Data storage device and method for operating non-volatile memory
An optimized operating method for a non-volatile memory. A microcontroller allocates the non-volatile memory to store write data issued by a host. The microcontroller dynamically adjusts a first-writing-mode threshold. The first-writing-mode threshold value is provided for the microcontroller to determine whether to use a first writing mode to allocate the non-volatile memory to store the write data issued by the host. In comparison with the first writing mode, more bits of data are stored in one storage cell in a second writing mode.
1. A data storage device, comprising:
a non-volatile memory; and
a microcontroller, allocating blocks of the non-volatile memory to store write data issued by a host,
wherein:
the microcontroller dynamically adjusts a first-writing-mode threshold;
the first-writing-mode threshold value is provided for the microcontroller to determine whether to use a first writing mode or a second writing mode to allocate the blocks of the non-volatile memory to store the write data issued by the host;
in comparison with the first writing mode, more bits of data are stored in one storage cell in the second writing mode;
when available blocks of the non-volatile memory is greater than the first-writing-mode threshold, the microcontroller programs the write data issued by the host to the non-volatile memory in the first writing mode;
when available blocks of the non-volatile memory is not greater than the first-writing-mode threshold, the microcontroller programs the write data issued by the host to the non-volatile memory in the second writing mode;
when releasing a space of the non-volatile memory by background operations, the microcontroller decreases the first-writing-mode threshold; and
the microcontroller performs the background operations without being requested to by the host.
2. The data storage device as claimed in claim 1 , wherein:
when releasing a space of the non-volatile memory by foreground operations, the microcontroller increases the first-writing-mode threshold; and
the microcontroller responds to the host by the foreground operations.
3. The data storage device as claimed in claim 1 , wherein:
the non-volatile memory is a flash memory managed in blocks;
in the first-writing mode, data is stored in single-level cells with each storage cell storing one bit of data; and
in the second-writing mode, each storage cell stores more than one bit.
4. The data storage device as claimed in claim 3 , wherein:
when using the second-writing mode to copy data stored in the first-writing mode and thereby a block is released to store subsequent write data issued by the host, the microcontroller increases the first-writing-mode threshold.
5. The data storage device as claimed in claim 3 , wherein:
when updating data and thereby a block is released, the microcontroller increases the first-writing-mode threshold.
6. The data storage device as claimed in claim 3 , wherein:
when releasing a block by garbage collection performed by background operations, the microcontroller decreases the first-writing-mode threshold; and
the microcontroller performs the background operations without being requested to by the host.
7. A method for operating a non-volatile memory, comprising:
allocating blocks of a non-volatile memory to store write data issued by a host;
dynamically adjusting a first-writing-mode threshold;
based on the first-writing-mode threshold value, determining whether to use a first writing mode or a second writing mode to allocate the blocks of the non-volatile memory to store the write data issued by the host,
wherein:
in comparison with the first writing mode, more bits of data are stored in one storage cell in the second writing mode;
when available blocks of the non-volatile memory is greater than the first-writing-mode threshold, t the write data issued by the host is programmed to the non-volatile memory in the first writing mode;
when available blocks of the non-volatile memory is not greater than the first-writing-mode threshold, the write data issued by the host is programmed to the non-volatile memory in the second writing mode;
when releasing a space of the non-volatile memory by background operations, the first-writing-mode threshold is decreased; and
the background operations are performed without being requested to by the host.
8. The method as claimed in claim 7 , further comprising:
increasing the first-writing-mode threshold when releasing a space of the non-volatile memory by foreground operations,
wherein the foreground operations are performed to respond to the host.
9. The method as claimed in claim 7 , wherein:
the non-volatile memory is a flash memory managed in blocks;
in the first-writing mode, data is stored in single-level cells with each storage cell storing one bit of data; and
in the second-writing mode, each storage cell stores more than one bit.
10. The method as claimed in claim 9 , wherein:
when using the second-writing mode to copy data stored in the first-writing mode and thereby a block is released to store subsequent write data issued by the host, the first-writing-mode threshold is increased.
11. The method as claimed in claim 9 , wherein:
when updating data and thereby a block is released, the first-writing-mode threshold is increased.
12. The method as claimed in claim 9 , further comprising:
decreasing the first-writing-mode threshold when releasing a block by garbage collection performed by background operations,
wherein the background operations are performed without being requested to by the host.