Golden Triangle Computers DiskTwin
DiskTwin, from Golden Triangle Computers, is a hardware and software disk twinning product that provides continuous backup of any SCSI volume you can mount on your Desktop. Whenever the Macintosh writes to one drive, DiskTwin writes identical information to a second drive, constantly providing you with a current backup.
DiskTwin consists of a NuBus board; an application; an INIT; and a cdev. The hardware acts as a second SCSI port, to which one or more twin drives can be connected. After installing and connecting the hardware, the two drives must be synchronized: You must create an exact duplicate of the primary drive on the twin. Once the two drives are in sync, any changes that you make to the primary drive are instantly carried out on the twin drive.
DiskTwin has an option called automatic cut-over, which causes the twin to replace the primary drive the instant a failure occurs. This feature can be critical for users worried about downtime. Unfortunately, if the drive failure is accompanied by a system crash, this feature does not function, and you have to change drives manually.
DiskTwin works silently and unobtrusively in the background. You never even know it's working, until disaster strikes and you need it.