What is SSD storage and what is PCIe SSD?
What is SSD storage and what is PCIe SSD? - Table of contents:
What is SSD storage?
When solid state storage was 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.
By examining what is SSD storage, you can also understand what the future will hold for their components, benefits and applications.
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).
SSD storage also has 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.
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 Giga transfer 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 Giga transfer speed, hitting 16 Gbps and 5 GT/s, respectively. Subsequent generations doubled bandwidth and Giga transfer 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 a 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 run on top of PCIe.
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 uses the standard SATA interface are an ideal option for content creators, IT professionals and everyday users. An SSDs with the standard SATA interface to achieve the maximum SATA interface limit of 560/530 MB/s sequential speeds.
What is the future of SSD storage?
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. The form factor will also continue to shrink.
What is a PCIe SSD?
Solid state drive (SSD) technology for the massesturned 30 this year. When it first launched, there was great anticipation, and for good reason. From the start, SSDs were faster and more reliable than traditional hard disk drives (HDDs). As the technology evolved, the chasm between HDDs and SSDs widened. Today, you’d be hard-pressed to find any computing device sold without an SSD installed or SSD compatibility.
The implementation of SSDs became even more pronounced in 2003 with the development of a low-latency computer expansion bus known as a peripheral component interconnect express (PCIe). A PCIe is a bus featuring high data transfer rates and little to no slow down.
So what is PCIe SSD used for, exactly? And why should you care? Below, we address four top questions about this technology and why it’s something that both consumers and businesses need.
PCIe SSDs are like other SSDs in that they use flash memory to store files and applications. Flash, unlike traditional HDDs, has no moving parts. It uses solid state chips that feature flash memory cells to retain data regardless of whether the system is turned on or not, and software is used to retrieve that data when it’s needed. HDDs, in contrast, have an actuator arm that physically reaches out and writes and reads data on a spinning disk. PCIe SSDs are distinct from other SSDs in that they access the computer’s PCIe slot, which is also used for high-speed video cards, memory and chips.
What’s the difference between a SATA-based SSD and a PCIe-based SSD?
PCIe SSDs are the most recent option available. There are actually four types of SSD form factors: serial advanced technology attachment (SATA), small computer system interface (SCSI), Fibre Channel, which was originally created for network-attached devices, and PCIe.
In the past, most SSDs connected to a computer via a SATA slot. SATA was built with HDDs in mind, and uses a special cable to connect a drive to the motherboard. This slot allows the SSD to read data at speeds of up to 550MBps and write at around 500MBps.
As mentioned, PCIe SSDs connect directly to the PCIe slot. A PCIe SSD is smaller in size than a SATA drive, and it plugs directly into a computer’s motherboard. SATA SSDs are connected via cables. The additional travel distance this adds for the data can increase latency.
What are the use cases of PCIe and SATA?
If PCIe SSDs are faster than SATA drives, why wouldn’t you simply opt for the PCIe standard instead? There are some distinct use cases for SATA. For one thing, older PCs and servers may not support PCIe, so if you’re looking to repurpose an older PC, SATA may be your only option. In addition, SATA SSDs are available in 2.5-inch models, while PCIe drives come in a variety of different sizes.
How has the PCIe standard changed over time?
While the actual connectivity hasn’t changed (a PCIe 1.0 device can snap into a PCIe 4.0 device and vice versa), PCIe 4.0 SSD is much faster than its predecessor, PCIe 3.0. For example, PCIe 3.0’s throughput is 1GBps per lane, which translates to an overall data transfer rate of up to 32GBps total. PCIe 4.0, however, provides twice the throughput rate per lane that 3.0 does, supporting transfer rates of up to 64GBps.