How To Program A Tad M10 Radioshack
21 February 2015 If you follow my,, or feeds, you may have noticed that I’ve been writing a PDP-8 Emulator for the iPad. Here’s a screenshot: My purpose in writing this emulator (other than sheer nostalgia) is to use it as a training tool for new programmers. I think every new programmer should spend a week or two programming one of these old machines. It seems to me that there is no better way to understand what a computer really is, than to touch a real computer and program it at the bit level, in machine language. Once you have done that, all the magic disappears and is replaced with cold, hard reality.
The RadioShack 3-in-one remote control will allow you to operate your television, VCR/DVD player and satellite/cable box without the need for separate In order to use your RadioShack 3-in-one remote control with your home entertainment equipment, you will need to properly program the device using. Macegr: geneb: geneb: heheheh: tjb1: geneb: stop picking your nose on camera: skwishy.
And, let me tell you, programming a PDP-8 is cold, hard, reality. Oh boy, is it ever! I’ve tried to be faithful to the machine and it’s environment. The front panel is a decent abstract representation of the original PDP8, and the lights blink appropriately, and with the correct data.
(though I couldn’t resist making the lights touch sensitive, like the ECP-18). The paper tapes in the reader and punch move at appropriate speeds, and the holes represent the true data.
They also make the right kinds of noises. The teletype prints at the appropriate speed (though you can speed it up if you want (you will)) and behaves very much like an ASR-33, making all the appropriate noises, and responding properly to carriage return and line feed characters, etc. (Yes, you can overprint!) I found some binary images of old PDP8 paper tapes, and managed to get them into my emulator by munging their format with a little C program I wrote, and then transporting them to the iPad using Dropbox. The results have been both satisfying and heart-wrenching. That ancient code works!
I sit in front of my half-pound, $600 iPad, in its nice little case, and its bluetooth keyboard, surrounded by programming manuals, and marked up listings of a program I am working on. And I realize that I’m using code written half a century ago by men and women (probably a lot of women back then) who hauled themselves up by their bootstraps to get that silly little machine working. A machine that weighed 500lbs, was the size of a refrigerator, and cost $20,000 in 1967. Could those men and women ever have guessed that their code would be running in a hand-held tablet computer and would be used to train programmers in the twenty-first century? Some – many – must still be alive. Amb tranx 160 transponder. I wonder what they’d think if they knew. My emulator is written in Lua, using the framework for the iPad.
This is a hugely convenient language for iPad development. Lua is fast (enough), and Codea has wonderful graphics primitives, and a simple, yet very effective graphics framework for developing highly interactive animated programs. This made the animation (and sound generation) of the front panel, the teletype, and the paper tape reader/punch a snap. Emulating the PDP8 internals was a bit of a challenge since Lua only has one numeric type: floating point. Doing 12-bit logic using floating point math is, uh, interesting. On the other hand, I get a huge kick out of watching FOCAL (FORmula CALculator: a language similar to Basic) run on my PDP-8, and do it’s own floating point math, using the logical operations that I concocted from Lua’s floating point math.
You should see those lights blink! The execution speed is about 4,000 instructions per second.
While that’s 1/7th the speed of a PDP8/S, it’s pretty impressive for an iPad running a “byte-code interpreted” language like Lua, emulating 12 bit logic using floating point math! I wasn’t expecting that kind of performance. It actually runs all that old DEC software at reasonable speed.
Even FOCAL runs fast enough to compute square roots in half a second or so. And, again, the blinking of the lights during a compile is deeply satisfying. Watch that and you’ll know where all those 1950s sci-fi movies got their ideas from.
##MODE-B Getting the Emulator working was really very easy. I’ve probably invested 30 hours in it overall; and that includes learning Codea and Lua. The development process was lickety-split. Codea’s Lua editor for the iPad is intuitive and powerful (though it has no refactorings ). The edit/test loop was, perhaps, 10 seconds long.
I could add a line or two of code, run the app, see the effect, and then hop back into the editor just like that. It was a satisfying treat, and I had a ball doing it. Of course I wrote tests for the tricky bits. Embarcadero rad studio serial number. I wrote a little test framework just for that purpose, and I put a TEST button on the front panel of the emulator to make it easy for me to run those tests. The emulation code itself would have been nearly impossible if I hadn’t had unit tests. And of course, I used the TDD discipline for that code. In the end, there were over 100 tests for the various instructions and behaviors of the PDP-8.