PS5 SSD & I/O Complex Patent

Aries

Administrator
Description


BACKGROUND

The present disclosure relates to an information processing device using a flash memory as a secondary storage device, an access controller, an information processing method and a computer program.

With increase in NAND (Not-AND) flash memory capacities, SSD (Solid State Drive) has come into application as a storage device that replaces a related art HDD (Hard Disk Drive). SSD is advantageous over HDD in that it can access data faster and consumes less power. On the other hand, SSD has a drawback in that it is less durable against repeated rewrites. Therefore, wear leveling, a technique that distributes an area to be rewritten, is used to rewrite data to the SSD. That is, when a rewrite request is issued from a host CPU (Central Processing Unit), a specified logical block address is replaced by a different physical address, thus distributing an area to be rewritten, to the extent possible, to a plurality of memory cells (refer, for example, to WO 2014/132346 A1).

SUMMARY

An address conversion table is necessary for such an arrangement to convert a logical block address into a physical address. An address conversion table generally accounts for about 0.1% in data size of a total SSD capacity. Naturally, a data size of the address conversion table increases with increase in flash memory capacity. It may be possible to cache part of the table to an external DRAM (Dynamic Random Access Memory) so as to efficiently refer to the address conversion table. However, the higher the efficiency pursued, the larger the DRAM capacity necessary. Further, the more frequently the table is referred to, the lower the command processing throughput due to latency involved in accessing the DRAM, possibly impairing the SSD access speed advantage.

The present disclosure has been devised in light of the foregoing, and it is desirable to provide a technology that ensures higher data access efficiency for an information processing device using an SSD.

A mode of the present disclosure relates to an information processing device. The information processing device includes a host unit adapted to request data access by specifying a logical address of a secondary storage device; and a controller adapted to accept the data access request and convert the logical address into a physical address using an address conversion table to perform data access to an associated area of the secondary storage device. An address space defined by the address conversion table includes a coarsely granular address space that collectively associates, with logical addresses, physical addresses that are in units larger than those in which data is read.

Another mode of the present disclosure relates to an access controller. The access controller for controlling data access from a host unit to a secondary storage device in an information processing device, includes a host controller adapted to convert a logical address of an access destination specified by the host unit into a physical address using an address conversion table; and a memory controller adapted to perform data access to the secondary storage device based on the physical address. An address space defined by the address conversion table includes a coarsely granular address space that collectively associates, with logical addresses, physical addresses that are in units larger than those in which data is read.

Still another mode of the present disclosure relates to an information processing method. The information processing method includes, by a host unit, requesting data access by specifying a logical address of a secondary storage device; and, by a controller, accepting the data access request and converting the logical address into a physical address using an address conversion table to perform data access to an associated area of the secondary storage device. An address space defined by the address conversion table includes a coarsely granular address space that collectively associates, with logical addresses, physical addresses that are in units larger than those in which data is read.

Still further mode of the present disclosure relates to a computer program. The computer program for a computer that controls data access from a host unit to a secondary storage device in an information processing device, includes, by a host controller, converting a logical address of an access destination specified by the host unit into a physical address using an address conversion table; and, by a memory controller, performing data access to the secondary storage device based on the physical address. An address space defined by the address conversion table includes a coarsely granular address space that collectively associates, with logical addresses, physical addresses that are in units larger than those in which data is read.

It should be noted that any combinations of the above components and any conversions of expressions of the present disclosure between "method," "device," "system," "computer program," "storage medium storing a computer program," and so on are also effective as modes of the present disclosure.

The present disclosure ensures higher efficiency in an information processing device using an SSD in terms of resources and processing time.

 
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