Noticed you guys have an (as yet undefined) computer engineering tag. Does this seem like your cup of tea?
I'm writing a little toy operating system using a mix of C and Assembly (it's not meant to be good/fast, just meant to learn from). I know that I can issue an interrupt (i think it's INT 0x15) to check the size of installed memory, which the BIOS does for you. My question is, how does it do this? There obviously needs to be a catch-all function that it performs, because it can't guarantee two systems have the same amount of memory.
When there is a bit of doubt I prefer to ask the community before migrating or referring people. Hope you don't mind.