Live data from Hacker News

Have you ever hurt yourself from your own code?

blog.nikitas.link

391–400 of 432 posts

Re: Have you ever hurt yourself from your own code?

#391
post #82

I wrote a layoff database for Nortel Networks from ~1998 to 2001. The way I got my notice of termination was while I was running some tests on the production database and needed a "negative" so I searched for a userid that was not present in the database: my own. When I saw my name in the list I called my manager and asked him what was going on. He said "Alex, why don't you head on home for the day and I'll call you…

live by the layoff db, die by the layoff db

Re: Have you ever hurt yourself from your own code?

#392
The context is building a robot for a sumo competition in university. By this time I am towards the end of my Phd, and regular strategies don't cut it anymore. We want to show off.

Since many of these robots use ultrasound locators based on echolocation to find other robots, we want to eliminate those from detecting us. One of the strategies we wanted to try, was to generate sound at the right frequency ourselves, which should completely ruin those sensors, thus making us invisible for no apparent reason.

So I bought a transducer used to clean ships, which was rated for use around the correct frequency. I connected it to a signal generator at an ultrasound frequency and wanted to test its effect on the echo sensor.

Now, I am doing this sitting in a noisy lab with a bunch of noisy instruments, robots whirring and computer fans. Some other people in a corner chatting away.

I put the transducer in front of the distance sensor, set up the program to print the distance measured, turn on the signal generator, and the whole room goes eerie silent.

I turn it off, and luckily the sound comes back immediately. It appears that if you pump 100+ decibels of ultrasound in a room, it actually drowns out other noise! This thing was quite powerful. After all, it was made for cleaning ships from foul.

At that point, I do realise I have no idea whether this is a safe thing to do for my hearing (and that of the audience), and shelve the idea. But I remember the split second where I thought I made myself and everyone else in the room deaf.

Re: Have you ever hurt yourself from your own code?

#393

Earlier quoted context omitted.

I wonder how long it will be before we can 3-D print a dam in place.

I mean, the novel of 3d printing is that it's just additive construction, don't we already build dams and almost all other structures that way already? A crane is just a bigger print arm :)

Yes, but the dream is to build physical things, just with software.

You type in your commands and then magic happens and something is build (after a while). Nothing to be done by hand (ideally)

But I would love to play with a fully automated remote controlled printer the size of an crane, though.

But then there should probably be no humans around.

Re: Have you ever hurt yourself from your own code?

#394
post #392

The context is building a robot for a sumo competition in university. By this time I am towards the end of my Phd, and regular strategies don't cut it anymore. We want to show off. Since many of these robots use ultrasound locators based on echolocation to find other robots, we want to eliminate those from detecting us. One of the strategies we wanted to try, was to generate sound at the right frequency ourselves, wh…

Did it affect the other people in the room, or were they too far away from it?

Re: Have you ever hurt yourself from your own code?

#395

Earlier quoted context omitted.

My bachelor's degree is in neurobiology and it would have been very interesting if this was reproducible in other people. Experiencing physical pain from visual stimuli (stimuli unrelated to light intensity, at least) is not something I've ever really heard of. You may have discovered the visual equivalent to the Brown Note.

I know in the past I felt pain while trying to say certain lies. I do not mean I felt uncomfortable, I mean I felt real pain. It is weird, but sometimes you can cause pain without a direct physical cause.

"It is weird, but sometimes you can cause pain without a direct physical cause."

Since the brain and the body are wired up pretty closely - this is not so weird at all.

Re: Have you ever hurt yourself from your own code?

#396

Earlier quoted context omitted.

Using the analogies above, a drill like that could put the trigger on the awkward handle, forcing the operator to use it

The second handle sometimes needs to be removed to fit into a narrow space. In that case, you set a torque limit and operate the drill with one hand.

That's fair; Maybe you need to hold two triggers, and the torque limit is reduced if you're only operating in "one hand mode"?

Re: Have you ever hurt yourself from your own code?

#397
post #394
post #392

The context is building a robot for a sumo competition in university. By this time I am towards the end of my Phd, and regular strategies don't cut it anymore. We want to show off. Since many of these robots use ultrasound locators based on echolocation to find other robots, we want to eliminate those from detecting us. One of the strategies we wanted to try, was to generate sound at the right frequency ourselves, wh…

Did it affect the other people in the room, or were they too far away from it?

It affected everyone in the room and to a lesser extent the next rooms over if the door was open.

Obviously, we did not shelve it right away since there seemed to be no permanent effect. Some people were really creeped out after they had been exposed in my first try. But this is an engineering lab, so soon enough the lab was filled with cowboys wanting to experience it and trying to figure out how it works. Meanwhile, the more safety minded people took a short break and went for some air outside.

We stopped after the professor figured out something odd was going on on his floor.

Re: Have you ever hurt yourself from your own code?

#398

Earlier quoted context omitted.

> Including the network share of my other computer’s /home. TIL network shares also get deleted in recursive deletions.

Unlike on Windows where each drive has its own letter (so I don't think it's possible to create a path including all drives), in Linux the filesystem originates from "/" and any additional drives or network shares are "mounted" into folders within that parent filesystem, so recursively deleting everything from the parent would also affect everything else.

Windows also has mounts onto subfolders.

Re: Have you ever hurt yourself from your own code?

#399
I always wanted to make an electric skateboard. After a few successful iterations, I decided to make a really fast one that could replace a car. I built my own lion battery out of ~500 18650s. It could go about 30 miles on a charge. It could go about 50mph. It was a very wide body with huge air filled tires. It could pull 10 of my friends up the steepest hill. It was very powerful because I installed an electric motorcycle engine on it. My one extra stupid move was I didn't account for the battery dying at high speeds. Normally I'd stop well before an empty battery but I only had 3 LEDs of primitive battery indication. And that only measured with voltage. Voltage fluctuates wildly in motorized vehicles. It died while only going about 20mph but up a steep hill. The sudden loss of forward momentum flung me off the board into the pavement where I flipped a few times and scrapped across the pavement for a while. Was a painful lesson.
Post reply on HN