PiDP or Altair-Duino?

[Dave Taylor]

I really do hope this question is allowed here , i don’t want to ruffle any feathers so please let me know if not allowed and I will remove immediately 

Just a little introduction I’m 50 years old and started out in the early 80’s with a Commodore VIC20 and went on from there 

I had read a little about the Altair’s and PDP’s and they have always fascinated me 

So now I can see you can actually build yourself one I just have to have one , but that’s the question, which one ?

I take it they are both pretty much the same really ? Or am I completely wrong about that ?

I can see both look quite similar regarding the building of them 

Has anyone built and used both ? Would love to hear your views 

And yes I will probably end up getting both :) 

Any help or advice would be greatly appreciated 

Dave 

[Chuck McManis]

Get the PiDP-11. The original Altair 8800 was essentially an homage to the minicomputers of the day (which was the PDP-11 from DEC).

What the Altair did was to give you something "close" to the experience of having your own mini-computer. But it really wasn't all that close given its memory limitations, lack of a memory management unit, and poor software support for more "interesting" things. 

So to really appreciate the PC revolution, you need a minicomputer first (which the PiDP-11 gets you) and then after you've familiarized yourself with that system and played with it, *then* get an Altair-duino or one of the HyNybble IMSAI 8080 emulators. That will give you an understanding of what people had to give up to get something "somewhat close" to the PDP experience. The next step would be an Apple II, Atari or Commodore C64 for the "next generation" PC experience, or the original 8088 IBM PC for the "next generation" business PC experience.

--Chuck

--
You received this message because you are subscribed to the Google Groups "[PiDP-11]" group.
To unsubscribe from this group and stop receiving emails from it, send an email to pidp-11+u...@googlegroups.com.
To view this discussion on the web visit https://groups.google.com/d/msgid/pidp-11/bd3ae835-f431-4c14-ab98-6fd461ed6b85%40googlegroups.com.

[sunnyboy010101]

I have bought and built the PiDP-8 kit, then the PiDP-11 kit, then the Altair-Duino kit. The PiDP kits use the Raspberry Pi as the hardware CPU "engine" to host the simh emulator that is the heart of the kit. I love them both. The Altair-Duino is a similar kit (lights & switches) but uses an Arduino as the CPU engine, and hosts it's own software emulator. Again, I love it. I bought the IMSAI 8080 emulator kit this past summer but have not had time to build it yet. It hosts a different CPU and emulation package. I expect I will love it as well. I also have the "Membership Card" (and ELF micro copy) and the Z80 Membership Card, though that is also not yet built.

All of these kits serve a similar yet different purpose. Similar in that you solder LEDs and switches to a circuit board, then fire up the designate CPU, load the software and then yell "IT'S ALIVE" in your best "Young Frankenstein" / Gene Wilder voice as it powers up for the first time. So if you are a kit builder, ... BUY ALL OF THEM.

If you only have a desire to revisit your youth and fight with one of the machines of that era, then you can pick the one that best feeds your desire. I never used a PDP8 (thank goodness) but got "hands on" with a PDP-11 running BSD Unix early on. (My first machine was feeding punch cards into a CDC Cyber. The second was the Honeywell Multics system at the University I attended). I've played on many systems since then, from "big iron" (IBM 3033) to various minicomputers from Harris and Data General to several DEC and IBM systems.

But I still love Unix and that meant (for me) the PiDP11 kit as my "most fun" kit to play with. But I still love all of them and so again, my recommendation is to BUY THEM ALL!!!

:-)

-R

To unsubscribe from this group and stop receiving emails from it, send an email to pid...@googlegroups.com.

[Steve Tockey]

I would add that of those choices, the PiDP-11/70 is the most powerful and the most flexible. You get a pretty hot processor and a big collection of different operating systems: RT-11, RSX-11M, RSTS-E, and several versions of Unix. There are also a whole host of programming languages: C, Basic, Fortran, Pascal, Macro-11, Forth, . . .

[Digby R.S. Tarvin]

I also have the full set (including an original PDP11/70 front panel and a CDC Cyber emulation for the 'mainframe' experience).

I concur on going for the 11/70 first. the 11/70 IMHO is the iconic 'blinkenlights' computer. The fundamental difference between the minis like the 11/70 and the micros is that the minis were implemented in discreet logic, and the lights reflected the internal processor state. Microcomputers are monolithic and there is very little access to internal state - so the lights were just another peripheral providing low cost input and output back when a video display terminal was an expensive piece of professional equipment. 

The first computers that I used were PDP11's and CDC Cyber mainframes as a university student. I looked at IMSAI's and ALTAIR's in electronics magazines but they were beyond my finances at the time, so the first computer I actually owned was after the lights and switches era - a Z80 based Exidy Sorcerer (integrated keyboard and video output).

They CDC cyber was not realy a blinkenlights machine. They were rather revolutionary at the time, using twin oscilloscope screens to display internal state.  Interactive users had remote terminals. The following is a screen shot of my 'cyber' console:

 

and a picture of a real one:

http://mentallandscape.com/Computer_CDC.htm 

 

You can run a cyber by downloading the 'dtcyber' emulator by Tom Hunter - no custom hardware required (although I have customized the console emulation on mine).

DigbyT

On Fri, 4 Oct 2019 at 05:56, Steve Tockey <steve...@gmail.com> wrote:

I would add that of those choices, the PiDP-11/70 is the most powerful and the most flexible. You get a pretty hot processor and a big collection of different operating systems: RT-11, RSX-11M, RSTS-E, and several versions of Unix. There are also a whole host of programming languages: C, Basic, Fortran, Pascal, Macro-11, Forth, . . .

--
You received this message because you are subscribed to the Google Groups "[PiDP-11]" group.

To unsubscribe from this group and stop receiving emails from it, send an email to pidp-11+u...@googlegroups.com.
To view this discussion on the web visit https://groups.google.com/d/msgid/pidp-11/646edb92-7f33-4e28-a271-39223241a0d9%40googlegroups.com.

[Tom Lake]

I own an AltairDuino, IMSAI 8080esp, PiDP-8i, PiDP-11 and an Altair 8800c. They are targeted at different audiences. Back in the day, most individuals couldn't afford a PDP-8 or PDP-11 so the universal nostalgia of having hands-on experience with one is limited to a small group of people like professional computer scientists and the students in Project DELTA (a fascinating story - Google it!) Many people sat at a terminal and ran TSS-8 BASIC or RSTS/E BASIC-PLUS programs but not many actually used the machine directly. With the Altair, everything changed. Suddenly a computer wasn't a mysterious machine ensconced in an air-conditioned, brightly-lit white room somewhere with tape drives whirring. Now it was a small box in your den or living room that you could program yourself. This changed the computer scene forever. For me, nostalgia is the key. I have eight terminals running on my PiDP-11 using the RSTS/E operating system and four terminals on my PiDP-8 running TSS-8. (If anyone has EDU-25 running, I'd like to hear about it!) but the Altair and IMSAI give me the most satisfaction. It all comes down to what YOU hope to get out of the replica computer experience. All the kits are easy to build (I did have trouble with the SMD SD card reader on the IMSAI) and provide a lot of fun. 

In any case, welcome to the wonderful world of blinkenlights. Don't ever let anyone make you feel guilty about your hobby or make you feel that their choice of computer is better than yours or you aren't as much of a fan as they are because you don't know how to do some of the things they do. Almost all the people on these forums are very helpful and patient. I've asked countless questions and all have been answered at least once. Sometimes I ask the same question a few times until I finally understand the concept. I know I can be annoying at times with my persistence but have made quite a few new friends here who don't mind dragging me along until that "AHA!" moment hits. I try to give back to the community when I can by answering questions by beginners and I hope I'm at least somewhat as patient as people have been with me.

Tom L

[Richard Stofer]

The PiDP-11 is orders of magnitudes more powerful than the Altair 8800 or any reasonable emulation.  Among other things, the 2.11BSD software for the PDP11/70 has a full networking stack, something that didn't work out all that well with a 64k memory space.  In fact, I'm not aware of anybody implementing such a thing.  There were some crude attempts at memory banking.

I have an original Altair 8800 that I bought back around '76 and I learned a heck of a lot about hardware and programming on that machine.  Made a few bucks writing BIOS code for companies wanting to add hard drives to Apple II's.  I also did a little work with that Z80 card Microsoft created for the Apple II.  Good times!

I have a couple of systems that run the CP/M 2.2 operating system including one based on a 50 MHz eZ80.  CP/M screams at 50 MHz!

But I also have two of the PiDP-11s and they are magnificent!  Besides networking, 2.11BSD includes a K&R version of the C compiler as well as a version of Pascal and two styles of assemblers.  These are real systems and can do real work.  There is code around to implement a web server so that's pretty cool.

Definitely start with the PiDP-11.

[Tom Lake]

While no one disputes that the PDP-11 was way more powerful than the Altair, I don't think that's the point of buying these replicas of old machines. Heck, an Intel Core i7 can run rings around the PDP-11 but where's the fun in that? If power and a network stack are your only goals, buy a modern machine. Well, that's my 2¢ anyway.

Tom L

[Stephen Williams]

Heretical opinion: don't buy either, get a kit which uses a real Z80 and hosts CP/M.

Examples are SmallZ80 on http://stack180.com, one of the CPUVille kits on http://cpuville.com or an RC2014 based kit mostly on http://tindie.com.

I know the Z80 & CP/M are less sophisticated that the DEC offerings and have less of a nostalgic feel that the Altair and Imsai simulators. The advantage over DEC is the amount of software and documentation available. Over the simulators, more control: with an Altairduino or IMSAI8080esp you are dependent on the developer of the simulator to accommodate the changes you want to make unless you are interested in developing your own simulator sideline.

There is also a certain pleasure in running on real hardware. If you have little or no experience of early micros I highly recommend the CPUVille kits: well documented and easy to build.

Downsides of this approach: you have to develop your own casework, which can itself be fun if you are into wood or metalworking (which I struggle at).

My experience: I've tried these over the last two or three years.

Genuine Z80:

CPUVille original version

CPUVille second version with front panel

Membership Card

SmallZ80

Various RC2014

Simulators:

Altair8080 clone

Altairduino (early and later versions)

Kenbak-1

IMSAI8080esp

PiDP8

PiDP11

If you will buy a simulator, I recommend the Altairduino.  The simulation is really good, including useful features such as support for multiple hardware configurations and built in extensions to the front panel which allow breakpoints in the simulated machine and single stepping with register visibility.

Good luck, whatever you choose.

My first kit, based on CPUVille board set and with some additional hardware changes to support an input switch register and more winky lights, mounted in a $6 picture frame:

[Dave Taylor]

Thanks everyone it’s very much appreciated 

Just need to hope now that I’m going to actually get hold of one as no stock :( 

[Richard Stofer]

There are also actual hardware reincarnations of Z80 machines up to and including one that runs CP/M.  I have a couple of versions of these systems and the Micro is on the way

https://rc2014.co.uk/

These lack any kind of front panel but it's probably not a stretch to include one given that all the bus signals are available on the backplane.

The  Micro by itself with no backplane support, is intended to run Microsoft Basic and nothing else.  It doesn't even have a storage device.  No worries, you can always use the terminal to upload and download entire files.  Probably have to slow down the upload speed to keep from outrunning the Basic command line.

For those who like playing with FPGAs, there is the T80 core (at OpenCores.org) which is a good implementation of the Z80.  One of my projects with this core was to hang a Compact Flash on the IO lines and implement CP/M 2.2.  Later, I decided to build PacMan using the originals ROMs.

https://www.fpgaarcade.com/kb/pacman/

I have seen a real Altair butched to use an FPGA as the entire system while still being connected to the front panel.  A better way to do that would be to use the eZ80 board with a daughter card to hold the FTDI serial chips (and connectors) along with the Compact Flash.  Either way, the retro value is messed up and Altairs sell for high dollars on eBay.

The reason I like 2.11BSD is that it is a complete development environment.  True, the version of C is archaic but it is also classic!  It is a simple stand-alone system that would make an ideal educational system.  It is very well documented, probably better than Linux, and since it doesn't have a graphical environment, many of the 'features' of Linux are omitted - that's nice!  Just write and run code on a simple machine.  2.11BSD isn't that much different than 4.1BSD and all the current BSD use this release as a basis.  In fact, I installed FreeBSD on a laptop just to have a more capable BSD platform than the PiDP-11.

For those interested in CS, the entire source code for the system is in /usr/src - this might be helpful for those who have to study Unix as part of a CS program.

The Altair, given disk drives and CP/M will also run C and Fortran but memory size will soon impede progress.  The CP/M Macro Assembler is quite good, I learned a lot from using it, nearly 40 years ago.

I also have a CompuPro Z80 system (blank front panel, rack mount) with dual 8" floppies and, yes, I have a bunch of those floppies.  About 16 years ago, I transferred all the files from floppy to compact flash using Kermit between a couple of systems.

[andy]

… continuing in the heretical vein, I would say the best one is hopefully-soon-to-be-announced PiDP-10 kit which Oscar is working on! :-)

cheers

Andy

[Adam Thornton]

> On Oct 6, 2019, at 7:45 AM, andy <lordha...@gmail.com> wrote:
>
> … continuing in the heretical vein, I would say the best one is hopefully-soon-to-be-announced PiDP-10 kit which Oscar is working on! :-)
>

If that turns out to be really a thing, I am so, so sold.

Adam

[Oscar Vermeulen]

Adam,

On Sun, 6 Oct 2019 at 19:47, Adam Thornton <atho...@gmail.com> wrote:

If that turns out to be really a thing, I am so, so sold.

Oh, it definitely *is* a thing. I am just procrastinating, I should give myself a kick on the backside to finish the prototype. But that turned out to be physically impossible, so I have to just discipline myself some other way. Time was scarce this year. But the PCB design is done, the panel is done, the prototype cases are in already. Now it's just the annoying phase of colour matching and deciding how to screw everything together (magnets this time, I think).

Then there's the trivial element of the software. Trivial for me, that is: there's been so much work done on the PDP-10 simh (and the ITS software project to run on it, look it up on github!) which really gives a good reason to have a PDP-10 at home now.

Kind regards,

Oscar.

[Adam Thornton]

Oh, I know about ITS and the state of simh (and klh10).  I did a port of Frotz (the Z-Machine interpreter, for running Infocom text adventures and latter-day community-written games produced in Inform) to TOPS-20, and I've been thinking about trying to do the same for ITS.  The problem, of course, being that TOPS-20 is pleasant to use, and ITS....not so much.  (There is also the problem of "There's an ANSI C for TOPS-20, while the C on ITS is slightly pre-K&R," where current Frotz sources are C99-but-not-far-from-ANSI, but that's largely a matter of finding a working unprotoize and then just grinding through the error messages.)

https://mvsevm.fsf.net has four running 36-bit systems (those are on a Pi 3B+--if you use Ubuntu you can easily get a 64-bit host OS, which makes 36-bit emulation a lot faster, which is worth noting for a PiDP-10), and several 16-bit systems (none of those are on my PiDP-11, which is usually just sitting on top of an RM-80 drive running a pretty idle pattern).  Perhaps today, but not likely, I will get around to taking the nicer-idle-task for 2.11bsd that was posted here a couple days ago, and porting that to v7, so I can get my pretty idle pattern and leave v7 Unix running and let it be the thing mvsevm hooks up to.

Adam

[Anthony Eros]

My first exposure to timeshared computing was Project DELTA in 1976.

I currently run a copy of the Project DELTA environment, including a copy of my high school’s (106,1) account, through SIMH.

I can’t wait to build my PiDP-11!

— Tony

--
You received this message because you are subscribed to the Google Groups "[PiDP-11]" group.
To unsubscribe from this group and stop receiving emails from it, send an email to pidp-11+u...@googlegroups.com.

To view this discussion on the web visit https://groups.google.com/d/msgid/pidp-11/4ec1bacf-c42b-4d9a-86c7-4f5f2f126dc5%40googlegroups.com.

[Mike Katz]

Oscar,

It was good to see you back on line yesterday.  I hope your mom is well.

I have the PiDP-11 half assembled with lots of pictures taken.  I have
not forgotten our deal.

My wife just got back from being out of the country for a month so my
"honey do" list is extremely long.

If you would like I can send you some of the unretouched pictures.

Your friend,

               Mike