It seems that there is a problem with the host SCSI Controller LSI Ultra320. Please use another controller for SCSI Pass Through. It was successfully tested with LSI 53C8xx and with Adaptec SCSI controllers.
Virtual tape is a an emulated tape drive which stores data in a file. Such a file is called a virtual tape image. The tape image format is compatible with the SIMH VAX emulator.
Yes, you can use it with AlphaVM-Pro. Using a SCSI-Pass-through unit you can connect a tape as well any SCSI device. To connect a SCSI tape to your host system you will need a compatible SCSI controller in your host system. Please note that RAID SCSI controllers cause problems with tape.