Someone Else’s Computer: The Prehistory of Cloud Computing

“There is no cloud,” goes the quip. “It’s just someone else’s computer.”

The joke gets at a key feature of cloud computing: Your data and the software to process it reside in a remote data center—perhaps owned by Amazon, Google, or Microsoft—which you share with many users even if it feels like it’s yours alone.

Remarkably, this was also true of a popular mode of computing in the 1960s, ’70s, and ’80s: time-sharing. Much of today’s cloud computing was directly prefigured in yesterday’s time-sharing. Users connected their terminals—often teletypes—to remote computers owned by a time-sharing company over telephone lines. These remote computers offered a variety of applications and services, as well as data storage. The key to such systems was the operating system, built to rapidly switch among the tasks for the many users, giving the illusion of a dedicated machine.

The pioneering firm Tymshare produced the button shown above along with the largest commercial computer network of its era. Called Tymnet, it spanned the globe and was by the late 1970s larger than the ARPANET. Compare this schematic of Tymnet, detailing all of its nodes, with the sparser schematics of the ARPANET [PDF] from the same era. By 1975, Tymshare was handling about 450,000 interactive sessions per month.

Ann Hardy is a crucial figure in the story of Tymshare and time-sharing. She began programming in the 1950s, developing software for the IBM Stretch supercomputer. Frustrated at the lack of opportunity and pay inequality for women at IBM—at one point she discovered she was paid less than half of what the lowest-paid man reporting to her was paid—Hardy left to study at the University of California, Berkeley, and then joined the Lawrence Livermore National Laboratory in 1962. At the lab, one of her projects involved an early and surprisingly successful time-sharing operating system.

In 1966, Hardy landed a job at Tymshare, which had been founded by two former General Electric employees looking to provide time-sharing services to aerospace companies. Tymshare had planned to use an operating system that had originated at UC Berkeley, but it wasn’t designed for commercial use, and so Hardy rewrote it.