To understand why Linux has become so popular, it is helpful to know a little bit about its history. The first version of UNIX was originally developed several decades ago and was used primarily as a research operating system in universities.
Usage Note: Disabled is the clear preference in contemporary American English for referring to people having either physical or mental impairments, with the impairments themselves preferably termed disabilities.
The Basics of Disability. Social Security's definition of disability is a mental or physical impairment that has lasted or is expected to last at least 12 months or result in your death and which prevents you from gainful employment.