Back in the 70s, I worked in the Ag industry. At that time, some self propelled windrowers (swathers) were coming out with hydrostatic transmissions. They were variable speed pump/motor combinations where one pump/motor ran each drive wheel. The ones I saw were mfged by Vickers and Sunstrand. The two pumps were in one housing, so you just coupled that to an engine, plumbed in the hydraulics (tanks, filter, hoses, control levers, etc).
The systems were pretty simple outside the pump.
The ones I worked around were very reliable. As long as the oil stayed clean and you didn't run it out of oil, it really lasted a LONG time. Run it out of oil or get some debris in it, it would trash out pretty quickly. Our systems were running about 3000 psi.
My understanding might be incorrect, but I think about that same time, HSTs were going into skid steer loaders and a few utility loaders/tractors.
The rest is history. Combines, tractors, skid steers, etc..
Ron
With what I can see of the Bota drive, it looks very similar to that old design. I'm sure it has new bells/whistles, but the parts manual shows an exploded view that is basically the same prinicipal.