K9 Mark 2 had some obvious commonalities with the Mark I that had preceded him. However, as he had almost completely lost his personal memories, he was forced to reacquaint himself with the world around him. Toward this end, he downloaded thousands of human movies onto his memdrive, which peppered his speech with 20th and 21st century English colloquialisms that his "brothers" did not typically employ. (TV: Alien Avatar) Despite his negative opinions of emotions, (TV: Mutant Copper) he asked questions about some, such as fear (TV: Fear Itself) and love (TV: Aeolian). He even showed some, laughing when he saved the day, feeling fear (TV: Fear Itself) and being angry. (TV: Regeneration)
In 1996, Sarah used K9 to hack into records and find Sam Jones' home address and later to translate Lost Boy's speech. (PROSE: Interference - Book One) K9 was briefly possessed by a malevolent entity, but was freed when Sarah accidentally electrocuted him. (PROSE: The Sow in Rut) K9 began slowly breaking down and eventually ended up deactivated in a cardboard box in Sarah's attic. (PROSE: Moving On) Hilda Winters had K9 dismantled and analysed. (AUDIO: Mirror, Signal, Manoeuvre)
Professor Frederick Marius, who invented the first K9 in the year 5000 while working on the asteroid K4067, described him as "my best friend and constant companion." Marius had a dog on Earth, but weight requirements did not allow him to bring his real dog into space, so he built K9. (TV: The Invisible Enemy) He built K9 by using the latest technology. Marius used his own medical computer, a state-of-the-art intraresponsive brain app, protective anti-radiation cladding, probes, a laser scapel, a vision and voice box and two scanning antennas. He put these parts together and created K9. (PROSE: One Man and His Dog) According to one account, the Professor copied the remnants of one of the versions of K9 created by the Doctor and given to Sarah Jane Smith. (PROSE: Tautology)
K9 was a popular enough character to warrant an attempt to spin him off into his own series. In addition to K9 dolls, there were also talking K9 toys produced by Palitoy, the speech provided by a miniature record inside the body of the toy. John Leeson provided the voice for K9 in all its appearances, except for Season 17 (which included the unfinished Shada) when it was voiced by David Brierley. When Shada was remade by Big Finish Productions, Leeson provided its voice.
When being imprisoned by the Sporraxx they tried to access K9's memory core. Memories that K9 had assumed to be erased were slowly coming back and the Sporraxx got to know more and more about K9's past. They reprogrammed K9 to protect a small spherical marauder bomb, that would destroy Earth. However K9 was able to break free of their control, because deep in his memories a sense of right and wrong prevailed. He took the bomb back into the Sporraxx space ship where it exploded. (COMIC: Short Circuit)
The practical challenges of working with the K9 prop have accompanied the robotic pooch in his return to Doctor Who. Producer Russell T Davies told SFX magazine, "Yes, just as we expected, multiple takes [were required] when he bumped into a door or veered off to the left. Lis Sladen did warn us, and she was right!" 2009 saw two different incarnations of K9 appear regularly in two Doctor Who spin-offs: Mark IV in the third series of BBC production The Sarah Jane Adventures, and a re-vamped Mark I in the Park Entertainment production K9.
Despite those drawbacks, K9 comes with a handful or so of predesigned filters and an option to customize. With more than 50 categories for organizing Web sites, and the keyword-free proprietary K9 rating system, the Web monitoring and blocking aspects of the software functioned well. K9 also has categories for blocking sites that have been detected as potential malware threats. Equally impressive, and a little bit scary, was the log that detailed not just blocked Web sites but also every Web site visited.
The handler and dog must also be able to pass the police test, which involves controlling the dog fully, even after giving the dog the attack command. The dog must stop immediately and fulfill any command it is given by the handler. There are specifications of training involved in using trained K9 police dogs in the airport, marine ports, railroads, in a metro station.
K9, occasionally written K-9, is the name of several fictional robotic canines (dogs, the name being a pun on the pronunciation of "canine") in the long-running British science fiction television series Doctor Who, first appearing in 1977. K9 has also been a central character in three of the series television spin-offs: the one-off K-9 and Company (1981), The Sarah Jane Adventures (2007–2011) and K-9 (2009–2010). Although not originally intended to be a recurring character in the series, K9 was kept in the show following his first appearance because he was expected to be popular with younger audiences. There have been at least four separate K9 units in the series, with the first two being companions of the Fourth Doctor. Voice actor John Leeson has provided the character's voice in most of his appearances, except during Season 17 of Doctor Who, in which David Brierley temporarily did so. The character was created by Bob Baker and Dave Martin, to whom rights to the character still belong; consequently, Baker's spin-off series K9, which is not BBC-produced, cannot directly reference events or characters from Doctor Who, though it attempts to be a part of that continuity.