Lars Brinkhofflarsbrinkhoff@mastodon.sdf.org
Oct 11, 2026, 6:57 AM
Replies
- Lars Brinkhofflarsbrinkhoff@mastodon.sdf.orgOct 11, 2026, 6:58 AM
⊟ is called the "origin character". It's used by the assembler to indicate the address of the next instruction. However, no one today remembers why that symbol was picked.
- Lars Brinkhofflarsbrinkhoff@mastodon.sdf.orgOct 12, 2026, 4:32 AM
I asked Mary Allen Wilkes about the origin character, she replied:
"Why not? I needed a unique character that had no other function."
Oct 11, 2026, 7:02 AM@larsbrinkhoff that's a very small number of characters by the way. Was it 5-bit?
- Lars Brinkhofflarsbrinkhoff@mastodon.sdf.orgOct 11, 2026, 7:03 AM
@loke 6 bits, so two characters per word. Here's a table from the LAP6 manual. Code 77 is not included; it's an end-of-file marker.
- Lars Brinkhofflarsbrinkhoff@mastodon.sdf.orgOct 11, 2026, 7:12 AM
@loke This is how they look on the display.
- Oct 11, 2026, 7:29 AM
@larsbrinkhoff what does the case a, b etc mean?
- Lars Brinkhofflarsbrinkhoff@mastodon.sdf.orgOct 11, 2026, 7:35 AM
@loke The keyboard doesn't have any SHIFT modifier. It has CASE instead, which must be pressed and then released before typing the "upper case" symbol. So typing CASE and then A gives you double quote. CASE CASE is underscore. CASE EOL is META. META is not a modifier, but to start a command. Just like M-x in Emacs.
Oct 11, 2026, 11:45 AM- Lars Brinkhofflarsbrinkhoff@mastodon.sdf.orgOct 11, 2026, 12:14 PM
@vnikolov I'll add it to the mythology.
🇺🇦 haxadecimal 🚫👑brouhaha@mastodon.socialOct 11, 2026, 7:13 AM@larsbrinkhoff
Lower right?- Lars Brinkhofflarsbrinkhoff@mastodon.sdf.orgOct 11, 2026, 7:19 AM
@brouhaha Yes thanks, will fix. I only had 50 years or so to learn telling left and right apart, and I'm not quite done with my training yet.
I do think I can tell right from wrong though.
