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kelli217

3D-printed miniature DEC VT-102 contains ESP32-based PDP-11 emulator

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Yeah, this came up on the PiDP-11 mailing list, as well. 

I've actually got a PiDP-11 on order, and I'm super excited to start putting it together. I've already got a couple of Altair 8800 emulators, and I'm hoping to get other Blinkenlights computers as well...

What I really want to see is a self-contained modern ASCII terminal built around a 14" or larger LCD screen and which has customizable firmware, so I can use it with different host systems.

I've actually written something like this for Windows, and it works well enough on Linux (with Mono installed) that I'm thinking about integrating that with an industrial LCD and a Pi in a case that looks either like the VT-100 or maybe like a Kaypro II. I just can't find a combination of project box and LCD that I really like, paired together. 

 

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I enjoyed the PDP-8 front panel replica and FPGA simulator that Steve Gibson demonstrated in an old episode of Security Now.

For my own part, the closest I ever got to using a PDP-11 was when I used to have a copy of Ersatz-11 running on an old 486 laptop, with an RK05 image file containing v7 Unix. That laptop still functioned as recently as six months ago, and it might still have the software and image in place.

My favorite terminal design was the ADM-3A, and Hackaday also has an article about someone integrating a Pi with one of those. (https://hackaday.com/2014/02/08/raspi-powered-adm-3a-dumb-terminal/) The terminal itself was still working, though, so it's not the same kind of project as building one's own terminal out of parts.

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1 hour ago, kelli217 said:

For my own part, the closest I ever got to using a PDP-11 was when I used to have a copy of Ersatz-11 running on an old 486 laptop, with an RK05 image file containing v7 Unix. That laptop still functioned as recently as six months ago, and it might still have the software and image in place

FYI, the Simh software used to run the PiDP is open source and can be run on any PC. 

You can also download and run the emulator on the Pi without the front panel; Unix v7 is on the list of operating systems preloaded in that SimH package.

 

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7 hours ago, TomXP411 said:

What I really want to see is a self-contained modern ASCII terminal built around a 14" or larger LCD screen and which has customizable firmware, so I can use it with different host systems.

I like this project - https://geoffg.net/terminal.html - it's really small, dumb and VT100 compatible. But you still need to add your favorite keyboard, monitor and case if you wish.

I did not get what you mean by "customizable firmware" and "different host systems". Dumb terminal is a dumb thing. Please, clarify.

Edited by Cyber
Different and updated version is here: https://hackaday.io/project/173216-ascii-video-terminal
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On 1/19/2021 at 9:19 PM, Cyber said:

I like this project - https://geoffg.net/terminal.html - it's really small, dumb and VT100 compatible. But you still need to add your favorite keyboard, monitor and case if you wish.

I was actually looking for something that will do HDMI. And the Geoffg firmware has too many shortcomings to do what I want - starting with a very incomplete implementation of the ANSI command set, not to mention being mono-only. 

 

On 1/19/2021 at 9:19 PM, Cyber said:

I did not get what you mean by "customizable firmware" and "different host systems". Dumb terminal is a dumb thing. Please, clarify.

When it comes to computer terminals, there's no such thing as a "dumb" terminal. not really... all CRT based terminals that have more than the simplest functionality are actually microcomputers, but with a very small and limited program on them. 

Something has to redraw the screen, 60 times a second. Something has to read the character ROM and turn those characters into pixels. Something has to read the serial port, listen for escape sequences, and position the cursor, set character attributes, and even just run the on-screen menus that set up the terminal's operation. Some terminals also have local disk storage, backscroll buffers, and can even handle multiple sessions at the same time, switching the screen between different sessions. 

And a modern terminal really needs to be able to handle more than one command set... while the ANSI/VT-102 command set became the most common standard, there actually were other terminal standards: Wang, IBM, ADM-31, and others had different command sets and even different serial protocols (IBM used something called Twinax, for example.) 

So what I want to build is a smart terminal that can do all of these things: it should have a local text buffer to allow editing of documents and programs locally. It should be able to transfer files via XMODEM, YMODEM, ZMODEM, and FTP. It should be able to switch command sets between ANSI, ADM-31, and whatever else I decide to code into the system. 

It should work with a USB keyboard, connect over USB, serial, Ethernet, and WiFi. And it should output HDMI video.

At some point, a terminal stops being a "terminal" and is basically a computer... and that's basically what happened in the 80s. In fact, one of the first "desktop computers" was literally a terminal that required the software to be loaded from removable media... someone got the idea they could put something other than terminal software on there, and so a computer was born. 

Anyway... what I'm thinking of doing is the opposite... taking a small, cheap computer, like a Pi, and mounting it with an LCD in a terminal chassis... making a flexible, configurable "terminal" that is based on a single board computer. 

 

Edited by TomXP411

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3 minutes ago, TomXP411 said:

So what I want to build is a smart terminal that can do all of these things: it should have a local text buffer to allow editing of documents and programs locally. It should be able to transfer files via XMODEM, YMODEM, ZMODEM, and FTP. It should be able to switch command sets between ANSI, ADM-31, and whatever else I decide to code into the system.

So in other words it should be able to easily switch between several different dumb modes (running them in parallel). And interact between these modes.

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Just now, Cyber said:

So in other words it should be able to easily switch between several different dumb modes (running them in parallel). And interact between these modes.

Among other things, yes. 

Long term, I want to replicate the features of my favorite DOS terminal program, Telemate... but I've got some other things to do before I get back to that project. 

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1 minute ago, TomXP411 said:

Long term, I want to replicate the features of my favorite DOS terminal program, Telemate... but I've got some other things to do before I get back to that project. 

Is this the one?

 

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7 hours ago, Cyber said:

Is this the one?

 

Yep. That's it. I spent many, many hours in front of Telemate.

Before that, I used Procomm Plus on PC, Dialogue 128 on the C128 (I loved the RAM disk), and some pretty obtuse terminal that came with my first modem, a 300 baud Volksmodem.

 

 

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8 hours ago, TomXP411 said:

Anyway... what I'm thinking of doing is the opposite... taking a small, cheap computer, like a Pi, and mounting it with an LCD in a terminal chassis... making a flexible, configurable "terminal" that is based on a single board computer. 

Pi is great, because it's powerful enough, and making your own projects is pretty easy. But what I hate about it is a long boot time, if you make your project around Linux OS. Boot time might be faster with custom OS, but it's a pain in the ass creating one.

I like Geoff's projects, because despite PIC32 might be an overkill for the tasks, they all boot instantly.

Objectively boot time is not a huge deal as long as device does its job. But I can't help myself, I like devices that start instantly.

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16 minutes ago, Cyber said:

Pi is great, because it's powerful enough, and making your own projects is pretty easy. But what I hate about it is a long boot time, if you make your project around Linux OS. Boot time might be faster with custom OS, but it's a pain in the ass creating one.

I like Geoff's projects, because despite PIC32 might be an overkill for the tasks, they all boot instantly.

Objectively boot time is not a huge deal as long as device does its job. But I can't help myself, I like devices that start instantly.

There is 'Faux86' for the Pi.  It's not linux based, it's an 8086 PC emulator that runs directly on the Pi, boots faster than a PC from that era.

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5 hours ago, Cyber said:

Pi is great, because it's powerful enough, and making your own projects is pretty easy. But what I hate about it is a long boot time, if you make your project around Linux OS. Boot time might be faster with custom OS, but it's a pain in the ass creating one.

I like Geoff's projects, because despite PIC32 might be an overkill for the tasks, they all boot instantly.

Objectively boot time is not a huge deal as long as device does its job. But I can't help myself, I like devices that start instantly.

Yeah, the boot time can be a little annoying. If you skip the GUI, it's less of an issue, thought.

There's also Circle, which lets you write software that runs directly on the Pi - no Linux required. That's worth taking a look at for someone writing terminal or thin client software. 

 

 

 

Edited by TomXP411
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On 1/19/2021 at 10:20 PM, kelli217 said:

My favorite terminal design was the ADM-3A, and Hackaday also has an article about someone integrating a Pi with one of those. (https://hackaday.com/2014/02/08/raspi-powered-adm-3a-dumb-terminal/) The terminal itself was still working, though, so it's not the same kind of project as building one's own terminal out of parts.

Hurry and you can buy one... (though looking at that PCB, I get the feeling that despite being solid state, there is way too many vintage components to maintain.  Reminds me of the “CPU-less”, logic-gate-only affairs.

https://www.ebay.com/itm/Vintage-1982-LSI-Lear-Seigler-Inc-ADM-3A-Computer-Display-Terminal/402729142617?_trkparms=aid%3D777001%26algo%3DDISCO.FEED%26ao%3D1%26asc%3D20200211172511%26meid%3D3321282d19224be5a9f19d0fb91bc195%26pid%3D101214%26rk%3D1%26rkt%3D1%26mehot%3Dnone%26itm%3D402729142617%26pmt%3D0%26noa%3D1%26pg%3D2380057%26algv%3DRecommendingSearch%26brand%3D&_trksid=p2380057.c101214.m46344&_trkparms=pageci%3Aced16e3c-7d41-11eb-907f-f2548a99469b|parentrq%3Aff95622d1770a4d3624ac984ffe8d71a|iid%3A1

 

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3 hours ago, EMwhite said:

Hurry and you can buy one... (though looking at that PCB, I get the feeling that despite being solid state, there is way too many vintage components to maintain.  Reminds me of the “CPU-less”, logic-gate-only affairs.

I don't happen to have $600 lying around, alas. 😄

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