This is a hybrid C-chan Remaster and original drawing by yours truly.

On the left is C-chan's Chibi GNU/Linux-tan, a gift to the site administrator of his former forum; it was meant to be part of a greater picture with more Linux-tans (e.g., RedHat-tan, ubuntu-tan, etc), but only GNU/Linux-tan was ever drawn. Among the revisions, line thinning and extra gradients were added to enhance her overall appearance, while her eye-style was also changed from the original version for reasons of experimentation. This is meant to be GNU/Linux-tan in 1999, and the design was meant to be a composite of the original GNU/Linux-tan created in Futaba Channel, as well as Juzo-kun's version.

On the right is my "2009" interpretation of GNU/Linux-tan, based on BellaCiello's version. Here she is seen as older, cheerier and more confident, given that the future for her and her family looks brighter every day. She's also seen wearing a more streamlined uniform, a Compiz Fusion cape, desktop environment earrings, an upgraded weapon (a halberd rather than a spear), and a Virtualized Helmet which despite appearances is several times more resistant to physical and magical attacks than her original helmet (and a lot more comfortable to). ^^

For a general idea of GNU/Linux-tan's backstory, feel free to check out BellaCielo's awesome manga on that very subject: