DR11 parallel interface

The DR11s were a series of parallel interfaces for the UNIBUS and QBUS. Some used DMA, others were programmed I/O. They included, for the UNIBUS:

• DR11 (sometimes called the DR11-A): programmed I/O, quad SPC slot
• DR11-B: DMA, 4-slot system unit
• DR11-C: single-board replacement for the DR11-A
• DR11-W: hex single-board replacement for the DR11-B

and for the QBUS:

• DRV11: as for the DR11, on a dual card
• DRV11-J: 4 DRV11's on a dual card
• DRV11-B: DMA, quad card, 18-bit DMA addresses
• DRV11-W: DMA, dual card, 22-bit DMA addresses

There is also a DRV11-C (M8040), but little is currently known about it.

All use the same interface, except the DRV11-J, which for space reasons uses a different header on the card.