Self-modifying code

[Harlan Feinstein]

Reasons for writing self-modifying code have been scarce, and have basically
centered around speed reasons.  Speed is not the only reasons why someone
would want to write s-m code.  I've seen a program for the IBM PC called 
PC-LOCK that prohibits one from accessing the hard disk without providing
a password.  The install and de-install programs are self-modifying to 
make tracing them all but impossible.  

One time last summer I changed my password right before the weekend, and
wouldn't you know it, come Monday I had no clue as to what the password was.
I tried all kinds of disassembly and debug tracing to no avail.  Hence, another
reasons for self-modifying code.

--harlan