51–60 of 70 posts
I love how the NOR gate is made visibly of two transistors.
Makes it pretty hard to hide an Internet backdoor in it. Seriously, I wonder if this is a way to make a secure and open computer, by implementing the deepest level of security functionality in slow but visibly trust-able hardware.
It is a fun project, but it is kind of a lie. Looking at the block diagram, there is a counter which addresses the microcode.
Why one would do this? Probably for fun; There’s no practical application of this that I can see.
What sort of simulator is required to go from “running” to ordering a prototype board 26 days later? I had assumed physical breadboards and wires and chips were always necessary to prototype... 2019-11-02 The first version of the MyNOR simulator is running. The circuit works! 2019-11-17 I have finished the work on the microcode. I added support for MyNOR to my cross-assembler myca. 2019-11-28 PCB layout completed. A…
When I was in university, we used Logisim[0] for our intro to digital logic class. I think you could probably simulate such a computer in this tool if you wanted something intuitive. Otherwise you can prepare your design in a high level logic language like Verilog and test it using Verilator [1]. Naturally there is always a risk when going from running in a simulator to the real PCB. [0] http://www.cburch.com/logisim…
Earlier quoted context omitted.
Solderless breadboards are the equivalent of exploratory programming. If you know what you want to make you might as well go for a PCB (you can simulate the logic quite nicely these days).
This doesn't work for high speed designs though. Probably anything over 20MHz will be difficult to make useful on a breadboard.
I wonder why he chose to use a discrete TTL gate for the ALU's nor gate instead of just another 74HC series IC.
Earlier quoted context omitted.
Makes it pretty hard to hide an Internet backdoor in it. Seriously, I wonder if this is a way to make a secure and open computer, by implementing the deepest level of security functionality in slow but visibly trust-able hardware.
While simplicity of design can engender trust, in this case it's the stuff around it that still needs complexity. Besides, people have already demonstrated single-gate backdoors that don't show up in most IC die photos.
Source? Not that I don't believe you, but the idea sounds fascinating
I love how the NOR gate is made visibly of two transistors.
Makes it pretty hard to hide an Internet backdoor in it. Seriously, I wonder if this is a way to make a secure and open computer, by implementing the deepest level of security functionality in slow but visibly trust-able hardware.
https://www.youtube.com/watch?v=RkTvDjhImwo
Here's how that is doing it:
https://www.youtube.com/watch?v=mzDTZuFJYX4
He's got several more, including this one which doesn't even use switches. You just tap the wire to toggle the LEDs:
https://www.youtube.com/watch?v=WvXKSSmItls
I have no idea how that one works.