-boot_driveno equ 7b00h
-num_read_tries equ 7b06h ; 2 bytes
-sect_pending equ 7b08h ; 2 bytes
-sect_per_track equ 7b0ah ; 2 bytes
-cur_head equ 7b0ch ; 2 bytes - current head
-start_sect equ 7b0eh ; 2 bytes - start sector in track
-destptr equ 7b10h ; 2 bytes - destination pointer
-num_heads equ 7b12h ; 2 bytes - number of heads
-cur_cyl equ 7b14h ; 2 bytes - current cylinder
+boot_driveno equ 0500h
+num_read_tries equ 0506h ; 2 bytes
+sect_pending equ 0508h ; 2 bytes
+sect_per_track equ 050ah ; 2 bytes
+cur_head equ 050ch ; 2 bytes - current head
+start_sect equ 050eh ; 2 bytes - start sector in track
+destptr equ 0510h ; 2 bytes - destination pointer
+num_heads equ 0512h ; 2 bytes - number of heads
+cur_cyl equ 0514h ; 2 bytes - current cylinder