I know there are some wizards out there that either know how to do this or that it can't be done, so here we go: I have an external drive I use for Time machine purposes, so I do regular backups. As a developer, the loss of my source files would be devastating. I was thinking it would be very comforting to, in addition to my Time Machine backup, I could copy all of my source to another disk, say an SD card or thumb drive. Is there a way to automate this duplication of data? Some sort of trick to run in terminal or something? Mirroring? I've never done this and wonder what solutions exist, besides the obvious: manually copy folder contents from HDD to SD card periodically. Thanks in advance!