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berikv commented on Let's Help NetBSD Cross the Finish Line Before 2025 Ends   mail-index.netbsd.org/net... · Posted by u/jaypatelani
layer8 · 5 months ago
berikv · 5 months ago
“Then there is the % address operator: user %domainB@domainA is first sent to domainA, which expands the rightmost (in this case, the only) percent sign to an @ sign. The address is now user@domainB, and the mailer happily forwards your message to domainB, which delivers it to user. This type of address is sometimes referred to as “Ye Olde ARPAnet Kludge,” and its use is discouraged“

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berikv commented on The Church FAQ   whatever.scalzi.com/2025/... · Posted by u/nivethan
berikv · a year ago
Please don’t terrify your contractors. They fix your place, and you want them on your side doing a good job.
berikv commented on Ask HN: What's the best implementation of Conway's Game of Life?    · Posted by u/jakemanger
selcuka · a year ago
This one is quite interesting:

https://oimo.io/works/life/

It was also featured on HN:

https://news.ycombinator.com/item?id=39799755

berikv · a year ago
This should be my new screensaver
berikv commented on Debugging: Indispensable rules for finding even the most elusive problems (2004)   dwheeler.com/essays/debug... · Posted by u/omkar-foss
berikv · a year ago
Personally, I’d start with divide and conquer. If you’re working on a relevant code base chances are that you can’t learn all the API spec and documentation because it’s just too much.
berikv · a year ago
Also: Fix every bug twice: Both the implementation and the “call site” — if at all possible
berikv commented on Debugging: Indispensable rules for finding even the most elusive problems (2004)   dwheeler.com/essays/debug... · Posted by u/omkar-foss
berikv · a year ago
Personally, I’d start with divide and conquer. If you’re working on a relevant code base chances are that you can’t learn all the API spec and documentation because it’s just too much.
berikv commented on Advanced Expressive Humanoid Whole-Body Control   exbody2.github.io/... · Posted by u/moatmoat
hwillis · a year ago
You misunderstand battery specs. It's a 13 string (more commonly, 13s) battery- a string is a number of cells wired in series. By convention that's a 48 volt battery, which matches with the 54 volt charger. In total that's a 421 watt-hour battery, for an average power of ~210 watts over 2 hours.

When you connect 2 9000 mAh cells in series, the resulting battery has 2x the voltage but the same mAh capacity. In parallel, the battery has the same voltage but 2x the mAh.

> My expectation on timescale is that genuinely general-purpose robots will need at least as much compute as a self-driving car (possibly more, that's a minimum), and have at most 1/10th the available power to do that (because they're physically smaller).

This seems logically flawed:

1. A car travels hundreds of miles from home. Why would a robot walk more than a while from a transport or home base? At short distances, if you truly need that power, it probably makes more sense to stream data/video over a direct low-latency connection. Long distance networking has a latency comparable to camera frame time, but even a normal wifi router can keep a lower latency than human nerve delay.

2. Humanoid robots will never be running at 85 mph past a bunch of people. They probably don't need to have the same compute throughput as a car, and definitely don't need to have the same reaction time.

berikv · a year ago
Correcting the correction:

> When you connect 2 9000 mAh cells in series, the resulting battery has 2x the voltage but the same mAh capacity. In parallel, the battery has the same voltage but 2x the mAh.

The relevant units are:

* Capacity (Q, in mAh, Ah, kWh, etc)

* Power (P, in Watts)

* Voltage (U, in Volts)

* Current (I, in Amperes)

* Duration (t, in mostly measured in hours)

And the relevant formulas are:

* P = U x I or Power equals Voltage(difference) times Current

* Q = P x t or Capacity equals Power times duration

From this we can establish that connecting batteries in series or in parallel will not change their Capacity. When having 13 batteries of 29000mAh, or 29Ah, you have 13 x 29 = 377Ah or 377000mAh. Connecting batteries in series or parallel does make a difference in voltage and current: a string in series will increase the voltage while keeping the current the same (theoretically, in practice you get less than the current of the weakest cell); a parallel setup will increase the maximum current while keeping the voltage the same (again, in theory).

berikv commented on Ask HN: What open source projects need help?    · Posted by u/aaronbrethorst
_fizz_buzz_ · a year ago
Kicad is amazing. I was trying to contribute a while ago. But setting everything up and compiling is a bit tricky. I think I will give it another shot.
berikv · a year ago
Same for me. I wanted to contribute, but the amount of dependencies needed to get a local build to run was a major hurdle.
berikv commented on Chi-fi tuning – Why it sounds piercing to Western ears (2020)   audioreviews.org/chi-fi-t... · Posted by u/userbinator
brookst · a year ago
Note that human hearing frequency response changes with age: https://journalotohns.biomedcentral.com/articles/10.1186/s40...

So headphone makers also have to target an age group, or at least average things out so it’s not right for anyone.

berikv · a year ago
Except that the argument here was about bass, and the paper shows that age dependent hearing frequency response varies mostly in the mid-high range.

u/berikv

KarmaCake day50February 10, 2021
About
iOS eng. Previously at Uber, Mobile.dev, Mobiquity, Philips, Ziggo

Electronic hobbyist, living in Utrecht, Netherlands

meet.hn/city/nl-Utrecht

Socials: - github.com/berikv

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