Wiz Biz

A five book series by Rick Cook, featuring Willian Irving Zumwalt, Wiz, a computer hacker that gets pulled into the World to help defeat the southern order of magicians. The first two books have been combined and can be found online at Baen's website. There's also a two-in-one omnibus for The Wizardry Cursed and The Wizardry Consulted.

This series contains examples of:

 * Author Existence Failure: Of a sort. Rick Cook went through heart surgery while writing the sixth book and when he had recovered, he found that he was no longer able to write fiction. Fragments of the book that had been written are available on his website.
 * Ethnic Magician: Bal-Simba
 * The Fair Folk: Duke Aelric and the elves
 * Heroes Want Redheads: Moira
 * I Choose to Stay: at the end of Wizard's Bane
 * Magic From Technology or technology as magic...
 * Nice Job Breaking It, Hero: Part of Wiz's effect on the world is releasing simple magical tools that empower the common people. He quickly finds out that, as with powerful computer tools, great disasters can be accomplished in ignorance.
 * One Michael Limit: averted in the third book with Mikey the villain and Mick the supporting hero.
 * Our Demons Are Different: in and of themselves, they, like magic, aren't good or evil, but are basically spells given shape and form.
 * Playful Hacker: Wiz
 * Powers As Programs: in spades. Demons are essentially spell codes given form.
 * Rewriting Reality: It takes Wiz a while to come to terms with the idea that reprogramming the magical world may not always be a good idea
 * Shown Their Work: there's a fair amount of detail about the programming language in the first book
 * Sufficiently Analyzed Magic: Inevitable when your protagonist is a computer programmer that becomes a wizard.
 * Summon Everyman Hero
 * True Name: One demon can kill you at will if your true name has ever been spoken in the World. In what is perhaps a Shout Out to Earthsea, Wiz often goes by "Sparrow."
 * White-Haired Pretty Girl: Shiara
 * Year Inside, Hour Outside: Time passes much more slowly inside the fairy realm; this is apparently June's backstory, and she's pretty traumatized by it. More helpfully, in the second book the heroes use a spell that doubles the hours of the night for them order to get their work done faster.