RC11 disk controller

From Computer History Wiki
(Redirected from RC11)
Jump to: navigation, search

The RC11 controller for the UNIBUS is a very early secondary storage controller for the PDP-11. It can handle up to 4 RS64 fixed-head disk drives, each with a capacity of 128 Kbytes of storage, organized in 32-word blocks.

The contents of each block are protected by a CRC.

Device registers

Register Abbreviation Address
Look Ahead Register RCLA 777440
Disk Address Register RCDA 777442
Disk Error Status Register RCER 777444
Disk Control and Status Register RCCS 777446
Word Count Register RCWC 777450
Current Address Register RCCA 777452
Maintenance Register RCMN 777454
Data Buffer Register RCDB 777456

777440: Look Ahead Register (RCLA)

Bad Address Unused Unit Number Track Number Sector Address
15 14 13 12 11 10 09 08 07 06 05 04 03 02 01 00

777442: Disk Address Register (RCDA)

Unused Unit Number Track Number Sector Address
15 14 13 12 11 10 09 08 07 06 05 04 03 02 01 00

777444: Disk Error Status Register (RCES)

Data Late Block Check Data Sync NXM Unused Timing Track Unused Address Parity Sync Address Disk Overflow Missed Xfer Unused
15 14 13 12 11 10 09 08 07 06 05 04 03 02 01 00

777446: Disk Control and Status Register (RCCS)

Special Condition Data Error Address Error Write Lock NXD Write Check Inhibit Address Abort Ready Interrupt Enable Ext Mem Mode Function Go
15 14 13 12 11 10 09 08 07 06 05 04 03 02 01 00

777450: Word Count Register (RCWC)

WC15 <---> WC00
15 14 13 12 11 10 09 08 07 06 05 04 03 02 01 00

777452: Current Address Register (RCCA)

BA15 <---> BA01 Unused
15 14 13 12 11 10 09 08 07 06 05 04 03 02 01 00

777454: Maintenance Register (RCMN)

Unit Select Write Enable Word Count DMA Request Address Found Clock Polarity DMA Enable Data Track Address Track Phase Lock Address Mark Data Mark Clock Track
15 14 13 12 11 10 09 08 07 06 05 04 03 02 01 00

777456: Data Buffer Register (RCDB)

DB15 <---> DB00
15 14 13 12 11 10 09 08 07 06 05 04 03 02 01 00