How exactly are bitcoins divided up?

[cfiziksh]

Is the smallest unit actually the base 10 number 10^-8?  Or is it some number written in binary scientific notation the way floating points are represented?

And what's the maximum number of units available?  Is it the exact base 10 number 2.1*10^15?

[DeathAndTaxes]

Yes. No. Yes.

Internally the blockchain and wallet express all values in terms of discrete satoshis (honorific name given) and stores them as integers.  There are no floating point or decimal values used in the network, clients, or blockchain.

1 Satoshi is 1E-8 BTC.

So if you send 1 BTC to a friend internally your wallet, the transaction, the blockchain all record it as sending 100000000 units.  The client simply abstracts this for you and shows 1.0.  Likewise if you want you could consider the block reward  5,000,000,000 satoshis, the network does.

Yes there will be exactly 2.1E15 satoshis issued on the network once every coin has been mined.  Us calling them 21 million BTC is simply an abstraction.

Technically Bitcoin could be modified to use a smaller discrete unit but as talked about in another thread even if BTC money supply was equal to global money supply 1 satoshi would only be worth ~ 3 cents so it is unlikely smaller units will ever be needed.

It does however annoy me that satoshi chose 1E-8 WTF?  Why not 1E-9 as in 1 nano Bitcoin (nBTC) as the discrete unit.

[cfiziksh]

Yes. No. Yes.

Internally the blockchain and wallet express all values in terms of satoshis (honorific name given).

1 Satoshi is 1E-8.

So if you send 1 BTC to a friend internally your wallet, the transaction, the blockchain all record it as sending

100000000

The client simply abstracts this for you and shows 1.0.  There are no floating point values (which is always bad in finances).  Everything is a discrete number of satoshis.

Yes there will be 2.1E15 satoshis on the network once every coin has been mined.  Us calling them 21 million BTC is simply an abstraction.

If you want you could consider the block reward  5,000,000,000 satoshis, the network does.

Ok, thanks. 

Where did the number 2.1e15 come from?  It seems like quite an arbitrary number to use.

[DeathAndTaxes]

My guess is Satoshi was an time traveling alien and it has some significance to his civilization.

Both the number of macro units and the value of the discrete unit seem "horribly" arbitrary.  Well any unit would be arbitrary but if you need an arbitrary number why not pick a "round" one?

[BurtW]

2.1e15 is 0x775F05A074000 so, you see, it is not totally arbitrary.

I swear, there is a secret message in there, you just need to decode it!

[cfiziksh]

2.1e15 is 0x775F05A074000 so, you see, it is not totally arbitrary.

I swear, there is a secret message in there, you just need to decode it!

OMG I just got that exact hash while mining! 

[gadsdengraphics]

It does however annoy me that satoshi chose 1E-8 WTF?  Why not 1E-9 as in 1 nano Bitcoin (nBTC) as the discrete unit.

There are 8 bits in a byte.  It's a natural number for most programmers and computer scientists.

[DeathAndTaxes]

It does however annoy me that satoshi chose 1E-8 WTF?  Why not 1E-9 as in 1 nano Bitcoin (nBTC) as the discrete unit.

There are 8 bits in a byte.  It's a natural number for most programmers and computer scientists.

1E-8 is decimal it has no relationship to 8 bits in a byte.
To represent 1E8 requires 28 bits and it is uneven.  2^28 = 2.68E8 vs 1 E8.
BTC has 2.1E15 units.  To represent that in binary requires 51 bits.

So to this programmer neither 1E-8, 1E8, nor 1E15 don't seem very "natural".  Then again I might just be weird.

[gadsdengraphics]

It does however annoy me that satoshi chose 1E-8 WTF?  Why not 1E-9 as in 1 nano Bitcoin (nBTC) as the discrete unit.

There are 8 bits in a byte.  It's a natural number for most programmers and computer scientists.

1E-8 is decimal it has no relationship to 8 bits in a byte.
To represent 1E8 requires 28 bits and it is uneven.  2^28 = 2.68E8 vs 1 E8.
BTC has 2.1E15 units.  To represent that in binary requires 51 bits.

So to this programmer neither 1E-8, 1E8, nor 1E15 don't seem very "natural".  Then again I might just be weird.

Yeah, I didn't say that 1e-8 made any sense from a mathematical standpoint - I just meant that if you asked 100 programmers to give you an arbitrary integer between 5 and 10 or so, "8" would likely have the highest incidence due to constant exposure

[matthewh3]

I think Satoshi Nakamoto was/is the start of the technological singularity - http://en.wikipedia.org/wiki/Technological_singularity 

[gadsdengraphics]

I think Satoshi Nakamoto was/is the start of the technological singularity - http://en.wikipedia.org/wiki/Technological_singularity 

Now there's a thought. Everyone to date has assumed Satoshi was human.

Perhaps he uses a pseudonym because he doesn't have a traditional name...

[Nim]

It does however annoy me that satoshi chose 1E-8 WTF?  Why not 1E-9 as in 1 nano Bitcoin (nBTC) as the discrete unit.

There are 8 bits in a byte.  It's a natural number for most programmers and computer scientists.

And engineers work in powers of 3 like stated above. Instead of saying 1E-8, we'd say 10E-9. Did he ever type out 1E-8? Because that would be a good indicator (to me) that he didn't have an engineering background.