Tivoization: A necessary Evil

Quoting:Should you get access to the source code of all the embedded computers running on your car? What about all the wiring diagrams, engineering specifications, design diagrams, etc? With all that information, it'd be pretty easy for anyone to make a knock-off of the car, or any of its components.

They can do that anyhow -- always could (and not infrequently actually did). But that's not actually even about users/owners, but about manufacturers.

It used to be my standard practice, whenever I bought a car, to acquire the pertinent third-party manual. I generally preferred Haynes manuals http://en.wikipedia.org/wiki/Haynes_Manuals (more useful to a nerd like me who'd managed to have not taken auto shop in highschool, and wouldn't have more specialized tools) but Chilton was even more popular, or at least better known easier to find (at the time, more geared to experienced, even professional or semi-professional auto mechanics, since bought out by Haynes).

These manuals were much more affordable than the manufacturers' Official manuals, and often more useful -- some professionals, with the Official manuals at hand, still preferred these third-party documentation efforts, at least for particular brands or models.

The manufacturers of course objected to this "unauthorized" products, issued grave warnings about the likely consequences of relying on them (FUD is not a phenomenon unique to the IT field) and IIRC even launched legal actions against the publishers (I don't recall which precise grounds -- possibly copyright infringement?) but the third parties are still around, and these days the manufacturers have learned to actively cooperate, as a measure to improve customer satisfaction, loyalty, and other more direct economic benefits.

But the official and the third-party manuals all included the mechanical drawings, circuit diagrams, torquing recommendations and such. And I presume they still do.

@Bernard: The information needed to tinker (or at least, make it easier) is the same information that makes it much easier to make knock-offs. What if your car has an electronic control module (I think they call it the "body controller" these days) that's basically a low-power computer that handles things like turning on and off the dome light at various times, and you want to change that? You'd need not only the source code to that microcontroller, but a way of reprogramming it too, which can range in complexity depending on the type of CPU being used; if it's something like a Microchip PIC, you could probably use ICSP (in-circuit serial programming), but you need a special programmer for that; Microchip gives away schematics for their programmer for free on the net, but other makers like Freescale require you to buy an expensive software package to use and program their microcontrollers. But if it's something like an ARM cpu, then it's running some kind of bootloader, perhaps U-boot, then I really don't know how that would be reprogrammed if there's no ethernet port; they probably program the flash chips at the factory somehow, and if you don't have a way of reprogramming it, you won't be able to modify it.

The whole point here is that for mfgrs to tell customers how to tinker with their products would involve giving away a lot of information, perhaps even making design changes to make it easier. What if the product is potted? Then there's no way at all to modify it without cutting it apart and somehow removing all the epoxy; good luck with that.

There's a big difference between mfgrs putting up roadblocks, and simply not bothering to make it easy (because with modern electronics, it's frequently very difficult to modify something once its manufactured just by the nature of the technology).