RSTS (/ˈrɨstɨs/) is a multi-user time-sharing operating system, initially developed by Evans, Griffiths, & Hart of Boston, and acquired by Digital Equipment Corporation ("DEC"), (now part of Hewlett Packard) for the PDP-11 series of 16-bit minicomputers. The first version of RSTS (RSTS-11, Version 1) was implemented in 1970 by DEC software engineers that developed the TSS-8 time-sharing operating system for the PDP-8.