IBM makes another breakthrough today with an announcement about tape data density. Unlike hard disk drive technologies that are hitting physical limits, IBM is proving that tape technology still has plenty of life in its future. When I first started working for IBM in Tucson, back in 1986, a 3420 tape reel held only 180MB of data, and a 3480 tape cartridge improved this to 200MB of data. Today's enterprise tapes, like 3592 cartridges for the TS1130 drives, or LTO4 cartridges for the IBM TS1040 drives, are half-inch wide, half-mile long, and can store 1 TB or more of data per cartridge, depending on how well the data can compress. To increase cartridge capacity, designers can make changes in three dimensions:
- Wider tape: The film industry tried this, going from 35mm to 70mm film, only to find that most cinemas did not want to upgrade their equipment. Keeping the media dimensions to half inch wide allows much of the engineering hardware to continue unchanged.
- Longer tape: The problem with longer tape is that either the reel inside gets fatter, or you need to develop flatter media to fit within the existing cartridge dimensions. Wider reels means a bigger tape cartridge external dimensions, forcing changes to shelving units, cartridge trays, and carrying units. The media just can't get any flatter without risking getting more brittle.
- Denser bit recording: once a convenient width and length were established, improving bit density turned out to be the best way to increase cartridge capacity.
Working with FujiFilm Corporation of Japan, my colleagues at IBM Research facility in Zurich were able to demonstrate an incredible 29.5 Gigabits per square inch, nearly 40 times more dense than today's commercial tape technology. In the near future, we will be able to hold a 35TB tape cartridge in our hand. There was actually a lot to make this happen, improved giant magentoresistive read/write heads, better servo patterns to stay on track, thinner tracks less than a micron thick, and better signal-to-noise processing to accomplish this. To learn more, you can read the [Press Release] or watch this quick [4-minute YouTube video].
Tape -- You've come a long way, baby!