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JustAPersonon Bytecode Breakdown: Unraveling Factorio's Lua Security Flaws

Eventually every game developer learns the hard way that they must remove the bytecode ability from lua's loadstring() function.

E.g. here's a 12 year old blogpost on the topic from the ROBLOX developers: https://archive.is/oXPyM

To be honest, it would probably be better off disabled by default. Its legitimate uses are pretty niche.

JustAPersonon Adventures of Linux Userspace at Meta [video]

Slides: https://cfp.all-systems-go.io/media/all-systems-go-2023/subm...

JustAPersonon The vital art of talking to strangers (2021)

I’ve spent years of therapy trying to overcome my fear of talking to strangers. Mostly it just feels inappropriate and unwanted; like I would be intruding on people. I can talk to strangers when there’s an appropriate social context (e.g. clerks / service people). But lacking the right context, it feels deeply uncomfortable.

Has anyone overcome this problem? Where would you go to interact with strangers–importantly where there’s an appropriate social context that permits interacting.

JustAPersonon Ask HN: Anyone go through Montessori education until age 12 (end of grade 6)?

Huh, is that the maximum number of students of the same age? To be clear, the Montessori school I went to had a little over 100 students with all 6 class years combined.

For context, in the US many public middle/high schools are like two orders of magnitude larger per class year. Many schools have like 1000 kids / class year.

JustAPersonon Ask HN: Anyone go through Montessori education until age 12 (end of grade 6)?

Yes, I went to a Montessori school through 6th grade (now 25 years old). I have mixed feelings about the experience.

I agree that it did well to set my up academically. I ended up going to middle/high schools that were relatively average academically, so I was pretty strong in all subjects in comparison to my peers. Ultimately I went to a very prestigious college and now work in a wonderful finance job I love. However in the many years of therapy I’ve had as an adult, I continue to identify Montessori school as a foundational contributor to my social anxiety, and ultimately my ensuing clinical depression over a lack of social life which haunted most of my college years.

My Montessori school had about 15-25 kids / class year. Some of the larger years were split into two groups with separate teachers. Every year, maybe one or two kids left to go to other schools and one or two new kids joined, but for the most part I grew up with the same core set of children for seven years. I honestly believe this had a permanent negative effect on my ability to socialize and form new friendships that I am only barely beginning to correct over a decade later. Admittedly I did not participate in any extracurricular outside of Montessori school (particularly because it had its own after-school programs). So when I transitioned to a public school for middle/high school, it was a sharp culture shock and I definitely struggled to fit in.

I think Montessori schools are worthwhile academically, but you should be careful to keep your children in contact with other kids outside the Montessori bubble.

JustAPersonon US Federal Reserve says its goal is ‘to get wages down’

A substantial portion is funded with newly issued debt.

https://fortune.com/2019/08/20/stock-buybacks-debt-financed/

https://www.bloomberg.com/news/articles/2019-01-27/debt-fina...

JustAPersonon MIT CSAIL network design principles

This article doesn't provide much context on the challenges of the building's architecture.

If the exterior[1][2] did not give any indication, the inside is quite difficult to navigate. Unless you're a grad student who lives and breathes this building (where most of the EECS department is located), you'd better allocate 10 minutes to finding the professor's office you intend to visit. I can't find great pics of the interior (only some floor plans[3][4]), but there's a variety of confusing stair cases, open atrium's spanning multiple floors, irregular floor plans and office layouts, and an abundance of cluttered spaces. No good flat surface goes unused.

I'd never considered that it would be impossible to provide comprehensive 2.4GHz coverage because of graph coloring problems. The point about certain 5GHz channels being effectively unreliable due to radar was also an interesting insight I'd never heard before.

[1]: https://files.catbox.moe/6z4ad2.jpeg

[2]: https://upload.wikimedia.org/wikipedia/commons/1/17/Stata_Ce...

[3]: https://csdl-images.computer.org/trans/tm/2018/05/figures/li...

[4]: https://i.pinimg.com/originals/80/f9/af/80f9af1c6cdc0c170cf6...

JustAPersonon Ask HN: Who wants to be hired? (November 2020)

Location: Boston, MA

Willing to relocate: NYC Only (specifically Manhattan)

Remote: Yes

Technologies: C++, Go, Rust, Java, Postgres SQL, Python, Linux

Résumé/CV: https://jpriest.me/pdfs/jpriest_resume_fall_2020.pdf

GitHub: https://github.com/JustAPerson

Email: jason@jpriest.me

I'm passionate about systems programming and performance engineering. I love learning about operating systems, compilers, and databases. In my free time, I'm writing my own C compiler in Rust, which you can find on my GitHub.

I currently work full time as a backend software engineer at a SaaS start up. I'm looking for opportunities that inspire my passions, so internal infrastructure that handles big data sets, high throughput, or low latency are areas I'm super interested in. I'm mostly looking for work in either C++, Go, or Rust. Other than those areas, I'm also deeply interested in open source software.

I am also finishing my degree in Computer Science at MIT this December. Looking for full time work starting in early 2021. Only interested in positions that are remote or in Boston or the Manhattan area of NYC.

JustAPersonon Compact nuclear fusion reactor is 'very likely to work,' studies suggest

https://www.youtube.com/watch?v=KkpqA8yG9T4

Here's a video lecture from the MIT Professor (Dennis Whyte) who was leading the research group that provided some of the key designs for the SPARC reactor. As the NYT article explains, that research has been spun out into a startup that raised $200M.

The key breakthrough is the advancement of REBCO tape superconductors which allow you to (1) generate record breaking magnetic field strengths (2) easily disassemble the super conducting loop for fast repairs / refuels / more modular design.

It's a long talk, but it's extremely fascinating. Basically everything becomes much easier once you can increase the magnetic field strength. This talk is fairly accessible to even relative laypeople who have a vague understanding of E&M physics.

JustAPersonon How to Create a Software Engineer Resume Hiring Managers Will Love

Does anyone have suggestions for how to check if your resume is correctly parsed by these tools?

JustAPersonon Western Digital Lawsuit for Shipping Slower SMR Hard Drives Including WD Red NAS

The notable quote:

> That 9 day and almost 14-hour rebuild means that using the WD Red 4TB SMR drive inadvertently in an array would lead to your data being vulnerable for around 9 days longer than the WD Red 4TB CMR drive or Seagate IronWolf.

The other 4TB drives they compared against completed in around 15 hours, meaning the SMR drive could potentially take 14x longer to rebuild a RAID.

JustAPersonon Why Is Facebook Not in the Cloud Business?

It's a combination of a lack of developer bandwidth, fatigue, and typical difficult google customer service. Previously it was just a sole backend developer who also did the server operations/SRE type stuff plus a couple front end web developers. To them, it quickly became just a fact of life after repeatedly failing to find a solution. The customer service people don't like that, because these short down times always happen during standard business hours (only time our service is ever used). Complaints about disrupted sales pitches or customer demos go ignored.

I'm joining as the second backend developer, so maybe while I'm still green and have the naive bravery, I will go give it another shot next time it happens. I don't know much about advanced networking, but we suspect there's some kind of partition happening frequently between our servers and our production firebase instance. Uncertain how to debug that and how to work around it. It usually affects all of our servers, which are located in a single data center. I suppose next time I will try to track down and inspect the socket being used by the firebase SDK, but I don't really know what to be looking for at that point.

JustAPersonon Why Is Facebook Not in the Cloud Business?

Not the person you responded to, but I just joined somewhere new and it's clear Firebase was the biggest mistake / is the biggest source of technical debt. It was helpful for bootstrapping 6 years ago, but now it stands out as the worst part of our tech stack. For our small shop, we will not be able to migrate any time soon.

- Most frustrating are the outages we have no control over. It seems like every other day, the server running our firebase instance mysteriously disappears from the internet. We can ping `my-app.fibaseio.com` but receive no events from it. This lasts anywhere from 5 to 25 minutes. Usually there is no blip in the firebase status page. The main devs have given up trying to debug it.

- We are nearing the resource limits of the paid plan for a single realtime database. We're working on splitting our one database into a master and sharding what we can.

- The particular eventual consistency and transaction semantics require workarounds everywhere. If you want an atomic transaction, you have to perform it on some common parent, but you are also encouraged to keep your data model flat and normalize as much as possible. Our integration test suite is tiny and horrendously slow because we cannot rely on Firebase to be timely, so there are huge timeouts everywhere that regularly take ages. Every past attempt at tuning the timeouts to be shorter eventually causes spurious failures a week later.

- Unless your data closely models the kind of chat application Firebase was built around, you end up needing a real database eventually. Not just to perform real queries with joins and complex logic, but also to essentially maintain indices that anemic mobile clients can use because the firebase filtered query semantics are limited to a single key. Now you need some kind of daemon to shuffle data in and out of your real database. Unfortunately, your real database is missing tons of foreign key constraints because that's the easiest way to handle firebase's eventual consistency.

That's just my take a month after joining somewhere intimately coupled to firebase.

JustAPersonon AMD Threadripper 3990X Scores Another Win: We Test New SPECWorkstation 3 Update

Perhaps the craziest part of these graphs is the 3970X, this generation's second best, versus the 2990WX, last generations very best Threadripper processor. Both have 32 cores/64 threads, but the 3970X has 2x the multithreaded performance, literally 100% faster under many workloads. Its base clock is 25% faster but there's still an enormous microarchitectural improvement. Part of this is moving away from the asymmetric NUMA topology of 2990WX. What a feat.

JustAPersonon Ask HN: Who wants to be hired? (February 2020)

Location: Boston

Remote: No

Willing to Relocate: Yes (NYC only)

Technologies: Rust (since 2014), C/C++, LLVM, performance engineering

Résumé/CV: https://jpriest.me/pdfs/jpriest_resume_spring_2020.pdf

Email: jason@jpriest.me

GitHub: https://github.com/JustAPerson/

MIT '19 new grad* looking for work in backend / systems software development. Passionate about anything performant. I tinker with compiler and operating system development in my free time.

JustAPersonon Ask HN: What were the things you did that made the biggest impact at your work?

For anyone curious about using something like this technique, Facebook has a similar tool.

https://github.com/facebookincubator/BOLT

JustAPersonon Ask HN: Who wants to be hired? (January 2020)

Location: Boston

Remote: No

Willing to relocate: Yes (Bay Area, Seattle, New York)

Technologies: Rust (since 2014), C++, LLVM

Resume/CV: https://jpriest.me/pdfs/jpriest_resume_spring_2020.pdf

Email: jason@jpriest.me

GitHub: https://github.com/JustAPerson/

MIT '19 new grad* looking for work in backend / systems software development. Passionate about anything performant. I tinker with compiler and operating system development in my free time.

JustAPersonon Intel Core I9-9990XE: Up to 5.0 GHz, Auction Only

I kind of like this trend of power-hungry beastly CPUs. The AMD 2990WX is also rated 250W (but for 32c/64t@3GHz). I have one with a 280mm AIO, and it sees high 60C under load at stock frequencies. I can only overclock to 3.4GHz while sustaining heavy compute 24/7 and that's probably drawing close to 400W and heats up to mid 80C (in a room with 20C ambient). It's a pleasant space heater for the winter.

Hoping to see AMD continue to push the HEDT threshold. Let the server market have their underclocked power-efficient processors. Though to be honest if things go much further I'm going to need a custom waterloop next generation.

JustAPersonon AT&T’s “5G E” network is not true 5G

This is not the first time AT&T has pretended to have a newer network than their infrastructure actually provides.

https://slate.com/technology/2012/03/4g-vs-3g-beware-of-the-...