Mark Twain Commentary on the MacBook Air

Mark Twain’s (1835-1910) words still relevant today for people who want to change established things hastily.

Ken's Techno Tidbits

One of my favorite posts to the Unicode mailing list came during a heated debate about “simplifying” certain character sets. I believe it was Joe Becker who re-posted Mark Twain’s humorous proposal for simplifying English spelling:

Mark Twain

In year 1, that useless letter “c” would be dropped to be replased either by “k” or “s;” and likewise, “x” would no longer be part of the alphabet. The only kase in which “c” ould be retained would be the “ch” formation, which will be dealth with later. Year 2 might reform the “w” spelling so that “which” and “one” would take the same konsonant wile year 3 might well abolish “y,” replasing it with “i;” and iear 4 might fiks the “g/j” anomali wonse and for all.

Jeneraly, then the improvement would kontinue iear bai iear with iear 5 doing awai with useless double konsonants; and iears 6-12 or so modifaiiing vowlz…

View original post 254 more words

Copy Directories with Symbolic Links via ssh

Although probably known in most circles it is worth repeating that scp by itself does not honor symbolic links. To overcome this limitation just combine tar and ssh, i.e., tar on sending side, untar on receiving side:

tar cf - /src/dir | ssh remotehost "cd /dst/dir ; tar xf -"

Usually this is even faster than using scp, as now only big chunks of data are transfered via TCP. Expect an almost twofold performance increase for larger directories which contain a couple of small files.

See also commandlinefu.

Average Size of Web Pages plus Prediction

Data from Average Web Page Size Triples Since 2008 extrapolated to the years 2014 and 2015 via exponential fitting.

Added 26-Mar-2017: Also see Most of the web really sucks if you have a slow connection by Dan Luu. In a more funny form see The Website Obesity Crisis by Maciej Cegłowski.


Using data from I graphed the development of web page sizes over the years. I also included the exponential fit:


As you can see, the 1/2 MB mark was cracked in 2009 and the 1 MB mark was cracked in 2012. Despite the seemingly random fluctuations, an exponential trend is clearly visible. The power 0.3 indicates that the web page sizes doubles about every 2.3 years. Assuming this exponential trend continues we will have these average sizes in the coming years:


2013 – ca. 1600 kb

2014 – ca. 2100 kb

2015 – ca. 2900 kb


So the 2 MB will probably be cracked in 2014 and in 2015 we will already be close to the 3 MB mark. Of course the trend is bound to flat out, but at this point there’s no telling when it will happen.

View original post by the Numbers: The July 2013 Hot List

Some statistics from WordPress just for month July, 2013. These sheer numbers almost sound unbelievable:

  • 1 million new blogs
  • 7 Exabyte of data
  • 1 billion pages accessed by mobile devices
  • 9 million YouTube videos embedded
  • 500.000 posts per e-mail
  • 200 posts per voice

The Blog

When you hit “Publish” and send your work out into the world, do you stop to think about the larger ecosystem in which your blog is embedded? After all, one of the things that makes a blog a blog and not simply a website is that it’s part of a larger community and conversation.

Well, we do, so we thought we’d take a look at July by the numbers to get a sense of the scope of your creations.

Ready? You might want to sit down first — you’re an impressive bunch!

You’re prolific.

You started 1,204,432 new blogs, for an average of 38,853 a day. Tuesday, July 2nd, was the most popular day to start a new blog.

You wrote a grand total of 11,549,273,687 words in 47,231,836 posts, which racked up 4,000,863,171 pageviews.

That’s 133,672 words every single minute…

… or 20,624 copies of the English translation of War and Peace…

… or 7,537,707,792,351,330 bytes of data…

View original post 356 more words

Design Notes on System for the Analysis of Order- and Stepsize Changes for Cyclic Composite Multistep Methods

For the numerical solution of the ordinary differential equation, initial value problem

y'=f(t,y), \quad y(t_0)=y_0,

one can use a cyclic composite multistep method of the form

\sum\limits_{i=0}^{m} A_i Y_{k+i} = h \sum\limits_{i=0}^{m} B_i Y'_{k+i}, \qquad A_i,B_i\in\mathbb{R}^{\ell\times\ell},


Y_k = \left( \begin{array}{c} y_{k\ell+1} \\ \vdots \\ y_{k\ell+\ell} \end{array} \right), \quad Y'_k = \left( \begin{array}{c} y'_{k\ell+1} \\ \vdots \\ y'_{k\ell+\ell} \end{array} \right), \quad y_i=y(t_i), \quad y'_i=f(t_i,y_i).

Continue reading

ssh and rsync for Android

I got somewhat tired of using FTP with my Android, even with lftp. Keeping multiple folders in sync is simply very cumbersome. If I only had rsync working on Android! I found SSHelper, written by Paul Lutus, see also Arachnoid.

SSHelper offers ssh, scp, rsync. You can ssh to your Android phone and issue commands like vi, ls, top, uptime, etc.

Put your public key into .ssh/authorized_keys on the smartphone then you can log-on without being prompted any password. This is very convenient.

Continue reading