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 a person with a disability as a person who has a physical or mental impairment that substantially limits one or more major life activity. This includes people who have a record of such an impairment, even if they do not currently have a disability.