Ghost editor and *viewer* software; subversions, changelogs, merges, rollbacks etc.

[vicky_molokh]

Greetings, all!

In one of the sessions, GM asked whether my character feels like he wants to restore a one-minute-ago version of himself and either perform a comparison or just be retold the latter events 'second-hand' by his NAI. While the dilemma was there if it was okay, I pointed out that I'm very unsure this is doable technically. He decided that it's better to check with the more knowledgeable, as neither he nor I could find much detail on such issues.

First, a big question is whether a comparison of two Ghost versions requires much in the way of special software. The minimum requirement seems to be a C7 computer (for running two of them, duh), while the maximum plausible requirement would be a C8 computer and a Ghost EDITOR software. But that's assuming the copies are totally separate.
If copies can be described by 'changelogs' (not small, but not more than 10% of the usual Ghost size), then perhaps comparing the two would actually be easier.
The whole reason for this comparison is figuring whether the Ghost in question is successfully infected with a certain meme. (It's almost a sure thing that the answer is Not Infected by now, but it'd be nice to know if there is an easy and reliable way of checking.)

Second, the issue of making minor fixes without resorting to full C8 Brain Hacking - rolling back some parts of a change in personality. Merging two ghosts is almost explicitly stated in canon (there's a lunar official who sends a shadow into a bedroom adventure, and wants to later merge that shadow into himself; canonically, even SAIs who like pretending they're humans don't express much interest in sex; so he's pretty much sure to be a human-ghost). But what about rollbacks, particularly as a response to a memetic infection?

Thoughts on any related issues are of course welcome too.

Thanks in advance!