It's not the machine with Jeremy Clarkson's "ideas" Notepad document saved to its hard drive, but something even more critical to the ongoing maintenance of one of the most important items in the car world -- it holds the power to connect to the McLaren F1 supercar.
Due to the F1 being a bit old now in supercar terms, the hardware needed to interface with it for servicing purposes is also a little antiquated -- hence McLaren's team needing a very specific model of laptop, the Compaq LTE 5280, in order to run a custom Conditional Access (CA) card that contains the proprietary interface needed to hook into the car.
Only this card is allowed to access the F1's ECU, in order to form a sort of hardware access control system that stops any old mechanic tinkering with the F1's core control systems.
Older readers might remember the internet legend of John Titor, an time traveller from the future who needed an old IBM machine to debug the systems of his time. Sadly, that was a load of rubbish, so much so that no one even bothered making it into a film. McLaren's coveting of ancient hardware is the real deal, with McLaren's needs driving the price of this particular old Compaq through the roof. [Jalopnik]