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Show HN: I made a discrete logic network card

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Re: Show HN: I made a discrete logic network card

#21

Post by ynoxinul »

artirdx wrote: post #10
ynoxinul wrote: post #3

Earlier quoted context omitted.

Building the network module took about a month, but writing the compiler took much more time.

Very impressive! Could you share some books, training, experiences that helped you reach this stage so a hobbyist could catch up? There are so many parts - compiler design, basic electronics, computer architecture etc. Maybe a blog post.

I have a CS/applied math background, my main job is software development, so I don't have problems with the software part. If you are interested in compiler design specifically, you can find a lot to read or to watch online.

When building my system, I was inspired by 8 bit retro computers like ZX Spectrum. Their architecture is straightforward and easy to understand.

Electronics just fascinates me, but I can't really point out a single source which gave me the insight. A lot of playing around with transistors, microcontrollers, logic gates gives the intution how to design stuff.

Re: Show HN: I made a discrete logic network card

#22

Post by RetroTechie »

Very cool stuff!

Only nitpick I'd have is that author decided to use a custom-design cpu.

Ok, "discrete logic only!" is a valid choice. And then keeping complexity to a minimum weighs heavily. But the downsides of that choice are also considerable:

-No interrupts (which are very useful)

-No existing software base to tap from. Somewhat-useful C compiler helps.. somewhat.

But who am I to question author's choices for a hobby project like this? Great stuff in any case.

Re: Show HN: I made a discrete logic network card

#24

Post by ynoxinul »

RetroTechie wrote: post #22

Very cool stuff! Only nitpick I'd have is that author decided to use a custom-design cpu. Ok, "discrete logic only!" is a valid choice. And then keeping complexity to a minimum weighs heavily. But the downsides of that choice are also considerable: -No interrupts (which are very useful) -No existing software base to tap from. Somewhat-useful C compiler helps.. somewhat. But who am I to question author's choices for a…

I started with a CPU and then built everything else around it. Using something like a Z80 just doesn't seem fun for me.

Re: Show HN: I made a discrete logic network card

#25

Post by JonChesterfield »

Towards the end is a link to a C compiler built for this project. https://github.com/imihajlow/ccpu-cc. Seems to have a linker and a libc as well. I have no real understanding of how complicated the hardware design part is but casually throwing a C compiler together is great.

Re: Show HN: I made a discrete logic network card

#26

Post by lionkor »

JonChesterfield wrote: post #25

Towards the end is a link to a C compiler built for this project. https://github.com/imihajlow/ccpu-cc . Seems to have a linker and a libc as well. I have no real understanding of how complicated the hardware design part is but casually throwing a C compiler together is great.

A C compiler written in Rust, in which the lang_c crate is used to parse the language.

Re: Show HN: I made a discrete logic network card

#27

Post by formerly_proven »

Physically a lot smaller than DEC's first SSI Ethernet card(-set): https://i.ebayimg.com/images/g/NEYAAOSw-mZlg0lZ/s-l1600.jpg (DEC DEUNA, those boards are over a foot long), though also a lot fewer features. DEUNA is a "real" NIC, it has tx/rx queues and handles all that autonomously. Does DMA, too. It of course comes with it's own on-card PDP-11 to run it.

Re: Show HN: I made a discrete logic network card

#28

Post by heinrichhartman »

RetroTechie wrote: post #22

Very cool stuff! Only nitpick I'd have is that author decided to use a custom-design cpu. Ok, "discrete logic only!" is a valid choice. And then keeping complexity to a minimum weighs heavily. But the downsides of that choice are also considerable: -No interrupts (which are very useful) -No existing software base to tap from. Somewhat-useful C compiler helps.. somewhat. But who am I to question author's choices for a…

What does "discrete logic" mean in this case? Why would this prevent interrupts?

Re: Show HN: I made a discrete logic network card

#29

Post by _factor »

A network card with opaque firmware is a 0-day away from becoming a global catastrophe.

Even RISC-V based switches like the Vega use proprietary switch chips (Wuhan China designed FSL91030M specifically), which is no better.

You can verify input/output to a certain extent, but this doesn’t preclude a timer based function call or a tailored packet activation.

I wonder why our society tolerates these unknowns. With the push towards WiFi replacing the majority of home networking, I’m not confident it will change any day soon.

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