remark – Page 2 – nullteilerfrei

Recursively set ownership in Windows

rattle remark, technology 2013-04-02

I have a folder data with stuff in it. I am not using an Administrator account on my Windows machine, and that folder is supposed to be owned by my user. When you search for how to take ownership of all files and folders in a certain directory recursively, you get told to use TAKEOWN, a lot. Well, it has a little catch: You can only really use it to take ownership. Not to give it. A much more giving command is

ICACLS C:\data /setowner rattle /T

Oh yea, it's the /T switch that makes it recursive.

Lenovo System Update somewhat demystified

rattle remark, technology 2013-03-09

Suppose you have a Laptop, which therefore must be a [ThinkPad](http://www.lenovo.com/products/us/laptop/thinkpad/). Let's also assume that you [use Windows 2008 as a workstation](http://www.win2008workstation.com/), just like [I do](/2012/03/22/turning-windows-2008-r2-into-a-workstation/). Then, you might run into some issues with [Lenovo System Update](http://support.lenovo.com/de_DE/detail.page?LegacyDocID=TVSU-UPDATE). To be precise, it tells you: > An error occurred while gathering user information. Then it stops. I will provide a solution to this problem which is not specific to Windows 2008 R2, and therefore, I hope that my solution will also work for future versions of Windows that are not out-of-the-box supported by SystemUpdate. Do you want to know more?

Convert WAV to MP3 with VLC

rattle remark, technology 2013-03-05

If you like electronic music, you obviously lurk getworkdonemusic.com all the time with jDownloader running, so you can copy the link to any nice track on the air and download it, slowly aquiring a groovy selection of electronic music for the lonely train hours where you have to get work done, offline style. Sometimes, however, these tracks are in wave format, for reasons that are completely beyond me. A quick google search for »convert WAV to MP3« points you towards a huge selection of shitware, when it could be so much easier: Fire up VLC, the best media player in the world ((This post refers to VLC media player 2.0.5 Twoflower.)) and go * Media, Convert/Save (Ctrl+R) * Add your file to the list. * Click the button that says Convert/Save. * Select a destination file. * Set the profile to Audio - MP3 and hit Start. Also, make sure you don't have VLC set to loop, because otherwise it'll spend the next few hours overwriting that file with the same converted MP3 again and again. True story.

Blog Size

rattle remark 2013-03-01

Looking at Roman's beautiful blog, I really couldn't take it no more. I finally removed that scourge of a tiny font size from the blag, now it is actually possible to read everything on a commonly shaped screen. At this point I wished this had been done in LESS, because then I would probably only have to change two variables in order to achieve, what now took me, approximately one hour.

A Yay for Community-Managed Textbooks

rattle mathematics, remark 2013-02-07

Most people probably know about the stacks project, but fewer might have heard about the CRing project. Now, there might be certain disadvantages to having a large number of contributors to a single document, but I would like to put some emphasis on the one, big advantage: You actually end up with a very complete reference, not just the narrower standpoint of one or two authors. If done correctly, group efforts of this sort are the perfect way to cover all basic (whatever that means) knowledge in some field. I really hope to see more areas pick up on the idea.

29c3

rattle remark 2012-12-28

We have arrived at the 29C3 and set up shop. We will talk a bit about elliptic curves and stuff, but whenever you find us hanging out in 1C, you can stick around and talk to us about anything.

Why I hate Facebook

rattle remark 2012-09-29

I do not have a Facebook account. Why don't I have a Facebook account? A couple reasons spring to mind: * I think that it's a pathetic, average, unimaginable kind of self-portrayal. * I do not want to give all kind of private details about my (social) life to some company with very questionable motives, let alone imprinting all that data into the internet for all eternity. * It eats up lots of time I could spend writing blog posts that noone reads. As a matter of fact, however, none of those is really the reason why I don't use Facebook. My reason not to use Facebook is that it is expected of me to use it. Let me clarify: People have stopped asking "Do you have a Facebook account?" and instead, they started asking > What's your Facebook account? Depending on who's asking, to them, my answer sounds a bit like "Oh I'm sorry, I do not have a Telephone." And indeed, that's a pretty good metaphor. Facebook is the best new tool of communication since mobile telephony was made available to the public. I remember when only very few people had a cellphone, because I was in elementary school then - and I had one. I got it for Christmas because I had begged and begged, I wanted no other present, just that cellphone. It caused all kinds of problems, teachers didn't want me to bring it to school, stuff like that. Can you imagine? Nowadays, that just sounds absurd. Nowadays, everyone has a cellphone, because that technology is so convenient that we got used to it, it has become vital to our way of life. You can not exist in the digital age, without a telephone. And Facebook is headed in the same direction - for a good reason. It's an incredibly powerful addition to existing communication, partly replacing old technology and combining others into an easily manageable framework to maintain all your social relations. And it's almost free - you are paying them with just your personal information, which they use for advertising and thelike. Frankly, I couldn't care less about that. In fact, I think that's totally fair. But at some point, it will have become socially impossible to not have a Facebook account. At that point, we have given a private company complete control over our respective social statuses. When you apply for a job, they first check your Facebook profile. When you chat up a stranger, you exchange Facebook information and that's the first they'll really know about you. Of course, Facebook wouldn't use that power to harm anyone, that'd be very bad for business. If I were Mr. Zuckerberg, I'd offer special premium Facebook profiles instead, for a certain fee of course. Let's say $10 a month and you just seem better than everyone else. Most people would get one, and at some point you just seem like a bum if you don't. So you pay the ten bucks, what the hell. And before you know it, everyone's paying Facebook fee every month. You're upset? You'd never do that? It's absurd? Well, you pay about that much for your cellphone, don't you? Nobody would refuse to use a cellphone just because he has to pay for the calls. Only, like, a crazy communist hermit bum would say such a thing. Now, you might say, alright! Facebook is worth paying money for it. What's the problem? The problem is that Facebook is neither controlled by the government nor by the market. They have no rivals, by design. Facebook does not interact with other social networks. That's different for cellphones - you have different vendors that live in a healthy state of competition. Same holds for email, regular mail, and basically all kinds of communication. Not one of them is monopolized. If we let a company monopolize our communication, we're screwed. Now, I am not actually very afraid that this will happen in such an apocalyptic manner. Things will work out alright. But right now, I don't think that it should be expected of everyone in the whole civilized world to have an account on that website, no matter how good it is. I am making a political statement by not having a Facebook account. Me not being a very politically active person, this is one hell of a statement.

The Transposition Operator and Notation

rattle mathematics, remark 2012-09-18

Let's say you have a matrix $A\in\mathrm{GL}_n$. How do we best denote the inverse of its transpose? You would probably write $(A^T)^{-1}$ or $(A^{-1})^T$ because it is the same. However, today at the office we decided to henceforth write $A^{-T}$ instead. It seems abusive at first, but I can make it formal for you, if you care for that kind of stuff. As we all know, the transpose of $A^T$ is $A$. In other words, the transposition operator $\vartheta:\mathrm{GL}_n\to\mathrm{GL}_n$ which maps $A$ to its transpose satisfies $\vartheta^2=1$. So far, the exponentiation map is defined as $\mathrm{GL}_n\times\mathbb{Z}\to\mathrm{GL}_n$ mapping $(A,k)\mapsto A^k$. We instead consider the ring $\mathbb{Z}[T]:=\mathbb{Z}[t]/(t^2)$ and extend the domain of the exponentiation map to $\mathrm{GL}_n\times\mathbb{Z}[T]_\ast$, where $\mathbb{Z}[T]_\ast$ denotes the homogeneous elements of $\mathbb{Z}[T]$. This way, you can write $A^{kT}$ instead of $(A^k)^T$ and you have $A^{kT^2}=A^k$ as required. Note that by restricting to homogeneous elements in $\mathbb{Z}[T]$, we get $A^{p+q}=A^pA^q$ and $A^{pq}=(A^p)^q$ for all $p,q\in\mathbb{Z}[T]_\ast$.

Magic the Gathering™ is Turing-Complete

rattle remark, technology 2012-09-14

Roman told us about a turing machine in Magic: The Gathering™. The design seems very complicated at first, I would have thought that there was an easier way to do it. However, with the 8 minutes invested so far, I did not come up with a better implementation.

Werde ADAC-Mitglied!

born remark 2012-08-05

Ich möchte an dieser Stelle einfach mal los werden, dass es sich wirklich lohnt, ADAC-Mitglied zu werden! Die holen einem aus jeder erdenklichen misslichen bis unlösbaren Lage raus (alles von, Tank auf der Autobahn leer bis man bleibt in Spanien liegen). Die 80€ im Jahr sind es wert!

Useless and/or Dysfunctional

born remark, technology 2012-05-25

Lars has put together a rather disturbingly large list of objects that are either useless or dyfunctional. Most of them have pretty YouTube Videos. Maybe one of them makes for a great gift. Do you want to look at them?