[Keyframe]

If OP or anyone else wants to see this firsthand.. well shit, I feel old now, but.. try an exercise into assembly programming of commodore 64. Get a VICE emulator and dig into it for a few weeks. It's real easy to get into, CPU (6502 based), video chip (VIC II), sound chip (famous SID), ROM chips.. they all love in this address space (yeah, not mentioning pages), CPU has three registers.. it's also real fun to get into, even to this day.

[jeroenhd]

There's a nice guide by Ben Eater on Youtube about a breadboard computers: https://www.youtube.com/playlist?list=PLowKtXNTBypFbtuVMUVXN...

It doesn't sport any modern features like DMA, but builds up from the core basics: a 6502 chip, a clock, and a blinking LED, all hooked up on a breadboard. He also built a basic VGA card and explains protocols like PS/2, USB, and SPI. It's a great introduction or refresher into the low level hardware concepts behind computers. You can even buy kits to play along at home!

[porknubbins]

I was going to say, watching Ben Eater and building his 6502 machine myself filled in so many gaps in knowledge or fuzzy areas around basic computer hardware. If OP sees this he should definitely consider building some of these after Nand2Tetris.

[656565656565]

This! except I (slightly redesigned and) built a common z80 setup, no comparison for knowledge gained from this single effort.

[zokier]

Is my understanding correct that compared to those historical architectures, modern GPUs are a lot more asynchronous?

What I mean that these days you'd issue a data transfer or program execution on the GPU, they will complete at its own pace and the CPU in the meanwhile continues executing other code; in contrast in those 8 bitters you'd poke a video register or whatev and expect that to have more immediate effect allowing those famous race the beam effects etc?

[simne]

It depends.

First, in modern systems you usually don't have direct access to GPU, but call syscall and than happen magic, something like this. And they all are multilayered architecture, mean, now normal, when systrace dump of some exception lists few hundreds functions, imagine how this slow.

This is because all modern systems except consoles, are direct descendants of business minicomputers, in which where most important, they could simultaneously run wallet and text processor (or electronic table, or email, etc), and these programs will not see each others memory, so errors in text will not lead to lost money from wallet.

Second, modern systems behave like NUMA architectures, or some people even named them distributed architectures, mean, that only CPU computing in userspace is fast.

In many cases you have choice, to do magic in sync way or async, but in any case, syscalls are extremely slow, in some cases could be few magnitudes slower than userspace CPU computing.

Sometimes lifesaver some sort of message passing architecture, so you send message to GPU and immediately could do your tasks without any waits at all (kernel periodically check messages mailboxes of all processes and when happen your turn it will read your message and do things and write answer).

But message passing is now rare, mostly as I know, used paradigm of direct syscall, and async means, kernel release your process just after receive syscall, sync means, your process will be released only after syscall finished processing data.

In 8bit systems, cpu frequency where very low, sometimes fraction of bus speed and there where very few layers, basically userlevel program could directly access hardware. So even formally their behavior named synchronous, but in reality they where very fast in most cases, except understandable waits, like when Atari ANTIC access videoram when you also trying to do that.

Reliability issues in 8bit and in consoles solved very simple ways - first, most where capable to run only one program, and second, console software where extremely reliable, and expensive, much more reliable than business software, sometimes exceeds reliability of military software or mainframe system software.

[Keyframe]

There were interrupts telling you when certain things happened. If anything, it was asynchronous. Big thing is also that you had to tally the cost of what you eere doing. There was a budget of how many cycles you got per line, per screen and then fit whatever you had to in that. With playing sound it was common to draw color when you fed the music into SID so you could tell, like a crude debug/ad hoc printf, how many cycles your music routines ate.

[vletal]

Nice exercise. Similarly I learned most about basic computer architecture by programing 8050 in ASM as well as C.

And I'm 32. Am I old yet? I'm not right? Right?

[silisili]

Sorry pal!

I remember playing Halo in my early 20's, and chatting with a guy from LA who was 34. Wow, he's so old, why was he still playing video games.

Here I sit in my late 30's...still playing games when I have time, denying that I'm old, despite the noises I make getting up and random aches and pains.

[vletal]

OK. I am definitely old...

- I have mostly no joy playing video games anymore these days.

- I found myself refusing some contemporary stuff in favour of stuff "I am used to".

Damn! I was always looking at my dad, not understanding that very same things :) Now I am a dad myself...

[silisili]

Haha same. I think the problem is that it seems to hit you all at once. I was pretty open minded and go with the flow until at least my early 30s, now I hate any kind of change at all.

Re: video games, I had a similar experience but play for different reasons. I used to have fun blasting people and chatting on xbox live... don't enjoy any of that anymore. All single player for me, and no FPS. A cool physics game like Rocket League(admittedly, not single player), or a puzzle game like The Turing Test, or a mystery game like Kona are way more interesting to me than say, Call of Duty.

[copperx]

> Am I old yet? I'm not right? Right?

Yes, but being old isn't bad. I, for one, long for the day when I'll be unable to produce and contribute to society.

[Keyframe]

40s are new thirties, my friend. Also, painkillers help.