some setup for filesystems

config.s

@@ -3,3 +3,4 @@ NUMSEG equ 4; TODO build system should calculate this value
 ; might be good to move one of these into the high memory area
 KERNEL_SEG equ 0x50
 STACK_SEG  equ 0x1050
+BOOTPART   equ 0 ; 0-3

src/boot.s

@@ -36,5 +36,28 @@ retf
 
 ; TODO filesystem and reserve space for mbr partition table
 
+times 446 - ($-$$) db 0
+times bootpart*16 db 0
+
+; some programs do not accept values with bits 0-6 set
+status db 0
+
+; chs offset :/
+off_head db 0
+off_sector_cyl db 0
+off_cyl_low db 0
+
+; https://en.wikipedia.org/wiki/Partition_type
+type db 0
+
+; chs... end?
+end_head db 0
+end_sector_cyl db 0
+end_cyl_low db 0
+
+; lba :)
+lba_off dd 0
+lba_len dd 0
+	
 times 510 - ($-$$) db 0
 dw 0xAA55