RK611 disk controller
The RK611 disk controller is the UNIBUS device controller for the RK06 and RK07 moving-head magnetic removable cartridge disk drives. All data transfers are done using DMA. Data is protected with a hardware-generated and checked error-correcting code (ECC); corrections (up to 11 bits) are done in software.
Implementation
The RK611 consists of a specially wired 9-slot backplane and five hex cards; these are:
| M7900 | UNIBUS interface module |
| M7901 | Register module |
| M7902 | Control module |
| M7903 | Data module |
| M7904 | Drive interface module |
At least three of the other slots are wired as UNIBUS SPC slots (and thus require G727 grant continuity cards to be inserted when no device is plugged into them); the status of the fourth appears to be 'unused'. The quad slot on the end is necessarily a plain SPC slot; the other hex slots are apparently MUD slots.
One RK611 can control up to 8 drives; a flat cable plugs into a Berg connector on one of the cards, and runs to a transition adapter on the back of the rack. From there, a round cable runs to the first drive, and similar cables connect the rest of the drives, in series. A terminator must be plugged into the 'out' port of the last drive in the series.
Backplane layout
Board locations (as seen from the board insertion side of the backplane, not the wire-wrap pin side, as is common in DEC documentation) are:
| Connector | ||||||
|---|---|---|---|---|---|---|
| Slot | A | B | C | D | E | F |
| 1 | UNIBUS In | SPC | ||||
| 2 | MUD/SPC | |||||
| 3 | MUD/SPC | |||||
| 4 | M7904 Drive interface | |||||
| 5 | M7903 Data | |||||
| 6 | M7902 Control | |||||
| 7 | M7901 Register | |||||
| 8 | M7900 UNIBUS interface | |||||
| 9 | UNIBUS Out | Unused? | ||||
Registers
The RK611 has no less than fifteen registers:
| Register | Abbreviation | Address |
|---|---|---|
| Control and Status Register 1 | RKCS1 | 777440 |
| Word Count Register | RKWC | 777442 |
| Bus Address Register | RKBA | 777444 |
| Disk Address Register | RKDA | 777446 |
| Control and Status Register 2 | RKCS2 | 777450 |
| Drive Status Register | RKDS | 777452 |
| Error Register | RKES | 777454 |
| Attention Summary and Offset | RKAS | 777456 |
| Desired Cylinder Register | RKDC | 777460 |
| Data Buffer Register | RKDB | 777464 |
| Maintenance Register 1 | RKMR1 | 777466 |
| ECC Position Register | RKECPS | 777470 |
| ECC Pattern Register | RKECPT | 777472 |
| Maintenance Register 2 | RKMR2 | 777474 |
| Maintenance Register 3 | RKMR3 | 777476 |
The addresses given assume the standard base address (0777440); if this is changed, so will the addresses. Note also that there is no register at 777462.
External links
- RK06/RK07 Disk Drive User's Manual (EK-RK067-UG-001) - The RK611 is covered in Chapter 7
- RK611 Field Maintenance Print Set (MP00105)
