Retrocomputers online

Here are a few websites hosted on properly old computers:

On a ZX81:

On a PDP-11/73 (offline at time of writing) linked from this page:

On a PiDP-11 (embedded emulation, simh on a raspberry pi) (archived here)

And here’s something slightly different - A PC/XT (8088) with 256k RAM on the web available to run your code:

I have in the past setup a BBC Micro on the 'net: connected via serial cable to a host which gatewayed serial to a TCP/IP connection.


Here’s another something slightly different; a modern retro-minicomputer (homebuilt) serving information about itself:

It is truly a glory to behold.


There’s also this “BBS” running on an Apple II with two Disk IIs:

The address is
but none of my web browsers are able to connect :frowning:

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Nice one - I see it’s a TCP/IP connection to port 6502, not HTTP at all. So try
nc 6502
telnet 6502

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Also probably related here’s a WAN DECnet, set up by the italian retrocomputing/hacker community, running at least since 2007:

Thanks for the heads up @EdS!
It works! :slight_smile:

p.s. I just found out that telnet is not available anymore on macOS 10.13 :frowning:


There is also the Magic-1 computer. Pure TTL, yet runs Minix…

it’s website:

you can normally telnet in, but I think it only allows one user at a time.

telnet 51515




Ken Shirriff’s Sinclair Scientific Calculator Emulator:

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Here’s a MyCPU build - there are several - running the Contiki OS and GUI, and browsing the web:

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It turns out the one surviving CDC-6500, at the Living Computer Museum + Labs, can be accessed online via ssh (by special arrangement)

(The CDC-6500 at the LCM in Seattle, from Martin Sauter’s blog)

* Authorized users only - All activity is monitored.
* To request access visit

See this blog post, where Martin Sauter has a quick go with Basic and then with Fortran:
Chasing Seymour, Supercomputing And Punchcards

they have a working CDC-6500, a machine of the first family of supercomputers and designed by Seymour Cray, which can be accessed over the Internet. All original manuals required to work with the machine are available in PDF format. There’s a PDF document on how to use the Interactive Terminal Facility (IAF) via ssh, a guide to the NOS operating system, programming manuals for Basic and Fortran and, very importantly, the PDF version to ‘Design of a Computer – The Control Data 6600‘ by Jim Thornton written in 1970. The combination of this material together with online access to the real machine creates a wonderful experience

(via this toot)

I’d love to see someone summarize some of the whys and wherefore’s of NOS.

We used it in college, but fact was we basically just mimic’d what folks told us to type in to get things done rather than so much understand why were doing it and what was actually happening.

For example, pretty much every program I ever worked on was just a single file exercise, both Fortran and Pascal (and a little BASIC). But, there was no linking step as we’re used to today. You ran the compiler, it created a file named “LGO” (which folklore said stood for “Load and Go”). You type LGO, and, shazam, your program worked.

But the idea of linking programs was never even brought up at a conceptual level. Not by the teachers, not by the crazy hacker kids I hung out with etc. (One group wrote a CPU simulator for the machine – and used to run all sorts of code that they normally weren’t able to execute. Found a host of holes and gaps in the system they could exploit.)

Another thing we had were DIRECT, or DIRECT ACCESS (I forget) files that were loaded in to your environment with the ATTACH command. Typically these were PROC files (basically JCL scripts). Folks shared utility libraries like this. But the concept itself, ATTACHing, DIRECT ACCESS, was never really explained – we just did it.

It was great working on this machine. Going form a Commodore PET to a CDC mainframe is a very mind expanding experience. I always felt students, later on, that went from whatever home computer they may have played with at home or school just to learn on the new PCs running DOS in the labs missed out on a lot of secondary, indirect education that you get working on a large multi-user platform that’s completely foreign is some aspects, but much of the same in others.