Notes Practice

linux 0.01 boot.s (copy from linux 0.01)

boot.s is  loaded at 0x7c00 by the  bios startup routines
and moves itself  out of the way to  address 0x90000, and
jumps there.It  then loads  the system at  0x10000, using
BIOS    interrupts.    Thereafter    it   disables    all
interrupts,moves the  system down to 0x0000  , changes to
protected mode and calls  the start of system. The system
then should  reinitialize the protected mode  in it's own
tables, and enables interrupts as needed.

boot.s (copy) 0.01 kernel size and paging

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.