OS header?

org $20000
db $80,$0F
dd (os.end-$20006) bswap dword
db $80,$12,$13,$00
db $80,$21,$05
db $80,$32,$25,$00
db $80,$A1,$07
db $80,$C2,$01,$00
db $80,$D6,$00,$03,$05,$00,$03,$05
db $80,$E6,$00,$03,$05,$00,$03,$05
db $00,$0D,$CF,$CF dup 0
db $80,$7F
dd (os.end-$20100) bswap dword
db $5a,$a5,$ff,$ff