Wow - this takes me back 40 years to the PDP-8/I we had at school (we were very lucky). I'm really impressed with what you've built. Would love to see it driving an ASR-33 teletype to make the nostalgia complete :-) I can still remember the OS/8 bootstrap for the PDP-8/F at college. 0030:6743, 0031:5031. Must have entered that on the panel hundreds of times. Happy days
The 'hard way'?!? LOL. When I was in high school, 1970s, I got the task often of reloading FOCAL into the school's PDP 8/L, when others powered it down without stopping it properly. The teacher would ambush me in the hallway on my way out at the end of the day to ask me me if I would stay and fix it (even as a freshman I knew more already about it than she did). I actually had basically memorized the octal codes for the RIM loader, entered by hand via the switches. I then loaded the rest, BIN loader and FOCAL, from paper tape via a teletype machine. Clunk, clunk, I still remember those teletype and paper tape reader noises. When you loaded FOCAL in seconds from the USB, I just laughed. You said it's done, and I was "you mean you didn't have to wait for forty minutes for the tape to be read to see if it loaded properly?" I also once programmed a PDP 8/S (that was no longer often used) to cycle the accumulator register lights like in your demo at one point, via machine code. I originally toggled that into memory by hand too. I thought of it as lobotomizing the PDP, because once that was loaded and run, it was not much good for anything else until it was restarted. You do bring back memories. ;)
Yes... It's actually quite difficult to make it as hard as it was in the old days. We'd need not only a replica paper tape reader for that, which is quite easy, but a replica paper tape punch. That's something nobody has yet succeeded in. In fact, I think the world has lost the skill to make mass produced fine mechanics. Then again, there must a good few miles of paper tape hidden in that USB stick!
It reminds me of those grumpy old men skits, "In our day we loaded bootstrap code by hand!.... and we liked it! We loved it!" Not to mention I've had some conversations with other computer folks that run akin to "wel, you think that's something, MY first computer, you had to crank it by hand!" LOL
I've been following your blog; very impressed with this project so far. The prototype looks great! It would be fun to see you toggle in a program with the front panel manually, to get a feel on how it's done on the PiDP :-)
Tobias Eriksson Thanks! I appreciate the encouragement. I'll do a RIM Loader toggle session soon, or find something creative that's even smaller. But it's done the same way as with the real PDP. One thing you can't do is zip your finger along the row of switches to reset them all. Because the switches require a bit more pressure to flip. I regret that bitterly... but can't have it all I guess :)
This made me smile. I've been reading "Hackers: Heroes of the Computer Revolution" www.amazon.com/gp/product/B003PDMKIY so it was cool to see how one of these machines would actually operate.
warlockd I'll only put the files up for general download after it has reached v1.0. But drop by the obsolescence.wix.com/obsolescence website and send me a msg with your email, and I'll send you the development repository login for the alpha version I have at the moment.
Anyone else thinking of using a thermal printer and CCD reader to emulate paper tape using real paper? Or full logic cassette mechanisms to get the "tape experience" somehow?
