DS20 Kit Fan Assy f. PSU -11 is an integral part of the ULTRIX family of UNIX operating systems currently running on both the 16-bit PDP-11 and 32-bit VAX-11 hardware sys- tems. This means a consistent migration path from the DS20 Kit Fan Assy f. PSU -11 family to the VAX line of processors. ULTRIX-11 is a general purpose, multiuser, interactive, timesharing operating system supporting Digital's memory-managed PDP-11 processors. It has drivers for most of DS20 Kit Fan Assy f. PSU's peripherals and most of the features found in UNIX V.7. These include a hierarchical file system with demountable volumes, compatible device and interprocess I/O, asynchronous processes, a system command language selectable on a per-user basis, over 100 subsystems, and a high degree of portability among processors. The functionality of the DS20 Kit Fan Assy f. PSU Timesharing System V.7 • TCP/IP networking via Ethernet • DS20 Kit Fan Assy f. PSU access (requires an ULTRIX-32 node running DECnet) • Source-level compatibility with AT&T UNIX System V • Performance enhancements DS20 Kit Fan Assy f. PSU • New processor and device support • New commands and programming languages • Improved reliability and maintainability • Online help facility DS20 Kit Fan Assy f. PSU • Wide range of software and hardware support service options • UNIX sublicensing for object code directly from Digital • Repackaged and enhanced technical documentation • Installation and configuration without source code • Availability of sources • Educational discounts on binary licenses and sources DS20 Kit Fan Assy f. PSU 16.51