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Write Bits Directly Onto a Hard Drive Platter?
kidcharles writes "I'm working on a project that requires writing bits to a magnetic hard drive platter in a completely controlled fashion. I need to be able to control exactly where 1s and 0s will appear physically on the platter. Normally when data is written to a drive the actual bits that get written are determined by the file system being used, as modified by whatever kind of error handling the drive itself is using (e.g. Reed-Solomon). All of the modern innovations in file systems and error handling are great for reliable and efficient data storage, but they are making my particular task quite daunting. My question for Slashdot: is there a way to get down to the 'bare metal' and write these bits? Any good utilities out there to do this? Obviously a free and open source solution would be preferable, but I'm open to anything at this point."
The cynic in me wonders if he is working for some hack start-up company trying to develop a DRM scheme for a hard drive, similar to the crap the studios do to DVD's to make them difficult to rip. Typically this involves creating some sort of currupt/invalid area on the disk that your particular device will know to ignore, but will lock up anyone else trying to read the data off the drive.
The optimist in me wonders if he is trying to defeat such a scheme.
We don't need to work like that any more.
The submitter appears to know enough about what he's asking to know that it's also impossible / completely impractical. Recording ones and zeros directly isn't done for a reason, submitter appears to understand this.
Keep in mind that the question is not just why the submitter wants to write directly to the magnetic domains of a hard disk, but why the submitter asked the question of how to write directly to a hard disk.
I can think of a number of reasons for the latter:
- The submitter could be an author writing some cyberpunk techno-thriller, and wanted some technical feedback from the 'experts' on Slashdot.
- The submitter could be a CIA drone trying to write a report on how it's impossible for the terrorists to somehow 'hide' data on hard drives that even 'dd' can't read.
- The submitter could be a troll.
That's just off the top of my head.
On the other hand, I seriously can't think of a good reason why anyone would want to actually damage a hard drive that way. If all you wanted to do is very precisely create a surface with a complex pattern of specifically oriented magnetic domains, there's easier ways. For example, there are equipment suppliers that can provide high-precision two axis steppers with ready to use computer control interfaces. It's not hard to get equipment that'll go down to atomic precision.
A whole chip? Really? That sounds hard. Just Ebay an old 20MB Seagate ST-225 MFM drive, and write whatever bits you want. It doesn't know any better.
Or, the submitter could contact Seagate or another drive manufacturer and ask what it would take to get a drive with special firmware that let him write 1's and 0's directly to the drive wherever he wanted. Basically, remove the intelligence on the drive.
It's not that impossible for drive manufacturers to do things like this for you, if you have the $$ to pay for it. I don't know what the cost would be, especially since he's really only [probably] looking for a few drives for this project. If it's grant-funded research, the grant would pay for it. If it's an independent project of some kind, he's in for a surprise.
I took a behind-doors tour of a major drive manufacturer a few years ago. During our visit, we were able to visit with engineers - one of whom was head of the firmware engineering team. He told us lots of stories about the firmware requests they've fulfilled. One example was a customer who supported lots of old PBX systems. These PBX systems ran software from a hard drive, but due to the age the system only supported drives up to (around) 200MB. Nobody made drives that small anymore, so this drive manufacturer re-wrote the firmware for them ($$) so a 120GB drive (the smallest they made at the time) would only recognize & address the first 200MB.
So yeah, I'm sure a drive manufacturer like Seagate could write custom firmware for him that would meet his project needs.