On Wednesday, June 19, 2013 9:46:42 AM UTC+12, Bob Eager wrote:
On Tue, 18 Jun 2013 14:36:37 -0700, Matty F wrote:



I patched a self-compiling compiler into a PDP-11 in 1982.

Once it worked, of course, it just compiled itself. Unless it had a new

bug, so I always had several old copies of the compiler.



This one is in lots of places, but worth reading if you've never seen

it...



http://scienceblogs.com/goodmath/200...nis-ritchie-a/


Thanks, most interesting - a compiler that inserts back-door code when it compiles itself. We had a decompiler, so any backdoor code could be seen. The decompiler was self-aware and refused to decompile itself (so that people couldn't see how it worked).

My compiler was not self-aware, but it did know about all the programs that were allowed to use password fields, and it used to generate different code (a call to a logging routine) for the unauthorised programs that people used to write and leave on people's computers in order to get their login details.