Western Digital Technologies, Inc.

Sandisk Technologies Inc.

Lakshmi Sowjanya Sunkavelli

Manoj M Shenoy

Ramanathan Muthiah

Stella Achtenberg

Gopu S

Silky Mohanty

Arunkumar Mani

Sabith Ali B N

Noor Mohamed A A

Niranjani Rajagopal

A three tier memory has an upper sub block, a lower sub block, and a middle sub block. In the present disclosure, rather than precharging the upper and lower sub blocks, use is made of the middle sub block using a firmware (FW) scheme. Upon receiving a write request from a host, the FW will route the data to the middle sub block (SB) through reverse order programming (ROP) so that the SBis pre-charged through the source side through the lower sub block (SB). Once the SBis written, data is then routed to the SBand then to the upper sub block (SB). When there is a garbage collection (GC) request, the FW will move the data from the SBand then erase the SB. Then the data moves from the SBand SBis erased. Finally, the data moves from the SBand then SBis erased.

Firmware scheme for 3 tier memories

Some data storage devices select blocks of memory from a free block pool and randomly allocate the blocks as primary and secondary blocks to redundantly store data in a write operation. However, some blocks, such as blocks on the edge of a plane, may not serve well as primary blocks. One example data storage device presented herein addresses this problem by allocating such blocks as secondary blocks instead of primary blocks.

Data storage device and method for intelligent block allocation

A storage system stores data in a primary block and a copy of the data in a secondary block. Parity bits are stored with the data and the copy of the data. A header with logical block information is stored with the copy of the data in the secondary block. The data in the primary block is not stored with a header, which allows more parity bits to be stored with the data in the primary block. This provides more robust error protection for the data stored in the primary block and reduces the need to rely upon the copy of the data in the secondary block.

Storage system and method for avoiding header to improve parity

A method and apparatus for identifying data that is to be accessible in a low power state of a data storage device, and store this data in a physical (or logical) block that will be accessible in a low power state of the data storage device. Low power accessible data may be identified by host metadata of the data, indicating access is needed in a low power state. In other embodiments, the data storage device may learn the power state in which data should be accessible. In these embodiments, a controller stores information regarding the power state of a namespace in which the data is stored as an indicator to make the data accessible in a low power state. Alternatively, the controller stores a previous power state in which the data was accessed as an indicator to make the data accessible in a low power state.

Data management for efficient low power mode handling in a storage device

A storage system erases blocks of memory prior to writing data to the blocks. Instead of erasing the blocks at the time the write operations are executed, the storage system pre-erases the blocks, which can improve performance. However, because program failure errors can occur if the blocks sit empty for a relatively-long period of time prior to programming, the storage system pre-erases the blocks upon a prediction that a host will send sequential write commands to the storage system that will use the blocks. Additionally or alternatively, the storage system can pre-erase a block upon determining that the number of write commands in a command queue in the storage system is above a threshold that represents a number of write commands needed to fill the block with data.

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Bengaluru, India

Lakshmi Sowjanya Sunkavelli