The Soul of an Old Machine: Revisiting the Timeless von Neumann Architecture

[1] http://www.polybus.com/hdlmaker/Resume.html

[0] https://bits.ashleyblewer.com/halt-and-catch-fire-syllabus/

"He traveled to a city, which was located, he would only say, somewhere in America. He walked into a building, just as though he belonged there, went down a hallway, and let himself quietly into a windowless room. The floor was torn up; a sort of trench filled with fat power cables traversed it. Along the far wall, at the end of the trench, stood a brand-new example of DEC’s VAX, enclosed in several large cabinets that vaguely resembled refrigerators. But to West’s surprise, one of the cabinets stood open and a man with tools was standing in front of it. A technician from DEC, still installing the machine, West figured.

Although West’s purposes were not illegal, they were sly, and he had no intention of embarrassing the friend who had given him permission to visit this room. If the technician had asked West to identify himself, West would not have lied, and he wouldn’t have answered the question either. But the moment went by. The technician didn’t inquire. West stood around and watched him work, and in a little while, the technician packed up his tools and left.

Then West closed the door, went back across the room to the computer, which was now all but fully assembled, and began to take it apart.

The cabinet he opened contained the VAX’s Central Processing Unit, known as the CPU—the heart of the physical machine. In the VAX, twenty-seven printed-circuit boards, arranged like books on a shelf, made up this thing of things. West spent most of the rest of the morning pulling out boards; he’d examine each one, then put it back.

..He examined the outside of the VAX’s chips—some had numbers on them that were like familiar names to him—and he counted the various types and the quantities of each. Later on, he looked at other pieces of the machine. He identified them generally too. He did more counting. And when he was all done, he added everything together and decided that it probably cost $22,500 to manufacture the essential hardware that comprised a VAX (which DEC was selling for somewhat more than $100,000). He left the machine exactly as he had found it."

The other two docking stations were built differently and had the wires run somewhere else.

EDIT: Typo

I remember this happening all the time in meetings. Every few minutes, the conversation would stop because a phone call was coming in and all the conference room phones started buzzing. One of those things that just fades away so you don't notice it coming to an end.

The solution I picked was to put the machine in Text/Graphics mode (instead of normal character rom text mode, this was back in the MS-DOS days), so the vertical sync rate then matched up with the swirling EM fields, and there was almost zero apparent motion.

The. I had to walk all the way back to the terminal room, and was a lot more careful the next time.

Neural network: created via training, does amazing things but (this is the area my knowledge is too small) it's bloody hard to decipher why is it doing the thing it does.

"Traditional" programming: you can (as in article) explain it down to the single most basic unit.

The events are covered in great detail in Jean Jennings Bartik's autobiography "Pioneer Programmer", according to her von Neumann really wasn't that instrumental to this particular project, nor did he mean to take credit for things -- it was others that were big fans of his that hyped up his accomplishments.

I attended a lecture by Mauchly's son, Bill, "History of the ENIAC", he explains how eniac was a dataflow computer that, when it was just switches and patch cables, could do operations in parallel. There's a DH Lehmer quote, "This was a highly parallel machine, before von Neumann spoiled it." https://youtu.be/EcWsNdyl264

[1] https://cloud.google.com/blog/products/ai-machine-learning/a...

[2] https://aws.amazon.com/blogs/aws/amazon-ecs-now-supports-ec2...

The goal of an FPGA is to get a signal through the chip in as few nanoSeconds as possible. It would be insane to rip out that hardware in that case.

However.... I care about throughput, and latency usually doesn't matter much. In many cases, you could tolerate startup delays in the milliseconds. Because everything is latched, clock skew isn't really an issue. All of the lines carrying data are short, VERY short, thus lower capacitance. I believe it'll be possible to bring the clock rates up into the Gigahertz. I think it'll be possible to push 500 Mhz on the Skywater 130 process that Tiny Tapeout uses. (Not outside of the chip, of course, but internally)

[edit/append]

Once you've got a working BitGrid chip rated for a given clock rate, it doesn't matter how you program it, because all logic is latched, the clock skew will always be within bounds. With an FPGA, you've got to run simulations, adjust timings, etc and wait for things to compile and optimize to fit the chip, this can sometimes take a day.

You compare apples with carrots.

Question is what you name CISC/RISC. If under CISC considered early single-chip stubs like 8080 or even x86 before AMD64, this is one history, but if CISC are IBM/360,/370,/390 and DEC PDP-11 or later, this is totally other drama. Same is with RISC.

What really important, genuine CISC typically have human-friendly instruction set, and even /360 assembler is comparable to C language; many RISCs are load/store architectures, don't have rich memory addressing modes, so by definition tied to work inside registers. Also, when compare similar level of manufacture and similar timeline, will easy see, 68k series have just 8 registers, but same era RISCs have at least 16.

Ideally, your working set fits into the registers, and that was most win feature or RISC, having relatively simple hardware (if compared to genuine CISC, like IBM-360 mainframes) they saved significant space on chip for more registers.

- Register-register operations are definitely avoid memory wall, so data cache become insignificant.

Sure, if we compare comparable, not apples vs carrots.

As a native English speaker, it was understandable but feels rather foreign because you never hear parts of computers referred to that way these days.