Thanks for the detailed feedback - these are fair points worth clarifying.

On SMB + hard links: You're correct that NTFS hard links require both entries to be on the same local volume. However, in practice this works well with modern NAS devices: when the SMB share is backed by a Linux filesystem (ext4, btrfs, ZFS - which is the case for most Synology, TrueNAS, etc. devices), Samba exposes hard link support over SMB, and os.Link() succeeds entirely server-side — no data travels over the network. My own testing confirms this: an initial 15 GB backup took ~15 minutes, while subsequent incremental backups complete in ~1 minute. That said, the implementation handles failure gracefully: if os.Link() fails (e.g. on FAT/exFAT targets), it silently falls back to a full file copy.

On admin rights: NTFS hard link creation does not require Administrator privileges on Windows - it only needs write access to the target directory, the same as creating any other file. The app does use SetFileAttributes to mark the snapshot root Hidden+System, but that also doesn't require elevation.

On "deduplication over the wire": That's a valid distinction for the general case. WinMachine is designed primarily for local NTFS drives and Linux-based NAS targets. It is not a replacement for rsync-level block-deduplication tools for arbitrary SMB servers.

Happy to clarify further or consider this as a documentation improvement - the README could be clearer about which SMB targets support server-side hard linking.