dosseg

.model small

.stack

.data

public sector_offset

;sector offset is half sector diaplay into full sector

; it must be a multiple of 16 & < 256

sector_offset dw 0

public current_sector_no,disk_drive_no

current_sector_no dw 0 ;initially sector 0

disk_drive_no dw 0 ;initially drive A:

public lines_before_sector,header_line_no,header_part_1,header_part_2

;lines before sector is the number of lines at the top

;of screen before the half sector display

lines_before_sector db 2

header_line_no db 0

header_part_1 db 'Disk',0

header_part_2 db 'Sector',0

.data?

public sector

;the entire sector up to 8192 is stored in this part of memory

sector db 8192 dup(?)

.code

extrn clear_screen:proc

extrn init_sec_disp:proc

extrn read_sector:proc

extrn init_sec_disp:proc

extrn write_header:proc

disk_patch proc

mov ax,dgroup

mov ds,ax

call clear_screen

call write_header

call read_sector

call init_sec_disp

mov ah,4ch

int 21h

disk_patch endp

end disk_patch