Wasei-eigo (Japanese-made English) term for an operating system; the standard term is オペレーティングシステム (OS). Used mostly in older or informal contexts.
wasei-eigo (Japanese-coined English), from operation system
See also: オペレーティングシステム
This operating system is no longer supported.
In the past, people sometimes said 'operation system,' but now 'OS' is the norm.
Wasei-eigo from English 'operation system'; the standard English term is 'operating system'.