Take the 2-minute tour ×
Super User is a question and answer site for computer enthusiasts and power users. It's 100% free, no registration required.

My Google-fu has been useless here, and my knowledge of low-level storage details is terrible.

Does a brand-new, right-off-the-shelf hard drive contain all random noise, or do they come with all zeroed-out bits? I've wondered for a while but it's mostly been a question to consider in passing. This may be a manufacturer-specific detail, however.

For context, I was considering whether or not an encrypted section of a disk would be identifiable by an adversary. Secure ciphers are (conjectured to be) indistinguishable from random noise, and so if new drives were all random noise, an adversary would be unable to identify an encrypted section. If new drives are all zero bits, however, it would be precisely the opposite.

share|improve this question
    
If you are worried format the drive yourself. There are tools that would make any default setting pointless to have. The answer to your question of course, since it has no filesystem, it really doesn't matter whats on the hdd because there isn't any data on it. –  Ramhound Jul 25 '13 at 18:19
    
Ramhound's right. Even if the contents of the encrypted files were indistinguishable from random noise, they still have to be stored in a well-structured file system in order to be retrievable. –  Mason Wheeler Jul 25 '13 at 18:30
    
@MasonWheeler: I'm not talking about encrypted file(s), I'm talking about an encrypted section on disk (encrypted sectors, I suppose) --- if such a thing is possible. Regardless of the application, I'm still interested in the answer to the question. I don't actually intend to write my own disk encryption software. I was mostly curious about the theoretical possibility. –  Reid Jul 25 '13 at 18:32
    
@Ramhound: What I'm asking is what is the data that exists before formatting. I don't know much about how low-level filesystem code works, but I assume there is an interface that offers some method of reading/writing raw sectors to/from the disk? The point of the thought exercise is to have deniable encryption, and putting a filesystem on the disk does not help in that regard. But these are all irrelevant contextual details. –  Reid Jul 25 '13 at 18:36
    
@Reid - A new disk contains no data nor any file system. I don't even think the disk would contain zeros as that would imply that all the bits are zeros and that simply wouldn't be the case it woudln't have any charge ( and a zero indicates a certain magnaetic charge ). –  Ramhound Jul 25 '13 at 18:41
show 4 more comments

2 Answers

up vote 6 down vote accepted

Disk drives are always low-level formatted at the factory. The bit pattern used might not be zero, but it certainly isn't random. See Wikipedia.

share|improve this answer
    
Interesting! Thanks for the link. I couldn't find the right terms to use for Google, since most of the links were something related to support. –  Reid Jul 25 '13 at 22:55
add comment

My understanding is that a new out of box hard drive should have all zeros. However, during all the packaging, transportation, testing, etc. that each new HDD experiences it is not out of the realm of possibility that a new drive might have some "1"s thrown in.

Ultimately, as much fun as this is to speculate, it really shouldn't matter, I doubt you would be able to identify a manufacturer that way and as soon as you write data even once the initial "signature" of the drive would be gone.

Interesting question though.

share|improve this answer
add comment

Your Answer

 
discard

By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.