Creating and using delta L2P entries
The present disclosure generally relates to more efficient use of a delta buffer. To Utilize the delta buffer, an efficiency can be gained by utilizing absolute delta entries and relative delta entries. The absolute delta entry will include the type of delta entry, the L2P table index, the L2P table offset, and the PBA. The relative delta entry will include the type of delta entry, the L2P table offset, and the PBA offset. The relative delta entry will utilize about half of the storage space of the absolute delta entry. The relative delta entry can be used after an absolute delta entry so long as the relative delta entry is for data stored in the same block as the previous delta entry. If data is stored in a different block, then the delta entry will be an absolute delta entry.
1. A data storage device, comprising:
one or more memory devices; and
a controller coupled to the one or more memory devices, wherein the controller is configured to:
create an absolute delta entry, wherein the absolute delta entry comprises a first number of bits, a type of entry, a table part index, a first offset in the table, and a physical block address (PBA);
create a relative delta entry, wherein the relative delta entry comprises a second number of bits, type of entry, a second offset in the table, and a PBA offset, wherein the first number of bits is greater than the second number of bits; and
store the relative delta entry and absolute delta entry in a delta buffer table, wherein the first offset in the table and the second offset in the table comprise an equal number of bits, and wherein the PBA comprises a greater number of bits than the PBA offset.
2. The data storage device of claim 1 , wherein the controller is further configured to:
create a second relative delta entry, wherein the second relative delta entry comprises a third number of bits; and
store the second relative delta entry in the delta buffer table.
3. The data storage device of claim 2 , wherein the third number of bits is equal to the second number of bits.
4. The data storage device of claim 1 , wherein creating the absolute delta entry comprises:
set a delta entry type equal to absolute;
set a delta entry table part index equal to table part index; and
set a delta entry PBA equal to PBA.
5. The data storage device of claim 4 , wherein the controller is further configured to perform the following:
set delta entry type equal to relative; and
set delta entry PBA offset equal to PBA minus a last absolute entry PBA.
6. The data storage device of claim 5 , wherein the delta entry PBA offset comprises fewer bits than the delta entry PBA.
7. The data storage device of claim 5 , wherein the relative entry does not include a table part index.
8. The data storage device of claim 1 , wherein the controller includes a flash translation layer (FTL) module.
9. The data storage device of claim 1 , wherein the controller is further configured to:
decode a delta buffer entry; and
determine whether the decoded delta buffer entry is an absolute delta entry.
10. The data storage device of claim 9 , wherein the controller is further configured to calculate an offset from PBA.
11. The data storage device of claim 10 , wherein a delta buffer is present, wherein the delta buffer comprises a plurality of regions and wherein a first entry in any region of the delta buffer is an absolute entry.
12. The data storage device of claim 11 , wherein the delta buffer comprises at least 64 regions.
13. The data storage device of claim 12 , wherein an offset is determined by a number of flash management units (FMUs).
14. A data storage device, comprising:
one or more memory devices; and
a controller coupled to the one or more memory devices, wherein the controller is configured to:
create an absolute delta entry, wherein the absolute delta entry comprises a first number of bits, wherein the first number of bits is between 55 and 64 bits;
create a relative delta entry, wherein the relative delta entry comprises a second number of bits, wherein the first number of bits is greater than the second number of bits, wherein the second number of bits is between 28 and 32 bits; and
store the relative delta entry and absolute delta entry in a delta buffer table.
15. The data storage device of claim 14 , wherein the first number of bits is 64 bits.
16. The data storage device of claim 15 , wherein the second number of bits is 32 bits.