Ultra3 SCSI – Terms & Terminology

Ultra3 SCSI **

Data transfers 160 megabytes per second, first defined in SPI-3

SCSI SPI-3 (SCSI Parallel Interface)

16 bit SCSI asynchronous commands with Synchronous data transfer rates up to 160 megabytes per second. LVD (Low Voltage Differential allowed in SCSI SPI-3. There are a lot of changes with SPI-3; High voltage differential (HVD SCSI) and the 32 bit data bus with the Q cable are obsolete, clocking is defined for LVD on both the rising and falling edges of the REQ/ACK clock – Double Transition (DT) defined, Cyclic Redundancy Check (CRC) defined, Domain Validation defined in SPI-3 and SPC-x, Packetized defined and Quick Arbitration Defined. **

** Ultra160/m is a specific implementation of Ultra3 that includes Fast-80DT, CRC and Domain Validation. Ultra160/m was developed by a group of SCSI suppliers and customers; it is not a STA recognized term.