I don’t have to review 4000 flash cards every day. Instead, I only need to review a handful, sometimes less than a dozen, because a software spaced repetition system (SRS) predicts when I’ll forget each flash card and makes me review it before I forget [1]. How can a program predict when I’ll forget something? The program, or rather its author, knows about the forgetting curve, which means that people forget new memories faster than they forget old memories. For example, if you just learned the Pythagorean theorem today and you don’t review it again, you’ll probably forget it by next week, but if you remember it from high school, you’ll probably remember it for at least the next year.
For a spaced repetition system to work, you must tell it how well you remember a fact each time you answer its flash card (i.e., you grade your memory). The program uses your grade to predict when you’ll forget that fact. Each time you remember something correctly, the program schedules it further away. For example, if you tell it you learned the Pythagorean theorem today, it makes you recall it tomorrow; if you answer correctly, it makes you recall it in six days, then in 12 days, then 20 days, and then 30, 50, 100 days, and so on. Within the first 18 months, you may only need to review each card 12 times. For 4,167 flash cards, that’s 50,000 reviews, which sounds like a lot but it’s an average of only 90 reviews a day to keep more than 4,000 flash cards memorized. That’s how I reviewed just three flash cards a minute, for 30 minutes a day for 18 months to memorize more than 4,000 flash cards. And I don’t intend to stop: In 30 years, with the same routine, I plan to memorize (and keep memorized) more than 100,000 flash cards.
Ikiwiki isn’t your typical wiki, but a program that turns documents into HTML (Figure 1). It doesn’t need a web server, CGI scripts, revision history, or anything else to reformat documents, so it doesn’t depend on any of them. Instead, separate plugins provide each of these features and more.
If you decide to keep track of page revisions, as most wikis do, you won’t store those revisions in a database. Instead, Ikiwiki stores revisions in revision control systems such as Subversion, Git, or Mercurial. This lets you edit your wiki with the us of any text editor, commandline program, or application. You can even edit your wiki offline. Of course, you can’t publish your changes until you’re back online.
Read More in the August 2009 Issue of Ubuntu User. (Sorry, no online link.)
Conkeror is a Web browser with an Emacs-style look, feel and configuration. It uses Firefox’s HTML rendering engine and works with most Firefox extensions, but it provides a keyboard-driven interface and makes excellent use of screen space. It’s a fitting Web browser for Netbooks with their imprecise touchpads and small screens. Conkeror uses the same free software license as Firefox.
Installing Conkeror
Users of Debian Lenny, Debian Sid and Ubuntu Jaunty should install the conkeror and conkeror-spawn-process-helper packages. Users of other distributions should install the XULRunner package (xulruner–1.9 or xulrunner). If you installed the Firefox package, that package installed XULRunner for you. After you install XULRunner, download a Conkeror snapshot and unpack it into your usual software directory—you don’t need to compile anything. See Resources for a link to the Conkeror snapshot download.
Most Twitter and other micro-blogging clients use the same interface as Twitter.com, but two new free software clients make Twitter easy to use from the command-line or an IRC client.
Twidge lets you send and receive Twitter or Identi.ca updates from the command-line. Although micro-blogging from the command-line may not appeal to you, the command-line makes it easy to fiddle with Twitter, and Twidge works well in shell scripts. For example, you can automate sending updates or filter out unwanted updates from your friends. Other Stories on LinuxPlanet
Debian and Ubuntu Jaunty users can install the “twidge” package. Other users should download the static executable from Twidge’s download page, run bunzip2 on the file, copy it to /usr/local/bin/twidge, and make it executable with the following command: chmod +x /usr/local/bin/twidge. You also need to install your distribution’s cURL package.
Ubuntu founder Mark Shuttleworth spent about $20 million to go into space, and he never got farther away from Earth than a few hundred miles. Using three free software programs, you can look at and virtually travel to places millions of miles away without leaving your GNU/Linux desktop or paying a dime.
The GNU GPL covers all three programs, and most major distributions include all of them as packages.
Stellarium
Stellarium lets you watch the night sky, learn about the stars, and find constellations without going outside or even waiting for dark. Stellarium won the SourceForge.net Project of the Month Award in May 2006, and Digitalis Education Solutions, Inc, uses Stellarium in portable planetarium projectors that sell for as much as $41,100.
The installation instructions in most free software reviews aren’t enough. If you decide a package sucks, how do you get rid of it? If a package rocks, how do you upgrade it? GNU Stow, a package manager for packages you compile and install yourself, provides an easy answer to both questions.
Many GNU/Linux distribution developers use Stow, so you’ll find it in the default package repositories of every major GNU/Linux distribution. Stow’s only dependency is Perl. If you use a distribution that includes neither Stow nor Perl, you can use Stow’s simple [bootstrapping instructions]http://www.gnu.org/software/stow/manual.html#SEC14) to install both.
Installing a package with Stow requires you to slightly modify the make install step of package installation (modifications in bold):
Cursing, I slapped my leg and stared at the man who killed me. He grinned back.
We we both participating in New Jersey’s first GNU/Linux LAN party. The games were free software and ran on GNU/Linux. The people were mostly geeks, mostly young, and entirely cool. The fear was that technical problems would kill the party; the reality was 12 hours of non-stop gaming.
Organizing a LAN party is mostly an exercise in common sense, but adding free software to the mix adds a few wrinkles and removes some others — for example, you won’t be worrying about cracking copy prevention schemes.
GNU Mailman is the most popular free software mailing list manager, and probably the most configurable; however, it normally requires you have a web and mail server always connected to the Internet. With a little extra work, you can run Mailman from your intermittently-connected GNU/Linux desktop.
Introduction
Normally Mailman’s workflow looks like figure 1. A mail server receives email, gives it to Mailman for processing, takes it back from Mailman, and delivers the email to the final recipients. The desktop Mailman workflow adjustments (see figure 2) add a few extra steps: mail is forwarded to, stored in, and downloaded from a mailbox before being received by a desktop mail server. These extra three steps are easy to setup, and this article integrates them into the normal Mailman setup procedure.
How are GNU/Linux users preparing for Linus Torvalds’ plan of world domination? By playing free software computer games based on the classic world conquest board game Risk. You can perfect your strategy by playing the games XFrisk, TEG, or Ksirk.
XFrisk
XFrisk uses the X toolkit (Xt), which was popular 15 years ago. XFrisk itself isn’t that old, but it shows the maturity of a classic X application, and most major GNU/Linux distributions include it in their default repositories. You can also download source code from XFrisk’s download page.
Taking frequent computer breaks can save you from a debilitating repetitive strain injury (RSI). However, if you’re like most people, you probably get caught up in your work and forget to take breaks as often as you should. The Workrave desktop applet can keep you on track.
Workrave is mature software, licensed under the GNU General Public License (GPL) and installable using the default package repositories of most GNU/Linux distributions. You can also download a binary executable for Microsoft Windows or the source code from the Workrave Web site.
If you install Workrave using a package manager, you can probably start it from either the Applications or Add Applet desktop menus. Otherwise, start Workrave from a command line or application launcher prompt by running the workrave command. Workrave starts as a desktop applet in your desktop environment’s panel; if you don’t have a desktop environment or a panel, Workrave can start as a small independent window.