mSQL is a historically important SQL database management system from Hughes Technologies.
From the mSQL User Guide, version 1.1:
Brad Pepers <[email protected]> has developed tcl_msql, a Tcl interface to mSQL. I can't recall which version of the API Brad was using when he wrote tcl_msql (Brad's been hacking on mSQL since the early days). I'm pretty sure that it'll work against release 1.0 and am even more sure that Brad will fix it if it doesn't (that's because he's _such_ a nice guy and Tcl/Tk users can be quire persuasive when they need to be).