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Amateur OS Sector layout

        This page contains the sector layout for Amateur OS
    on the boot floppy. To make things easier, I'm going
    to use a 2 stage boot. The boot sector code will check
    the machine and load the second stage from sectors
    marked used in the FAT. The second stage will then
    find the kernel and continue loading.

HEAD 0 TRACK 0 SECTOR 1
This is a regular bootstrap. It will do the following:

Set the BPB
Load the banner from disk to video memory
Test for 486
Set the A20 line
Load second stage boot into memory
Jump to second stage

    HEAD 0 TRACK 0 SECTOR 2
        This is the location for the modified FAT table.
    The first three sectors have been marked used. This
    cause DOS to start the first file above the second
    stage loader and the banner code.
    Complete July 4, 2001

    HEAD 1 TRACK 0 SECTOR 16
        This 512 bytes is for the banner. 512 bytes is
    enough for 3 lines in text mode. The banner was made
    in QuickBasic 4.5 and bsaveed to a file. The bsave
    header was stripped off and the file padded to 512.
    Complete July 1, 2001

    HEAD 1 TRACK 0 SECTOR 17, 18
        These two sectors are for the second stage loader.
    It will do the following:

Setup Real Flat mode (??)
Load boot sector
Calculate location of directory
Load directory into memory
Scan directory for kernel file name
Locate and load all parts of the kernel into memory
Jump to kernel

    A normal boot sector can do all this in 512 bytes. 1K
    should give a little elbow room.
    Completed

Keep an eye on the log page for posting of the code.

If you have a comment or question, please feel free
to send me an Email.