boot loader disk buffer

Recently I found some simple source code of a bootloader.The following is the simple one stage boot loader

BITS 16
org 0x7c00
start:
   mov ax,07c0h
   add ax, 288
   mov ss,ax
   mov sp,4096
   ...
   ...

from MikeOS

the memory layout reserve a 4kb disk buffer.

just like this:

start from 0x7c00

|MBR(512)........|4kb disk buffer............|4kb stack .....|

what I don't understand is that why a disk buffer is needed? Can somebody helps me. sorry for my stupid question, but I google for a long time 开发者_运维百科and can not get what I want.

The simple answer is that the disk buffer is used to load first the root directory and then the File Allocation Table in order to load the named file from the root directory.

The happy answer is that the latest code is available at the MikeOS website.