Jeff Duntemann's Contrapositive Diary Rotating Header Image

February 20th, 2009:

A Chart, If You Can Read It

The last couple of evenings I’ve been working at fulfilling a promise I reneged on ten years ago. Somewhere in the text of the second edition of Assembly Language Step By Step (which I was writing in the summer of 1999) I promised readers an ASCII chart as one of the appendices. I then plum forgot, and the book appeared in 2000 without that appendix. I still get emails from people asking me where they could find the chart, and have to reply in my best sheepish email voice that no chart exists anywhere in the book.

So this time I thought to put things right. I sat down in front of InDesign and figured out an ASCII chart format for the full 256-character extended set, and drew me an ASCII chart. For the encoding I used Code Page 437, which is what they now call the IBM PC ROM character set. Whether they could name it or not, CP437 was much beloved of DOS text-mode programmers, with all four card suits and more box-draw characters than anybody ever knew what to do with. The chart will fit comfortably (if snugly) on a single page in what we in publishing call “computer trim,” and I consider it a complete success, at least if you have good eyesight or a set of readers within easy reach.


As best I can tell, there is no encoding option available for Konsole (or any other Linux terminal emulator that I have) for Code Page 437. As close as I’ve come is IBM-850, which has fewer box-draw characters and more non-English alphabet glyphs. Of course, once you have a chart, it’s no big deal to find a new set of glyphs and sub them in, which is what I’ll be doing in coming days. In the meantime, if you have any use at all for a CP437 ASCII chart, here it is. I’ll post the one for IBM-850 when I finish it. Ten years late, I guess, but better late than never.