A version of the SCSI command specification. SCSI-2 shares the original SCSI' s asynchronous and synchronous modes and adds a "Fast SCSI" mode (<10MB/s) and "Wide SCSI" (16 bit, <20MB/s or rarely 32 bit). Another major enhancement was the definition of command sets for different device classes. SCSI-1 was rather minimalistic in this respect which led to various incompatibilities especially for devices other than hard-disks. SCSI-2 addresses that problem. allowing scanners, {hard disk drive}s, {CD-ROM} drives, tapes and many other devices to be connected. Normal SCSI-2 equipment (not wide or differential) can be connected to a SCSI-1 bus and vice versa. (1995-04-19)
