A virus checker is much much more than a simple file scanner looking for signature code. That sort of scanning has closing the gate after horse has bolted logic. Boot sector, memory resident, email attachments are just some of the things you are going to miss. Virus scanners are invasive and onmipresent. They examine most system calls and disk read/writes to do their job properly - that is why things like NAV consume about 50% of system resources (try running perl code with and without NAV running if you don't believe me). Tripwire works along the lines you are thinking of.

When speed is a real issue C or ASM piss all over Perl or any other high level language. Compare Norton Scandisk to M$ Scandisk for speed to get some idea of how fast tight code can be (or how slow crap code can be)

cheers

tachyon

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