Back-to-front Unix house Mt Xinu Inc, Berkeley, California has come out with a version of the Mach 3.0 microkernel developed at Carnegie Mellon University as an add-on to its Mach386 product: it runs on Intel 80386 and 80486-based AT-bus computer systems and provides complete Mach 3.0 microkernel source code, a complete build environment which enables users that do not have a detailed knowledge of Carnegie Mellon University system development tools to modify and rebuild the Mach 3.0 kernel, a binary version of a BSD server which makes it possible to run the Mach 3.0 kernel and the BSD server in place of the standard integrated 2.5 Mach kernel provided with Mach386, source code for many system-specific utilities, which have been modified to operate with Mach 3.0, and a source-code example of a simple Unix-like server. The Mach 3.0 add-on is targeted at researchers and early-adopters of microkernel technology, and does not require an Unix System Laboratories Inc source licence. The Mach386 package costs $1,000 including the Mach 2.5 kernel, the 4.3 BSD interface and utilities, GNU utilities from the Free Software Foundation (GCC, GDB, GAS, Emacs, and Bison) on-line reference manuals, a networking module, an X Window System 11.4 module and a supplemental on-line documentation module. The Mach 3.0 add-on sells for another $200.