It has been suggested that in order to make a program in c: activated as soon as the floppy is accessed one should make a prog no bigger than 512 byes using asm and that it should use only bios int and put it into the boot sector of the floppy disk . can any body suggest me which bios int function can be used to load and run a prog in my c: . i can see only dos int function which can load and run another prog , unable to spot the bios int funtion. Also can u please tell me how i can make really small prog less than 512 bytes . sanjeev

>can any body suggest me which bios int >function can be used to load and run a prog >in my c: . i can see only dos int function >which can load and run another prog , >unable to spot the bios int funtion. Yeah, I can't find one either. But maybe your asm prog could run it manually, by moving the program into memory and changing the code pointers to the prog. That might be a little difficult, so what if you did this: Code in floppy: Load Code in hard into memory change code pointers Code in hard: use dos interrupt 21,4b to run prog in hard Prog in hard: The program you want to run. So just make a simple asm prog and put it with your main program (so you don't have to load as much into memory) and run that one from your program on the floppy. Btw - I don't know if your way of running a prog on floppy hit is correct, but if so, this should work. >can u please tell me how i can make really >small prog less than 512 bytes All you need the file to be is a header and the code pointer change, so it should be way under 512 bytes. That's 512 straight binary commands you can use(not counting arrays and larger value accesses)! That's a lot. Also: why do you want a prog that runs on your hard drive on floppy access? Remember, that's EVERY time the floppy rehits! Just curious...