By default how many data points does graphite send/give?

When we request a metric's data-points in graphite say - http://graphite-server/render?target=&width=1200&height=750&format=json how many data points are retrieved (i.e. how many data-points does it return by default if we don't specify 'from' and 'until' parameters?).

1. Does graphite give all the datapoints from the whisper database? or
2. does it give all the data-points that fall under the first retention policy period? or
3. does it return certain number of data-points?

For my local graphite instance I see that by default it returns all the data-points within last 24 hours. But, in my companies server I see that the graphite is returning data-points for last 30 hours.

Recently, I read somewhere that by default graphite gives/sends data-points of 24hours. (In the question, I said I saw data-points of last 30hrs in my companies graphite-instance. But, that's not true (maybe I miss understood it :)). Even the graphite instance in my company by default is sending data-points for last 24hrs :))