By default, you get snapshots every minute for the last hour, every hour for the last day, and every day into perpetuity. This is configurable. You can set as many cadences as you wish, with the ability to configure their frequency and lifetimes.
Actually, snapshots are like btrfs volumes in many ways, meaning they can be mounted, read from, and written to as desired. This allows the filesystem root to just be another snapshot with a default backup cadence as described above.
The gefs(4) manpage [0] has more info for those interested. It's a short and sweet read. The source [1], is under 12k lines of well-written code, comments and whitespace included. The author is also extremely responsive to issues and a pleasure to talk shop with.
Anyway, given the parsimony of the OS and the small community size, I find 9front to be a really nice incubator for playing around with new ideas.
[0]:https://man.9front.org/4/gefs [1]:https://git.9front.org/plan9front/9front/front/sys/src/cmd/g...
We need more of this type of project today. It is the old Internet, still alive.
It is possible to assert the point is to identify outsiders. Or exclude. Or test to find insiders, to welcome people who chose to align, or not.
I never invested enough to feel I'd even knocked on the door, let alone incanted a phrase to be let in. However I have known IRL and online many who did and they aren't bad people. Or even really exclusive or excluding. They just have a culture. And if it excludes the dismal or the misaligned or the fame seekers and hangers on, that's probably not just a side effect.
Compsci is littered with ingroups and outsiders. The people who get invited to Tannenbaums workshops. The people who got invited once and never again. The people who don't get invites. This is normal. Not everyone gets invited to join the royal society and not everyone wants to.
Some people assert its an intelligence test but I remain a fan of the aphorism from "war games" - the only winning move is not to play.
EDIT: website is just an inside joke and not helpful. OS is real but also not helpful. https://www.reddit.com/r/plan9/comments/1mr6cyr/comment/n8xp...