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pedrolins

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Ask HN: Books about the little guy beating the big guy?

2 points·by pedrolins·2 anni fa·4 comments

Ask HN: How does an OS become aware of memory layout?

2 points·by pedrolins·3 anni fa·2 comments

Ask HN: How does a CPU communicate with a GPU?

148 points·by pedrolins·4 anni fa·98 comments

Ask HN: Advice on a live video processing project

3 points·by pedrolins·4 anni fa·4 comments

comments

pedrolins
·8 mesi fa·discuss
> How do these people stay motivated to do anything. It can't just be money, right?

It’s making money to spend quality time with loved ones and pay the bills. For some people that’s enough (no judgement).
pedrolins
·8 mesi fa·discuss
I was excited to check out lecture videos thinking they were public, but quickly saw that they were closed.

One of the things I miss most about the pandemic was how all of these institutions opened up for the world. Lately they have been closing down not only newer course offerings but also putting old videos private. Even MIT OCW falls apart once you get into some advanced graduate courses.

I understand that universities should prioritize their alumni, but there’s literally no cost in making the underlying material (especially lectures!) available on the internet. It delivers immense value to the world.
pedrolins
·2 anni fa·discuss
This is awesome! I’ve given up learning graphics programming in the past due to the fragmented ecosystem of libraries. It just felt overwhelming. This seems exactly what I’ve been missing.
pedrolins
·3 anni fa·discuss
This is amazing!! I've found myself writing selenium scripts to automate tasks for my dad's job (things such as getting a name from a spreadsheet, putting that name in a website's search box and from there repeating the same actions for 100s of names) and saved him a ton of time. Making browser automation more accessible by just showing the machine how to do it will definitely make lots of people's lives easier. Can't wait to mess around with it.
pedrolins
·3 anni fa·discuss
I was at a talk given by the president of Embraer-X (that's an Embraer subsidiary that looks into these riskier ventures), and he got into the details of how they validated their business plan of using these vehicles for urban transportation.

They offered helicopter rides to one of Rio's major airports and charged R$100 per passenger (according to him, that's an accurate estimate of future prices once they make their eVTOL) at a loss just to see if there was demand. They got booked the entire year in advance.
pedrolins
·3 anni fa·discuss
I have faced this myself, and the aimless excitement can create a lot of frustration in new programmers. Programming is a unique tool in the sense that it has the ability to glaringly show the programmer's lack (or wealth) of vision.
pedrolins
·4 anni fa·discuss
I have been journaling for 2 years on and off. In the beginning it had extremely positive effects on my development as a person.

After a while the sense of effectiveness that came from writing constantly started to fizzle out and I'd feel like going in circles in my writing.For a while, I wouldn't write and I'd feel guilt and would attribute negative aspects of my life to my lack of writing, which led me back to daily writing. This was a recurring thing in my life.

After a while I just concluded that the valuable thing journaling teaches you is the importance of exploring your ideas and thoughts. Doing it religiously or with harsh constraints is no good. There must be time to explore and to just do things for a bit - that until some sort of critical mass is reached or some idea shows up that you want to discuss.

I think what confuses a lot of people is what one means with "journaling". If it's just writing about your day, I don't see that much utility in it. Effective journaling ends up being an alternative name for writing and reflecting without objective in my experience.
pedrolins
·4 anni fa·discuss
I find it very interesting that you mention looking at the history of ISA's first in order to understand the current iteration of the technology.

I was reading the RISC-V privileged ISA recently and the amount of seemingly arbitrary registers and behaviours that must be implemented to support a UNIX-like OS is crazy, and that got me thinking about the history behind all of these things that the hardware must support in order to support the OS.

But thank you for the pointers, I'll definitely use this.
pedrolins
·4 anni fa·discuss
It doesn't really answer my question, but from what I've seen in the TOC I'd say it's equivalent to an introductory course on computer architecture + computer systems and some cryptography as well. Kind of an introduction (don't get me wrong with the word 'introduction', it covers a decent amount of material) to the most important concepts and technologies that guide computers and the internet.
pedrolins
·4 anni fa·discuss
Yeah, as I've read other responses to my post I've been able to better define my difficulties in understanding CPU-GPU communication. I was having a hard time separating the MMIO concept from the communications protocol that ties together all of these devices (based on what you've explained that'd be PCIe). I actually haven't learned about PCIe as of yet, so the way you've introduced the concept has set me up to further look into it, thanks.
pedrolins
·4 anni fa·discuss
Yeah, your explanation really hits the nail in regards to what I was trying to understand - MMIO coupled with all of that bus dynamic of a master and slave going on. It's clear to me now that my knowledge gap resides in not knowing enough about interconnects. Thanks a lot!

I do wonder, why aren't interconnects more emphasized in the courses I took? All I've seen was just oversimplified pictures of the process. Your explanation goes just enough into the lower-level aspects of the process to allow me to piece it.
pedrolins
·4 anni fa·discuss
Wow. Just skimmed across that chapter and that looks like a great resource. No wonder I couldn't find it in any of my searching sessions, I'd never think a book titled like that would cover hardware concepts so extensively. This will definitely help me in understanding buses better. Thank you.
pedrolins
·4 anni fa·discuss
I’m not an assembly programmer, but I’ve learned assembly as part of introductory CS courses (computer architecture classes) and the approachable alternative you’re looking for is the assembly language of a RISC architecture such as ARM, MIPS, or RISC-V. I’d recommend learning the latter because of how approachable it is.
pedrolins
·4 anni fa·discuss
It’s very unfortunate to read such a statement - Isaacson’s “The Innovators” is an amazing book that never lost its objectivity throughout my readings.
pedrolins
·4 anni fa·discuss
There's no particular reason for collecting images this way other than that's what the hardware I have allow (an ESP32CAM).

> There are super cheap cameras that output rtsp streams.

Yeah I forgot about that. I think that if I can't get my current setup to work I'll buy one, thanks for the advice. I didn't think of buying an RTSP camera because I thought these cameras were made for local networks only given that it's the standard protocol for security cameras (I didn't know what RTSP was until I actually started working on this)

> GStreamer is pretty neat for this sort of stuff. More flexible than FFMpeg for this sort of use case.

Thanks for the recommendation, I'll read their docs

> I also don't understand the "ffmpeg finishes .. mid-transmission" part .. are you getting chopped images in your video stream?

It's just that when I execute ffmpeg on my terminal in parallel with receiving + writing the image files to a folder, the ffmpeg process finishes (instead of continuing indefinitely as long as I'm receiving files) because it goes faster than the actual rate at which files are coming. I found that the -re flag tells ffmpeg to process files at the same frame rate of video - which is exactly what I'd need, since that would ensure it would go on as long as I had images coming - but since I'm processing JPEGs I don't have a constant frame rate, so that's what I'm trying to figure out right now in order to make it work.
pedrolins
·4 anni fa·discuss
Yeah, the Pi would definitely be a better choice for this but even the Pi Zero would be 2x the price of the ESP32CAM I'm using (which in the country I live isn't as cheap as in the US).

> I've had a small amount of experience with this sort of thing, though not with the full blown streaming apps like OBS

My main issue has been to understand the workflow around livestreaming video. I have ok knowledge of networking but just hadn't really come across this domain, though thank you for sharing.
pedrolins
·5 anni fa·discuss
I wouldn't have gotten nearly as much enjoyment out of the series (including the 2 sequels after the trilogy) if I hadn't read Asimov's Robot Series. I know that the whole "you don't get it because you haven't read these other books" thing is kind of cliché, but I really do think that the majority of the joy I got from Foundation was because of how it connected with the Robot Series.

But of course, part of the enjoyment should come from the book itself. I'd say that the book does get better as new threats to the Foundation appear, but the premise largely stays the same throughout the trilogy: will the Seldon Plan succeed?

(NOTE) The reading sequence for me went something like: 1. Caves of Steel 2. Naked Sun 3. I, Robot 4. Robots of Dawn 5. Foundation Trilogy

EDIT: remove redundant last paragraph
pedrolins
·5 anni fa·discuss
- Energy and Civilization by Vaclav Smill - May be a bit dense sometimes in raw data but overall provides an awesome overview of how humanity has used and continues to use energy, from a historical, economical and physical perspective.

- The Emperor of All Maladies: A Biography of Cancer by Siddhartha Mukherjee - A very well written narrative of medicine's fight against cancer (though the author also goes into detail into other aspects of pre-modern medicine) that really executes on explaining how modern day cancer treatment came to be and what are the probable next steps towards a cure.