File IO to unpartioned data

Hi,

I am wondering what the possibilities are for writing files to an unpartitioned area of a disk, i.e the free space area. Now this would obviously mean i would have no file system or partition tables etc to work with.

The problem is im not sure on the best way to approach this and what tools i would need, so im after some advice on languages/library's i could use to do the job. For example, could it be done with something high level like C++ or would i need to go down to assembly.

To make things more difficult a cross-platform (windows/linux) would be preferred.

From what I can think up, I would need to have some kind of 'virtual' file system that my program knows about, and can use to read/write files from the disk area. I'm really just not sure about the actual IO.

Thanks for any advice,

Jack

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Originally Posted by (TNT)

Now this would obviously mean i would have no file system or partition tables etc to work with.

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No - you have a partition table with partitions that don't span the entire disk. Or you have a completely blank disk, or you're not using partition tables.

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The problem is im not sure on the best way to approach this and what tools i would need,

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What exactly are you trying to do? Why do you want to write files in unpartitioned space? Offer the forum more insight on what you're trying to accomplish - there may be a Better Way.

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To make things more difficult a cross-platform (windows/linux) would be preferred.

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Probably not going to happen, unless there's a library out there that I'm unaware of that bridges the gaps.

If you're on Linux, I think it's just as easy as opening one of the /dev/hd? files. Granted, if there's anything on that drive, you need to know exactly what you're doing, or you will lose data. It probably also won't work on mounted drives and you'll need root privileges. Windows is an entirely different story. Again, what exactly do you want to do?

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From what I can think up, I would need to have some kind of 'virtual' file system that my program knows about, and can use to read/write files from the disk area.

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Why reinvent the wheel? Whatever you're using now has a perfectly good file system on it...

File systems are not simple things - even something as primitive as FAT32 would be a considerable task. If hiding data is what you're after, then putting it in unpartitioned space is a waste of time/effort. There are tools to look in those places. You're better off encrypting your data with a reasonable algorithm in my opinion, and putting the files in some easier-to-access place.

Thanks for the info, and sorry i didn't provide more information. The reason i was looking into it was for a form of stenography, the data is already encrypted i was just wondering if i could extend my project by making the encrypted data hidden and appear purely as random data in the free space of the drive, hence adding a form of 'plausible deniability'.

Maybe this is an unrealistic idea though, especially with a cross-platform requirement.

TrueCrypt
- is open source
- is cross-platform
- has steganographic features for plausible deniability