If you’ve ever looked at the document files created by Microsoft Word, you’ll find that the text is there amongst all sorts of hieroglyphics. Furthermore, it also includes some of the text that you’ve previously deleted, which has been a known security issue. Up until today I didn’t know why this was the case, although I suspected it was due to remnants from the ability to have multiple undo functionality.

It turns out that Microsoft Word derives its file format from Bravo and BravoX. Two word processors developed by some guys at Xerox who left en masse to join Microsoft in around 1982-3. The first version of Microsoft Word was essential a port of BravoX to MS-DOS. BravoX stored its files by doing a straight memory dump. The legacy of this file format lives on today in the current versions of Microsoft Word.

To read more about this, and more, visit Bruce Damer’s Personal Histories of the Desktop User Interface.