A 70 TB tape cartridge: too much, too late?
IBM and Fujifilm have demonstrated a technology that, if productized, could give us a 70 TB LTO tape cartridge. Is tape dead - or merely sleeping?
Vacuum column, 800bpi tape drives Magnetic tape is the oldest digital storage technology still in use. Once mass storage meant tape storage because drums - and later, disks - were tiny and absurdly expensive. Tape predates disk technology by almost a decade, but it's retreated to niche archiving applications.
They demonstrated a density of 29.5 billion bits per square inch on linear tape. Linear tape uses a stationary head to lay data down in long straight tracks. Video tape has a rotating head that lays down short tracks that angle across the tape.
Linear tape is more reliable for data applications due to reduced tape wear and more accurate positioning. Disks are approaching 1 trillion bits per square inch - but tapes have a lot more area.
If economics and manufacturing technology allow this could lead to a single tape cartridge with a 35 TB of uncompressed data capacity. Since tape drives typically compress data at a 2 to 1 ratio this means 70 TB of data in a single LTO (linear tape open) cartridge.
Current LTO tapes, even with compression, file at about 2 TB per cartridge -- the same as high-end disk drives. In nine months those 2 TB disks will cost about the same as single LTO cartridge. Why store data on disk where it is so much faster to access?
Defenders point to tape's energy efficiency -- write once and shelve without consuming more energy for decades -- but people like the convenience of random-access data. If this drive industry woke up and started offering archive quality disks -- Seagate sold an automotive hard drive that carried a 10 year warranty -- much of the remaining tape market would disappear.
Lifespan is another benefit of tape technology. I recently transferred a 20-year-old VHS tape that hadn't been looked at in at least 10 years to my computer. There was some drop out but the picture was very watchable. Try that with a 20 year old disk drive.
Technology The IBM/Fuji film team attributed their success to four technologies.
- Advanced nano particle technology -- they limited the size of the barium ferrite particles to 1600 nm3 -- approximately 1/3 of current metal particle volume.
- Advanced nano coating technology -- a smooth and thin magnetic layer with very low variability reduced signal fluctuation significantly, enabling more accurate signal processing.
- Advanced nano dispersion -- a new material controlled agglomeration enabling more uniform dispersion of the nano particles.
- Nano perpendicular orientation -- taking advantage of the barium ferrite particles crystal magnetic anisotropy, a perpendicular orientation improved high-frequency characteristics.
Let's see: mass production of tiny uniform nanoscale particles; mass production of an extremely smooth and thin magnetic layer; and careful control of the particle dispersion and orientation. What could be simpler? Hey, make it cheap too.
A read/write head that can use all that would be a plus, too. Is that too much to ask?
The Storage Bits take Regardless of whether you think tape has a long-term future, this is an impressive demonstration. When I introduced DLT at DEC, we were thrilled to get to 2.6 GB on a tape cartridge.
Like most such demonstrations this has both a marketing message and a technical message. The marketing message is "tape has a lot of life left in it" but the hidden technology message is "it will be many years before you see a 70 TB tape cartridge."
If they can get the cartridge to market in the next 5 years, they'll can charge 5x what a disk costs - because the capacity is so much higher than any single disk. If they can't - well, it was a neat tech demo.
Nevertheless, tape remains the most proven archival storage medium for digital data. Tape may yet live to see that 70 TB cartridge delivered.
Comments welcome, of course. I used an audio cassette recorder for mass storage on my first computer. Couldn't afford $800 for a 144 KB floppy disk. I now have 11 disks - and 2 optical drives - on my Mac Pro. That cassette recorder was my 1st - and last - tape drive.