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Jeroen W. Pluimers on .NET, C#, Delphi, databases, and personal interests

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Archive for October, 2019

AnyDesk remote desktop – on my list of things to test

Posted by jpluimers on 2019/10/21

After getting fed up by TeamViewer for the umptieth time because inter-version compatibility issues, I think I’m going to try this:

[WayBack] AnyDesk Remote Desktop

AnyDesk is the world’s most comfortable remote desktop application. Access all your programs, documents and files from anywhere, without having to entrust your data to a cloud service.

–jeroen

Posted in LifeHacker, Power User | Leave a Comment »

“Error: Xcode alone is not sufficient on Sierra.”

Posted by jpluimers on 2019/10/21

Once in a while, despite having Xcode, the Xcode command-line tools, homebrew and ruby installed on your Mac OS X / Mac OS / whatever it is called now, you get this on the console:

Error: Xcode alone is not sufficient on Sierra.
Install the Command Line Tools:
xcode-select --install

Running the commandxcode-select --install makes it even more confusing:

It’s probably Apple trying to tell you “Xcode is out of date”, but they should certainly show that in a more obvious way and redirect to the App Store that does show it:

–jeroen

Posted in Development, Software Development, xCode/Mac/iPad/iPhone/iOS/cocoa | Leave a Comment »

WayBack machine now rate limits your requests and blocks if you go over it

Posted by jpluimers on 2019/10/19

Got this a while ago while saving a bunch of links for my blog; unfortunately the email address did not respond for information

Too Many Requests

We are limiting the number of URLs you can submit to be Archived to the Wayback Machine, using the Save Page Now features, to no more than 15 per minute.

If you submit more than that we will block Save Page Now requests from your IP number for one day.

Please feel free to write to us at info@archive.org if you have questions about this. Please include your IP address and any URLs in the email so we can provide you with better service.

I wish there was a queue service that would make you wait longer, but does fulfill the request.

–jeroen

Posted in Internet, InternetArchive, Power User, WayBack machine | Leave a Comment »

Reminder to politicians: concrete blocks do not help against trucks

Posted by jpluimers on 2019/10/18

These physics lessens at school were useful after all.

TL;DR:

A concrete block of ~1.500kg will loose against a truck of ~9.000kg, especially if that drives 50 km/hour.

It will not stop the truck, but will start moving by itself in unexpected directions and speeds becoming a projectile by itself or worse: usually pieces break off traveling at quite high speed.

The video below shows what happens.

Beton blocks

Over the last year or so, concrete blocks are deployed in many places of the public areas. The usual deeper motivation is to protect against traffic.

The blocks are put on the ground without anchoring for a variety of motivations like flexibility, ease of deployment/removal, cost of blocks (EUR ~100 each) versus anchoring (EUR ~250 per block) in a non-interconnected way.

Often, the rectangular lego-like blocks with 8 bumps are used which come in two varieties: 40cm high (easier to sit on, look more friendly) of a mere 1200kg or 80cm high (look more massive) of only 2400kg.

Other concrete blocks used are roughly the same dimensions, so an average weight of ~1500kg is reasonable.

Trucks

An average truck (at about 10.000 kg) isn’t a static object. In cities they are usually allowed to drive at 50 km/hour, but during assassination attempts they drove much faster and also were much heavier.

Let’s assume however that a truck used is less heavy (not all bad people are smart to get a really heavy truck) at ~9.000kg.

Truck concrete collision

The assumptions so far: a truck of 9.000kg at 50 km/hour against a concrete block of 1.500kg at standstill.

Even though a collision with a truck looses some energy, a moving truck has a lot of it. So most of the energy from the truck will be partially or fully transferred via its momentum to the concrete block(s).

The physics involved here are about momentum:

  • momentum = mass * velocity
  • momentum in a system is conserved

Before colliding, the truck has momentum, but the concrete block does not. After the collision, the momentum is divided over truck and concrete block so they both have a velocity.

A few cases that can happen, usually in a combined fashion:

  1. The truck comes to a full stop and all momentum is transferred to the block. The block now travels 9.000/1.500 * 50 km/h which is 200 km/h if it was in front of the truck.
  2. If the concrete wasn’t fully in front of the truck, the truck will move in another direction as well as the concrete block. Those directions are hard to predict for the public.
  3. Part of the concrete comes off during collision. Since their weight is smaller, their speed will be higher (because momentum is conserved) and direction even less predictable.

–jeroen

References

Read the rest of this entry »

Posted in LifeHacker, Power User, science | Leave a Comment »

Sam Knutson on Twitter: ““Every piece of equipment is shipped from the factory able to successfully complete n power cycles and you only find out n at n+1” Anonymous IBM Customer Engineer (CE)… 

Posted by jpluimers on 2019/10/18

[WayBackSam Knutson on Twitter: ““Every piece of equipment is shipped from the factory able to successfully complete n power cycles and you only find out n at n+1” Anonymous IBM Customer Engineer (CE)… .

I could not track down earlier versions of the image than 2005; see the images below.

Failures

[WayBack] flowcart troubleshooting komputer | superplayboy:

–jeroen

Posted in Hardware, LifeHacker, Power User | Leave a Comment »

 
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