When solid state storage were invented over half a century ago and then made widely commercially available, their effect was transformative — the technology has played a major role in the evolution of storage, gaming, business and computing. But by examining SSDs, you can also understand what the future will hold for their components, benefits and applications.
What is SSD storage?
Solid state drive (SSD) storage uses non-volatile solid state chips that feature flash memory cells to store data on a long-term basis. Unlike traditional hard disk drives (HDDs), which use magnetic platters spinning at high speeds to using an actuator arm reminiscent of a record player, SSDs require no moving parts. Instead, the storage solution depends entirely on flash memory to store data, making them much faster at reading and writing data, both ad hoc and in sustained operations.
Using a mesh of electrical cells in a NAND — a type of non-volatile flash memory — to store data, SSDs include an embedded processor known as the controller. It runs firmware-level code to help the drive operate and bridge the media to the host computer via the interface bus. Today’s SSDs don’t require an additional power source that maintains an electrical current into the device at all times to preserve the data. This makes them increasingly more reliable than traditional HDDs (from a mechanical and data integrity standpoint).
SSDs also have built-in technology that further improves read/write speeds, making them faster than traditional HDDs. Historically, HDDs included a bit of memory within the drive hardware itself (typically eight or 16 MBs) to increase the perceived read/write performance. If the data a user wants to read or write can be stored within the high-performing cache memory, the drive temporarily stores the data in the fast memory modules. It then reports back to the operating system once this is complete, triggering the drive to transfer the data from the cache to the much slower magnetic media. This doesn’t always work, as only a small portion of the drive’s total data is cached at any time, and if data isn’t in the cache, it has to be read from the slower physical medium.
SSDs utilize the same kind of concept involving a cache, except they include dynamic random access memory (DRAM) chips — a type of semiconductor memory commonly used in PCs and servers — within the controller hardware on the SSD itself. Ranging from 64 MBs all the way up to GBs, they buffer requests to improve the life of the drive and serve short bursts of read/write requests faster than the regular drive memory allows. These caches are essential in enterprise storage applications, including heavily used file servers and database servers.
When were SSDs first available?
The use of flash memory for longer-term storage has been around since the 1950s, but those solutions were generally in mainframes or larger minicomputers. They also required battery backups to preserve the contents of the memory when the machine was not powered by the host, as those solutions used volatile memory.
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Since then, the technology has gotten smaller and faster, and it no longer requires battery backup. Performance has skyrocketed too, as new PC bus interfaces have made it possible for data transfer rates to far exceed the standard rates that traditional spinning media would saturate. They’re also less expensive today, even compared to the first SSD drive released in 1991 — a 20MB SSD that sold for $1,000.
Applications for SSDs
There are multiple benefits to using SSDs for production storage applications. Because SSDs have no moving mechanical components, they use less power, are more resistant to drops or rough handling, operate almost silently, and read quickly with less latency. Additionally, since there are no spinning platters or actuator arms, there is no need to wait for the physical parts to ramp up to operating speed. This feature eliminates a performance hit that hard drives cannot escape. SSDs are also lightweight, which makes them ideal for laptops, small form factor machines and high-capacity storage area networks in a smaller footprint.
Because of these advantages, SSDs are popular for the following applications:
- To host both the database engine and the database itself for quick access.
- As a “hot” tier in a stratified network storage archive, where frequently accessed data can be retrieved and rewritten very quickly.
- In situations where physical shocks are a possibility and HDDs would present an untenable risk to system reliability.
- In gaming, where the user is often moving through new environments.
- In business settings where you need your operating system and applications to load quickly.
How to choose the right SSD for your needs
Over the past few years, there have been several changes to SSDs. One of the most recent updates is the use of the PCIe interface (a low-latency computer expansion bus also known as a peripheral component interconnect express) instead of over other interface technologies, such as serial advanced technology attachment (SATA).
PCIe SSDs interface with a system via its PCIe slot — the same slot that is used for high-speed video cards, memory and chips. PCIe 1.0 launched in 2003, with a transfer rate of 2.5 gigatransfer per second (GT/s) and a total bandwidth of 8 Gbps. GT/s measures the number of bits per second that the bus can move or transfer.
Several years later, PCIe 2.0 was introduced, doubling both the bandwidth and the gigatransfer speed, hitting 16 Gbps and 5 GT/s, respectively. Subsequent generations doubled bandwidth and gigatransfer speeds with each new iteration. PCIe 3.0, for instance, features 32Gbps bandwidth and 8 GT/s.
Most recently, SSDs started using the PCIe 4.0 specification, which features bandwidth of 64 Gbps and a 16 GT/s rate. PCIe is now being paired with the non-volatile memory host controller interface specification (NVMe), a communications protocol for high-speed storage systems that runs on top of PCIe.
This development means that users who are looking for blazing-fast speeds and high reliability can tap SSDs that feature PCIe 4.0 connectivity. Samsung 980 PRO, which is PCIe 4.0 compatible, utilizes these latest advances. The drive delivers read speeds up to 7,000MBps, making it twice as fast as PCIe 3.0 SSDs and 12.7 times faster than some SATA SSDs. PCIe’s take the place of SATA in terms of high bandwidth interface.
However, not everyone has a PCIe-enabled system, and some may have PCIe slots in conjunction with other system add-ons, like memory or graphics cards. In these cases, other SSDs like the Samsung 870 EVO are an ideal option for content creators, IT professionals and everyday users. An 870 EVO uses the standard SATA interface to achieve the maximum SATA interface limit of 560/530 MB/s sequential speeds. Samsung 870 QVO also achieves the maximum SATA interface limit, with offerings in the 1, 2, 4, and 8 TB 2.5-inch SATA form factor configurations.
What does the future hold?
In the short term, capacities will continue to ramp up, while the cost per GB for SSDs will continue to decrease. New form factors that increase the number of parallel data transmission lanes between storage and the host bus will emerge to increase the speed and quality of the NAND storage medium.
The physical layer of cells that holds the blocks and pages will improve, offering better reliability and performance. Form factor will also continue to shrink. In 2021, Samsung announced it had reduced cell volume by up to 35%, making its 176-layer 7th-generation V-NAND SSD offering similar in height to its previous generation.
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