[dmidecode] Determining Current and Maximum RAM

[Anthony Wright]

I'm trying to use dmidecode to work out what the current amount of ram 
available is and what is the maximum amount the motherboard will support 
for any given PC. I've tested on a few PCs and I seem to be doing ok, 
but I'm not sure if this will work on all systems, and I'm a little 
confused by what appears to be two types of recording memory.

There appears to be Physical Memory Arrays (type 16) and Memory Devices 
(type 17) which is what I'm using at the moment. However there also 
seems to be Memory Controllers (type 5) and Memory Modules (type 6) 
which I ignore. Of the limited number of motherboards I've tested most 
only report type 16 & 17 handles, but one reports the same memory under 
handles of both sets of types, and the two sets disagree - under the 
Physical Memory Arrays it reports a maximum capacity of 256 MB, while 
under Memory Controller it reports a maximum capacity of 512 MB.

Could anybody explain the difference between Memory Controllers and 
Physical Memory Arrays as seen by dmidecode, how I should interpret them 
and how reliable the numbers are likely to be?

Alternatively could you tell me whether there's a better way of getting 
this information out of the motherboard? Ideally I'd like a little 
program that analyses the motherboard, works out the specification of 
the memory that's already there and tells me the specification of the 
memory it will support e.g. 2 x 256MB modules PC-133 non-ecc.

Thanks,

Tony Wright.