There's also our Ohio Scientific 560Z "Processor Lab" reproduction:
http://www.glitchwrks.com/2017/02/26/osi-560z-build It uses the Intersil IM6100 and executes PDP-8 code. Memory management is implemented in handlers written in 6502 assembly on the host system, so you can have whatever memory management you like. I believe one of the guys on the osiweb.org forums has PDP-8/e memory management working. I don't know if he has OS/8 running yet, but does have at least FOCAL going. You of course need a 12-bit memory board, which we also make (uses modern components, works with FeRAM for a core-like experience). And you'll need some sort of host system, the simplest being an Ohio Scientific 502 at the moment (basically a single-board 6502 system with serial console). That's probably the cheapest/most reliable *non-emulation* route. Of course, emulation is going to be both cheaper and more reliable. Thanks, Jonathan On Tue, Oct 23, 2018 at 12:17 AM Paul Anderson via cctalk < cctalk@classiccmp.org> wrote: > Hi Carlos, > > With the cost of PDP-8 parts and the need for maintenance and repair, if > you can find an emulator that will do what you want, go for it. > > Paul > > On Mon, Oct 22, 2018 at 10:39 PM Carlos E Murillo-Sanchez via cctalk < > cctalk@classiccmp.org> wrote: > > > Greetings all... > > > > I have been pondering something and would love to receive feedback from > > you. The thing > > is, I would like to have something pdp8-ish that would allow me to play > > a little bit > > with the programming languages that were available for these machines, > > FORTRAN 4K and > > FORTRAN IV in particular. Now, I would love to be able to time some > > FORTRAN jobs just > > to get an idea about what it was like back then. I am aware of PiDP-8, > > simh, as well as > > SBC6120, SBC6120RBC. > > > > I happen to have three VT78 cpu boards (sans the RAM board) and two > > vt278 cpu boards. > > All were in rather sorry condition; I picked them up from a junk pile > > that was stacked > > several feet high and in which the contents were mostly random. Thus, > > the VT78 boards' > > components were scratched and in fact two of them are missing the > > control panel ROM chip. > > Otherwise they are complete, but I am missing the RAM boards. The VT278 > > boards > > were further abused by someone who yanked out the oscillators and a few > > TTL chips, > > damaging several traces, which I have now repaired. Alas, only one of > > them has the > > HM6120 cpu chip, and I do not know if it is good or not. Both are > > missing the SMC5037 > > CRT generator chip. Other than that, they are complete. > > > > So, now that we all know what I have, let me say out loud what I've been > > thinking: > > > > If I try to build actual hardware: > > > > I've read that the VT278 has serious software compatibility issues with > > older software > > due to the use of the HM6121 I/O chip. So even if I get an adequate > > keyboard, buy the > > CRT chip and manage to use it to drive a monitor, I would need an > > original floppy drive > > system and media, because I do not have the DP278 serial comms board > > that would allow me > > to send the VT278 a program to run; > > > > For the VT78, I would need to hack a memory board, and, since it can be > > coaxed to accept > > a program to run if it is fooled into thinking that it is loading a > > program from an > > MR78/paper tape, perhaps I could make it boot something. I would need > > to wire-up > > and arduino or something like it to translate the keyboard and display > > terminal > > chatter in the serial console into something usable. But, that's three > > hardware > > projects (memory board, MR78-like contraption, microcontrolled serial > > console > > translator)... > > > > The last hardware option is to go and make an SBC6120RBC; I would need > > to buy > > programmers for the GAL/PAL devices, and I've heard that not all > > programmers can deal > > with the kind of chips used in it. And, if it turns out that the HM6120 > > chip that I > > have is bad, I would have to hunt down one of those rare beasts.. It > > would be awesome, though, > > to have an SBC6120RBC up and running, and be able to time actual > > hardware running > > FORTRAN. > > > > And then comes the emulation option, with the PiDP-8. I have to say > > that the emulation > > of the blinkenlights is very, very attractive to me, and this option is > > a no-brainer > > hardware-wise. > > > > So... am I missing something in my estimation of the effort involved in > > these options? > > > > What would _you_ do? > > > > Carlos. > > > > >