The Cafes » 2009 » September

I have two 23″ monitors on my desktop at work, and have worked that way for about three years now (aside from a brief flirtation with a single 30″ monitor in California). On Windows and Linux this is an incredibly productive setup. I can have a full screen IDE open on one and a full-screen web browser open in the other. The web browser gives me a huge reference library and easy access to a lot of apps including e-mail, calendar, and more, and the IDE lets me do my work. I can easily switch back and forth between them to surf or edit. It’s a smooth and fluid workflow. Even a single monitor twice the size doesn’t work as well since you can’t easily organize the two applications on the screen.

I’m a programmer but the same is true for anyone who works primarily in one large application. For instance, for designers it might be Photoshop or QuarkXPress. For writers it may be Microsoft Word. For business folks it could be Excel. We all need a web browser open and we all need our main productivity app. On Windows and Linux these days, this just works. You plug-in two monitors. You open two apps. You move between them as you feel like it, and do your work. This is what it looks like:

On the Mac, however, it doesn’t work. The Mac, which was perhaps the first platform to support multiple monitors, certainly the first consumer platform, a two monitor setup looks like this:

Do you see the difference?
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The following example, taken from an introductory text in object oriented programming, demonstrates a common flaw in object oriented design. Can you spot it?

public class Rectangle {

  private double width;
  private double height;

  public void setWidth(double width) {
    this.width = width;
  }

  public void setHeight(double height) {
    this.height = height;
  }

  public double getHeight() {
    return this.height;
  }

  public double getWidth() {
    return this.width;
  }

  public double getPerimeter() {
    return 2*width + 2*height;
  }

  public double getArea() {
    return width * height;
  }

}

public class Square extends Rectangle {

  public void setSide(double size) {
    setWidth(size);
    setHeight(size);
  }

}

(I’ve changed the language and rewritten the code to protect the guilty.)
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