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Done! PiDP-8/I, my PDP-8 replica

Most are just Linux distros; RISC OS is an exception, which you may remember from the Acorn Archimedes. Apparently, the latest incarnations can still run BBC BASIC.
 
Chuck(G) said:
Just curious; is the interest in this due to the lights and switches? Is that why a VT78 doesn't even raise an eyebrow--no blinkenlights?

FWIW, there a Chinese seller on eBay who claims to have lots of IM6120 chips--and has sold a bunch.
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I bought one of these early last year for an SBC6120 that I'm slowly efforting. Chip looks authentic enough with the correct markings and patina, but will know shortly whether they're the real deal.

Tom
 
yo oscar if u wanted to get me a 3d model of replica switches to fit ontop of ur stuff i could look into cost of doing some high end 3d printer work im currently toying with rejoining my local maker space.
 
dave_m said:
Hi Chuck, I knew SIMH ran on Windows and Linux systems, but on a little Raspberry Pi? Does the Pi runs Linux?
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Yes, and Oscar's PiDP-8/l (via SIMH) can use the cheapest Pi model A. In addition to SIMH it also manages the front panel. There's info on Oscar's web page, but the 'technical details' part can't be linked to directly (must be some javascript stuff), so I just quote part of it:
"I almost discarded the Raspberry Pi as a basis for the PiDP because almost anytime the topic of real-time multiplexing on the Pi is mentioned, the consensus is that the Pi is too slow/Unix is unfit for running led multiplexing.

Those comments turned out to be complete rubbish. Linux on a Pi is plenty fast enough to run a process that flips pin settings every 30ms with good consistency. In fact, that takes so little of the Pi's CPU power that you can not only run a PDP emulator concurrently, but also just use the Pi's GUI and run any other program you want. Even surf the web whilst the PDP emulator is running and the front panel blinks away."
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Tor said:
Yes, and Oscar's PiDP-8/l (via SIMH) can use the cheapest Pi model A. In addition to SIMH it also manages the front panel. There's info on Oscar's web page,
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Tor,
Thanks, the more of read about this PiDP-8, the more I want one! What a brilliant idea. Adding a PDP-8 front panel to the SIMH turns it from a dry software simulator into an experience. Of course one does not get all the fan noise, but you can't get everything. ;)
-Dave
 
It looks like something that would benefit from a deeper enclosure. Hmm. I wonder how hard it would be to adapt it to a rackmount blanking plate.....
 
dave_m said:
Of course one does not get all the fan noise, but you can't get everything. ;)
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Well, Oscar could do what Mike did with his Altair Clone project - there is a real fan, cooling an almost completely empty box, just so that you can hear a fan when it's powered on. :)
 
Tor said:
Well, Oscar could do what Mike did with his Altair Clone project - there is a real fan, cooling an almost completely empty box, just so that you can hear a fan when it's powered on. :)
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Ok, that solves the fan noise. Now we just need some TTY noise to complete it.
 
tradde said:
Ok, that solves the fan noise. Now we just need some TTY noise to complete it.
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Just a side note. I never noticed that Bernhard Baehr's Mac simulator of a pdp-8 actually can produce TTY sounds. Was quite cool to hear.
 
Tor said:
Originally Posted by dave_m
Of course one does not get all the fan noise, but you can't get everything

Well, Oscar could do what Mike did with his Altair Clone project - there is a real fan, cooling an almost completely empty box, just so that you can hear a fan when it's powered on. :)
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Actually, I've been thinking that a little speaker in the otherwise rather empty PiDP box would add something.

Something fake, for sure, but that befits a 2015 replica.

Not so much fan noises, but TTY sounds. It's a bit of a clinical experience if you stick in a "paper tape" USB stick with Focal, and everything is loaded silently in a second. Some modest TTY clicking gives useful (using the word loosely here) feedback. Emulation sounds are a very simple option to add given that the Pi has a sound output headphone jack. I'm not going to add it in the base kit, but it's trivial to add in afterwards.

Regards,

Oscar.
 
Oscar said:
I'm not going to add it in the base kit, but it's trivial to add in afterwards.
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Oscar,
Good, do not allow 'Requirements Creep' at this stage or we may never get our hands on the PiDP-8. :)

I was just kidding about the fan noise, but Teletype sounds may be a nice touch for a future mod kit. I bet people born after 1969 have never heard its distinctive sound. But please leave out the sound of old line printers! ;)

-Dave
 
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