A storage room at the University of Utah’s John and Marcia Price College of Engineering has yielded a discovery from more than a half-century ago: a nine-track magnetic tape that could hold the only known copy of an important early computer operating system.
Robert Ricci, research professor in the Kahlert School of Computing, first shared the find on Mastodon. The tape’s label suggests it contains a copy of UNIX Version 4, a pivotal 1973 release from Bell Labs.
UNIX v4 marked a turning point in computer science. It was the first versions of UNIX to be largely rewritten in the C programming language, paving the way for its portability and massive influence on later operating systems—including BSD, Linux, and macOS. Until now, historians and enthusiasts had access only to fragmentary pieces of this early UNIX version.
“The UNIX operating system, originally developed at Bell Labs, is the precursor to the operating systems that power our computers, smartphones, and servers today,” Ricci says. “Many of the early versions were only sent to a small number of universities and research institutions, so not many surviving copies exist.”
“This version was long thought to be lost forever,” he says.
The researchers plan to personally transport the reel to the Computer History Museum in Mountain View, California, for careful imaging and preservation. Reading the tape will be challenging: nine-track reels require specialized, aging hardware, and magnetic media degrade over time. There’s also no guarantee that the program is even on the tape; such reels were commonly reused and overwritten.
If the data is there and proves recoverable, however, it could provide a window into a transformative moment in software history.