Yes, that is exactly what prompted the thinking about Plan9 on a PDP11/70. I have already organized a PiDP11 kit to be shipped to me when I get home in December - so that I can experiment without running the risk of blowing up my old original 11/70 front panel. But a (simulated) 11/70 with a nice front panel isn't so interesting unless I have some interesting PDP11 software to run on it.
A small Plan9/Inferno implementation could be integrated into a larger network and allow the old hardware to integrate seamlessly with other things. Such as exporting a device that lets other hosts write to the lights and read from the switches, for example.. Regards. DigbyT On Tue, 9 Oct 2018 at 14:23, David Arnold <dav...@pobox.com> wrote: > On 9 Oct 2018, at 14:08, Digby R.S. Tarvin <digby...@gmail.com> wrote: > > > <…> > > So I don't think it i would be worth a substantial rewrite to get it >>> going. It is a shame that there don't seem to have been any more powerful >>> machines with a comparably elegant architecture and attractive front panel >>> :) >>> >> >> An attractive front panel for nearly any machine is just a soldering >> iron, LEDs and some logic chips away. As far as elegant architectures, some >> are very nice: MIPS is kind of retro but elegant, RISC-V is nice, 680x0 >> machines can be had a reasonable prices, and POWER is kind of cool. I know >> I shouldn't, but I have a soft spot for ARM. >> > > I have thought about it, but there are a couple of problems (in addition > to my lack artistic talent when it comes to building physically attractive > enclosures).. One is the sheer number of LEDs required to display all of > the address and data lines in a modern architecture. Mainly an issue if I > want to use the old PDP11/70 front panel that I had saved for the purpose, > I suppose. The other problem is getting access to the all of the machine > state that was displayable on a mini computer console. Virtual addresses, > User/Kernel mode, register contents etc are all hard to get at. I have > toyed with using JTAG etc, but there always seems to be something that I > can't get to. So it is hard to do more than resort to a software controlled > front panel. I used to have a little box of LEDs and switches that I > plugged into the parallel port on PCs, and had my BSDi kernel modified to > update it as part of the clock interrupt. But now the parallel ports are > becoming rare and you can't update LEDs connected via USB in a single > instruction... :-/ > > > Probably not quite what you’re after, but the PiDP8 and PiDP11 kits will > get you an (arguably) attractive front panel without requiring artistic > talent. > > http://obsolescence.wixsite.com/obsolescence/pidp-11 > > I’ve not looked into how the front-panel is driven (from SIMH, I guess?), > but perhaps it could be suitably massaged? > > > > d > >
