Appliance, including a flash memory, that is robust under power failure

A method of operating an appliance that includes a host device and a memory unit, the memory unit including a nonvolatile memory, the method comprising the steps of:

• (a) providing a volatile cache memory for caching data prior to writing said data to the nonvolatile memory;
• and
• (b) upon interruption of power to the memory unit, selectively writing only a portion of said data then cached in said volatile cache memory to the nonvolatile memory.

A method of operating an appliance that includes a host device and a memory unit, the memory unit including a nonvolatile memory, the method comprising the steps of:

• (a) providing a volatile memory for storing only system data;
• and
• (b) only upon interruption of power to the memory unit, selectively writing at least a portion of said system data then stored in said volatile memory to the nonvolatile memory.

A method of operating an appliance that includes a host device and a memory unit, the memory unit including a nonvolatile memory, the method comprising the steps of:

• (a) providing a volatile memory for storing data;
• and
• (b) upon interruption of power to the memory unit, writing to the nonvolatile memory at least a portion of said data of only one data class then stored in said volatile memory, said one data class being selected from the group consisting of system data and user data.

A method of operating an appliance that includes a host device and a memory unit, the memory unit including a nonvolatile memory, the method comprising the steps of:

• (a) providing a volatile memory for storing system data;
• (b) only upon interruption of power to the memory unit, selectively writing at least a portion of said system data then stored in said volatile memory to the nonvolatile memory;
• wherein said at least portion of said data includes file allocation data.

A method of operating an appliance that includes a host device and a memory unit, the memory unit including a nonvolatile memory, the method comprising the steps of:

• (a) providing a volatile memory for storing system data;
• (b) only upon interruption of power to the memory unit, selectively writing at least a portion of said system data then stored in said volatile memory to the nonvolatile memory;
• wherein said at least portion of said data includes a copy of a memory buffer that is used by the host device to accumulate user data.

A method of operating an appliance that includes a host device and a memory unit, the memory unit including a nonvolatile memory, the method comprising the steps of:

• (a) providing a volatile memory for storing system data;
• (b) only upon interruption of power to the memory unit, selectively writing at least a portion of said system data then stored in said volatile memory to the nonvolatile memory;
• wherein said at least portion of said data includes a description of a status of the host device.

A method of operating an appliance that includes a host device and a memory unit, the memory unit including a nonvolatile memory, the method comprising the steps of:

• (a) providing a volatile memory for storing system data;
• (b) only upon interruption of power to the memory unit, selectively writing at least a portion of said system data then stored in said volatile memory to the nonvolatile memory;
• wherein said at least portion of said data includes an identification of an interrupted operation.