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IBM Sets Areal Density Record for Magnetic Tape
digitalPhant0m writes to tell us that IBM researchers have set a new world record for areal data density on linear magnetic tape, weighing in at around 29.5 billion bits per square inch. This achievement is roughly 39 times the density of current industry standard magnetic tape. "To achieve this feat, IBM Research has developed several new critical technologies, and for the past three years worked closely with FUJIFILM to optimize its next-generation dual-coat magnetic tape based on barium ferrite (BaFe) particles. [...] These new technologies are estimated to enable cartridge capacities that could hold up to 35 trillion bytes (terabytes) of uncompressed data. This is about 44 times the capacity of today's IBM LTO Generation 4 cartridge. A capacity of 35 terabytes of data is sufficient to store the text of 35 million books, which would require 248 miles (399 km) of bookshelves."
The biggest issue with tape is keeping the density and cartridge capacity up. Even though tapes and magnetic hard drives share a lot in common, storing data on rust is where the similarities end. Tape media contacts the head and is read while the head is contacting, as opposed to HDDs which float very close to the surface of a disk. So, the material the magnetic domains are on has to be sturdy enough for physical contact. Tape does have an advantage that it has more space to store data than a disk platter. However, a lot of that space is taken up by error correction, since there is no way to relocate bad sectors on the fly with tape, and if a block goes bad, it goes bad, no way to recover without ECC, or a way to duplicate the lost data.
What tape has over hard disks is simplicity. A DLT or LTO-5 tape has one reel for a moving part. Compare that to a hard disk which has the platters, the heads, the wires, and the motors. Drop a tape, and it almost certainly is recoverable. Drop a hard disk, and a person never knows if the hard drive is completely dead, or will die very soon due to the impact. This is also important when it comes to archiving. Tapes, you can put in their cases, drop them axis vertical in an Iron Maiden tub, and your data is secure. With hard disks, you have to put them in padded boxes to help dampen vibrations which can kill the drive.
Tape drive makers are also responding to the clarion call of encryption. HP's LTO-4 line supports SPIN/SPOUT encryption capabilities. You can set it to use the same passphrase on multiple tapes, or use backup software which sets a different key on each tape and manages which key goes to which tape for better security. Software like Retrospect, Backup Exec, or bru also offer AES encryption with libraries certified by the US government. So, a tape backup is decently secure.
Tapes can be set to be read-only. This is important because it means that a tape read on a compromised machine won't be able to be tampered with. Some tape systems (DLT) offer WORM functionality to allow for secure archiving of data with the data cryptographically signed by the tape drive. This is important when one has to deal with HIPAA and archiving of data for 7 years, or the FAA and archiving airplane data for 50 years.
Tapes are fast. This is also one of their weaknesses. If you don't feed them the full amount of their pipeline, the tape drive has to stop and reverse. "Shoe-shining" is not good for tape life, nor the life on heads. So one needs to have tape drives preferably on a computer with the I/O paths to handle it [1].
Finally, once you buy the drive, tapes are the best bang for byte you can get. Even older tape formats like LTO-4 that give 800 gigs native for $40 is still fairly cheap for the capacity.
[1]: Ideally, the best use of tape is a network backup server with a good RAID array. You back the machines up to the array, then copy the data to tape. This way, network glitches do not slow down the data being slapped on the tapes.