1# ScsiPeripheral_DeviceMemMap 2<!--Kit: Driver Development Kit--> 3<!--Subsystem: Driver--> 4<!--Owner: @lixinsheng2--> 5<!--Designer: @w00373942--> 6<!--Tester: @dong-dongzhen--> 7<!--Adviser: @w_Machine_cc--> 8 9## Overview 10 11Represents the device memory mapping created by calling **OH_ScsiPeripheral_CreateDeviceMemMap**. The buffer that uses the device memory mapping can provide better performance. 12 13**Since**: 18 14 15**Related module**: [SCSIPeripheralDDK](capi-scsiperipheralddk.md) 16 17**Header file**: [scsi_peripheral_types.h](capi-scsi-peripheral-types-h.md) 18 19## Summary 20 21### Member Variables 22 23| Name| Description| 24| -- | -- | 25| uint8_t* const address | Buffer address.| 26| const size_t size | Buffer size.| 27| uint32_t offset | Offset of the used buffer. The default value is **0**, indicating that there is no offset and the buffer starts from the specified address.| 28| uint32_t bufferLength | Length of the used buffer. By default, the value is equal to the size of the buffer, indicating that the entire buffer is used.| 29| uint32_t transferredLength | Length of the data to be transferred.| 30