A method and apparatus to improve the read/write performance of a hard drive is presented. The hard drive includes solid state, non-volatile (NV) memory as a read/write cache. Data specified by the operating system is stored in the NV memory. The operating system provides a list of data to be put in NV memory. The data includes data to be pinned in NV memory and data that is dynamic. Pinned data persists in NV memory until the operating system commands it to be flushed. Dynamic data can be flushed by the hard drive controller. Data sent by an application for storage is temporary stored in NV memory in data blocks until the operating system commits it to the disk.