Driver-Taper protocol
Communication method
driver talks via two pipes connected to taper's stdin and stdout. The commands and responses are plain text.
Command sequence during backup operation
- driver initialises taper with: START-TAPER <datestamp> to which taper replies with: TAPER-OK or, for fatal errors, with: TAPER-ERROR [<message>]
- driver can ask taper to to copy a file from the holding disk to tape: FILE-WRITE <handle> <filename> <host> <disk> <level> or directly from a dumper: PORT-WRITE <handle> <host> <disk> <level> or exit at the end of the run: QUIT
- taper responds to the PORT-WRITE command with: PORT <port> which driver should then hand on to dumper in a PORT-DUMP command.
- If the copy to tape finishes correctly taper replies with: DONE <handle> [<message>]
- If something goes wrong with the tape, taper can request that the dump be retried at a later time with: TRY-AGAIN <handle> [<message>] or, for fatal errors, be abandoned with: TAPE-ERROR <handle> [<message>]
Other commands
- If driver says something that taper doesn't recognise it responds with: BAD-COMMAND <message>
- taper responds to the QUIT command with: QUITING
Protocol data
| data | description |
|---|---|
| <datestamp> | Date as "yymmdd" |
| <handle> | Request ID |
| <filename> | Name of file on the holding disk where backup will be written to |
| <port> | Taper port to send the backup data to |
| <host> | Hostname of the client |
| <disk> | Disk on the client being backed up |
| <level> | Dump level being used for backup |
| <message> | Error or Status message |