BACKGROUND

Field

This disclosure is generally related to electronic devices and more particularly to storage devices.

Background

Storage devices enable users to store and retrieve data. Examples of storage devices include non-volatile memory devices. A non-volatile memory generally retains data after a power cycle. An example of a non-volatile memory is a flash memory, which may include array(s) of NAND cells on one or more dies. Flash memory may be found in solid-state devices (SSDs), Secure Digital (SD) cards, and the like.

A flash storage device may store control information associated with data. For example, a flash storage device may maintain control tables that include a mapping of logical addresses to physical addresses. This control tables are used to track the physical location of logical sectors, or blocks, in the flash memory. The control tables are stored in the non-volatile memory to enable access to the stored data after a power cycle.

When writing data to an open block (i.e. an un-programmed or partially programmed block) of the flash memory, the flash storage device may identify the physical address of the block associated with the logical address in which the data is to be stored, and may then write the data to the open block at the identified physical address. When the open block becomes fully programmed (i.e. a closed block), the flash storage device may erase existing data in the closed block and then write additional data to the now-erased (open) block. Similarly, the flash storage device may erase data in other closed blocks before writing additional data to those blocks as well.

However, in some cases after programming the open block, the flash storage device may experience back-to-back (i.e. consecutive) erase failures when attempting to erase the other closed blocks. As a result, these closed blocks may be identified as grown bad blocks (GBBs), even though the closed blocks may actually be good blocks in other situations (e.g. the blocks may have been successfully erased prior to programming the open block). Over time, if the entire population of closed blocks is identified as GBBs due to such erase failures, the flash storage device may enter a read-only (RO) mode, preventing further data writes to the flash memory.

SUMMARY

One aspect of a storage device is disclosed herein. The storage device includes a controller. The controller is configured to program an open block, and to attempt to erase a plurality of closed blocks following the programming of the open block. In response to a number of consecutive erase failures after programming the open block meeting a threshold, the controller is further configured to identify the open block as a bad block.

Another aspect of a storage device is disclosed herein. The storage device includes a controller. The controller is configured to program an open block a plurality of times, to attempt to erase a plurality of closed blocks after each of the plurality of times, and to identify the open block as a bad block when a number of consecutive erase failures after programming the open block meets a threshold after each of the plurality of times.

A further aspect of a storage device is disclosed herein. The storage device includes a controller. The controller is configured to program an open block a number of times, to attempt to erase a plurality of closed blocks the number of times, and to identify the open block as a bad block when the attempt to erase the plurality of closed blocks fails the number of times.

It is understood that other aspects of the storage device and method will become readily apparent to those skilled in the art from the following detailed description, wherein various aspects of apparatuses and methods are shown and described by way of illustration. As will be realized, these aspects may be implemented in other and different forms and its several details are capable of modification in various other respects. Accordingly, the drawings and detailed description are to be regarded as illustrative in nature and not as restrictive.

