One of the most commonly used storage devices is the USB flash drive, with commercial and industrial-level options available. Unfortunately, they are prone to wearing out over time. Other flash memory drives use wear leveling as a standard, but what about USB drives?
USB flash drives do not use wear leveling as a standard, but it is used in all industrial-grade USB drives. It is a technique for prolonging the storage device’s lifespan and improving efficiency, but it requires more memory than commercial-grade USB drives.
Keep reading to find out more about wear leveling in USB flash drives and other ways you can prolong your storage device’s lifespan.
How To Keep USB Flash Drives From Wearing Out
As mentioned in the introduction, wear leveling is a method that helps prevent flash memory storage devices from wearing out. Basically, it’s a program that distributes the load of reading/writing around all the units within the drive.
Wear leveling is standard in all SSD drives but is not always available in commercial-grade USB flash drives.
Here are a few other steps you can take to keep your USB flash drive from wearing out:
- Cover the connector. Dust and dirt from the air surrounding the connector can settle on it and cause damage over time, not to mention the effect of weather conditions.
- Avoid extreme temperature fluctuations. Extreme heat or cold can damage the hardware structures of a USB flash drive.
- Store it in a dry place. Humidity can cause corrosion on any electrical device, so it’s always recommended to store your USB stick in a cool, dry place.
- Eject the drive out of your computer. Avoid disconnecting the USB drive from your computer without clicking on “Eject”. This protects the device from errors caused when data is not fully written/erased.
- Avoid plugging it in for prolonged periods. This protects your USB stick from power surges, overheating, and simply using up the lifespan of its hardware components.
For more commercial users, the aforementioned measures are more important than wear leveling. That is because a typical USB flash drive has a lifespan of over 100,000 read and write cycles. In other words, you’re more likely to damage the USB stick by other means before it wears out due to erase cycles (i.e., erasing and writing new data on a segment of the device’s memory).
What Is Wear Leveling?
Wear leveling is a protective measure used in flash memory devices to extend the lifespan of erasable memory limitations. It also increases the efficiency of flash memory devices because each segment is used to full capacity before the next segment is chosen for data storage.
Essentially, this process distributes rewriting on all segments of memory storage devices. Wear leveling was created because conventionally-used file systems such as NTFS create excessive wear on the same area when used with flash memory storage devices.
This is because those file systems were originally designed for use on magnetic disks such as HDD (Hard Disk Drive) and floppy disks. Today’s storage devices use NAND flash controllers (also called memory chips) to manage the data stored on the device for more efficient access.
However, without wear leveling, the lifespan of flash memory devices suffers significantly. For larger storage devices such as SSD, wear leveling is an industry standard used to protect the device from data loss by improving reliability and durability.
Types of Wear Leveling Mechanisms
If a USB flash drive comes with wear leveling, there are generally two variations of this mechanism: local and global.
Let’s take a look at each type of wear leveling that NAND flash controllers use:
Local Wear Leveling
When each chip in products with multiple chips is managed separately, the wear leveling mechanism is considered local.
There are two types of local wear leveling which are used in flash memory drives, such as USB sticks.
Here we have a suboptimal mechanism of wear leveling, whereby blocks are only repositioned if they are set for rewriting. Using non-volatile memory, the flash memory drive counts rewrites. A map of logical block addresses is made and linked to the physical drive.
Read-only or rarely updated data written on a block in flash memory with dynamic wear leveling does not move at all—that is, the distribution of ‘wear’ is inefficient and unequal.
Note that with dynamic wear leveling, the device will still have usable storage blocks that have remained unused because they were marked as invalid (either read-only or infrequently updated).
This is a more efficient mechanism of wear leveling. It distributes the wear equally among all blocks in a flash memory drive, and a map of the logical block addresses is still created and linked to the physical drive. However, those blocks which are marked as “invalid” are routinely moved around to empty blocks.
The effect this rotational strategy has is that all the blocks are used at approximately the same rate. The result is that the storage device is used to its full capacity. When the device becomes obsolete, most of the blocks will have used up almost all their potential lifespan.
It’s worth noting that static wear leveling generally results in a shorter lifespan when compared to devices using dynamic wear leveling.
Global Wear Leveling
This is a more complex and sophisticated way of managing wear leveling in storage devices. To further distribute the load on the entire storage device’s blocks for more efficient use of the NAND flash controller, a global wear leveling system manages the blocks within all the chips of a multi-chip storage device together.
As USB flash drives are becoming able to store increasing amounts of data, this expanded scope of managing wear leveling is essential for increasing efficiency and extending the lifespan of today’s memory storage devices.
Although wear leveling is not a standard feature of USB flash drives, other protective measures can be taken to protect them from deterioration. Wear leveling is an important feature used in other flash memory devices and high-end USB flash drives to prolong their lifespan by increasing their reliability and making them more durable.