For your purposes, MACH is an implementation of UN*X. It is still under development, but people are starting to use it. I'm not sure if "interface" means your customer just wants to log into a MACH machine (with Telnet), or plans to use TCP/IP connections, or wants to do RPC using the functions that come with NFS. For most purposes you can get away with treating it like UN*X. Hope this helps. ______ HUNTER