What is “SCSI-2” and how is it different from SCSI-1?
For hard drives, “SCSI-2” basically means that the drive supports a stricter command set. The physical interface is usually identical. For other device types, “SCSI-2” means a lot more, because the original SCSI standard didn’t define much in the way of device types and command sets, so most devices use proprietary command sets. SCSI-2 standardises the command sets for most types of devices. There are three special types of interface that you might see mentioned: “Fast SCSI” supports data transfer at twice the speed of the original SCSI standard (10 MB per second vs 5 MB per second). This will not be a compatibility issue, as it is just the maximum transfer speed supported by the drive. The Apple II cannot transfer more than one megabyte per second. “Wide SCSI” uses a different cable arrangement to double the width of the data path (16 bits instead of 8 bits). A wide SCSI drive cannot be used with an Apple II, unless it can also operated in “narrow” mode with the original 50-pin connec
