From Computer History Wiki
2.11BSD is a release of UNIX for the PDP-11 by a consortium of CSRG and the USENIX Association. It only ran on PDP-11 models with Supervisor mode. It was basically the same as 2.10BSD, with some upgrades.
Some of the things that were added were:
- Support for full 4.3BSD networking (using Supervisor mode)
- Support for long filenames
- 4.3BSD applications that were missing from 2.10BSD