Chainsaws use oil to lubricate the chain. The usage is quite minor, probably less than 1cc per minute of work. The oil is normally supplied from a refillable compartment to the chain only when the chainsaw is running.
How is the delivery managed?
A pump? The capillary effect?
If it's a pump, I'd be interested in details - I mean, I have a hard time imagining a pump this slow (<1cc/min) supplied from the high-RPM engine... or does it use an extensive gearbox to slow down? A separate motor?
[note: I mean the oil used for chain lubrication, not mixed with fuel for the two-stroke engine of motorsaw]