memory size for kernel

[Armin Schindler]

When linuxbiosmain() calls set_memory_size() it
reduces the totalram by 2MB, why ?
I compared the ram sizes with the original BIOS, and
found out that removing only the lower 1MB is correct
(at least gives the same memory sizes). So why
does linuxbiosmain() "totalram - 2048" ?

thanx,
Armin