Easter eggs -- hidden code in software applications -- have been around almost as long as the four-minute warning, and they now seem to be multiplying.
From their origins as simple hidden commands such as the once-obscure Ctrl-Alt-Delete, which was embraced by the public after publication in a magazine, Easter eggs are now everywhere.
Gamers have long been familiar with Easter eggs, and many of the latest applications contain them: Adobe Photoshop and Quark Xpress have relatively simple Easter eggs, while Microsoft has gone a little further with Excel in which a driving game replaces the flight over a 3D landscape that was hidden within Excel 97.
Instructions for these can be found in ZDNet UK's Easter egg gallery.
But Easter eggs are not top of everyone's menu; they tend to be relatively rare in open-source code, for instance. This is not so much part of the open-source ethos as it is a necessary consequence of the nature of open source: you can examine the source code to see what's there, so there will be few surprises.
"You won't find Easter eggs in open-source software to the same extent that you find them in proprietary software," says Malcolm Yates of Linux distributor SuSE. "Although we do have one or two in SuSE Linux."
Among those is an Easter egg that can be found during installation of the new version of SuSE Linux, which is due out shortly. "During installation of 8.0, when the system has been analysed and you see the installation recommendations in the setup window," says Yates, "press CTRL+SHIFT+ALT+L... and watch the penguins that drop onto open windows, scuttle across the top, and fall off."
Red Hat is slightly more conservative. "The open-source development model makes the whole concept of Easter eggs difficult," says technical specialist Mark Baker. "If all the source code is available then it is impossible to really hide anything." However, Baker said, there are "certain quirks" in Red Hat Linux. "If you do certain things then you might get humorous messages." Baker cites the 'Printer on Fire' alert as one example. This obtained by forcing a real printer jam while printing, then issuing a second print command.
There is a more serious side to Easter eggs though, says Baker. "It is one of the key benefits of open source that you can check that the software is doing what it's supposed to do. You can check there is no irrelevant code. Easter eggs are quite amusing, but from a more serious point of view they make the application bigger; in Linux we do have humorous error messages, but not hidden applications -- that would not pass our QA."