Six programs — SETUP, VIEW, FIND, ADD, DEL, PRINT — that turn an HP-28S into an address book. Four fields per person: first name, last name, phone number, address. You put them on the stack in that order, in quotes, and run ADD.
Four strings on the stack, then ADD. The manual's own example.
The neat part is VIEW. Give it a field number and it pulls that field out of every entry, then calls MENU:
ELSE 1 d
START s GET d ROLLD
NEXT d →LIST MENU s
END
MENU loads the 28S’s own softkey menu — the six boxes across the bottom of the screen, right under the display. So the last names appear as physical buttons, and NEXT pages through them. He didn’t write a picker; he handed the list to the calculator’s menu system and let the hardware be the picker. Then you press USER to get back to the program menu and run FIND.
PRINT sends the lot to an HP infrared printer, which was the machine’s only output of any kind.
What it cost to keep
The 28S had no wire port and no storage. Nothing could be saved anywhere, ever. The address book lived in RAM and nowhere else, which means a memory clear — a dropped calculator, dead batteries, one bad SYSEVAL while writing something else — took the whole thing with it, and the only recovery was typing every name, number and address back in by hand on a calculator keyboard.
Knowing that, someone still built it, still added a delete function, still wrote a printer routine. That is not a demo. That’s a thing you carry.
Transcribed from six notebook pages. Written on the same machine as Space Chase and DOODL, in the same year, in the same handwriting.