Adventures in Mainframes, Text-based Messaging, and iXML

When pointy brackets still meant SGML, an aerospace working group produced a text-based messaging specification, S2000M Issue 2.1, intended in parts for hardware up to twice its age. While the current version of that specification prescribes XML, the old one, a mystifying mix of compact syntax and semantics, is not about to go away anytime soon, even though the hardware is. Change in the aerospace industry is often driven not by technological breakthroughs but necessity; in this case a trusty old mainframe computer about to be decommissioned and there being no time to move to the 21st century in an orderly fashion. This, then, is the story of that old text-based format and the necessity of keeping it around by introducing a more modern approach.