Which id should not be used while assigning ids to SCSI peripherals?

When assigning IDs to SCSI peripherals, ID 0 should generally not be used for devices other than the SCSI host controller itself. This is because ID 0 is typically reserved for the SCSI initiator, which is responsible for sending commands to other devices on the bus. Using ID 0 for other peripherals can lead to conflicts and communication issues within the SCSI chain. It's best to allocate IDs 1 through 6 or 7 for other devices, depending on the SCSI standard in use.