In the early 20th century, famous American economist elvin fisher developed the theory of economic gain. In its book "the nature of capital and yield", first, the concept of yield is analyzed in terms of the performance of earnings, and three different types of benefits are proposed: Further market analysis showed that he could make a small profit and lose money, and the time needed was long, so he decided to draw out the money as soon as possible for other deals. He's going to lose up to $1,000 on the pound. He was more concerned about how much he might lose than the pound. In the trade memo, he noted that if the price of a certain day in the city was not to the profit target, and not to "stop the loss point", the transaction would be closed. 3. The cost of accounting earnings is listed in historical cost. Due to the current accounting practice in the enterprise asset is measured at the historical cost in, with the cost nature is the historical cost has been derived from the law of the transfer, so as to determine the income is an important factor in the cost and the historical cost. Xpoint fills the cost and cost gap between high speed and high cost DRAM and low cost NAND. Does this technology engulf DRAM and NAND markets? Customers who purchase a large number of Xpoint chip/drives may purchase fewer DRAM chips and NAND chips/drives.