155.

In an example, the controller 150 includes, or is otherwise associated with, a cross-temperature mitigation system 180 and a temperature detection system 185. Although the cross-temperature mitigation system 180 and the temperature detection system 185 are shown separately, the temperature detection system 185 may be part of the cross-temperature mitigation system 180 and vice versa. Additionally, the cross-temperature mitigation system 180 and/or the temperature detection system 185 may be packaged functional hardware units designed for use with other components/systems, a portion of a program code (e.g., software or firmware) executable by a processor or processing circuitry, or a self-contained hardware and/or software component that interfaces with other components and/or systems.

In an example, the cross-temperature mitigation system 180 is operable to determine which copy of preloaded content 190 to return to the host device 105 when a read command, associated with the preloaded content 190, is received by the controller 150. For example, when a read command is received by the controller 150, the cross-temperature mitigation system 180 determines a current operating temperature of the data storage device 110.

In an example, the current operating temperature of the data storage device 110 is determined by and/or received from the temperature detection system 185. For example, the temperature detection system 185 includes a temperature probe, a temperature sensor or other temperature measurement device that enables the temperature detection system 185 to determine or identify a current operating temperature of the data storage device 110. When the temperature detection system 185 determines the current operating temperature of the data storage device 110, the determined operating temperature is provided to the cross-temperature mitigation system 180.

The cross-temperature mitigation system 180 uses the operating temperature to determine which copy of the preloaded content 190 to return to the host device 105 based, at least in part, on the temperature, or simulated temperature, at which each copy of preloaded content 190 was written to the data storage device 110. In an example, the cross-temperature mitigation system 180 makes the determination based on which copy of preloaded content 190 is associated with a temperature that is closest to the determined operating temperature of the data storage device 110. For example, if the determined operating temperature of the data storage device 110 is ten degrees Celsius, the cross-temperature mitigation system 180 selects a copy of preloaded content that was written to the data storage device at twenty degrees Celsius.

In another example, the cross-temperature mitigation system 180 makes the determination on performance metrics or characteristics associated with each copy of preloaded content 190 and the determined operating temperature of the data storage device. For example, the cross-temperature mitigation system 180 accesses a table or chart that includes information regarding a temperature at which a copy of preloaded content 190 was written, a range of operating temperatures that the copy of preloaded content is useable with and performance metrics associated with the range of temperatures.

For example and referring to FIG. 2, FIG. 2 illustrates a table 200 that shows how different copies of preloaded content are associated with different performance metrics according to an example. In an example, the information in the table 200 is generated during a factory setting and is made available to a data storage device and/or a cross-temperature mitigation system, such as, for example, the data storage device 110 (FIG. 1) and/or the cross-temperature mitigation system 180 (FIG. 1).

In this example, multiple copies of preloaded content have been stored on the data storage device. Further, each copy of preloaded content is associated with a different temperature or range of temperatures. For example, a first copy of preloaded content 210 is associated with a first operating temperature range 220 or is associated with a particular operating temperature (either a physical operating temperature or a simulated operating temperature).

Likewise, a second copy of preloaded content 240 is associated with a second operating temperature range 250. In an example, the first operating temperature range 220 is different from the second operating temperature range 250. In another example, the first operating temperature range 220 and the second operating temperature range 250 at least partially overlap. Additionally, the data storage device includes an Nth copy of preloaded content 270. The Nth copy of preloaded content 270 is associated with a Nth operating temperature range 280.

As shown in FIG. 2, each copy of preloaded content is associated with performance metrics. For example, the first copy of preloaded content 210 is associated with first performance metrics 230, the second copy of preloaded content 240 is associated with second performance metrics 260 and the Nth copy of preloaded content 270 is associated with Nth performance metrics.

When the cross-temperature mitigation system determines the current operating temperature of the data storage device, the cross-temperature mitigation system checks the table 200 and determines, based on the performance metrics in the table and the operating temperature range, whether to choose the first copy of preloaded content 210, the second copy of preloaded content 240 or the Nth copy of preloaded content 270. The determined copy of preloaded content is decoded and provided to the host device. For example, and referring back to FIG. 1, the determined copy of preloaded content 190 is decoded (e.g., ECC decoded by an error correction code system 195) and subsequently returned to the host device 105.

In an example, the cross-temperature mitigation system 180 is also operable to determine whether and when one or more copies of the preloaded content 190 should be deleted or erased from the data storage device 100. In an example, the cross-temperature mitigation system 180 deletes portions of one or more copies of the preloaded content 190. For example, different portions of preloaded content 190 may be designated as more important when compared with other portions. In such an example, the more important portions of the preloaded content 190 would not be deleted (or would be deleted after the less important portions are deleted). In another example, the cross-temperature mitigation system 180 deletes the entire copy of preloaded content 190.

In an example, the cross-temperature mitigation system 180 determines to delete or erase the one or more copies of preloaded content 190 based on a determined storage capacity of the data storage device 110. For example, if the data storage device reaches a threshold amount stored data, the cross-temperature mitigation system 180 determines to free up additional space on the data storage device by deleting one or more copies of the preloaded content. In an example, the copies of preloaded content are ranked according to one or more metrics. In an example, the one or more metrics include, but are not limited to, a least recently used copy, a least recently used temperature range and so on.

When the one or more copies are identified for deletion, the cross-temperature mitigation system 180 causes the one or more copies (or portions of the one or more copies) to be erased. In an example, the deletion of the one or more copies are part of a garbage collection operation that is executed as a background process of the data storage device 110.

In an example, prior to deletion, the copy of preloaded content 190 that is selected for deletion is used to correct one or more errors that may be present in a copy of preloaded content 190 that is being kept. For example, the cross-temperature mitigation system 180 or an error correction system compares the various copies of preloaded content 190 and uses a majority rule approach to determine whether any errors are present in the copy (or copies) of preloaded content 190 that will be kept. Reading several versions of the same preloaded content can improve the reliability readings of error correction code (ECC) in low-density parity check (LDPC) codes and other ECC mechanisms.

In another example, the different copies of preloaded content 190 may be used for improved decoder initialization. For example, the copies of preloaded content 190 may be used for setting log likelihood ratio (LLR) values of each of the codeword bits as a function of the value of the corresponding bit within the multiple copies. For example, each bit is assigned a bit reliability as a function of the level of agreement among the multiple copies. This will improve the read throughput and correction capability of the LDPC decoder.

FIG. 3 illustrates a method 300 for selecting a copy of preloaded content to return to a host device based on a determined operating temperature of a data storage device according to an example. In an example, the method 300 is performed by a cross-temperature mitigation system of a data storage device, such as, for example, the cross-temperature mitigation system 180 shown and described with respect to FIG. 1.

Additionally, in an example, the data storage device includes two or more copies of preloaded content. Each copy of preloaded content is written to the data storage device at different physical operating temperatures or at different simulated operating temperatures.

Method 300 begins when the data storage device receives (310) a command from a host device. In an example, the command is received by a controller (e.g., the controller 150 (FIG. 1)). When the command is received, the controller determines (320) whether the command is a read command that requests data associated with the preloaded content. For example, the controller accesses metadata associated with the command to determine the type and/or the location of the data associated with received command.

If the controller determines (320) that the command is not a request for preloaded content, the controller causes the command to be executed (330) and the method 300 is repeated. However, if the controller determines (320) that the command is a request for preloaded content, the controller causes the cross-temperature mitigation system to determine (340) a current operating temperature of the data storage device. For example, the cross-temperature mitigation system accesses or otherwise causes a temperature detection system (e.g., temperature detection system 185 (FIG. 1)) to measure the current operating temperature of the data storage device using a temperature detection circuit, a temperature detection sensor or any other temperature reading device.

When the current operating temperature of the data storage device is determined, the cross-temperature mitigation system compares the current operating temperature to a write temperature, or a range of temperatures, associated with each copy of preloaded content. In an example, the write temperature, or the range of temperatures, associated with each copy of preloaded content is a physical write temperature. For example, each copy of preloaded content is written to the data storage device when the data storage device was physically operating at different temperatures.

In another example, the write temperature, or the range of temperatures, associated with each copy of preloaded content is a simulated write temperature. For example, one or more write parameters associated with each copy of preloaded content are manipulated or changed such that a temperature coefficient associated with one or more memory cells of the data storage device model different write temperatures from the perspective of the memory cell. The cross-temperature mitigation system then selects (350) a copy of preloaded content based, at least in part, on the comparison.

In an example, the cross-temperature mitigation system selects a particular copy of preloaded content based on a determination as to which copy of preloaded content is associated with a write temperature that is closest to the determined operating temperature of the data storage device 110. For example, if the determined operating temperature of the data storage device is ten degrees Celsius, the cross-temperature mitigation system selects the copy of preloaded content that was written to the data storage device at twenty degrees Celsius rather than the copy of preloaded content that was written at fifty degrees Celsius.

In another example, the cross-temperature mitigation system makes the determination on performance metrics or characteristics associated with each copy of preloaded content. For example, the cross-temperature mitigation system accesses a table (e.g., the table 200 FIG. 2)) that includes information regarding a temperature at which each copy of preloaded content was written, a range of operating temperatures that the copy of preloaded content should be selected for and/or performance metrics associated with the range of temperatures.

When a particular copy of preloaded content is identified and/or selected, the selected copy of preloaded content is decoded (360) and the decoded copy of preloaded content is returned (370) to the host device.

FIG. 4 illustrates a method 400 for deleting a copy of preloaded content from a data storage device according to an example. In an example, the method 400 is performed by a cross-temperature mitigation system of a data storage device such as, for example, the cross-temperature mitigation system 180 shown and described with respect to FIG. 1.

In an example, the method 400 begins when a current capacity of the data storage device is determined (410). In an example, the determination about the capacity of the data storage device is continuously monitored. In another example, the capacity of the data storage device is periodically monitored.

A determination is made as to whether the capacity of the data storage device is over a threshold (420). If the controller and/or the cross-temperature mitigation system determines that the capacity of the data storage device is not over a threshold, the method 400 is repeated. However, if the controller and/or the cross-temperatures mitigation system determines (420) that the capacity of the data storage device had reached or exceeds a capacity threshold, the cross-temperature mitigation system determines (430) an access frequency of one or more copies of the preloaded content.

In an example, the access frequency includes a determination as to which copies of preloaded content are used most frequently or most recently. In another example, the different copies of preloaded content are dynamically ordered. In such examples, the ordering of the copies of preloaded content is based, at least in part, on an extrapolation of recently used read temperatures and/or by accumulating statistics about the overall frequency of the occurring read temperatures. For example, a copy of preloaded content that has a write temperature that is associated with an operating temperature that has not been reached (or has not been reached for over a threshold period of time) will be erased before a copy of preloaded content that is associated with an operating temperature that was reached more recently.

Based, at least in part, on the determined access frequency, an identified copy (or one or more portions of the identified copy) of preloaded content is deleted (440).

FIG. 5-FIG. 6 describe example storage devices that may be used with or otherwise implement the various features described herein. For example, the storage devices shown and described with respect to FIG. 5-FIG. 6 may include various systems and components that are similar to the systems and components shown and described with respect to FIG. 1. For example, the controller 640 shown and described with respect to FIG. 6 may be similar to the controller 150 of FIG. 1. Likewise, the memory dies 605 may be similar to the first memory die 165 and/or the second memory die 170 of FIG. 1.

FIG. 5 is a perspective view of a storage device 500 that includes three-dimensional (3D) stacked non-volatile memory according to an example. In this example, the storage device 500 includes a substrate 510. Blocks of memory cells are included on or above the substrate 510. The blocks may include a first block (BLK0 520) and a second block (BLK1 530). Each block may be formed of memory cells (e.g., non-volatile memory elements). The substrate 510 may also include a peripheral area 540 having support circuits that are used by the first block and the second block.

The substrate 510 may also carry circuits under the blocks, along with one or more lower metal layers which are patterned in conductive paths to carry signals from the circuits. The blocks may be formed in an intermediate region 550 of the storage device 500. The storage device may also include an upper region 560. The upper region 560 may include one or more upper metal layers that are patterned in conductive paths to carry signals from the circuits. Each block of memory cells may include a stacked area of memory cells. In an example, alternating levels of the stack represent word lines. While two blocks are depicted, additional blocks may be used and extend in the x-direction and/or the y-direction.

In an example, a length of a plane of the substrate 510 in the x-direction represents a direction in which signal paths for word lines or control gate lines extend (e.g., a word line or drain-end select gate (SGD) line direction) and the width of the plane of the substrate 510 in the y-direction represents a direction in which signal paths for bit lines extend (e.g., a bit line direction). The z-direction represents a height of the storage device 500.

FIG. 6 is a functional block diagram of a storage device 600 according to an example. In an example, the storage device 600 may be the 3D stacked non-volatile storage device 500 shown and described with respect to FIG. 5. The components depicted in FIG. 6 may be electrical circuits. In an example, the storage device 600 includes one or more memory dies 605. Each memory die 605 includes a three-dimensional memory structure 610 of memory cells (e.g., a 3D array of memory cells), control circuitry 615, and read/write circuits 620. In another example, a two-dimensional array of memory cells may be used. The memory structure 610 is addressable by word lines using a first decoder 625 (e.g., a row decoder) and by bit lines using a second decoder 630 (e.g., a column decoder). The read/write circuits 620 may also include multiple sense blocks 635 including SB1, SB2, . . . , SBp (e.g., sensing circuitry) which allow pages of the memory cells to be read or programmed in parallel. The sense blocks 635 may include bit line drivers.

In an example, a controller 640 is included in the same storage device 600 as the one or more memory dies 605. In another example, the controller 640 is formed on a die that is bonded to a memory die 605, in which case each memory die 605 may have its own controller 640. In yet another example, a controller die controls all of the memory dies 605.

Commands and data may be transferred between a host 645 and the controller 640 using a data bus 650. Commands and data may also be transferred between the controller 640 and one or more of the memory dies 605 by way of lines 655. In one example, the memory die 605 includes a set of input and/or output (I/O) pins that connect to lines 655.

The memory structure 610 may also include one or more arrays of memory cells. The memory cells may be arranged in a three-dimensional array or a two-dimensional array. The memory structure 610 may include any type of non-volatile memory that is formed on one or more physical levels of arrays of memory cells having an active area disposed above a silicon substrate. The memory structure 610 may be in a non-volatile memory device having circuitry associated with the operation of the memory cells, whether the associated circuitry is above or within the substrate.

The control circuitry 615 works in conjunction with the read/write circuits 620 to perform memory operations (e.g., erase, program, read, and others) on the memory structure 610. The control circuitry 615 may include registers, ROM fuses, and other devices for storing default values such as base voltages and other parameters.

The control circuitry 615 may also include a state machine 660, an on-chip address decoder 665 and a power control module 670. The state machine 660 may provide chip-level control of various memory operations. The state machine 660 may be programmable by software. In another example, the state machine 660 does not use software and is completely implemented in hardware (e.g., electrical circuits).

The on-chip address decoder 665 may provide an address interface between addresses used by host 645 and/or the controller 640 to a hardware address used by the first decoder 625 and the second decoder 630.

The power control module 670 may control power and voltages that are supplied to the word lines and bit lines during memory operations. The power control module