Memory device

A memory device including:

• a nonvolatile memory;
• a buffer memory having a higher access speed than the nonvolatile memory;
• and a control circuit,
• wherein, in response to a read command inputted from the outside, the control circuit consults rewritable preread data management tables that associate logical addresses of preread data and buffer memory addresses for storing the preread data, determines whether the buffer memory holds data specified by the command, if the buffer memory holds the data, outputs data read from the buffer memory to the outside, and otherwise, outputs data read from the nonvolatile memory to the outside.

A memory device including:

• a nonvolatile memory;
• a buffer memory having a higher access speed than the nonvolatile memory;
• and a control circuit,
• wherein in response to a preread command inputted from the outside, the control circuit creates a preread data management table that associates a logical address of preread data specified by the command and a buffer memory address for storing the preread data, and reads data specified by the command from the nonvolatile memory and stores the data in the buffer memory as preread data so that the preread data stored in the buffer memory can be outputted to the outside.