Both ends
The final SCSI device in the chain of devices must be terminated. If you have only one device and it's attached to a SCSI port, you must terminate that device. If you have two or more SCSI devices that are linked together and to a shared SCSI Port ie: SCSI Port, Device #1, Device #2, etc, then the final device in the 'chain' must be terminated to allow for proper recognition. The SCSI Port also requires a terminator as well.
Performance may suffer; the initiator (SCSI controller) may not see the SCSI targets (i.e, disks) ... or they may disappear at some really bad time; or performance might be great but you will get a lot of errors and data corruption ; The correct answer depends on a lot of variables including cable length; whether or not the controller and/or any of the disks are terminated; type of SCSI you use; quality of SCSI cabling; and SCSI device physical topology. Your computer may not even boot or spin up the whatever is connected to the SCSI controller. Bottom line, SCSI absolutely must be terminated properly. If it isn't, bad things may happen at unpredictable times.
The host adapter is assigned SCSI ID 7, which has the highest priority over all other devices.
SCSI is a type of interface used for computer components such as hard drives, optical drives, scanners and tape drives. It is a competing technology to standard IDE (Integrated Drive Electronics). While the less expensive IDE technology is built into motherboards, SCSI is a technology that must be added by purchasing a SCSI controller. The SCSI card fits into an internal PCI slot. SCSI devices are then connected to this card.
SCSI-2
DB25 SCSI connector50 pin SCSI connector
SCSI 3
SCSI, Fast SCSI, Ultra SCSI, Ultra2 SCSI: 8 devices Wide SCSI, Fast Wide SCSI, Ultra Wide SCSI, Wide Ultra2 SCSI, Ultra3 SCSI, Ultra160 and 160+ and Ultra320 : 16 devices Of course, the number of devices supported depends not only on protocol limitations, but cable length, number of cables used, etc.
Back in its days, SCSI was often used for high-performance hard disks for use with server-type computers. However, it must be noted that the days of SCSI are well and truly over, replaced by faster and less expensive interfaces such as SATA.
Serial attached SCSI
Ultra wide SCSI. wide SCSI buses support 16 devices, rather than the eight devices specified in regular SCSI.
scsi-3