Carrez: The real problem with Java in Linux distros

Posted Sep 26, 2010 18:01 UTC (Sun) by elanthis (guest, #6227)
In reply to: Carrez: The real problem with Java in Linux distros by cesarb
Parent article: Carrez: The real problem with Java in Linux distros

It has nothing to do with the DRM. It's what they use for the interactive programs found on some Blu-ray discs. Think of the DVD menus you're used to, but now add actual Turing-complete language, some small bit of data storage, and an Internet connection. Someone thought it would be neat to include that kind of interactive content on a movie. (I disagree and think it's stupid as hell, but that's not particularly relevant.)

Carrez: The real problem with Java in Linux distros

Posted Sep 27, 2010 13:15 UTC (Mon) by cesarb (subscriber, #6266) [Link]

Yes, it has to do with the DRM. I looked again at the long (38 pages) thread (it was easy to find again, it is one of the references from that Wikipedia article), and at the related threads that branch from it. This is from the first post on one of the branched threads:

> BD-J does not only provide the menu/gui for convenient movie playback. The BD-J applications (Xlets) also interact with the content code (BD+) via TRAP_ApplicationLayer. A basic BD-J platform implementation is therefor required to properly repair BD+ corrupted movies.

http://forum.doom9.org/showpost.php?p=1254307&postcou...

Carrez: The real problem with Java in Linux distros

Posted Sep 27, 2010 13:56 UTC (Mon) by sorpigal (guest, #36106) [Link]

I think they think that this whole web site fad will go away if they can deliver similarly dynamic content to people's TVs in a manner that is slick and (most importantly) under studio control.

Just imagine! Why get a computer and a web browser and all that complication if you can just insert your Info-Acces Blueray and get a sanitized subset of available information!

Carrez: The real problem with Java in Linux distros

Posted Sep 30, 2010 15:09 UTC (Thu) by BenHutchings (subscriber, #37955) [Link] (1 responses)

DVD menus are also controlled by a program running on a virtual machine. The VM is Turing-complete but is limited to 128 instructions per menu, 16 16-bit general-purpose registers and no memory.

Sorry, but this is NOT Turing-complete VM

Posted Oct 2, 2010 22:35 UTC (Sat) by khim (subscriber, #9252) [Link]

For Turing-completeness you need some kind of ENDLESS memory. It may be tape (as in Turing or Post machines), memory (well, most CPUs have finite memory so they are fully not Turing-complete - yet 2^64 is usually "good enough") or just a few counters (three is enough - but they must be unbound!).

DVD VM has very limited memory so it's not Turing-complete...