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We are generating more and more data. Hard drives are maxed out. Archives therefore rely on tapes – including the SRF.
Swiss radio and television not only broadcasts and streams, it also collects: 200,000 hours of video and one million hours of audio material are stored in the digital archive.
There is space for all of this on the surface of a delivery van: two rows of racks, each about six meters long and almost two meters high, filled with ribbons. In between, two robots race around, transporting the cassettes from the rack to a drive.
Although ten to fifteen thousand hours of top-quality video material and up to 70,000 hours of audio material are added every year, the digital archive in the basement always takes up the same amount of space.
Seven million books fit in one hand
This is possible because every two years a new tape generation with twice the capacity comes onto the market. The technology from the 1950s is currently experiencing a second spring among the operators of large archives.
The tapes in the cassettes are reminiscent of the old video cassettes: a thin plastic tape, 12.7 millimeters wide, one kilometer long, rolled up about the size of the palm of a hand. The second roll is in the reader. A “cartridge” is therefore only about half the size of a VHS cassette. This saves space in the archive.
A tape of the latest generation costs around 100 francs and offers 18 terabytes. This corresponds roughly to the text of 7.5 million electronic books. Soon it will be 15 million or 36 terabytes.
Legend:
Second generation LTO tape: Current cartridges look the same, but can store 18 terabytes.
Austinmurphy, Wikipedia
Smaller than a virus
There is no end in sight to this increase. Experts at the IBM laboratory in Rüschlikon have developed a device with which they can store 500 terabytes on a tape. This is possible because tapes are written much less densely than hard disks, explains Simeon Furrer, who researches new tape technologies for IBM.
A bit on a tape of the latest generation is 50 nanometers long – shorter than an HI virus, but still quite long: “With hard drives, the length is still a quarter,” says Simeon Furrer.
There is even more potential for compaction across the board. Currently there are 10,000 tracks next to each other on a tape. In the future, a tape will be able to be written on several tens of thousands of tracks.
Tape machines: safe but expensive
This is made possible by drives that can write to 32 tracks simultaneously. If the first 32 tracks are full after one kilometer, the device engages reverse gear, moves the read and write heads sideways and begins to write again.
In the last 15 years, out of 1000 tapes in the archive that are in daily use, only one tape was no longer readable.
During the writing process, the data is continuously read in again and checked. If an error occurs, it will be corrected. This makes tapes an extremely secure storage medium. Martin Blumenstein, head of the SRF archive, confirms: “In the last 15 years, out of 1000 tapes in the archive that are in daily use, only one tape was no longer readable.”
The sophisticated error correction and the high-precision mechanics in the devices have their price: a drive costs several thousand francs. An archive on tapes is therefore not worthwhile for consumers, even if a single cartridge is cheap.
Nevertheless, everyone benefits from the rapid development: it is quite possible that photos and videos from smartphones will end up in a tape archive in the future – for example on YouTube, Instagram or Tiktok.