Seagate Ultra 320 - Manual (Page 128)

114 Parallel SCSI Interface Product Manual, Rev. A
Logical reconnections occur on the successful target transmission and initiator receipt of a SPI L_Q informa-
tion unit for an existing I/O process. The logical reconnection reestablishes the I_T_L_Q nexus for that I/O pro-
cess.
SCSI devices using information unit transfers may receive several commands during an initial connection. This
occurs when a SCSI initiator port uses the multiple command option in the SPI L_Q information unit. For each
SPI L_Q received with a multiple command type or a last command type, a logical connection occurs and an
I_T_L_Q nexus is formed.
If there is a phase change to a MESSAGE OUT phase or a MESSAGE IN phase, then there is no logical dis-
connect and the I_T_L_Q nexus remains in place. If a DT DATA phase follows the message phase, then the
L_Q portion of the current I_T_L_Q nexus shall be replaced with the L_Q in the next SPI L_Q information unit.