-> I need some hint! Inside an interrupt handler i did the following.
-> sti 
-> mov ah,34h 
-> int 21h 
-> mov dl,es:[bx] 
-> cmp dl,01h 
-> je not_safe ....
[...]
-> The tsr seem to work fine until i type few keys and lock up very
-> hard! I wonder what wrong i did?
Your code thinks that it's unsafe to call Dos only when the InDos flag 
is 01h. This is a logical error. It's actually unsafe to call Dos when 
the InDos flag is anything but zero. Try this:
   CMP DL, 00h
   JNE not_safe
Take care.
 ** Dyslexia: it can warn without striking!
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