OpenNT

A POSIX-based Unix subsystem for Windows NT from Microsoft. Introduced in 1996, it was originally developed by Softway Systems, Inc., San Francisco, CA, which Microsoft acquired in 1999. OpenNT enabled Unix programs to run natively under NT and also be recompiled into the Windows environment. It was rebranded as Interix. See Subsystem for UNIX-based Applications and Interix.