IBM mainframe based document formatting system
Author: IBM Corporation Manual: http://publibz.boulder.ibm.com/cgi-bin/bookmgr_OS390/BOOKS/DSM09M00/CCONTENTS?DT=19921029171840 Family: MarkupLanguage Platform: IBM Mainframe License: Commercial
Script developed a package of macros called "GML" which was the predecessor of SGML, XML, etc.
There is also a free version originally from the University of Waterloo, now available from [Open Watcom] that also runs on PCs, though it is not completely compatible with the IBM version.