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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

#61

Post by nsxwolf »

reaperducer wrote: post #59
jbboehr wrote: post #55

Earlier quoted context omitted.

> "what I have is so valuable that other people want to take it!" While I do agree this may apply somewhat to the original topic, your dig at suburbanites seems like a mischaracterization. Perhaps the upper/upper-middle classes feel this way. I would expect most other folks are primarily worried about being murdered during the event.

While I do agree this may apply somewhat to the original topic, your dig at suburbanites seems like a mischaracterization. I would expect most other folks are primarily worried about being murdered during the event. With the murder rate in America near historic lows, I think the person you're replying to is spot-on. It's a lot of hysteria fueled by social media, foreign actors, and the fact that security paranoia is…

These statistics do not help anyone create a reasonable personal risk assessment.

Murder is at an all time low! But my sister in law is a drug addict, and last year she got mad so her boyfriend shot and killed a family member right in their nice suburban foyer.

There's more to it than that.

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

#62

Post by jiveturkey »

ynoxinul wrote: post #20
jiveturkey wrote: post #14

> Fixing the frame length doesn’t have any effect on higher-level protocols because they encode the packet size in their headers and do not rely on the actual Ethernet frame length. Interesting. I just wrote a packet decoder and I specifically verify at each layer that the lower layer length matches. So for IP, in my decoder the IP datagram length must match exactly the ethernet frame length + link layer header. I di…

I'm sending my long frames out to the network and no OS I have has any problem with that. I've read somewhere that long frames are actually used by some routers to store metadata after the packet.

wireshark doesn’t complain either?

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

#63

Post by dboreham »

SAI_Peregrinus wrote: post #35
mogoh wrote: post #31

Sorry for this naive question, but isn't every network card build out of discrete logic components?

No, most use much more complicated ICs. This isn't fully discrete (individual transistors, diodes, etc.) but only uses 7400-series logic ICs, not ASICs.

> isn't fully discrete (individual transistors, diodes, etc.) but only uses 7400-series logic

Which is exactly what "discrete logic" means.

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

#64

Post by dboreham »

RetroTechie wrote: post #32
heinrichhartman wrote: post #28

Earlier quoted context omitted.

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

> What does "discrete logic" mean in this case? 74xx series ICs (eg. 74ACT family in case of the cpu, if I read correctly). More generally, it may refer to "basic logic elements whose function is easily inspected". > Why would this prevent interrupts? Not at all - in theory. In practice, interrupt support tends to complicate cpu designs. Complicate = more logic = more ICs. So builder decided against it & chose not to…

Just to clarify: CPUs built with discrete logic can definitely have interrupts (e.g. PDP-11/45, VAX 11/780).

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

#65

Post by ynoxinul »

jiveturkey wrote: post #62
ynoxinul wrote: post #20

Earlier quoted context omitted.

I'm sending my long frames out to the network and no OS I have has any problem with that. I've read somewhere that long frames are actually used by some routers to store metadata after the packet.

wireshark doesn’t complain either?

Of course not. Long frames are totally valid.

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

#66

Post by 15155 »

yjftsjthsd-h wrote: post #46

So this is for an all-custom computer, which is rather more impressive on its own (to say nothing of "So I made a C compiler."), but now I'm curious what the minimal implementation of an ethernet card for a "normal" PC would be. I suspect a lot of it would be very similar, up to that you could do checksums on the PC's CPU (probably just baked into the driver). It'd need to be attached - either bare serial or more use…

Implementing NICs in FPGAs (typically with PCIe attachment) is super common.

Regarding USB: CDC-NCM isn't hard to implement in any MCU but implementing a USB HS PHY basically requires ASIC hardware.

If you use a $0.30 USB HS ULPI PHY, one could implement USB CDC-NCM in an FPGA pretty easily.

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

#67

Post by 15155 »

pjc50 wrote: post #50
yjftsjthsd-h wrote: post #46

So this is for an all-custom computer, which is rather more impressive on its own (to say nothing of "So I made a C compiler."), but now I'm curious what the minimal implementation of an ethernet card for a "normal" PC would be. I suspect a lot of it would be very similar, up to that you could do checksums on the PC's CPU (probably just baked into the driver). It'd need to be attached - either bare serial or more use…

USB is arguably much more complicated than 10base2 internet, which pre-dates it by a long way. In fact, if you're trying to use either PCIe or USB to connect to a 10base2 ethernet network, either of those will be far more work than the Ethernet side. You might be able to persuade a FTDI-style USB device to bit-bang 10base2 Ethernet for you. You'd implement a "PHY" side which translates the wire traffic to a clean bit…

USB LS/FS are pretty implementable in select FPGAs and MCUs without a dedicated PHY.

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

#68

Post by mrob »

dboreham wrote: post #63
SAI_Peregrinus wrote: post #35

Earlier quoted context omitted.

No, most use much more complicated ICs. This isn't fully discrete (individual transistors, diodes, etc.) but only uses 7400-series logic ICs, not ASICs.

> isn't fully discrete (individual transistors, diodes, etc.) but only uses 7400-series logic Which is exactly what "discrete logic" means.

Although they're not common nowadays, the 7400 series includes some more highly integrated parts, including a complete ALU. There's no exact criteria for what "discrete logic" means, but I don't think anybody would accept a complete integrated ALU. To me, it means things like gates, multiplexers, or flip-flops: things that can be made with a few tens of transistors at most.

"Discrete logic" computers usually use integrated RAM chips, but seeing as RAM is usually drawn separately from logic on block diagrams, I think this is still acceptable. However, the popular trick of using an EEPROM as a giant lookup table for your ALU is in my opinion not "discrete logic".

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

#69

Post by dspillett »

pbronez wrote: post #52
frabert wrote: post #13

Earlier quoted context omitted.

Lack of motivation to work on more technical stuff after having done the same all day at work? Mental exhaustion? Wanting to spend the remaining free time with loved ones instead?

I’ve found it empowering to say “this is fascinating to me, and I would enjoy spending significant time diving into it, but I choose not to prioritize that right now.” This works much better for me than simply griping that “I don’t have time to X”. It acknowledges that I COULD make time for X, but it isn’t worth the current cost.

As I slowly dig myself out of a little burn-out rut, I am trying to develop this sort of reaction as a habit.

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

#70

Post by fsckboy »

ynoxinul wrote: post #58
yjftsjthsd-h wrote: post #46

So this is for an all-custom computer, which is rather more impressive on its own (to say nothing of "So I made a C compiler."), but now I'm curious what the minimal implementation of an ethernet card for a "normal" PC would be. I suspect a lot of it would be very similar, up to that you could do checksums on the PC's CPU (probably just baked into the driver). It'd need to be attached - either bare serial or more use…

If a normal PC had an ISA bus (like they did 30 years ago), my network card could have been connected to it with just some minor modifications.

not being pedantic, just rounding out the record, ISA's follow-on, EISA, had already been around a while and was already sunsetting 30 years ago because PCI had already been invented. VESA also was ending its brief flash of glory.
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