5 ms·

Well, I disagree with yours! What cases are you thinking of when you say "Plenty of people are still using technology developed thousands of years ago even whe

by kragen 2y ago

Well, I disagree with yours! What cases are you thinking of when you say "Plenty of people are still using technology developed thousands of years ago even when there are modern alternatives that are thousands of times more efficient"? I considered hand sewing, cultivation with digging sticks instead of tractors, cooking over wood fires, walking, execution by stoning, handwriting, and several other possibilities, but none of them fit your description. In most cases the modern alternatives are less efficient but easier to use, but in every case I can think of where the efficiency ratio reaches a thousand or more in favor of the new technology, the thousands-of-years-old technology is abandoned, except by tiny minorities who are either impoverished or deliberately engaging in creative anachronisms. I don't think "the relative simplicity of old technology" is a good argument for attempting to control your tractor with a Z80 instead of an ATSAMD20. You have to hook up the Z80 to external memory chips (both RAM and ROM) and an external clock crystal, supply it with 5 volts (regulated with, I think, ±2% precision), provide it with much more current (which means bypassing it with bigger capacitors, which pushes you towards scarcer, shorter-lived, less-reliable electrolytics), and program it in assembly language or Forth. The ATSAMD20 has RAM, ROM, and clock on chip and can run on anywhere from 1.62 to 3.63 volts, and you can program it in C or MicroPython. (C compilers for the Z80 do exist but for most tasks performance is prohibitively poor.) You can regulate the ATSAMD20's voltage adequately with a couple of LEDs and a resistor, or in many cases just a resistor divider consisting of a pencil lead or a potentiometer. It would be pragmatically useful to use a Z80 if you have an existing Z80 codebase, or if you're familiar with the Z80 but not anything current, or if you have Z80 documentation but not documentation for anything current, or if you can get a Z80 but not anything current. (One particular case of this last is if the microcontrollers you have access to are all mask-programmed and don't have an "external access" pin like the 8048, 8051, and 80C196 family to force them to execute code from external memory. In that case the fact that the Z80 has no built-in code memory is an advantage instead of a disadvantage. But, if you can get Flash-programmed microcontrollers, you can generally reprogram their Flash.) Incidentally, the Z80 itself "only" uses about 500 milliwatts, and there are Z80 clones that run on somewhat less power and require less extensive external supporting circuitry. (Boston Scientific's pacemakers run on a Z80 softcore in an FPGA, for example, so they don't have to take the risk of writing new firmware.) But the Z80's other drawbacks remain.

ewzimm 2y ago
I appreciate the thought and detail you put into these responses. That's beyond the scope of what I anticipated discussing. The types of things I had in mind are old techniques that people use for processing materials, like running a primitive forge or extracting energy from burning plant material or manual labor. What's the energy efficiency difference between generating electricity with a hand crank vs. a nuclear reactor? Even if you take into account all the inputs it takes to build and run the reactor, the overall output to input energy ratio is much higher, but it relies on a lot of infrastructure to get to that point. The type of efficiency I'm thinking of is precisely the energy required to maintain and run something vs. the work you get out of it. In the same way, while old computers are much less efficient, models like these that have been manufactured for decades and exist all over might end up being a better fit in some cases, even with less efficiency. I can appreciate that the integration of components in newer machines like the ATSAMD20 can reduce complexity in many ways, but projects like CollapseOS are specifically meant to create code that can handle low-level complexity and make these things easier to use and maintain. The Z80 voltage is 5V+/-5%, so right around what you were thinking. Considering the precision required for voltage regulation required is smart, but if you were having to replace crystals, they are simple and low frequency, 2-16Mhz, and lots have been produced, and once again the fact that it uses parts that have been produced for decades and widely distributed may be an advantage. Your point about documentation is a good one. It does require more complicated programming, but there are plenty of paper books out there (also digitally archived) that in many situations might be easier to locate because they have been so widely distributed over time. If I look at archive.org for ATSAMD20 I come up empty, but Z80 gives me tons of results like this: https://archive.org/details/Programming_the_Z-80_2nd_Edition_1980_Rodnay_Zaks/page/29/mode/2up https://archive.org/details/Programming_the_Z-80_2nd_Edition... Anyway, thank you again for taking so much time to respond so thoughfully. You make great points, but I'm still convinced that it's worthwhile to make old hardware useful and resilient in situations where people have limited access to resources, people who may still want to deploy some forms of automation using what's available. Projects like this one will hopefully never be used for their intended purpose, but they may form a basis for other interesting uses of technology and finding ways to take advantage of available computing resources even as machines become more complicated.
- 2y ago

by kragen 2y ago

ewzimm 2y ago

I appreciate the thought and detail you put into these responses. That's beyond the scope of what I anticipated discussing. The types of things I had in mind are old techniques that people use for processing materials, like running a primitive forge or extracting energy from burning plant material or manual labor. What's the energy efficiency difference between generating electricity with a hand crank vs. a nuclear reactor? Even if you take into account all the inputs it takes to build and run the reactor, the overall output to input energy ratio is much higher, but it relies on a lot of infrastructure to get to that point. The type of efficiency I'm thinking of is precisely the energy required to maintain and run something vs. the work you get out of it. In the same way, while old computers are much less efficient, models like these that have been manufactured for decades and exist all over might end up being a better fit in some cases, even with less efficiency. I can appreciate that the integration of components in newer machines like the ATSAMD20 can reduce complexity in many ways, but projects like CollapseOS are specifically meant to create code that can handle low-level complexity and make these things easier to use and maintain. The Z80 voltage is 5V+/-5%, so right around what you were thinking. Considering the precision required for voltage regulation required is smart, but if you were having to replace crystals, they are simple and low frequency, 2-16Mhz, and lots have been produced, and once again the fact that it uses parts that have been produced for decades and widely distributed may be an advantage. Your point about documentation is a good one. It does require more complicated programming, but there are plenty of paper books out there (also digitally archived) that in many situations might be easier to locate because they have been so widely distributed over time. If I look at archive.org for ATSAMD20 I come up empty, but Z80 gives me tons of results like this: https://archive.org/details/Programming_the_Z-80_2nd_Edition_1980_Rodnay_Zaks/page/29/mode/2up https://archive.org/details/Programming_the_Z-80_2nd_Edition... Anyway, thank you again for taking so much time to respond so thoughfully. You make great points, but I'm still convinced that it's worthwhile to make old hardware useful and resilient in situations where people have limited access to resources, people who may still want to deploy some forms of automation using what's available. Projects like this one will hopefully never be used for their intended purpose, but they may form a basis for other interesting uses of technology and finding ways to take advantage of available computing resources even as machines become more complicated.

2y ago