From mboxrd@z Thu Jan 1 00:00:00 1970 MIME-Version: 1.0 References: <7BBE2FFB-21F5-469C-B06F-D9C4C1E0AA57@pobox.com> In-Reply-To: <7BBE2FFB-21F5-469C-B06F-D9C4C1E0AA57@pobox.com> From: "Digby R.S. Tarvin" Date: Tue, 9 Oct 2018 15:52:22 +1100 Message-ID: To: Fans of the OS Plan 9 from Bell Labs <9fans@9fans.net> Content-Type: multipart/alternative; boundary="000000000000f837990577c47fab" Subject: Re: [9fans] PDP11 Topicbox-Message-UUID: e920b586-ead9-11e9-9d60-3106f5b1d025 --000000000000f837990577c47fab Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable 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 wrote: > On 9 Oct 2018, at 14:08, Digby R.S. Tarvin wrote: > > > <=E2=80=A6> > > 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 powerf= ul >>> machines with a comparably elegant architecture and attractive front pa= nel >>> :) >>> >> >> An attractive front panel for nearly any machine is just a soldering >> iron, LEDs and some logic chips away. As far as elegant architectures, s= ome >> 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 kn= ow >> 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 attractiv= e > 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 controll= ed > 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=E2=80=99re after, but the PiDP8 and PiDP11 ki= ts will > get you an (arguably) attractive front panel without requiring artistic > talent. > > http://obsolescence.wixsite.com/obsolescence/pidp-11 > > I=E2=80=99ve not looked into how the front-panel is driven (from SIMH, I = guess?), > but perhaps it could be suitably massaged? > > > > d > > --000000000000f837990577c47fab Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable
Yes, that is exactly what prompted the thinking about Plan= 9 on a PDP11/70. I have already organized a PiDP11 kit to be shipped to me = when I get home in December=C2=A0 - so that I can experiment without runnin= g the risk of blowing up my old original 11/70 front panel. But a (simulate= d) 11/70 with a nice front panel isn't so interesting unless I have som= e 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 export= ing a device that lets other hosts write to the lights and read from the sw= itches, for example..=C2=A0

Regards.
DigbyT

On Tue, 9 Oc= t 2018 at 14:23, David Arnold <david= a@pobox.com> wrote:
On 9 Oct 20= 18, at 14:08, Digby R.S. Tarvin <digbyt42@gmail.com> wrote:
<= br>
<=E2=80=A6>

So I don't think it i would be worth a substan= tial rewrite to get it going. It is a shame that there don't seem to ha= ve been any more powerful machines with a comparably elegant architecture a= nd attractive front panel :)

An= attractive front panel for nearly any machine is just a soldering iron, LE= Ds and some logic chips away. As far as elegant architectures, some are ver= y nice: MIPS is kind of retro but elegant, RISC-V is nice, 680x0 machines c= an be had a reasonable prices, and POWER is kind of cool. I know I shouldn&= #39;t, but I have a soft spot for ARM.
<= br>
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)..=C2=A0 One is the sheer number of LEDs required to= display all of the address and data lines in a modern architecture.=C2=A0 = Mainly an issue if I want to use the old PDP11/70 front panel that I had sa= ved 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. V= irtual addresses, User/Kernel mode, register contents etc are all hard to g= et at. I have toyed with using JTAG etc, but there always seems to be somet= hing that I can't get to. So it is hard to do more than resort to a sof= tware controlled front panel. I used to have a little box of LEDs and switc= hes that I plugged into the parallel port on PCs, and had my BSDi kernel mo= dified to update it as part of the clock interrupt. But now the parallel po= rts are becoming rare and you can't update LEDs connected via USB in a = single instruction... :-/

Probably not quite what you=E2=80=99re after, but the PiDP8 and PiDP11 kit= s will get you an (arguably) attractive front panel without requiring artis= tic talent.


I=E2=80=99= ve not looked into how the front-panel is driven (from SIMH, I guess?), but= perhaps it could be suitably massaged?


=

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