Physical Memory Organistaion (Currently Studying but need help understandin)

Hey guys,
Im currently studying Operating Systems, but have missed a few lectures and now find it extreamlly difficult to catch up, and need some help understanding physical memory. I need some help understanding how memory is stored and accessed. The organisation of storage which is little-endian and big-endian I need to understand a bit aswell.

If you could direct me to a few useful websites or just briefly explain to me the stuff would be of great help. I also need a better understaning of DIMMs as well as concest of (PC3200 DDR2)

Thanks a lot

Boyan

 

These will probably lead you where you want to go;
http://www.pcguide.com/ref/ram/index.htm
http://en.wikipedia.org/wiki/Category:Computer_memory
http://www.howstuffworks.com/ram.htm