Alan Cox is a programmer heavily involved in the development of the Linux kernel since its early days (1991). He maintained an old branch (2.2.x), and his own versions of the previous stable branch (2.4.x) (signified by an "ac" in the version, for example 2.4.3-ac1). He was commonly regarded as being the "second in command" after Linus Torvalds himself, although this has changed over time. Cox is employed by Red Hat and lives in Swansea, Wales with his wife, Telsa.
He was one of the people involved in AberMUD.
He is an ardent supporter of programming freedom, and an outspoken opponent of software patents, the DMCA and the CBDTPA. He resigned from a subgroup of Usenix in protest, and said he would not visit the United States for fear of being imprisoned after the arrest of Dmitry Sklyarov for DMCA violations.
Cox was the recipient of FSFs 2003 Award for the Advancement of Free Software at the FOSDEM conference in Brussels.