dagar
Re:ROS 2 Iron Irwini Release
on Wednesday May 24, 2023 @03:15PM (#36062727)
> It would also help to have compile-time guarantees about which nodes are running.
I haven't had a chance to try it yet, but in theory I like the idea of something like Zenoh Flow to describe the larger data flow graph. https://zenoh.io/blog/2023-02-10-zenoh-flow/
> But I always like to say, why spend 5ns calling a function when you could spend 1ms waiting for a context switch or 50ms for the next event loop to tick over?
I think your context switch timing is off by several orders of magnitude, but regardless these things aren't one extreme or the other. For sharing data across threads, to an external system, or logging and visualization I still like pub/sub (and I've seen more than my share of horrible abuse), but it definitely shouldn't be treated as one size fits all.
Re:ROS 2 Iron Irwini Release
on Wednesday May 24, 2023 @02:02PM (#36061833)
> And this is the crux of where we disagree. This is a messy part of reality which should be, as far as possible, abstracted away from the algorithms which need to operate on the data presented to them. If I'm running a Kalman filter I don't want to have to design in my filter around frequent gyroscope dropouts because image captures are happening, I want my system to have guaranteed behaviour that this won't happen.
Annoyingly in a lot of real world setups you can't have these guarantees. Your gyroscope, camera, etc are all producing data asynchronously often with slightly different clocks, and they all have different little idiosyncrasies and failure modes.
For example the Mars helicopter almost crashed because it missed a single frame. https://mars.nasa.gov/technology/helicopter/status/305/survi... If possible you absolutely want to fix the frame drop in the first place, but your algorithm should also be able to handle the drop out (or at least reset/recover).
Re:ROS 2 Iron Irwini Release
on Wednesday May 24, 2023 @01:33PM (#36061476)
> A better system would take ideas from game engine design and realtime system execution budgets, with cascaded controllers on separate threads with dedicated compute resources for components that need higher update rates.
This is how I've structured a control system, but using a pub/sub system to share data across those boundaries (and log/inspect in general). "Nodes" that share some resource or fundamentally run back to back based on the data flow can live in the same thread. Higher rate components (eg inner loop controller) live in a thread with a much higher priority. All of this is event driven, deterministic, and testable.
If you have more details about the system you're imagining I'd love to learn more, because so far I don't see what's incompatible with what you've described.
Re:Ask HN: What interesting problems are you working on?
on Saturday September 17, 2022 @11:39AM (#32878382)
Is this anything you're ready to share? I'm interested in something similar in the context of Drones.
Re:The ASUS Zenbook UX305 Review
on Wednesday March 25, 2015 @06:10PM (#9266330)
The new newer X1 Carbon (3rd gen) fixed the keyboard.
http://shop.lenovo.com/us/en/laptops/thinkpad/x-series/x1-ca...
Re:Battery power alone can be used to track Android phones
on Monday February 23, 2015 @12:29PM (#9095560)
I honestly don't understand why this is a problem. Isn't it enough that the app says it requires my location when I install it?
If you don't like the required permissions no one is forcing you to install it.
Re:Arch Linux on MacBook Pro Retina 2014
on Saturday January 17, 2015 @01:36PM (#8905091)
Any X or T series with intel video tends to work pretty well. I've personally had great results with Ubuntu on a T410, T420, T520, T530, X1, X60 in the last few years.
Re:Google Inbox
on Wednesday October 22, 2014 @03:22PM (#8494567)
"Gmail cards are currently not available when using Google Now with a Google Apps account."
Re:When Will the Rest of Us Get Google Fiber?
on Monday February 04, 2013 @08:56PM (#5168570)
It's back in stock now.
Ships in 2-3 weeks.
https://play.google.com/store/devices/details?id=nexus_4_16g...
Re:Android users outraged over Motorola's broken promise
on Saturday October 06, 2012 @03:06PM (#4621358)
but the original Nexus will still receive the latest google maps, gmail, etc that aren't tied to the OS version like they are in iOS.
Re:Android users outraged over Motorola's broken promise
on Saturday October 06, 2012 @10:19AM (#4620586)
You can download the updates directly from Google for all nexus devices.
https://developers.google.com/android/nexus/images
Re:Analyzing XKCD: Click and Drag
on Wednesday September 19, 2012 @04:52PM (#4545525)
Here's each tile scaled from 2048x2048 -> 512x512.
http://dagar.ca/xkcd_1110_combined_512.png
I haven't been able to find libraries that can handle the full 165888x65536 10 gigapixel image.
Re:Analyzing XKCD: Click and Drag
on Wednesday September 19, 2012 @12:20PM (#4544201)
Re:Apple Must Publish Notice Samsung Didn’t Copy IPad In U.K.
on Wednesday July 18, 2012 @02:51PM (#4262256)
corporations are people...
Re:Leaked Nexus 7 specs and price
on Monday June 25, 2012 @05:11PM (#4158767)
It has a 138% larger screen area than the Galaxy Nexus (4.65") and 222% larger area than the Nexus S (4"). I don't believe calling it mildly bigger is accurate.
http://www.displaywars.com/4,65-inch-16x9-vs-7-inch-16x10 http://www.displaywars.com/4-inch-16x9-vs-7-inch-16x10
Re:What's the point of Android now?
on Thursday April 05, 2012 @03:02PM (#3804054)
The Nexus One was released January 2010. You might be thinking of the Nexus S that was released last year.
Re:Show HN: GPS + Calendar + Traffic = always on time
on Monday March 05, 2012 @03:23PM (#3668189)
Damn, I've been working on nearly the same thing for a little while now.
Nicely done!
Re:The New Apple Advantage
on Saturday September 10, 2011 @12:28AM (#2980801)
A fairer comparison might be the X220 with the 6 cell battery which is about 2.9 lbs and around 10 hours (advertised). It also has a 12.5" IPS screen.
I believe the 3.6 lbs you mentioned is with the 9 cell 15 hour battery.
For comparison the 11" and 13" Macbook Airs are rated 5 and 7 hours, respectively.
Re:iCloud’s Real Purpose is to Kill Windows
on Tuesday June 07, 2011 @04:29PM (#2630722)
Personally, I'd much rather choose google's cloud for this reason.
http://www.dataliberation.org/
Re:iCloud’s Real Purpose is to Kill Windows
on Tuesday June 07, 2011 @01:20PM (#2630012)
"Having been shown the way by Apple, I expect Google to shortly do the same thing, adding automated backup, synchronization and migration to Android and Chrome."
Doesn't my android phone already do this?
Re:AT&T to Acquire T-Mobile USA for $39 Billion
on Sunday March 20, 2011 @10:43PM (#2348178)
Actually at&t prepaid is about the same.
$100, 10 cents/minute, 1 year expiration = 1000 minutes
Re:Build An Opensource Dropbox Clone
on Wednesday September 01, 2010 @11:56PM (#1655241)
-fastcheck
do fast (and slightly unsafe) update detection on windows
Re:The New Browser Wars: Will Ubuntu drop Firefox for Google Chrome?
on Saturday May 15, 2010 @04:57PM (#1350635)
It is since lucid.