Xinu - "Xinu Is Not Unix". A Unix-like operating system. Originally developed in the 1980's.
Apparently xinu uses Tcl.. From the documentation:"The Xinu shell also understands Tcl scripts. A few sample Tcl scripts have been included and are described in the TCL(1) manual page."WJP If you read the Xinu manual pages it turns out that the Xinu shell doesn't actually understand Tcl. It isn't a Tcl shell in the sense that tclsh is. All it means is that they provide their own version of Tcl and that the shell has the standard Unix ability to pass scripts in another language off to the appropriate interpreter using the #! mechanism. So it isn't really different from other Unix-type systems except for the fact that Xinu promotes Tcl a bit.
According to the xinu page on wikipedia .. it 'continues to be used for operating systm and networking courses at universities around the world.'I stumbled upon it when looking around at stuff related to z80 based embedded processors.. it seems Zilogs 'eZ80' processor 'supports a free TCP/IP stack and operating system based on XINU'. I wonder if this also runs Tcl - and what versions?
[ANON] - Hm... - Tcl in a paged 16-bit address space? Curious!George Peter Staplin - I have 2 books about Xinu. It's a very well structured system. Operating System Design - The Xinu Approach, and a TCP/IP book featuring Xinu, with a complete implementation.