Solid-State Drives

K. Almas INFO 300 Tech Brief: SSD & HDD

The modern hard disk drive is has undergone astonishing changes and periodic innovation since the first was developed in the 1950s. The original, developed by IBM, was larger than hundreds of modern HDDs combined and held an insignificant amount of data by today’s standards (Santo Domingo). This large machine may not resemble any of the common HDD form factors common currently, but the method of reading and writing is the evidence of they are distant relatives. Continual improvements to HDDs and the demand associated with the increased popularity of personal computing led to the existence of the compact, efficient, and nonvolatile hard disk drives that are now a commodity. Commercialization increased the competition among manufacturers to develop the best storage device drove innovation. This innovation ultimately leading to the prevalence of solid-state storage. With likeness to the evolution of the HDD, the earlier solid-state drives were novel, expensive, and not considered adequate for application in consumer products. Incremental innovation has made SSDs a continuously growing threat to the obsolescence of HDDs.

Description of the Technology

Hard disk drives (HDD) have been the prominent means of data storage in computing for several decades. They function by manipulating and reading magnetic coating on spinning platters with a mechanical arm to provide nonvolatile storage, that is, storage of data that is withheld without a constant power supply. Since their advent in the 1950s HDDs have evolved from using dozens of 24 inch platters in order to store a miniscule amount of data, to many form factors with much higher capacity suitable for numerous applications. Additionally, the platters’ rate of rotation has increased performance in modern hard drives (Santo Domingo). Since their creation, the same essential technology has been adapted to interface with various devices, even as device interface standards have changed. HDDs are commonly used as PC secondary storage in a 2.5 inch form factor as well as external personal storage, all the way up to enterprise network attached storage in 3.5 inch form factors for redundant arrays. These small-form modern HDDs offer up to 10TB of storage capacity (Santo Domingo). Advancement of HDD technology as a whole since its creation at IBM has increased their efficiency, lowered their rate of failure, and made them the optimal storage choice for the price. This low price is pivotal to HDD’s standing as a storage medium currently. Hard disk drives however face imminent obsolescence as the difference in price per gigabyte as compared to solid-state storage shrinks.

Solid-state drives (SSDs) deliver the same basic utility of hard disk drives, providing nonvolatile storage of data, even if the device to which it is attached is powered off. They however do so by a different method. As opposed to the mechanical arm that is key for HDD writing and reading, SSDs have a processor (or controller) with software including instructions for reading, writing, and locating data it stores on the cells within the drive’s flash memory chips. This process requires no moving parts which greatly contribute to the benefits associated with solid-state storage. The controller is able to read data much faster than hard drives, partially because fragmentation of associated data is not necessary as it is with HDDs, which often rely on the mechanical arm to read data across multiple sectors of different platters (Dipert). The lack of moving parts also decreases latency and improves durability of the drive, which is also able to better function during physical movement. These advantages among others of solid-state drives have driven their development in recent years. Various SSDs are now manufactured to provide storage to most any system compatible with hard disk drives (Dipert). Aside from the increasing number of devices being manufactured with solid-state drive as internal storage, form factors of SSDs include 2.5 inch drives for replacing PC hard drives with SATA interface, 1.8 inch drives for mobile devices, 3.5 inch drives for enterprise needs with serial-attach SCSI interface, external drives, and other alternatives that include PCIe and USB host interfaces. (Santo Domingo)

Advantages of SSDs

SSDs are capable of storing larger amounts of data, 60 TB maximum, using less physical space than HDDs which have a maximum capacity of 12 TB. This factor will likely be of great importance as mobile devices evolve. Also favoring their mobility, solid-state drives are far less fragile than HDDs and their performance is not compromised by movement. The media controller component of SSDs allows for faster data reading and retrieval, as well as decreased latency compared to a mechanical arm positioning itself repetitively for defragmentation (Dipert).

SSD Disadvantages

SSDs are currently significantly more expensive than HDD alternatives, therefore they have been perceived as a special feature in the devices they come installed in, the devices being priced accordingly. The flash cells that comprise the physical storage area of data in a solid-state drive are perishable in nature. Each time a cell is written in, wear occurs, leaving that cell with less of a life span. This inherently shortens the potential lifespan of the entire SSD. (Hutchinson)

Developmental aspects of SSDs indicate that these issues are going to be addressed in further innovation. Currently, to extend the life of solid-state drives and their flash cells, controllers are equipped with instructions that use cells an equal amount in order to mitigate the risk of a cell’s failure making the drive faulty or useless in its entirety (Hutchinson). Additionally, the price per GB on SSD drives will decrease as innovation progresses and manufacturing become more efficient.

An Arguement for Hard Disk Drives

Even when taking into account all of HDDs’ shortcomings as compared to solid-state drives, several aspects make HDDs an acceptable choice. They have been commoditized. Hard disk drives have reached their market maturity and the price based competition for this product has made them very affordable. A consumer facing a decision between a 1 TB HDD for $40-$50, and a 1 TB SSD for roughly $230, would be able to justify choosing the hard disk drive if that’s all the capacity needed. Furthermore, HDDs are still capable of faster data writing than SSDs. (Santo Domingo)

The Storage Market

The global computer hardware industry’s performance is heavily influenced by the sales of PCs, and other devices like notebooks and tablets. Secondary storage devices are no exception to this, in fact, other industries such as smartphone manufacturing call for such inputs. PC sales however have been in decline in recent years, consumers replacing them less frequently, one factor that cause the industry to have negative growth since 2012. Storage devices account for 10% of the industry’s revenue. While this has been adversely affected by the downturn of demand for PCs, the increasing demand for storing information over the internet has created demand for mass data storage devices from those who store this information has offset this. This trend is projected to continue in the next five years.

In regard to SSDs and HDDs, hard disk drives are remain more prominent because of their affordability and presence in other products. SSDs quickly told hold of the 1.8 inch form factor because of such a drive’s suitability with small mobile devices. It is worth mentioning that advancements in technology and demand for new and improved products has decreased demand for the closer-to-obsolete products the industry still offers, this desire for more computing capability could be reflected by the predicted rise in SSD sales if there is a matching sharp decline in HDD sales. (Ulama)

The HDD markets top companies include Western Digital, Seagate, and Toshiba. The biggest SSD manufactures follow with their respective portion of the 33.705 SSD units sold during Q2 2016: Samsung(40.8%), Intel(6.8%), Western Digital(13.6%), Kingston(9.4%), and Toshiba(6%). The amount of units sold in Q2 2016 showed an increase of 41.2% from Q2 2015, the largest portion of those being sold to client segment consumers (Shilov). The dimensions on which competition is based among these competitors include SSD unit capacity, for which Seagate aspires to set a new standard for, with the announcement of its soon to be released 60 TB SAS SSD. (McCallion)

Since the market for these devices is competitive and heavily influenced by macroeconomic factors, the participating firms should be mindful that their solid-state drive offerings are comparable to those of competitors or preferred by consumers. Each should be anticipating and strategizing for the influx in demand for solid-state storage and the obsolescence of hard disk drives. Trends in technological advancement in this industry should also be given attention. 3D NAND, multilayer structure of flash memory cells, for instance is predicted to account for 50% of NAND output in Q3 2017. Similar to how NAND is used in SSDs, this innovation allows for multiple times more date storage (3DNAND). The projected prominence of a new technology as such before SSDs have had their day is expressive of how computer storage will continue to thrive on obsolescence.

Capacity

Seagate's 60TB SSD is the largest to date!

Form Factors

Range includes compatability with 3.5" HDD interface for redundnant flash arrays to consumer external storage.

Applications

From PCs to enterprise scalable use, and imminently everwhere in between!