[TUHS] Re: Compatibility question

One problem that the VT100 emulators may have is that they behave according to the published VT100 specifications rather than the actual hardware behavior. The VT100 had notoriously buggy firmware. Alan Kotok, one of DEC's early engineers, encountered some of these and was annoyed enough about it that he wrote a program to generate a complete list of escape sequences--legal and illegal--which he fed to his VT100 terminal. The results were highly entertaining. Some perfectly valid escape sequences were mishandled by the firmware and had behavior that didn't match the documentation. Even worse, some illegal escape sequences caused catastrophic behavior, such as the terminal freezing with the alarm continuously on--the only way out was to power-cycle the terminal. One particularly nasty escape sequence caused corruption of the EPROM such that the terminal crashed on power-up or restart, resulting in an infinite crash-and-restart loop that could only be fixed by sending the terminal in for a factory reset. Kotok published his results within DEC engineering and shortly thereafter "email bombs" containing escape sequences that triggered some of the milder of the bugs started circulating. The VAX/VMS mail utility had to be changed to filter out escape sequences by default. -Paul W.