Spyke

Replies

Comment on

Physics

Reply in thread

We have a mathematical model, Navier-Stokes (NS), that seems to describe motion of fluids well. In practice NS and related approximation models with simpler numerical solutions can be used to derive useful results. In that sense we can simulate turbulence for some sets of conditions and get useful approximations out. In general it’s still an open problem if NS has, given an initial velocity field, a solution that is globally defined and smooth. Practically this means we don’t know one way or the other if NS has initial conditions under which the velocity or pressure fields of the solution tend to infinity in finite time. This is the unsolved Navier-Stokes problem.

https://en.m.wikipedia.org/wiki/Navier%E2%80%93Stokes_existence_and_smoothness

Comment on

Feds: Critical Software Must Drop C/C++ by 2026 or Face Risk

Reply in thread

It’s one backed by a lot of data. One example is from the Android project.

The percent of vulnerabilities caused by memory safety issues continues to correlate closely with the development language that’s used for new code. Memory safety issues, which accounted for 76% of Android vulnerabilities in 2019, and are currently 24% in 2024, well below the 70% industry norm, and continuing to drop.

https://security.googleblog.com/2024/09/eliminating-memory-safety-vulnerabilities-Android.html

There’s an argument that critical infrastructure software vendors are already meeting standards for basic, non-memory related items. Yes, there are other categories, but memory safety is one that’s harder to verify. Moving to memory safe languages is an ensure a category of correctness. This excludes usage of unsafe escape hatches.

Comment on

a few error handlers from a project im working on

I’m going to whoosh the joke for a moment.

Avoid allocating memory in sig segv handlers. I worked at a company once that had written their own handlers that tried to print a stack trace. I was fortunate enough to find a machine in a test environment that segfaulted while allocating memory. The handler then caused a deadlock in a call to malloc (through new). I ended up rewriting the handler to fix two sources of memory allocation. First I preallocate enough space to do string manipulations in the handler. Second I made eager calls to a few libc functions used in the handler to avoid memory allocation from lazy binding from ld.so.

Comment on

RIP America

Reply in thread

I’m not disagreeing. The report isn’t clear. This is written by people asking Congress for a budget cut.

NSF programs indirectly impact millions of people, reaching PreK-12 students and teachers, the general public, and researchers

The actual impact to the pipeline may be far larger.

Comment on

*Permanently Deleted*

Reply in thread

RD1 generates power 99% of the year and collects solar radiation by autonomously redirecting its reflectors toward a concentrator to focus sunlight throughout each day. RD2 uses flat panels, with solar cells facing away from Earth and microwave emitters facing toward the Earth. RD2 generates power 60% of the year due to its limited capability to reposition itself or redirect solar radiation toward its solar cells.

https://ntrs.nasa.gov/api/citations/20230017756/downloads/ASCEND%20SBSP%20Final%2005162024.pdf

Comment on

Gen Z is actually taking sick days, unlike their older coworkers. It’s redefining the workplace

Sick leave in the U.S. increased 55% in 2023 compared to 2019, according to new data from human resources platform Dayforce, which collected data from more than 1,500 of its clients. … employees younger than 36 are leading the charge, with a 29% leap in the amount of sick leave they took from 2024 compared to 2019.

How does the group leading the charge have a smaller increase than the increase of the aggregate? Was there a decline between ‘23 to ‘24? Am I misinterpreting?

Edit: I suppose it could also indicate that the under 36 demographic could have had a significant growth in proportion.

news

Comment on

Tesla board members, executive sell off over $100 million of stock in recent weeks

Looking into the sale by James he shared in his form 4 filing that his sale was to cover the transaction cost in exercising his non-qualified stock options (NSO). This sale results in closing part* of his NSO grant and acquisition of 477,011 shares. The net cash value of the sale comes out to $196k. This should result in ordinary income tax of roughly $42M.

* I’m not actually sure how NSOs work here. It’s unclear to me if there are still exercisable options in this grant or any other outstanding grants.

The shares were sold to cover the exercise price relating to the exercise of stock options to purchase 531,787 shares, which are scheduled to expire in 2025.

https://www.sec.gov/Archives/edgar/data/1318605/000177134025000004/xslF345X05/edgardoc.xml

memes

Comment on

It's the dream

Reply in thread

She’s complaining about the phrase “giving time back”. It’s a phrase used in corporate settings that is often used for small amounts of time. The meaning isn’t really important, but I find it’s used by individuals as a way of “virtue signaling” that everyone in the meeting are busy with other priorities.

Hopefully it’s a phrase that will pass quickly like many other corporate phrases.