Three Laws of Robotics card-readers in "The Caves of Steel" have a capacity of only a few kilobytes per square centimeter of storage medium. "Aurora", in particular, presents a sequence of historical developments which explains the lack of nanotechnology — a partial retcon, in a sense, of Asimov's timeline. There are three Fourth Laws written by authors other than Asimov. The 1974 Lyuben Dilov novel, "Icarus's Way" (a.k.a., "The Trip of Icarus") introduced a Fourth Law of robotics: Dilov gives reasons for the fourth safeguard in this way: "The last Law has put an end to the expensive aberrations of designers to give psychorobots
Sci-Fi on the Rock Apart from the media guest Q&A's, autographs and photo sessions, there are many other workshops during the festival, these change yearly but in the past have included: Making its first appearance at Sci-Fi on the Rock 2009, the Cantina is an informal concert/variety show held on one of the evenings of the festival. Performers opt to play Sci-Fi related music, known as Filk, but that is not always the case. The Cantina features performances by musicians involved with the festival, an open mic, and there is an improvised acting piece prepared that audience members are call upon to perform. The