem with this scheme is that two single-bit errors in the same dword will cancel each other out and the parity bit will not flag an NMI. (an NMI is a non-maskable interrupt, usually causing a shutdown or BSOD). Parity memory does not allow for error correction, just detection.

ECC memory is much more sophisticated and requires quite a bit more memory than parity. ECC uses 5-bits to protect an 8-bit word, 6 for a 16-bit word, 7 for a 32-bit word and 8 for a 64-bit word. ECC systems can correct single and multi-bit errors on the fly depending on your setup, mobo/CPU, etc. It's interesting to note that ECC modules can't act as parity modules, but parity modules can act as ECC modules given chipset support.

ECC memory is slower than parity memory, but obviously much more useful.

As for your particular setup, many of the older motherboards (SDR mainboards) had serious limitations of their memory controllers which became manifest in several ways.

Some will not be able to see x16 (by sixteen) memory chips or above, some cannot run PC133 memory modules, and what might be happening in your case (as suggested above) is that many of the PC133 memory moduels lacked a PC100 or PC66 SPD table entry which caused erratic behavior in systems unable to run PC133 memory at 133MHz.

My guess is that your modules are fine since the same error is occuring with both of them, rather I'd say they are somewhat incompatible with your system. If you could look on the motherboard and tell me the exact make/model of it, I could dig up some specs for you.

PLUR
CK