STAIRS ran under the OS/360 operating system under the CICS or IMS transaction monitors, and supported IBM 3270 display terminals.
[1] STAIRS was introduced as a product in 1973, but had previously been developed in-house by IBM in support of its antitrust lawsuit in 1969.
Originally the product was called simply STAIRS but, with the advent of IBM's "/Virtual Storage" operating systems (such as OS/VS1), the non-CMS versions were later renamed to STAIRS/VS.
STAIRS was initially released as an application running under IMS and CICS, but a VM/CMS implementation was developed by IBM Canada in the late 1970s and marketed mostly in Europe, called STAIRS/CMS.
The data (in the non-CMS implementations) was stored in basic direct access method (BDAM) files, which caused upgrade and portability problems later in its life-cycle.