Ultra160, or Ultra3 SCSI, is the SCSI Trade Association's definition for a transfer rate up to 160MB/s. Devices running in Ultra160 mode must operate in LVD mode, and must report as SCSI-3 devices.
Not only will all variations of Ultra160 and Ultra3 SCSI work with older generations of SCSI, all Ultra160 and Ultra3 devices are interoperable irrespective of the name used by its vendor.
Ultra3 SCSI can encompass any one or all of the five features in the latest specification. Several SCSI vendors subsequently defined Ultra160 SCSI as a specific implementation of three of the five Ultra3 SCSI features. These three core features are double edge clocking, cyclical redundancy checking (CRC) and domain validation. To date, every vendor that has announced a new generation SCSI product, whether under the Ultra3 or Ultra160 name, has included these three core features.
Several vendors use a modified Ultra160 SCSI name, such as Ultra160+, for their latest SCSI technology. These vendors have added a feature to the set of three core features in order to differentiate their products. However, all of the implementations, regardless of what they are called, and regardless of whether or not they have an additional feature, support the three core features defined in the current SCSI specification.
The name Ultra160 SCSI is now recognized by the industry's SCSI Trade Association (STA) to identify designs with these three key features. The association has further added credibility to the naming by establishing Ultra320 and Ultra640 as the names for future generations of SCSI technology. Each of these generations is expected to have a specific set of feature enhancements and are also expected to offer full backward compatibility with prior generations of SCSI.