RF11 disk controller
From Computer History Wiki
The RF11 controller from DEC for the UNIBUS is an early secondary storage controller for the PDP-11. It can interface with up to eight RS11 fixed-head magnetic disk drives; each has a capacity of 512 Kbytes of storage.
Unlike all other DEC disk controllers, the RF11 can read or write individual words.
Like many of the early large peripheral controllers for the PDP-11, it was a large custom wire-wrapped backplane which bolted into the front of a 19 inch rack, such as an H960; into it plugged about 40 small M-Series FLIP CHIPs.
Device registers
| Register | Abbreviation | Address |
|---|---|---|
| Disk Control Status Register | DCS | 777460 |
| Word Count Register | WC | 777462 |
| Current Memory Address | CMA | 777464 |
| Disk Address Register | DAR | 777466 |
| Disk Address Extension Error Register | DAE | 777470 |
| Data Buffer Register | DBR | 777472 |
| Maintenance Register | MA | 777474 |
| Address of Disk Segment Register | ADS | 777476 |
