This also happens for NCERT, Medical Entrance Examinations, Engineering Entrance Examinations among several others. No Legal action has been taken in the recent past to stop such recollection, despite the fact that it merely promotes rote learning, textual recall or fundamental pattern matching. Interestingly, in India, no one has referred to this practice as cheating, although it is. It is only in the past two years that Computer Aided Tests which shuffle questions and stagger timelines are being introduced to avoid this practice. Enforcement of legal sanctions in India especially across Educational boards, Varsities and Corporate Testing groups have not been easy.
Question papers, by themselves for any test are never copyrighted officially. Most Board question papers in India, Pakistan, Sri Lanka, Bangladesh and Nepal do not come with any Copyright notices. Boards and Academic members have until recently been in the dark about 'Copyright Law' and have little idea as to how it is enforced. A vast number of books published are not registered for copyright, nor do they have ISBN assigned to them.
Part of the issue is the inability to enforce exclusivity on 'recalled' or 'reproduced' testing material. Another part is ignorance of the full extent of 'Copyright Law' itself, though this is significant in nations like India and China where their implementation has only now begun.
Bad blocks are inherent in NAND flash. SLC NAND Flash devices are more reliable (have fewer errors) and costly. MLC NAND Flash devices are less reliable (have more inherent errors) but are affordable and easily available. NAND Flash devices are known to progressively degrade until the number of bad blocks is too high to reliably store data. Inherent errors during manufacturing increase on usage (both read and write.) Most Flash Storage Devices will ultimately become too error-prone to store data. The industry might want to justify inherent errors (and gradually increasing errors) by calling it a fingerprint. They are still searching for techniques to make NAND Flash more reliable.
The article fails to provide mathematical basis to prove that two NAND flashes cannot have the same bad blocks on manufacturing or at some point of usage thereby obscuring identity. NAND flash controllers are designed to check and resolve errors using known algorithms. Most controllers allow hardware to hide errors while allowing OS device drivers to read the NAND flash medium. The Operating System and the NAND Flash Controller are at least two points were any such fingerprint can be compromised. The Filesystem adds another layer of abstraction. The number of "Real" bad blocks and remaps is usually stored on the NAND Flash. Altering the Bad Block Table is not difficult.
Hard Disks interestingly have similar failure rates and complex issues like Data remanence which have been studied. I wonder why no one proposed a signature scheme for using errors on Hard Drive Platters to identify them. Computer Forensics for Hard Drives has a longer track record of being studied. Marketing fud can be ignored.
I read both the articles posted. They do not qualify as the best investigation reports. They seem to be building "What if" scenarios from all data that is available. Other A330 failures (no recent crashes reported) and Other places where ice in Pitot tubes led to failure (The Wikipedia article has a lot of information on this and planes which had problems notably, the X31.) The investigators are clearly under pressure to say what they have found and they are unable to report "nothing" to the press. With no luck in recovering the Black Box, the investigators (like they talk about Pilots not good at flying aircraft without the aid of in-flight safety systems) have to do it the old forensic way (reminds me of Crichton's Airframe). That is going to take time and the press, the Aircraft companies using A330s are impatient to know why.
Clearly no recent theory has come close to deducing the true reason for the crash. As I remember the first news item that appeared on the AF447 was that the plane "vanished" from Radar and was sought for by the Brazilian Air Force before the crash site was positively identified. The last exchanges between the Pilot and the Aircraft tower followed by an automated message from the aircraft remain the main clues apart from the debris in this horrific accident.
Link to Original Source
Link to Original Source