Wow... You have no idea about flash!

Magnetic Storage:
R/W Limit: Unlimited
Reliability: High
Density: Extremely High
Bandwidth: Very High
Random Access: Low

SSD:
R/W Limit: Moderate
Reliability: Low
Density: Very Low
Bandwidth: Very High
Random Access: Extremely High

The user who posted about read disturbs and ecc sounds like he's actually read a few journal articles about flash design.

I'm a PhD student studying magnetism, and one thing I can say for sure is that DVD/BR media is not the way to go. Professionally printed media (the silver bottom) uses a stamp to make a mechanical impression, not unlike vinyl records. Once sealed, it last forever. Writable media uses a die, and unless you store your media at 0K, finite temperatures will cause the die to diffuse and the media become useless. This takes much less time than people think. Good disks will last 10 years, cheap ones only a few years. The problem is that it's impossible to tell anymore who is making the good disks, since all of the production lines get shared by many brands.

Alternatively, magnetic storage isn't that great either (tapes or HDDs). For both a HDD and tape, thermal fluctuations cause random data to be lost, but hard drives are designed to recover this data and correct it. If you pull your hard drive off line for several years, it doesn't have the opportunity to constantly scan itself and check for these errors, so never expect an unpowered hard drive to store data for long periods of time - they just are not designed to do this.

As previous users have pointed out, software raid is the only way to go. Hardware raid provides a single point of failure, and is really only suitable for high performance and short term reliability, not long term reliability.

Tape drives also have the same thermal fluctuations issue, but because the magnetic grains can be much larger (tapes have 1000's of times more surface area to store the same amount of data) they can go much longer. I would still "refresh" my tapes every year or two though.

Based on your requirements, I would suggest tape first, then a large software raid of HDDs. Anything else is just not safe!

Also as a note to others... be careful not to judge someone for driving a huge car when you view it as 'unnecessary.' I hate the fact that I have to buy inefficient vehicles, but I didn't chose my height...

I really hate the push for mandatory reduction in fuel consumption. One of the primary ways they do this is by reducing the drag coefficient, which means lowering the roof. I am 6'5" and I cannot find a car that fits me anymore. It used to be that trucks and SUVs had much more headroom, but even now when I try the newer models, the roof is so low I cannot sit up. Besides serious discomfort, it also adds severe safety hazards. Most people don't think about the roofline, but because they keep on lowing the roof, my vision gets cut off at the top of the window. The consequence is that I cannot see strait out, but I have to look down. When I come to a stoplight, I cannot see the lights unless I lean into the passenger seat. I once ran a red light and my wife screamed... I didn't even see there was a light because it was above my vision. I don't have a problem with reducing emissions, and, protecting our environment is important, but please don't push a 'one size fits all' car on me that was made for someone 8 inches shorter than I am!

I agree that kidcharles might be asking for more than he thinks. Normally, the drive is accessed using LBA. Depending on how the physical media was grown (where defects formed) the LBA will correspond to different parts of the platter on every drive, even if they came off the assembly line in pairs. Furthermore, when you say you want to control where the 1's and 0's are stored, this is a bit of a misnomer. The data is NRZI encoded, and the ones and zeros are actually stored in the presence or absence of a domain wall. If you were referring to controlling the relative placement of the data (inner or outer part of the platter) then you may have some luck with the firmware. As others have pointed out, in this case your best shot would be to ask for a drive with custom firmware. It will cost you, but they already have diagnostic firmware that does this, and they would just need to make a stripped down version that doesn't allow you access to the features they don't trust you with (which is most of them). Good luck :)