Is there a good write-only backup solution?The best case would be incremental backups to DVDs since they don't allow modification.Layered on top of that would be a git-like difference algorithm that stored changes rather than whole files.Truly ideal would be a "write through" backup solution so that the "backup" sits between the computer and the hard drive, writing journal-like changes "on the fly".Such a solution would make ransomware useless. Even if you encrypt the whole filesystem the backup device could do a git restore.Does such a solution exist?If so, is there a better medium write-only medium than DVDs?