This is so much better not being a programmer, and having no context. I just get to watch this get posted and people are enjoying whatever the fuck this is, and that makes me happy
TBF this is not really about programming. You have to be knowledgeable about how computers work and their history for this one.
Okay, so go on... I, too, am hardly a programmer yet hangs out here anyway and have no idea of what this is all about, haha.
The weird text the main bird is rattling off it something called "Assembly". Many programming languages don't really tell the computer what to do, they more or less outline the behavior they want, and then another program called a compiler turns that into 1s and 0s that a computer can actually understand. If you've ever heard of binary, that's what these 1s and 0s are. Assembly is one level of abstraction* above the 1s and 0s. It is a good way for humans to understand what a computer is actually doing without having to look at the original programming code, and without 1s and 0s. So the main bird represents a computer doing it's thing, running some program.
Then comes the crow with a "Hello It's me. The Keyboard! Someone pressed the letter e." The crow represents something called an interrupt, which is exactly what it sounds like. It interrupts the normal flow of a program to signal to a computer "Hey, you need to deal with this. Like, now."
The reason why he is a keyboard is because that is how old keyboards used to work. Before USB ruled the world, mice and keyboards used something called a PS2 port. If you ever saw an old mouse or keyboard with a green or purple plug on one end instead of a USB, then that's the old style we are talking about.
Modern USB keyboards are a little more polite and will wait in a line until the computer is ready to deal with whatever the human just typed, but old PS2 keyboards used interrupts to demand attention. This was really important for old slow computers that needed to respond to user input ASAP. Modern computers can handle that sort of thing a little bit better.
I think that is enough context to understand the meme.
*Not really: see ISA layer and micro-ops for more information
This is a great explanation!
But I do have to say, you darn kids with your fancy newfangled PS/2 input.. in my days we had proper serial or DIN ports!
I saw a computer with a parallel port at work the other day.
No idea why it had it, it also had a couple blue USB3 ports. Also VGA and HDMI, and a bicolour PS/2. Damn weird mainboard.
Zoomer intern was wondering what it was and I got to tell him about parallel and serial and all that. Made me feel nostalgic. And old.
"Work" computers will often have legacy ports because maybe you need it to connect to some old printer.
There are a lot of places still using old-style dot matrix printers or other weird old hardware. Point-of-sale systems made to this day often come with a bunch of serial, or not quite serial, ports.
Ohhhhhhh.
Huh.
Also, wasn't it even once stylized like "PS/2," come to think of it? I did very vaguely remember learning about interrupts (as nouns, lol), but this makes it far clearer, thanks!
There's a Youtube channel called Ben Eater that does a great job of explaining computing from first principles. He built a computer out of discrete components on breadboards. He also has a great series where he wires up a 6502 microprocessor and basically builds a little 8-bit microcomputer around it, again on breadboards, in a way that you'll get. He sells them as kits, so you can play at home if you want. They're also just nice educational evening calm time viewing.
Yup, it was fully known as IBM PS/2, for "Personal System 2". IBM wasn't happy about how the original PC system got cloned to hell and back, so they designed a more proprietary and patentable system. Suffice to say it was a massive failure, what with it being incompatible with basically all of third party hardware. But the keyboard and mouse ports were widely regarded as a good idea! (and probably not as patentable)
I’m surprised no one interrupted you 🤔
I wonder how many people think this meme is about autocorrect for "mov".
You’re the sane one, unbroken by the Knowledge.
Such an interrupting crow
"knock knock"
"Who's there"
"The interrupting cow"
"The interrupting cow wh.." "MOOOOOOO"
Immediately pushes FLAGS, CS, and IP onto the stack, clears IF, and jumps to the cow Service Routine at 0x0000:0x0040
I thought of a better version: Immediately stacks everything I'm carrying and jumps on the cow
It's the CORVID-19
This irqs me
The thing that bothers me the most here is that the meme is using 64bit assembly instructions, which did not exist at the time keyboards were using IRQs to communicate. 🤣
Did they upgrade PS/2 to use something other than interrupts? Because my earliest 64-bit CPU was in a computer manufactured in the early 00s and I'm pretty sure that mobo still had actual PS/2 ports, not USB converters or something.
I viscerally recall, and don't think kids now will ever fully comprehend the one week where all 4 wheels fell off the meme bus and this was what people were literally posting. I'm legitimately triggered.
I remember laughing at this meme and now I turn my nose up at 6-7
USB keyboards yelling into the void in the background hoping to be noticed.
This is legit the biggest lol. Yes I’m aware this is the PS/2 path only and today it’s actually polling on USB or Bluetooth keyboards but this really tickled me. The face of that CPU bird!
I used to game with a guy that swore by ps/2 keyboard for the interrupt supposedly making his inputs easier to perfectly time, but he got into a heated argument with my other gaming buddy over whether or not his mobo just had a usb ps/2 port that was basically a built in adapter and I never heard from either of them since.
I wish arch was a thing back then so I could have thrown in the standard line and have the last laugh.
This is funnier than it is. :)
I can't explain but these birds have Toronto accents
Can someone smarter than me explain what mov rax, rbx. Does it read keyboard input?
It moves the value of register (a CPU memory cell) rbx to register rax. It's not that important though.
Basically the comic shows that the CPU is happily chugging along, executing instructions when suddenly the keyboard sends an interrupt telling the CPU it must stop all work and listen to whatever it has to say.
That was how keyboards worked before USB (back when they used PS/2 or DIN connectors). With USB it's the other way around: the device gets polled X times per second to check if it has any data to send.
Iirc the south bridge now aggregates masked interrupts and groups them together instead of pestering the CPU a whole bunch
It's irrelevant to the humor, it's just an arbitrary x86 instruction. The point is that keyboard inputs (with a PS/2 keyboard) interrupt whatever the computer is doing
Though to answer your question, it moves the value from the rbx register to the rbx register
Oh ok, I didn't know keyboards used to do that
These are some assembly instructions that the computer is happily running with no keyboard input. The keyboard input is then coming in as an interrupt demanding immediate processing which is silencing the poor background bird process.
Uh-oh! We might have a STUCK NMI ERROR on our hands here.
USB keyboards don't use interrupts, but instead poll at a fixed frequency.
Technically, interrupts are still often involved... just from the USB controller on the state of the polling instead of the keyboard directly on a keypress
Some keyboards implement the USB Boot Keyboard profile specified in the USB Device Class Definition for Human Interface Devices (HID) v1.11 and are explicitly configured to use the boot protocol. These are limited to 6-key rollover (6KRO) and will interrupt the CPU every time the keyboard is polled (even if there is no state change) unless the USB controller is programmed to tell the keyboard to respond with negative acknowledgments, which the USB controller discards in hardware without interrupting the CPU, when there are no state changes to report
https://en.wikipedia.org/wiki/USB_human_interface_device_class#Keyboards
Is this assembly?
not sure, i'll have to ask my machine about it, this seems to be their level
IRET
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