http://linode.com/backups
Quote:
There are four backup slots: Three of the slots are executed and rotated automatically: a daily backup, a 2-7 day old backup, and an 8-14 day old backup. The fourth backup slot is a user-initiated snapshot and remains in place until another user-initiated snapshot is taken.
Quote:
The backup system operates on files, not at the block level.
You can restore through the Linode Manager. I'm not 100% sure what your last question means, but the restore process brings your disk images back as a whole, rather than per-file selection. Hope that helps!