QBus Cards: CMD CQD-220/M/TM

CMD CQD-200/M/TM QBus SCSI Controller

The CMD CQD-220 is a QBus SCSI controller that supports the MSCP and TMSCP protocols and SCSI optical, magnetic disk and tape drives. Unlike the Emulex UC07/UC08 SCSI controllers, the CQD-220 doesnt seem to require any special configuration when adding new disks. I was able to just plug in the drive and use it - no need to go into firmware and write special formats. The manual lists three main variants: CQD-220/M (Disk only), CQD-220/T (tape only), and CQD-220/TM (Disk and Tape). The T means TMSCP and the M means MSCP. There are various other versions that support features like shadowing (/TMS), MicroVAX III enclosures (CQD-223), etc.

Features

16-bit microprocessor
18- or 22-Bit Q-Bus MSCP compatible
Block mode DMA
Virtual data buffer
Command queuing and seek optimization
Support up to 7 SCSI devices
SCSI bus transfer rate up to 4.8MB/sec (SYNC) and 3.0MB/sec (ASYNC)
Support magnetic disk and tape
ANSI compatible tape format
Support disconnect reconnect capability
On-board utility to format qualify drives
Automatic drive configuration
Dynamic defect management

Configuration

I have never had to reconfigure my two controllers (they were already configured in the machine they came with) so I have not looked into the configuration options. The user manual should have plenty of detail though.

Cables

Both of my CQD-220s just have a standard 50-pin narrow SCSI connector on the edge of the card - no funny pinouts or anything like that. I cant say anything about the MicroVAX III (CQD-223) versions.