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I decided to build a nine-bit computer

madned.substack.com

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Re: I decided to build a nine-bit computer

#41

Post by emteycz »

andai wrote: post #18
PragmaticPulp wrote: post #16

Earlier quoted context omitted.

Basically anything with significant real-time requirements or high bandwidth requires an external FPGA or microcontroller. Embedded Linux is great, but if you’re trying to do something like read from a high-speed ADC then the only way to do it is with an FPGA. The FPGA reads from the ADC at precise intervals and buffers the data. The embedded Linux system can then periodically read the buffer with all of the jitter a…

Noob question, in this instance would a realtime OS or a unikernel also solve the problem?

The problem is, machine code is not the lowest level, there is also processor microcode. Machine code doesn't give you a hard real-time guarantee, the execution is still too approximate. FPGA enables you to work on/below the microcode level.

Re: I decided to build a nine-bit computer

#42

Post by IncRnd »

einpoklum wrote: post #25

> I decided to build a nine-bit computer Somehow I was sure that sentence was going to end with "... in MineCraft!"

Here is a computer created in MineCraft! Wow, it's actually v5.0. The intro starts at 1:22. [1]

[1] https://www.youtube.com/watch?v=SbO0tqH8f5I

Re: I decided to build a nine-bit computer

#45

Post by thehappypm »

mad_ned wrote: post #21
thehappypm wrote: post #13

Unbelievably tangential but your dog is very cute and I want to see more pictures!

Wish granted! @the.bessie.report on Instagram

I love this account! My dog also is a great pup, with some behaviors we’re working on, like barking and reactivity. From the scenery it looks like central MA if I had to guess too!

Re: I decided to build a nine-bit computer

#48

Post by googamooga »

pjdesno wrote: post #22

Long ago I interned for the group supporting the C-30 ARPANET IMP. At one point the IMP was a 16-bit machine, emulating the old Honeywell (?) minicomputer that the original IMP code was written for. At some point they needed more memory, so they lashed on another 4-bit bit slice, and it became a 20-bit machine. There was an alternate microcode load for it, which implemented an instruction set similar to that of a PDP…

I have working PDP-11/23 in my possession and last couple of months I’m trying to convince myself that I have enough soldering skills to solder four additional memory lanes on its backplane to increase memory limit from 256KB to 4096KB. Otherwise even though I install a processor able to work with 22bit addresses only 18bit addressing will be available.

Re: I decided to build a nine-bit computer

#49

Post by kragen »

buescher wrote: post #14
googamooga wrote: post #7

Ternary logic based computer Setun with 9-bit "bytes" was developed in late fifties in the USSR. Not much info on about it in English, unfortunately. https://en.wikipedia.org/wiki/Setun

Ternary on binary systems usually uses a 2-bit "trit" with an extra potential state. That's even how the later Setun machines did it, from what I understand. Oh yes, and the Soviets even developed their own trinary Forth dialect for them.

Even the original Setun machine worked that way, as it turned out, if we believe Willis Ware's contemporary report on Soviet computers.

Re: I decided to build a nine-bit computer

#50

Post by malkia »

jacquesm wrote: post #34

https://en.wikipedia.org/wiki/UNIVAC_1100/2200_series Had a 36 bit word length resulting in a 9 bit 'byte'.

I was coming to mention this, though I think my memory goes back to some LISP machine (and was related to car/cdr and related encoding if I'm not mistaken)
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