SCSI Commands

• SCSI commands pass data in one direction only. If you want to send some data and then receive some data, you need to use two separate SCSI commands.
• Some common SCSI commands: READ, WRITE, Send Diagnostics, Receive Diagnostics, Inquiry, Test Unit Ready.
• Each command returns a status code. A special code named 'mode sense' means there is an extra 'sense data' to be received, which contains an explanation for the cause of the problem.
• In order to allow a pipeline of commands, it is possible to attach a tag to a command. The tag is a single byte, so at most 255 commands may be pending.

Originally written by guy keren