Non-volatile storage addressing using multiple tables
The non-volatile storage solid state drive (SSD) has non-volatile memory (NVM), random access memory (RAM) capable of being accessed at a higher speed than this NVM, and a control unit for controlling accesses to the NVM and to the RAM. The control unit stores in the NVM an address translation table that translates a logical address given to access this NVM to a physical address after dividing it into multiple tables, and stores in the RAM the multiple address translation tables-sub on RAM that have been divided into multiple tables.
1. A non-volatile storage, comprising:
first memory of non-volatile type;
second memory having an access speed that is faster than the first memory; and
a control unit for controlling accesses to the first memory and to the second memory;
wherein the control unit stores, in the first memory, an address table for translating a logical address of data of the first memory to a physical address, the address translation table including a plurality of address translation subtables,
wherein the control unit stores, in the second memory, a cache of the address translation table, and an address table including a physical address for each address translation subtable stored in the first memory,
wherein a renewed range of the cache is rewritten to the first memory using a data size of N*2* a physical page size of the first memory, where N is an integer,
wherein modifying the range of the cache modifies the size of the address translation table,
wherein a larger cache range creates a larger address translation table,
wherein a smaller cache range creates a smaller address translation table, and
wherein the physical page size of the first memory is larger than a size of the address translation subtable.
2. In The non-volatile storage according to claim 1 ,
wherein the second memory is Dynamic Random Access Memory.
3. The non-volatile storage according to claim 1 ,
wherein the control unit performs wear leveling of the address translation table using the address table.
4. The non-volatile storage according to claim 1 ,
wherein each address translation subtable includes a plurality of physical addresses.
5. The non-volatile storage according to claim 1 ,
wherein, when the control unit performs a rewrite operation on first data:
second data is added to the first data,
the first and second data are written to the first memory, and
the cache of the address translation table is updated, and
wherein a data management size of the rewrite operation is N*2* the physical page size of the first memory.
6. The non-volatile storage according to claim 5 ,
wherein the second data is read from the first memory before being added to the first data.