Electronic trading is the general term for OTC trading in international futures exchanges. Over-the-counter transactions of American exchanges often use electronic transactions and Internet transactions. Electronic disk exists in the form of computer expansion card and works by inserting it into the bus slot of the motherboard. When the computer is plugged into the electronic disk, the system can be started from the electronic disk. Because the information of electronic disk exists on the chip, it has the advantages of fast working speed, high stability and strong confidentiality. Electronic disk uses semiconductor chips to store data, which has the characteristics of small size, low power consumption and strong earthquake resistance. Therefore, various electronic disks are widely used as external storage of embedded systems. Commonly used electronic disks are: NandFlash, DOC, DOM, CF, SM, MS, MMC, SD.