What ever happened to Tandem and NonStop OS 2047

Mikko Nahkola

When I started at Tandem in 1981, they were selling systems with from two to 16 custom 16-bit minicomputers interconnected by a duplexed bus. Each mini had its own memory and copy of the OS, and every I-O device was reachable from multiple CPUs. Software was written in Tandem's TAL language. Application processes were paired: a primary process would checkpoint its state to a backup process on another CPU; if a problem occurred, a whole CPU would go down and the backup processes would become primary. The OS was elegant and spare, relied on message pbutting between processes. File system ran in its own process, for example.

The company started selling fault tolerance, but what attracted many customers was easy expandability, and the networking implementation that allowed systems to interconnect easily. We had a global scope single system image: one could open a file anywhere with a path name likeSVLDEV.$USER01.TOMV.DATA.

Tandem had a swimming pool behind the main building, with TANDEM in tiles on the bottom (Google Earth is too fuzzy for me to see if it still says that. 37d 19m 36.07s N, 122d 00m 35.25s W) where we used to stand around and drink beer at the Friday Beer Busts.