frank's completely different set of rules for the matrix (i would call them houserules, but let's face it, they're somewhat beyond the houserule point) have descriptions for the various core operating systems. while not canon as such, i don't believe there is any canonical fluff that says what they *do* look like, and frank's descriptions are at least as valid as anyone else's in that case

[edit] bah, ninja'd![/edit]