JWZ documents his adventures in bringing a 1982/3 vintage Ann Arbor Ambassador 60 terminal (a rare portrait-orientation terminal) back into service -- fitting it with a Raspberry Pi and a new power-supply and getting it to boot its beautiful green-screen.
I don't remember how I ended up with it -- I probably liberated it from work some time in the late 80s. But it served me well.
At one point, I built a 50' serial cable so that I could drag the terminal out onto the back deck and work outside. I remember also routing audio for a headphone jack over some of the unused lines inside that cable, since I didn't have speakers outside.
An elegant cable, from a simpler age.
Here's the problem with this device, as you can see in the video: the character buffer on the serial port is not large. I'm guessing it is dozens of bytes deep. Dozens. And the CPU that moves those bytes from the serial port into display memory is... not fast. So it keeps up pretty well at 4800 baud, but at 9600, or when you light up the afterburners and go for the full 19,200, it falls behind.
The way terminals deal with this is flow control: either end can say, "Hold up, I am suffering" and data transmission stops until the other side is ready. The proper way to do this over a serial connection is with DSR/DTR lines, which are extra copper on the RS-232 cable, one for each side, that signal when we're ready to go. But as noted, the not-quite-a-serial-port that Pis have doesn't have that. Which leaves you with inline flow control, XON and XOFF, typically the ASCII bytes ^S to stop and ^Q to resume.
You guys, I got my Ono-Sendai working again!
When I was a kid, my whole circle of D&D-playing, science-fiction reading pals was really into Roger Zelazny's ten-volume Chronicles of Amber, but somehow I never read it; for years, I'd intended to correct this oversight, but I never seemed to find the time -- after all, there's more amazing new stuff than I can […]
I'm in the midst of couple of weeks' worth of lectures, public events and teaching, and you can catch me in Toronto (for Word on the Street, Seeding Utopias and Resisting Dystopias and 6 Degrees); Newry, ME (Maine Library Association) and Portland, ME (in conversation with James Patrick Kelly).
In 2017, Banksy painted a giant mural on a wall in Dover, England depicting a worker chiseling a star off the EU flag, by way of a comment on the Brexit vote; now, parties unknown have painted over that mural, whitewashing it. Banksy is philosophical about this development: "Oh. I had planned that on the […]
Studies have shown cannabidiol (more popularly known as CBD) to be effective in two main areas: Pain relief and stress relief. Both of those make the non-psychoactive, cannabis-derived compound a natural for topical creams. There’s no shortage of CBD products out there, but here’s eight of our favorites, all specifically designed for dermatological use – […]
If you’re part of the maker community, you know Make:. Though Make: magazine is off the shelves as of this year, the eBooks and resources put out by Maker Media are still a fantastic resource for the new generation of tinkerers, hackers, and robotics geeks. If you’re in that tribe, listen up: they’ve released a […]
Life isn’t getting any less hectic, and pressure cookers are a quick, healthy solution for a growing number of kitchens. But if you thought your Instant Pot was versatile, there’s a major upgrade on the market: The Yedi 9-in-1 Total Package Instant Programmable Pressure Cooker. If you’ve somehow never used a pressure cooker before, try […]