The adjective "long-haired" is well-attested to have been in

slang use among scientists and engineers during the early

1950s; it was equivalent to modern "hairy" and was very likely

ancestral to the hackish use. In fact the noun "long-hair"

was at the time used to describe a hairy person. Both senses

probably passed out of use when long hair was adopted as a

signature trait by the 1960s counterculture, leaving hackish

"hairy" as a sort of stunted mutant relic.