A solid state drive (SSD) is an electronic storage drive built on solid state architecture.
SSDs are built with NAND and NOR flash memory to store non-volatile data and dynamic random access memory (DRAM).
A SSD and magnetic hard disk drive (HDD) share a similar purpose.
A SSD is also known as a solid state disk (SSD) or electronic disk drive.
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SSD history, emergence in enterprise storage
The earliest solid-state drives generally were designed for consumer devices. The debut of the Apple iPod in 2005 marked the first notable flash-based device to broadly penetrate the consumer market.
EMC -- now known as Dell EMC -- is credited with being the first vendor to include SSDs in enterprise storage hardware when it added the technology to its Symmetrix disk arrays in 2008. That spawned the advent of hybrid flash arrays that combine flash drives and HDDs. For the most part, enterprise SSDs in hybrid arrays are used for caching reads in flash. This is due to the higher cost and lower endurance of SSDs when compared to HDDs
Image of an SSD.
The earliest commercially designed SSDs were made with enterprise multi-level cell (enterprise MLC) flash technology, which has enhanced write cycles compared to consumer-grade MLC. Newer enterprise SSDs are being marketed that use triple-level cell (TLC). SSDs made with 3D NAND represent the next evolution. IBM, Samsung and Toshiba have produced and marketed SSDs with 3D NAND, in which flash memory cells are stacked atop one another in vertical layers. Toshiba sold off its flash chip business in 2017.
Enterprise adoption of flash is on the rise as a result of improvements in solid-state wear performance and falling flash prices, although tightening global flash supplies have stalled the price drop. Experts contend SSDs are starting to supplant traditional disk in some use cases, although flash drives and HDDs are expected to coexist in many enterprises for the foreseeable future. For example, SSDs are geared for high-performance storage, but less so for long-term archiving and backup, which typically use fixed disk.
What are solid-state drives used for?
SSDs provide faster storage and other performance benefits than fixed disk. Businesses with a rapidly expanding need for higher input/output (I/O) have fueled the development and adoption of SSDs. Because SSDs offer lower latency than HDDs, they can efficiently handle both heavy read and random workloads. That lower latency stems from the ability of a flash SSD to read data directly and immediately from a specific flash SSD cell location.
An all-flash array takes only SSDs as storage. A hybrid flash array combines disk storage and SSDs with the flash used to cache hot data that is later written to disk or tape. In server-side flash configurations, SSDs are installed in x86 computers to support targeted workloads, sometimes in conjunction with networked storage.
High-performance servers, laptops, desktops or any application that needs to deliver information in real time or near real time can benefit from solid-state drive technology. Those characteristics make enterprise SSDs suitable to offload reads from transaction-heavy databases, to alleviate boot storms with virtual desktop infrastructure (VDI), or inside a storage array to stage hot data locally for off-site storage in a hybrid cloud scenario.
SSDs are used in a range of consumer devices, including computer games, digital cameras, digital music players, laptops, PCs, smartphones, tablets and thumb drives. These devices are not engineered to provide the same level of performance or durability as an enterprise SSD.
Major features
Several features characterize the design of an SSD. Because it uses no moving parts, an SSD is not subject to the mechanical failure that occurs with HDDs. It is also quieter and consumes less power than its disk counterpart. And because SSDs weigh less than hard drives, they are good fits for laptop and mobile computing devices.
In addition, the SSD controller software includes predictive analytics that alert a user in advance of a potential drive failure. Because flash memory is malleable, all-flash array vendors can manipulate the usable storage capacity with data reduction techniques.
SSDs usually are built with single-level cell (SLC) or MLC flash memory. SLC drives store 1 bit of data per cell of flash media. MLC-based SSDs double the drive capacity by writing data in two segments. Newer SSDs, known as TLC, are being marketed that store 3 bits of data per flash cell. TLC is less expensive than SLC or MLC, which makes it an attractive option for manufacturers of consumer-based flash devices. TLC-based SSDs deliver more flash capacity and are cheaper than MLC or SLC, albeit with a higher likelihood for bit rot due to having eight states within the cell.
Semiconductor manufacturers continue to engineer smaller and smaller chipsets that enable highly dense SSDs. Intel, Micron, Samsung and Western Digital offer SSDs based on 64-layer NAND flash. Currently, Korean flash maker SK Hynix has claimed the densest SSD -- a 72-layer 256 GB 3D NAND device. In 2018, Intel and Micron introduced quad-level-cell NAND.
SSD manufacturers
The SSD market is dominated by a handful of large manufacturers, including Intel, Kingston Technology, Micron, SK Hynix, Samsung, SanDisk, Seagate Technology, Viking Technology and Western Digital Corp. Micron, Samsung and Seagate produce and sell NAND flash chipsets to solid-state drive vendors, and also market branded SSDs based on their own flash chips.
Storage capacity on the earliest SSDs was limited in comparison to legacy HDDs. More recently, SSD manufacturers have moved the needle by pumping out larger capacity flash drives. Intel, Micron, Samsung and Western Digital offer SSDs based on 64-layer NAND flash.
In 2018, former all-flash array maker Nimbus Data introduced a 100 TB SSD. Korean flash maker SK Hynix has claimed the densest SSD -- a 72-layer 256 GB 3D NAND device.
Among established SSD makers, Samsung and Seagate are in a duel to see who wins the SSD capacity wars. The Samsung PM1643 SSDs packs 30 TB of capacity in a 2.5-inch form factor. Seagate has previewed a 60 TB SSD for enterprises.
SSD pricing
Historically, pricing for SSDs has been much higher than that of conventional hard drives. Due to improvements in manufacturing technology and expanded chip capacity, SSD prices had been dropping, allowing consumers and enterprise-level customers to re-evaluate SSDs as viable alternatives to conventional storage. That phenomenon has reversed itself several times in recent years.
The market price for SSDs is influenced by Moore's Law, as much as supply and demand. More steps are needed to engineer a dense 3D NAND SSD, compared to the 2D NAND process. Manufacturers have struggled to increase the yields to ensure they met global demand, with mixed results in recent years.
Between 2015 and 2017, global demand for flash chips outstripped the supply. As a result, SSD manufacturers had to scramble to fill their pipelines. Fluctuating demand for flash chips has kept pricing for SSDs variable, but the price for an SSD remains higher than that of an HDD.
A June 2018 report from TrendForce, a research firm headquartered in Taipei, Taiwan, said contract prices started to fall due to an oversupply of flash chips. The resulting price drop helped to fuel increased adoption of client SSDs, including PCIe drives.
M2.SSD
M.2 SSDs are designed to enable high-performance Storage in thin, power-constrained
devices, Such as ultrabook and tablet computers. They are generally smaller than mSATA
Initially IntroduceSSDs, for which they are intended as an alternative. ... .
An M.2 SSD supports up to 4 lanes of PCIe
2 lanes PCIe 2.0 = 1GB/s
2 lanes PCIe 3.0 = 2GB/s
4 lanes PCIe 3.0 = 4GB/s
Overview of M.2
d as “NGFF” for Next Generation Form Factor, soon became “M.2”; initial proposal in SATA-IO and PCI-SIG.
Detailed M.2 specifications are included in the PCI-SIG M.2 spec; the SATA version of M.2 is described in the SATA v3.2 spec.
Intended to resolve the extensibility issues with mSATA SSD.
Brings superior throughput capability to “Ultra thin and light” computing, by leaping past the plateau of 6.0 Gbps SATA.
Enables 2- or 4-lane transfer speeds ~ 900 MB/s (read) & 800 MB/s (write) for first generation drives. Significantly faster in the x4 options to come!
Interface is keyed to denote interface and device type!
Described as a “Socket”, Socket 2 configuration is for SATA or PCIe x2 Socket 3 configuration is for PCIe in a x4 configuration
Height in Z-dimension also has options
S = single-sided; D = double-sided, as below:
M.2 PROS
1. More Speed!
If you’ve ever switched an SSD for a HDD, you know the effect some better storage can have on your experience. Some M.2 SSD’s are designed for the PCIe connector, which has far more potential than the previous standard for SSD's, SATA. Add that to the sheer difference in speed of SSD technologies, and you’ll find that reasonably priced M.2 SSD’s can fetch you 15x the speed of the fastest hard drives.
You’ll also be able to find some M.2 SSDs that take advantage of the NVME protocol, which offers much lower latency. Operating systems such as Windows utilize your computer's storage all the time, so an upgrade will make everything feel smoother. The difference will also be evident in the improved computer boot times and shortened video game load screens.
2. Compact Form Factor
M.2 has actually been used as storage in notebooks and laptops for years, but, we never saw the speed difference because it still used the old SATA connectors.
Typical 2.5 inch SSDs are about the size of your entire hand, but most M.2 SSDs could lie on two or three fingers. Better yet, M.2 connectors plug right into the motherboard, so there’s no need for extra cabling.
M.2 drives reduce the weight of SSDs from 50g to around 7 grams, about the weight of a leaf on a tree.
If you’re making a portable build, then an M.2 SSD should be a serious consideration to reduce space and weight.
3. It's the future
All three innovations, M.2, PCIe storage and NVME, are all expected to dominate the consumer market in a few years.
We’ve seen new M.2 projects come out of all the major storage manufacturers, including Samsung, Intel and Western Digital. If you get your hands on a computer that supports M.2 drives, you'll open up plenty of upgrade options in the years to come.
M.2 CONS
1. Compatibility Issues
Finding an M.2 drive that will fit your motherboard can be a bit difficult if you’re not familiar with computer hardware.
M.2 drives come with so many complications, we thought we'd list them out:
M.2 connectors only support certain ‘keys’, so can only connect to connectors with the same keying.
Not all M.2 drives and connection points will support NVME, the faster data transfer protocol.
You might need to switch your M.2 drive to PICe mode in your computer BIOS.
M.2 drives that use the SATA connection may reduce overall computer performance.
Before you’ll buy, you’ll need to check that your motherboard supports M.2 and explore your connection options and necessary setup steps.
