<div dir="ltr"><div dir="ltr"><br></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Sun, Dec 17, 2023 at 11:48 AM Paul Winalski <<a href="mailto:paul.winalski@gmail.com">paul.winalski@gmail.com</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">One problem that the VT100 emulators may have is that they behave<br>
according to the published VT100 specifications rather than the actual<br>
hardware behavior.<br></blockquote><div><br></div><div>They behave like the author of the emulator thinks the documentation describes.</div><div>But often, ambiguity in descriptions lead to bad decisions here, especially when</div><div>you go to the far right of the screen, the bottom right corner, etc. There's several</div><div>quirks of VT100 behavior that just aren't clearly documented. They aren't bugs,</div><div>per se, but people depend on that behavior.</div><div> </div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">
The VT100 had notoriously buggy firmware. Alan Kotok, one of DEC's<br>
early engineers, encountered some of these and was annoyed enough<br>
about it that he wrote a program to generate a complete list of escape<br>
sequences--legal and illegal--which he fed to his VT100 terminal. The<br>
results were highly entertaining. Some perfectly valid escape<br>
sequences were mishandled by the firmware and had behavior that didn't<br>
match the documentation. Even worse, some illegal escape sequences<br>
caused catastrophic behavior, such as the terminal freezing with the<br>
alarm continuously on--the only way out was to power-cycle the<br>
terminal. One particularly nasty escape sequence caused corruption of<br>
the EPROM such that the terminal crashed on power-up or restart,<br>
resulting in an infinite crash-and-restart loop that could only be<br>
fixed by sending the terminal in for a factory reset.<br>
<br>
Kotok published his results within DEC engineering and shortly<br>
thereafter "email bombs" containing escape sequences that triggered<br>
some of the milder of the bugs started circulating. The VAX/VMS mail<br>
utility had to be changed to filter out escape sequences by default.<br></blockquote><div><br></div><div>Yea... Those are fun... I wonder how many got fixed in later versions?</div><div><br></div><div>I'd also read somewhere that VT220 development was slowed by</div><div>having to behave exactly the same way as the VT100s (the above</div><div>example was one given)... But at least they had the benefit of being</div><div>able to look at the old firmware code... At least I'd suppose that was</div><div>a benefit...</div><div><br></div><div>Warner </div></div></div>