It seems obvious enough that questions about an Osborne 1 computer would be on-topic here, but what about new machines built using old 8-bit microprocessors? There are still computer kits available based on the Z80, 6502, CDP1802, etc. Occasionally, these can mix with newer parts to provide capabilities such as TCP/IP network access or interfacing to Arduino shields.

Many of these old microprocessors are still manufactured, so it's possible to create an entirely new computer with a core architecture envisioned in the 1970s.

I'd posit that such machines still qualify for retrocomputing discussion, as it is the design rather than the fabrication date of the silicon that truly dates the CPU, but it may be worth some discussion.


I would have to say it depends.

Taking a design, something like Grant Searle's minimal component computers into account, and using all discrete logic, I'd argue would almost have to be considered retro at it's heart. While the designs are minimalist, they can also run versions of the original OS. For example, his 6809 6-chip computer runs a version of the CoCo BASIC link.

How would that NOT be retro? In building the computer and learning what each component does, while running an retro OS, I would think it's about as retro as you could get. He also has designs for a CP/M and 6502 machine as well. While they may not be the original machines, by building one you're certainly learning what made them tick.

I don't know that I'd consider micro-controller versions of these machines as retro. There's a project for a CoCo on FPGA that can run at 25Mhz, but, it's all in software, on a development board.

  • Elsewhere (well, here) there's discussion on whether emulators are on-topic. The prevailing notion seems to be that it can be, if the question similarly relates to what is being emulated rather than the emulator itself. Something like an FPGA implementation of an old computer might be thought of in the same way.
    – Dave Ruske
    Apr 21 '16 at 21:59
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    So long as there is a strong link to the old machines in the topic of the question, I think yes. Context is the key, I think. An all new rebuild of a classic circuit seems more on topic than an MCU implementation, but if the MCU implementation question relates to a timing artifact which is unique to the original machine then the detail of the question is the history, and the reason for interest is the modern part. May 19 '16 at 18:02

Probably not, unless you are building a retrocomputer clone, or kit that borrows heavily or exclusively from retrocomputer designs specifically.

New applications using old parts and old designs are, well, pretty common in modern electronics design.

That is to say, there isn't much "retro" about simply using silicon that was designed years ago. Fabs tend to pump out old designs instead of retooling because it is very cost-effective to do so.

i.e., using a 6502 to build a little computer is probably off-topic, while using a 6502 and some old and modern equipment to build a KIM-1 clone is probably on-topic.

But this is probably quite contextual.

  • 2
    It does get fuzzy. Here's someone who has interfaced a Z80 and CDP1802 to Arduino shields: olduino.wordpress.com The CDP1802 machine is, in essence, a miniature clone of the 1976 Popular Electronics ELF: sunrise-ev.com/membershipcard.htm The Z80 machine is a bit more original in its design, but obviously targeted at a similar audience: sunrise-ev.com/z80.htm
    – Dave Ruske
    Apr 21 '16 at 16:07
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    It's true. My only concern is that the overlap (electronics design) with whatever retrocomputing is might be narrow. Certainly there are a lot of people who burn solder to keep old computers going (I certainly do). But designing circuits, some of which have been around for decades, is just electronics. To quote myself from another thread: "many of those people don't consider what they do as retro". That being said I'm inclined to let the community sort this out based on the kinds of questions we get. Come up with an EE heavy question that intersects enough to satisfy the community, I'm happy.
    – user12
    Apr 21 '16 at 16:18

I feel like there's no definitive answer to this, but if you're writing code for a home-built 6502, Z80 or 68k machine then chances are there will be a crossover between what you're doing and old machines that used the same processors.

My gut feeling is that most questions would fit, but a general rule for all won't work. For example if a question is about a home brew machine and issues with ethernet then I wouldn't say it fit this site.

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