TARDIS is the name given to the ships that were invented by the Time Lords to facilitiate travel through both time and space. Such was the sophistication of Timelord technology that a Tardis (an acryoymn for Time And Relative Dimension In Space) was grown rather than built. They maintained a constant link to the Eye of Harmony Gallifrey which was placed deep beneath the Capitol. In addition to the Eye of Harmony, Tardises also relied on mercury which was stored in fluid links within the central control console. a Tardis also requires the installation of zeiton 7 ore in order to traverse the space/time continum and artron energy in order to maintain smooth transition of power throughout the ships. It has recently been revealed that in the case of the Doctor's Tardis, it draws it's power from the universe using huon energy. This maybe an alternative source of power as the eye or harmony persumably no longer exists due to the destruction of Gallifrey.
In order for a Tardis to become fully operational it must have the biological imprint of a Timelord. This is where an extract of Timelord DNA is stored within the Tardis thereby allowing a symbiotic link to take place. This allows a Timelord to achieve greater control and withstand the stresses of Time Travel. This ability is also extended to non Time Lord passengers which is why human and other travellers have been able to travel with the Doctor unharmed.
All Tardises are dimensionally transcendental which means the interior dimensions exist within a different dimension from the exterior. This explains why the interior of Tardis has an infinate number of rooms when the exterior may appears rather small as is the case with the Doctor's Tardis.
His Tardis is an old type 40 TT capsule (Time Travel capsule being the formal name given to all Tardises). This particular model was obsolete and was due to be decomissioned when it was stolen (or borrowed as he put it) by the Doctor when he escaped from Gallifrey. I should point out that all Tardises are equipped with anti theft devices. In this case as the Doctor illegally entered this Tardis he was subjected to a severe mental assult by the Tardises telepathic devices. This resulted in some permanent damage resulting in the Doctor being unable to fully understand or pilot it. Why he attempted this when he must've know what would happen is unknown but it would seem he was prepared to risk the injuries he sustained rather than stay any longer on Gallifrey.
Upon entering a TARDIS the first room encountered is the Console room. This houses a central console consisting of 6 panels and a central transparent column in the centre. The panels are responsible for the control of all major aspects of the Tardis functions with the exception being the fault locator which was situated elsewhere in the console room. I have used the original console design when describing the use of the six panels as there appears to be the most detail when describing the functions of said panels.
Panel 1 governs the audio unit, course acceptance unit and safety precaution switch. The audio unit is one of six with one being installed on each panel. They govern the reception of sounds transmitted from outside the ship. It is fair to assume that this function has been intergrated into one unit on one panel during the console's various upgrades. There are 3 lights which indicate the direction of time travel, from left to right they indicate past present and future travel through time. Next is the Course acceptance unit. This is a computer dedicated to the safe dematerialisation of the Tardis. Once this unit is activated the computer is ready to accept the co-ordinates . Dematerialisation is impossible without first activating this unit. Once in flight however course details may be altered and a new destination selected. Following the course acceptance unit is the safety precaution switch. This prevents the Tardis from materialisation in a dangerous or hostile environment to itself. However this does not mean that the occupants of the Tardis would be protected. So if the ship were in the path of an object that would not harm it then the switch would not be activated even if said object presented a hazard to the occupants. This has since been replaced by the H.A.D.S. (Hostile Action Displacement System). The HADS is designed to protect both the Tardis and its occupants.
