Quote from: flix on March 18, 2016, 03:12:49 PM

So... let's say that we want 20 million people to be able to use Bitcoin as P2P cash regularly (say once a day).

20.000.000 tx/day --> 232 tx/s or 13.889 tx/min --> 138.890 tx/ block

Currently txs are on average 250 bytes... but let's say that we can somehow get that down to 100 bytes... (I've see discussion on several ways of doing this).

140.000 txs x 100 bytes = 14.000.000 = 14MB

What would be the big tech constraint in 2020 preventing 14MB blocks?

Memory? Bandwidth? latency?

i understand you dont want to talk about the centralization aspects of banks and visa. but please "pretend" we are talking about banks and visa just in the context of end user method of usage, rather than the technicals of controls behind the scenes. then it helps 'lay' people get to the basics of your debate about long term store vs daily spends

anyway

using blockstreams doomsday story of comparing bitcoin to possible Visa..(dont worry i hate it too, but relax, think of it from the end-user usage not the who controls it mindset)

visa averages each customer does 40 transactions a year.

bitcoin currently has 2.5mill users and based on the maths of ACTUAL average transactions per block(2000tx=500byte/tx)
2000tx(block)*144(day)*365(year)=105mill .. which not surprisingly also corresponds to a 40tx/user per year.. (kinda funny that)

after all not everyone will use it daily. some use it a couple times a day some use it once a month. hense the 40tx/year is a good average as proven by both bitcoin and visa

so 20million people doing 40 transactions/year to compare both visa and bitcoins current usage =
8mb maxblocksize hard rule doing traditional transactions.
4.2mb maxblocksize hard rule doing Segwit transactions with a real data storage of 8mb (based on segwit and laudas assumption of 190% capacity)
4.2mb maxblocksize hard rule doing Segwit transactions and confidential payment codes with a real data storage of 12mb

so we went from 1000 tx in 2013(0.5mb block due to DB bug) its going to be 2mb+segwit in 2017(hoping to be sooner personally). and based on technology growth. a 4.2mb +segwit wont be a big deal by 2020

in short by summer 2017 bitcoin can handle 10million people doing similar daily transactions like they would using bitcoin or visa today
give it 4 years there wont be an issue with 20million. (ONLY if people dont stupidly use confidential payment codes extra feature by default)