Darcs vs Surround SCM

Darcs is a free, open-source version control system for Linux, macOS, Windows, and self-hosted deployment. It organizes work around patches, or changes, instead of snapshots. Every working directory is its own repository, allowing users to record changes offline and push them to another repository later. Interactive commands let users select changes for a patch, pull individual changes, and edit or discard a patch before sending it. Branching works by pushing and pulling between repositories, with each repository treated as a branch. The darcs send command supports email collaboration, so maintainers can accept or reject proposed patches without granting commit privileges. The project names hub.darcs.net and darcsweb for repository hosting. Darcs is written in Haskell and can be installed through Cabal, Stack, Nix, platform binaries, or a source tarball. It is volunteer-run and a Software Freedom Conservancy member.

Surround SCM has no write-up on Specifiction yet; its figures are above.