WE HUMANS are hoarders. We love to amass information. And these days, with digital storage at our fingertips, we stockpile ludicrous amounts of the stuff, whether it is on hard drives at home or in the cloud. You might be surprised to discover, however, that a hefty chunk of the information we are holding on to today – from backups of your emails and photos to particle collision data from the Large Hadron Collider – is stored not on sleek hard drives, but on clunky plastic cartridges containing coiled ribbons of magnetic tape.
That’s right, much of the world’s data is stored on tape – many thousands of kilometres of the stuff. While that may induce nostalgia for those who are old enough to remember making mixtapes and recording songs off the radio to cassette, tape technology has advanced enormously. So much so that researchers today are increasing its storage capacity at a rate that outstrips its rivals.
Even tape has its limits, though. We are generating so much data that eventually it will be impossible to store everything. Then what?
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To be clear, the tape we are talking about here isn’t quite the same as the cassettes that were once stacked high in the bedrooms of children of the 1980s, even if it is basically the same technology. The difference is that old-fashioned cassette tape is analogue, whereas the version used for data storage today is digital – meaning the information is stored in zeroes and ones.
Better than hard drives
When IBM brought the first commercial digital tape storage system to market in 1952, it could store 2 megabytes of data on one large reel. Today, its tapes are much smaller and yet they hold 20 terabytes of data, or 60 terabytes in a compressed format – increasing capacity by about 10 million-fold in 70 years. A single cartridge can hold more than a kilometre of digital tape, and the cartridges are stored in automated libraries, the largest of which can hold up to 23,000 of them.
To access the data, robots move back and forth on rails through the racks of cartridges. They work impressively fast, but it still takes 90 seconds for a robot to find the cartridge, remove the tape, put it on a drive and find the data on the reel, whereas a hard drive can retrieve your information in 10 milliseconds. Which is part of the reason why hard drives have long dominated data storage.
Then again, not all data needs to be retrieved at lightning speeds. From satellite imagery and surveillance camera footage to countless backups of your emails, tweets and financial records, archival data is known in the trade as “cold” data. Digital tape has survived and thrived as a means to store it because it offers several advantages over hard drives.
For starters, tape is secure and reliable. If it isn’t in use, it is safely tucked away inside its cartridge, disconnected from the internet, offering a robust defence against any errors or faults in computer programs, as well as cyberattacks. “If the cartridge isn’t mounted into a drive, no one can modify the data,” says IBM scientist . In 2011, a and affected data copies stored on hard drives. Luckily, Google had backed up the emails to digital tape and people’s accounts could be restored.
Most importantly, tape is cheap – which is appealing for what Lantz calls “hyper-scale cloud companies” like Microsoft Azure, Google and Meta. This is mostly backups of stuff like your inbox and your endless photos of your dog, as well as things like smart home security recordings, analytics, manufacturing logs and myriad other stuff besides.
In the past, to meet growing demand for data storage, these companies would just buy more hard drives. But the capacity of hard drives isn’t growing fast enough to keep up because they only have a limited amount of room to write data.
Magnetic tape is different. “We have a kilometre of tape, a huge surface area,” says Lantz. “We can keep scaling the technology.” They do it by shrinking the parts of a drive that can retrieve and record data, so that smaller bits of information can be recorded on the tape. You can think of it as the difference between using a thick marker pen to write on an A4 sheet of paper and using a fineliner on an A3 sheet. As a result, tape’s storage capacity continues to grow and that will carry on for a while yet. “We can keep scaling tape and doubling the capacity every two and a half years for at least 20 more years,” says Lantz.
For all its retro prowess, however, tape will also run out of space one day. We are producing more data than we can store. To grasp just how much, consider the zettabyte – roughly equivalent to 250 billion DVDs. In 2020, we produced some 59 zettabytes of data; projections suggest that by 2025 we will be generating 175 zettabytes every year. “It’ll reach a point where the entire planetary mass would have to be some form of digital data storage or programmable matter in order to sustain the digitisation of the world,” says Melvin Vopson at the University of Portsmouth, UK.
We are going to need new technologies, he says. Researchers are exploring the possibilities of storing data with photons and DNA. One of the most intriguing solutions, however, is using lasers to encode data into silica glass by creating nanostructures that a microscope can read. at the University of Southampton, UK, who has already worked with Microsoft to design a silica-based storage system, says the data becomes “virtually eternal” because silica glass is resilient to pretty much everything, from extreme temperatures and moisture to magnetism and radiation. It is thought to remain stable at room temperature for 300 billion billion years, which means it could guard our precious data long after the sun dies.
We just have to hope that whoever finds the glass has the technology to discover what is inside – and an interest in the minutiae of our old social media posts and cat pictures.
A CASSETTE COMEBACK
As digital tape maintains its place as the hottest tech in “cold” data storage (see main story), old-fashioned music cassette tapes are seeing a revival. According to the British Phonographic Industry, 185,000 cassette tapes were sold in the UK in 2021, a 19 per cent increase from 2020 and the highest total since 2003. More artists, including Olivia Rodrigo and Billie Eilish, are now releasing music on tapes.
But audio on cassette doesn’t sound as good as hi-res streaming, so what is the appeal? Well, it is the same reason vinyl has made a comeback – the enduring lure of retro technology. Earlier this year, a series of experiments carried out by a team including psychologist Matthew Fisher at Yale University showed that people tend to prefer technology they think was invented before they were born, an effect that holds even when the technology isn’t as old as people think.
For some, it is also about leaving a physical legacy. “It’s for the novelty, but also the archival nature,” says Cal King from London, who has recently started buying music tapes. “Nobody will go through my Spotify playlists when I die, but they’ll have boxes of my cassettes.”
