After the target has received the READ command (and has determined that there will be a delay), it disconnects from the SCSI bus by sending a DISCONNECT message and by going to the BUS FREE phase.
After the target retrieves the requested data from the peripheral device it arbitrates for the SCSI bus. Upon winning arbitration, it reselects the initiator and sends an IDENTIFY message to the initiator via the MESSAGE IN phase. This revives the I_T_L nexus so that the initiator can retrieve the correct set of pointers for the I/O process. The initiator restores the active pointers to their most recent saved values (which, in this case, are the initial values) and the target continues (as in the single command example) to finish the I/O process.
If target wishes to disconnect after transferring part of the data (e.g. while crossing a cylinder boundary), it may do so by sending a SAVE DATA POINTER message and a DISCONNECT message to the initiator and then disconnecting. When reconnection is completed, the current data pointer is restored to its value immediately prior to the SAVE DATA POINTER message.
On those occasions when an error or exception condition occurs and the target elects to repeat the information transfer, the target may repeat the transfer by either issuing a RESTORE POINTERS message or by disconnecting without issuing a SAVE DATA POINTER message. When reconnection is completed, the most recent saved pointer values are restored.