Long, long ago in the days of NeXTStep v. 2.1, I was working on a big development project that had some pretty buggy apps. Somebody that I worked with had an app which showed the size of your ever increasing swap file. The thing that I didn't like about it was that it used a huge font so that when you displayed a big number, like 28934144, it took up a sizable chunk of screen real estate.
I was a beginning NeXTStep (that was how it was capitalized back then) programmer and thought that it'd be good exercise to put this one little piece of information onto an icon. Thus was born WatchSwap.
Until WatchSwap's only major revision (about a year ago), it displayed the full number of bytes. Now it displays the size in megabytes with one decimal place accuracy. So, the number above (my current swap file size) is displayed as "27.6 MB".
This icon fits nicely on my dock and tells me when I've been doing too many compiles and it's time to reboot my machine (I usually reboot my Compaq when the swap file is larger than 30-35 meg). No, it doesn't actually tell me... maybe that's something that should be added. Okay, I just added it. So now it's version 1.6 and there's been more than one revision.
As with most of this stuff, there is no warranty. Feel free to make changes, but please don't charge money for this and do include my name in the credits.