Abstract: This application describes a system startup method and apparatus. The method may include establishing a mapping relationship between address space of a first storage device and address space of a second storage device. The method may also include receiving a read/write request sent to the first storage device. Furthermore, the method may include when the read/write request is a write request for the first storage device, writing data to a second address in the second storage device based on a first address in the first storage device in the write request and the mapping relationship. Or, when the read/write request is a read request for the first storage device, determining whether data has been written to a fourth address corresponding to a third address in the read request. The method may further include reading data from the fourth address when the data has been written to the fourth address, or reading data from the third address when no data has been written to the fourth address.

Abstract: Embodiments of this application relate to the field of storage technologies, and disclose a data backup method and a terminal, to back up user data in a terminal when the terminal cannot be used. A specific solution is as follows: A terminal includes a first data partition, and the first data partition supports to start an operating system when the terminal is powered on. The terminal starts the operating system by using a second data partition after detecting a power-on failure of the terminal or detecting a preset operation of a user. The second data partition is a blank data partition. After the operating system is successfully started, the terminal transmits user data in the first data partition to a first storage medium. The first storage medium is located outside the terminal and is connected to the terminal.

Abstract: This application describes a system startup method and apparatus. The method may include establishing a mapping relationship between address space of a first storage device and address space of a second storage device. The method may also include receiving a read/write request sent to the first storage device. Furthermore, the method may include when the read/write request is a write request for the first storage device, writing data to a second address in the second storage device based on a first address in the first storage device in the write request and the mapping relationship. Or, when the read/write request is a read request for the first storage device, determining whether data has been written to a fourth address corresponding to a third address in the read request. The method may further include reading data from the fourth address when the data has been written to the fourth address, or reading data from the third address when no data has been written to the fourth address.