Etymology of "beta" meaning advance info

Starting my rock climbing in the late 80's in the gunks I can say that this was the only word I ever heard from day 1 to describe any level of intelligence gathered on a particular route. I have used it ever since to garner any such intel....

The first time I heard this term was in a Rock & Ice magazine article. It might have been in the 1980s or early 1990s. The title of the article was "Fifty classic rock climbs in America betamaxed" (or something like that).

The shorter version ("beta") came later as I recall.

then it does derive from Betamax after all.  Thanks -- I'll send this thread off the to OED for posterity (or not

Interesting. I always thought beta was called beta because it's secondary information, as opposed to firsthand personal experience, which would be alpha.

THAT'S WHAT I THOUGHT TOO.

Climber talk originating in the Gunks. Long animated descriptions of crux sequences by the likes of Kevin Bein and company in the late-1970s and early-1980s. Beta is best heard with a thick Bronx accent. Yo!

Where do i sign up for the brotha and sista hood of the gore-tex pants?