I read a story of a man threw away is hard drive with almost 7,500 bitcoin on it, then later realised that it worth huge amount of money which he is trying to get back the drive which he found difficult. Now my question is that does it mean all this 7,500 bitcoin are gone completely?
If the Hard drive cannot be recovered, the Bitcoin is lost forever.
But is the man uninformed about Bitcoin? or he is unaware of the Bitcoin on the hard drive?
If he actually buys the Bitcoin, I believe he should be able to tell that it is still there, and he should be checking the Bitcoin Market since he has invested in Bitcoin.
Oh, I think I know what the OP is talking about! It's that crazy story about the guy who threw out some old hard drives, and they ended up in a dump. But then he wanted to dig them up again, so he asked the government for permission. Apparently, he was one of the bitcoin miners from the old days, and those hard drives had a whole bunch of them on there.
Can it be possible to know the people the are in position of all the bitcoin in circulation or know the number of units in total circulation?
OP, we can't really tell if some bitcoins are lost forever or not. Even if they don't move from a particular address for ten or more years, that still doesn't mean those bitcoins will never be in circulation again.