🚀 go-pugleaf

I'm writing a small TSR to flash the Scroll Lock LED as a hard disk
activity indicator.  I've successfully hooked onto interrupt 13h, but
I found that this interrupt doesn't get called quite as often as I thought.

Then I started trying to hook onto interrupt 21h, to trap some of it's
disk actions (opening/closing files, searching for files etc.).  I use
int 21h itself to read the previous vector/set my new vector.  I guess
this shouldn't be the problem?  

Then I copied the interrupt handler that I wrote for Int 13h to another
proc, which does exactly the same:
- at entrance it toggles the LED
- then it calls the old interrupt handler
- then it toggles the LED again
- then it returns with an iret

This compiles and links alright (TASM & TLINK), i run it and am returned
directly to the DOS prompt as I'm supposed to be...  But when I do any
serious disk activity, the PC crashes (by not serious I mean that 4dos'
file name completion feature works... I can also change disks and dirs.)

I know I should have supplied the source code... but I'll try this first...


-- 
Regards from Robert Schmidt, PC C/asm is my game, fast graphics is my 
pain  -  Watch for my VGA/SB demo!
     e-mail to robert@solan.unit.no
 snail-mail to Stud.techn. Robert Schmidt, stud.post 170,
               Norwegian Institute of Technology, Trondheim, NORWAY