'Meditation' is considered 12 units of concentration, so 12 * 12 seconds which is 144 seconds.
So technically, according to the definition of the old school meditators practicing 1000s of years ago, you are not really 'meditating' until the mind is fixed in one place for at least 144 seconds.
Which yogic meditation tradition? There are dozens if not hundreds of them, interpreted in a myriad of different ways by thousands if not millions of teachers across the millennia.
I am well aware. The interpretation mainly comes from the Raja Yoga Tradition which is more concerned with meditation as the vehicle to some form of enlightenment.
The quote is according to the Kurma Purana.
My comment above was not attempting to be authoritative just adding some interesting thoughts to the discussion, thats all.