The Mainframe Six (2022)
6 months ago
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- Six companies remain in the mainframe industry: Hitachi, NEC, Fujitsu, Atos (formerly Bull), Unisys, and IBM.
- IBM has a global presence with 3000-7000 Z customers, offering high-performance systems.
- Unisys operates globally, with concentrations in Latin America (MCP) and East Asia (OS 2200). MCP is common in banking/telecom, OS 2200 in airline/government.
- Fujitsu is mostly global (excluding North America), with distinct mainframe families like BS2000 (Germany) and GS21 (Japan). Estimated 1000-1500 customers.
- Hitachi now markets exclusively in Japan, rebadging IBM Z CPUs. Estimated 200-300 sites.
- Atos owns Bull's GCOS 7 (32-bit, EBCDIC) and GCOS 8 (36-bit, ASCII), with fewer than 100 combined sites, mostly in Western Europe.
- NEC's ACOS-4 runs on custom processors, with 200-400 sites, primarily in Japan.