Windows versioning
VSS / Shadow Copy on a schedule, with a restore drill — not a job that only said it finished.
Protocols
Backup and remote, written down.
Versioning, 3-2-1, and contract-authorized remote control. Platform detail — scripts, patch rings, recordings — lives on Capabilities.
Linux versioning
LVM, Btrfs, ZFS, or Borg/Restic. Same restore goal as Windows.
3-2-1
Onsite copy plus an offsite replica. Immutable or object-lock when the design calls for it.
Contract remote
Interactive desktop only under the signed MSA, with MFA, roles, and session audit.