The only known copy of UNIX version 4, the first UNIX written in C, was recovered from a 50-year-old magnetic tape found in a Utah university storeroom. The data was largely intact and has been preserved and made available online, offering a rare glimpse into early UNIX development.
Storing data for decades or centuries requires finding a storage format that can be trusted to last. Digital storage media like hard drives and SSDs can degrade over time and eventually fail, while file format obsolescence can make data unreadable. Archival-grade optical discs like M-DISC promise to last hundreds or even thousands of years, while magnetic tape can last for up to 50 years or more. Cloud storage is not an option for truly long-term storage.