currently system is atmost 8*65536 bytes long. This should be no problem even in the future. I want to keep it simple.This 512 size kernel kB kernel size should be enough - infact more would mean we should have to move not just these startup routines, but also do something about the cache memory(block I/O devices.the area left over in the lower 640kB is meant for these.No oher memory is assumed to be "physical", ie all memory above 1Mb is demand paging. All addresses under 1Mb are guaranteed to match their physical addresses.