Yup, that's all correct.

And going the other way is just a simple PUT command. For example, these two commands copy the drive to a PC, and then write it back again (pointless in itself):

GET /dev/hda junk
PUT junk /dev/hda

Those just use "junk" as the name for the file on the PC side. Or one could omit that, and the two lines become:

GET /dev/hda
put hda /dev/hda

Cheers