Are USB thumb drives as vulnerable to memory loss and failure as HDD?
Ase they Solid State devices?
What is their technology?
USB thumb drives are solid state devices. In electronics, "solid state" means that circuits are built entirely from solid materials, in contrast to other technologies that use vacuum or gas-discharge tubes, or electro-mechanical devices with moving parts.
The difference between USB thumbdrives and what is marketed as "SSD" drives is the type of NAND flash memory used (as well as the device capacity, and what interface is used). But, in technical terms, USB thumbdrives are SSDs, as are drives based on volatile memory and software-based storage technologies like RAM disks.
As far as "memory loss and failure" vulnerability, solid state devices are not vulnerable to the same failure modes as standard hard drives. They won't suffer mechanical failure and they can't be erased by a powerful magnet. Instead, flash memory is vulnerable to other failure modes. Some failure modes can affect both types of drive; EMP, extreme circuit overload (think lightning strike), fire damage, and severe corrosion of interface contacts are just a sampling of the possibilities.
SSD or flash drives store information as electrical charges on a silicon chip. The charges are stored as a positive or negative charge similar to a capacitor. They are more reliable because they do not suffer from mechanical failure like regular magnetic disk hard drives. Solid state devices are a major improvement over magnetic storage but they are not invincible. The EMP from a nuclear detonation could wipe/alter/damage the charges on the chip thus destroying data.
I have personally lost 3 magnetic disk hard drives because of mechanical failure. By the way 2 of the drives where made by Toshiba. I now use a SSD (solid state drive) hard drive for my laptop and have not had any problems yet but I dont trust anything manmade. A good practice is to back up all files often.
There is a disadvantage to making everything smaller and more energy efficient - it is very delicate!!!!
If a media blackout was ever desired by anyone with the power (good guys or bad guys) it could easly be done by any weapon that causes an Electro Magnetic Pulse (EMP).
In my practical experience, thumb-drives are equally as prone to failure as hard drives, but for different reasons. Like SurDin said, eventually the flash cells wear out and fail (often leading to data loss, or at the very least preventing the flash memory from storing any new data). Frequent erasure or re-writing of data on a flash drive leads to quicker failure, due to the "flashing" process that sends a surge of electricity to clear the contents of a memory cell.
Again, from a practical standpoint, I have seen just as many flash drives fail as hard drives. I'm an on-site computer technician and I carry most of my software toolset on a flash drive. Because I run applications directly from the flash drive, a lot of writes/rewrites occur. At my current, almost daily use of my flash-drive I go through about one a year.
Another consideration is cost. Flash memory has a vastly higher per-gigabyte cost than contemporary magnetic or optical mediums.
Finally, there is the speed impact to consider. Flash memory is usually faster than optical mediums (CD, DVD), but usually has much a much slower consecutive read/write speed than magnetic mediums (Harddrive).
Since you said that you were looking for a place to backup your music, I would recommend an external harddrive. The cost per gigabyte will save you in the long run, the reliability is at least as high as flash memory, and it's the fastest option. www.newegg.com has some excellent deals on external hard drives.
About the technology:
Flash is a technology based on a quantum effect. What happens is that you read the charge of a cell that is surrounded by insulating material. When you want to write to the cell high(er) voltage is applied to the pad near the cell, and electrons tunnel into the cell.(Wikipedia)
This makes Flash invulnerable to mechanical stress, that was the biggest problem of HDDs, but since there is a chance for the electrons to pass through the insulator surrounding the cell, it deteriorates over time, and depending on the size and quality of Flash cells, they have finite writing quantity.(Usually between 1000 and 100000 times), afterwards you'll see bad sectors appearing like on regular hard drives.