Here's a genealogy tree on Obama that I've been aware of for several years. http://www.wargs.com/political/obama.html The base site that is, not Obama's particular tree. It has it as Kapiolani. I have a tendency to believe that Obama knows what hospital he was born in.
This site built by the Chicago Sun Times built Obama's family tree and gives sources. http://www.suntimes.com/images/cds/MP3/obamatree.pdf
Thanks; if you notice, in my posting #223, the wargs.com site is mentioned in my third paragraph and the same link is given as you give in #231.
I looked at the sources for the pdf in your second paragraph, and it also lists the same wargs.com website as a reference --- and that's the same reference that's given as the source for the June 7th Wikipedia revision that introduced Kapiolani Hospital to the Barack Obama article.
As to whether he knows what hospital he was born in, I imagine he does, but I cannot find a single thing on any his personal pages anywhere that gives that information. For instance, his Senate webpage says "Barack Obama was born on August 4th, 1961, in Hawaii to Barack Obama, Sr. and Ann Dunham." (http://obama.senate.gov/about/.) His campaign website says "Barack Obama was born in Hawaii on August 4th, 1961. His father, Barack Obama Sr., was born and raised in a small village in Kenya, where he grew up herding goats with his own father, who was a domestic servant to the British." (http://www.barackobama.com/learn/meet_barack.php.)