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The Evolution of QLC Flash Storage

Flash Storage has come a long way since its debut in the ’80s and then later commercialized into NAND-based removable memory card format in the mid-’90s. Unlike other kinds of data storage, flash memory stands out as an “electronically erasable programmable read-only memory form of computer memory,” also known as EEPROM, and does not require a power source to retain data, making flash memory an appealing option for individuals and organizations looking for fast, fail-proof data storage they can rely on.

The first flash memory drive was only capable of storing 128 megabits of data, but has continuously evolved ever since. Since its inception, we now have the capability of storing over 7 Terabytes of data in flash storage. It’s quite an impressive evolution of quad-level cell NAND (QLC) flash memory form.

How did we get here? Let’s take a look at the evolution of QLC flash memory.

About Flash Storage

When Fujio developed flash storage, he created a solid-state technology that uses memory chips for writing and storing data. It utilizes non-volatile memory, which means that data is not lost when the power is turned off. It is also highly available, consumes less energy, and takes up less space than legacy mechanical disk storage solutions.

Now, flash storage ranges in solutions. Individual consumers can transport files and data on portable flash USB drives, and organizations can also make use of entire enterprise-level arrays. With solid-state drives, flash storage also offers rapid response times with only microseconds of latency compared to hard drives with disks or other moving components.

How does flash storage work? A basic flash memory cell is comprised of a storage transistor that has:
● A control gate
● A floating gate

These floating gates are insulated from the rest of the transistor by a thin oxide layer or a dielectric material. The floating gate stores electrical charge and controls the flow of the electrical current in each flash cell. Electrons are added or removed from this floating gate to change the transistor’s threshold voltage, impacting whether the cell has been programmed as a binary “zero” or as a “one.”

Each flash architecture includes a memory array that’s been stacked with a large number of these flash cells to store large volumes of data in a small, compact, quick storage solution.

The Introduction of Single-Level Cell Memory

One of the largest innovations in flash memory was the advent of single-level cell flash memory. Single-level cell (SLC) flash is a kind of solid-state storage. It stores one bit of data per cell. SLC flash storage has one of two states:
● Programmed (0)
● Erased (1)

This state is determined by the level of charge that’s been applied to the cell. The benefit? Since there are only two choices, programmed or erased, zero or one, the state of each cell can be interpreted very quickly. This also reduces the chance of bit errors.

Individual SCL memory cells have a relatively long life; they can sustain around 100,000 write operations before they fail.

Single-level cell NAND (“not and”) flash storage made its way to the market in 2008 for commercial and industrial applications that required high performance and longevity in compact flash cards or solid-state drive formats. SLC stores one bit of data per cell of flash media, hence the name “single-level cells” characterize the one block storing of data. There are pros and cons of this SLC system.

The Benefits of SLC Flash Memory:
● Reduced Read/Write error
● Broader temperature resistance
● Lower power consumption
● Higher cell endurance and the longest-lasting flash storage

The Disadvantages of SLC Flash Memory:
● SLC storage is expensive, so it is saved for performance-heavy applications
● Limited availability for higher capacity storage

Generally, SLC memory is used in commercial and industrial applications and embedded systems that need high levels of performance and long-term reliability. It’s a high-grade of flash memory that offers exceptional, enduring performance, but it does come with a high price.

The Rise of Multi-Level Cells Memory

The next development in flash memory after SLC flash is multi-level cell memory.

SLC Storage has a good use case for enterprise organizations that don’t mind the costly price tag and prefers dependability, but for small business organizations and the average consumer, there is Multi-level cell (MLC) and Triple-level Cell (TLC) flash. MLC and TLC flash storage can come at a fraction of SLC storage and is preferred for industries that use applications that don’t require long-term reliability like with SLC flash.

MLC and TLC can store more than one bit of data per memory cell, as opposed to SLC storage, to reduce storage costs due to data density. As the name suggests, an MLC cell can represent multiple values and four different states:
● 00, or close to 75 percent full
● 01, or close to 50 percent full
● 10, or close to 100 percent full
● 11, or close to 25 percent full

With technological advances in software applications and memory reading software, MLC and TLC flash storage have significantly reduced bit error rates where it is now possible for industrial and commercial use.

The benefit of MLC storage? Storage capacity may be increased without any corresponding increase in processing complexity. They also offer higher density and lower cost per bit compared to SLC memory, making them a high-powered, lower-cost option.

The Innovation of Nexsan QLC Flash Storage

With more innovation in CPU computation, processing power, and the increasing demand for storage, developers introduced NAND flash memory chips with quad-level cells (QLC) in 2009. The term “quad-level cell” refers to flash technology geared to storing four bits of data using 16 different states, which results in 16 different voltages. Since then, Nexsan has engineered a QLC Flash storage solution for any size organization for top performance, whether it is an enterprise or small business.

Nexsan has developed a QLC NAND flash storage solution with the highest performance and cost-effectiveness in a conveniently compact form factor. Nexsan’s E-Series 18F (E18F), E-Series 32F (E32F), and BEAST Elite F solutions provide access to high capacity storage for performance-sensitive workloads. These engineered solutions can handle the most demanding enterprise environments with optimum price, performance, and robust connectivity. The design and functionalities revolve around three concepts:
● Diverse capacity
● Performance
● Ease of expansion

The Nexsan QLC solutions can handle the kinds of operations that fuel businesses. Its QLC flash solution stores up to 33% more data than TLC in every memory cell for a density-performing solution. With innovative designs, QLC flash storage can meet today’s business technology objectives such as:
● Real-time analytics
● Machine learning
● Artificial intelligence
● Big data
● Media content delivery
● User authentication

Now organizations can power their entire enterprise on QLC Flash, leveraging the solution’s remarkable endurance. QLC Flash’s “block size” storage indicates how much data is transferring at a time. Whenever the QLC SSD is writing block sizes less than 16K, the drive interprets them as sequential writes, which are “gentler” or increase endurance and allow the drive to last longer.

Nexsan understands how important an organization’s number of data writes per day (DWPD); therefore, the engineers designed a QLC flash solution that can support a write bandwidth of up to 200 terabytes per day. It is projected that 96% of SSD shipments in 2022 will be less than or equal to 1DWPD making read-intensive drives significant for future business’s needs. Its endurance features can also eliminate bottlenecks and other performance issues when dealing with a three-tier temperature (Hot, cool/warm, and cold) storage system.

Finding the right storage solution for your organization can be simple with the help of Nexsan’s storage solution experts. When you are ready to explore your flash storage options and find the one that fits your performance needs and budget, you have access to our full menu of storage solutions to select, and that list is growing every day. Contact us now to discover more!