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 ADA defines an individual with a disability as a person who: (1) has a physical or mental impairment that substantially limits a major life activity, (2) has a record or history of a substantially limiting impairment, or (3) is regarded or perceived by an employer as having a substantially limiting impairment.