What is the ruling on purchasing a computer device in installments from a bank at a price higher than its cash price, given that the increase does not constitute bank interest?

Purchasing goods through a bank takes two forms: The first is for the bank to be merely a financier, lending the customer the price of the commodity in exchange for a sum plus an increase. This form is forbidden because it is a loan with interest (riba). The second is for the bank to genuinely purchase the commodity and then sell it to the customer for a higher deferred price. This is permissible and is called Murabaha to the one who commands the purchase, provided that the bank does not conclude the sale with the customer until it has purchased the commodity. It is not permissible for the seller (the bank or otherwise) to impose a fine on the customer for late payment of installments, as this fine is a form of usury.