PSOS

[real-time operating system] pSOS (Portable Software On Silicon) is a real time operating system (RTOS), created in about 1982 by Alfred Chao, and developed/marketed for the first part of its life by his company Software Components Group (SCG). In the 1980s pSOS rapidly became the RTOS of choice for all embedded systems based on the Motorol...
Found on http://en.wikipedia.org/wiki/PSOS_(real-time_operating_system)

psos

parent standing over sholder
Found on http://www.noslang.com/dictionary/p/

PSOs

Problem Solving Officers
Found on https://www.encyclo.co.uk/local/21417
No exact match found