Program Saveboot;
Uses DOS, CRT;
type sectortype = array[0. .511] of byte;
var sectorbuffer:sectortype;
filename:string;
bootfile:file of byte;
regs:registers;
x, option, drivenum:integer;
continue:boolean;

Function
Sector_Read (D, T, H, S : integer):byte;
     begin with regs
     do
         begin 
         es:= seg(sectorbuffer);
         bx:= ofs(sectorbuffer);
         ch:= t;
         cl:= s;
         dh:= h;
         dl:= d;
         ah:= 2;
         al:= 1;
         intr (19, regs);
     end;
SECTOR_READ:= regs.ah;
end;

Function 
Sector_Write (D, T, H, S : integer):byte;
     begin with regs
     do
         begin 
         es:= seg(sectorbuffer);
         bx:= ofs(sectorbuffer);
         ch:= t;
         cl:= s;
         dh:= h;
         dl:= d;
         ah:= 3;
         al:= 1;
         intr (19, regs);
     end;
SECTOR_WRITE:= regs.ah;
end;

begin fillchar (regs, sizeof(regs), 0);
     repeat repeat clrscr;
     writeln;
     writeln ('Boot Saver 1.0');
     writeln;
     writeln ('1) Read and save boot sector');
     writeln ('2) Load file and overwrite boot sector');
     writeln ('3) Quit');
     writeln;
     write ('Enter Option:  ');
     readln (option);

     until ((option > 0) and (option < 4));
     if option = 1
	   then begin
	     writeln ('Enter drive to load Boot sector from (0=a, 1=b...)');
         write (' : ');
         readln (drivenum);
         write ('Enter filename to save to:  ');
         readln (filename);
         assign (bootfile, filename);
         rewrite (bootfile);
         if Sector_Read (drivenum, 0, 0, 1) = 0 
         then for x:= 0 to 511
	       do
	         write (bootfile, sectorbuffer[x]);
	         close (bootfile);
	       end;

	 if option = 2 
	   then begin 
	     write ('Enter file name to load from to:  ');
	     readln (filename);
	     writeln ('Enter drive to overwrite Boot sector on (0=a,1=b)');
	     write (' : ');
	     readln (drivenum);
	     assign (bootfile, filename);
	     reset (bootfile);
	     for x:= 0 to 511
	       do
	         read (bootfile, sectorbuffer[x]);
	         close (bootfile);
	         if Sector_Write (drivenum, 0, 0, 1) = 0 
	           then 
	             writeln ('OK, all done.');
	     end;
	  until option = 3
end.