While it is common to associate mainframe computers with IBM, the reality is that several manufacturers produced mainframe computers from the late 1950s through the 1970s. The group of manufacturers was often referred to as "Snow White and the Seven Dwarfs". In that context, Snow White was IBM and the seven dwarfs were Burroughs, UNIVAC, NCR, Control Data Corporation, Honeywell, General Electric and RCA. IBM will likely be a major player in the emerging generation of mainframe computing. However, this time its competition will come from giant competitors, not dwarfs.

https://www.networkworld.com/article/2212166/lan-wan/snow-white-and-the-seven-dwarfs.html

As developers of new applications come to rely on the ease and power of the cloud, the mainframe remains a powerhouse for tasks computers have performed for decades, such as transactions. IBM has realized it can no longer make money selling traditional hardware, >>and as of late, the company has been focusing its efforts on software and data analytics, including a recently announced partnership with Twitter.<< But investing in industrial-grade hardware still aligns with IBM's focus on serving as an engine for business. Business is more mobile than ever. Yet however lightweight those mobile devices feel in your pocket, they can still make good use of a big, powerful machine chugging away in a back room, not going anywhere.

https://www.wired.com/2015/01/z13-mainframe/