Answer questions about cards, banks?

Question

Payment systems

1. What is a processing center, processing in particular, and who is often a processing center.
2. How often do you still pay with magnetic flat?
3. Does visa paywawe have mastercard "something else (replace)" and what is the contactless payment technology for jcb, unionpay, amex?
4. The posts say that pos terminals until the "reconciliation of the results" funds are not debited, but frozen at the client. How does it look to him? (as a regular purchase or as a reserved amount)
5. Is the procedure in 4 questions similar to holding funds on card verification sites (amazon, google)?
6. When buying, for example, on aliexpress, in my Internet bank in the payment status it says "in processing" is this the same hold for their return in which case?
5.1 Does alibaba also receive money for the seller's goods in my account or is it just kept by me as before the reconciliation of the results?
7. As on the websites of banks, acquiring services and payment forms of LARGE sites, they will find out whether such a card exists or not, up to the last digit in the number.
8. Payment systems were invented so that banks do not enter into agreements on the transfer of money from their customers among themselves many times. Does this mean that all banks are connected to all PSs? And if the bank is connected to the visa and issues visa cards, and the bank acquirer of the store only to the mastercard, will the buyer with the visa card be able to pay in the store accepting the mastercard?
9. Recommend a thematic forum on the subject of cards and everything connected with them.

Answer 1

Read D. Artimovich's book "Electronic Payments on the Internet" and his articles
artimovich.com/book/e-platezi.epub
https://habr.com/ru/users/tc40/posts/