Solid state storage (SSS) is a method of data storage accomplished by using
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| Solid State Hard Disk |
Today’s SSDs are different from hard drives when it comes to data storage.SSDs are sophisticated storage devices that use non-moving memory chips, mostly non-volatile NAND flash, instead of the rotating magnetic disks found in hard drives. Hard drives can take the data directly from the host and write it to the rotating media. In contrast, SSDs can’t write a single bit of information without first erasing and then rewriting very large blocks of data at one time (also referred to as P/E).Because SSDs and hard drives have different strengths in terms of efficiency, they complement each other and can co-exist. SSDs deliver ultra-fast random data access (inputs-outputs per second, or IOPS, performance), low power consumption, small size and high physical resilience (due to no moving parts)—but they cost more. Hard drives provide fast sequential data access with high capacity, endurance and reliability at a much lower price.
A process known as Wear-leveling is used by an SSD controller to maximize the life of the flash memory. This technique levels the wear across all blocks by distributing data writes across the flash memory devices.
Solid state hard drives (SSDs) store data through the use of semi-conductors. Though they can cost substantially more than your traditional magnetic hard drive, they offer a few advantages:
Lower Power Consumption - SSDs consume less power because they have no moving parts. This attribute makes them less susceptible to physical shock and latency.
Faster Data Access - In normal situations, data is written and read from random locations on the disk. The lack of moving parts in SSDs cuts down on random read and write latency functions.
Increased Reliability - While the point can be argued, the lack of moving components makes SSDs less susceptible to head crash. They store, read and write information slightly differently than magnetic hard drives. For this reason, they are less susceptible to the problems magnetic hardware experience.
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| SOLID STATE HARD DISK DRIVE (SSD) |
What are the challenges facing SSD?
There are three primary concerns impacting SSD adoption in the enterprise:
Endurance and reliability, a lack of industry standards, and high cost.
Endurance/Reliability Concerns
SSDs wear out over time. NAND flash memory can only be written a certain
number of times to each block (or cell). SLC memory generally sustains 50,000 program/erase (P/E) cycles, while MLC memory is generally ten times less at 5000 cycles. Once a block (or cell) is written to its limit, the block starts to forget what is stored and data corruption can occur. Seagate is actively developing techniques such as wear leveling algorithms to address endurance and reliability concerns.
Lack of Standards
SSDs store data differently than hard drives; therefore the time-tested and fieldproven industry standards used by hard drives do not equally apply when working with NAND flash technology. Seagate is actively leading SSS industry standards development through organizations such as JEDEC and SNIA to advance SSD adoption in the enterprise.
High Cost
To date, the cost of SLC memory is roughly three times higher than MLC memory due to two factors. First, MLC NAND stores two bits of data per cell and can provide twice the storage per square millimeter of silicon (the main cost of the memory). Second, the volume of MLC is roughly 90 percent of all NAND flash, further increasing the economies of scale in its production.Today, manufacturing facilities (fabs) are primarily focused on building MLC memory. Significant investment is needed to re-calibrate or build fabs that are designed to meet the quality, consistency and support levels required in the enterprise. Fabs are expensive and sophisticated operations.
Solid State Hard Drive Development
Solid state hard drives were first developed over 40 years ago; however, until recently SSDs were prohibitively expensive for the average consumer, making it impossible for computer manufacturers to include SSDs in their products. The surge in mobile computing devices has created a demand for solid state hard drives, leading tech companies to focus on developing low-cost, high-quality flash-based memory devices. As a result, solid state hard drives are now affordable and readily available, making them a good alternative to traditional hard disk drives (HDDs).Most solid state hard drives use high-density NAND type flash memory, the same type of memory that is common in SD data cards and portable USB drives. The first mass-produced computer to use a solid state hard drive was the MacBook Air, an ultra-portable laptop introduced by Apple in 2008. Since then other manufacturers have begun including SSDs in their products, allowing them to build faster, lighter machines that are mobile-friendly. Consumers can now choose from a wide variety of replacement solid state hard drives that can be used to upgrade an existing hard drive or for use as an external data storage device.
How To Choose a Solid State Hard Drive
To upgrade your existing mechanical hard drive to a solid state drive, check both the dimensions and connectivity of your system. Most computers use a standard SATA cable hard drive interface, however, some require an ATA drive cable (also known as IDE or PATA). 2.5" is the most common solid state hard drive measurement, while some systems use either a 1.8" or a 3.5" drive. Adapters are readily available that allow 2.5" drives to be mounted in a standard desktop 3.5" hard drive bay. Once you know the size and interface type you need, consider how much actual data storage space you need on your hard drive. Thanks to the emergence of cloud-based computing and external drives, onboard hard drive capacities have been shrinking. At the bare minimum, choose a SSD that can comfortably accommodate your operating system along with some other software. For most users, a 60GB hard drive is the absolute minimum, while a 120GB drive will allow some room for data and additional programs.
Comparison of SSDs with memory cards
While both memory cards and most SSDs use flash memory, they serve very different markets and purposes. Each has a number of different attributes which are optimized and adjusted to best meet the needs of particular users. Some of these characteristics include power consumption, performance, size, and reliability.
SSDs were originally designed for use in a computer system. The first units were intended to replace or augment hard disk drives, so the operating system recognized them as a hard drive. Originally, solid state drives were even shaped and mounted in the computer like hard drives. Later SSDs became smaller and more compact, eventually developing their own unique form factors. The SSD was designed to be installed permanently inside a computer.
In contrast, memory cards (such as Secure Digital (SD), CompactFlash (CF) and many others) were originally designed for digital cameras and later found their way into cell phones, gaming devices, GPS units, etc. Most memory cards are physically smaller than SSDs, and designed to be inserted and removed repeatedly.There are adapters which enable some memory cards to interface to a computer, allowing use as an SSD, but they are not intended to be the primary storage device in the computer. The typical CompactFlash card interface is three to four times slower than an SSD. As memory cards are not designed to tolerate the amount of reading and writing which occurs during typical computer use, their data may get damaged unless special procedures are taken to reduce the wear on the card to a minimum.
Data recovery and secure deletion
Solid state drives have set new challenges for data recovery companies, as the way of storing data is much more non-linear and complex than that of hard disk drives.The strategy the drive operates by internally can largely vary between manufacturers and, the TRIM command zeroes the whole range of a deleted file. Wear leveling also means that the physical address of the data and the address exposed to the operating system are different.
As for secure deletion of data, using the ATA Secure Erase command is recommended, as the drive itself knows the most effective method to truly reset its data. A program such as Parted Magic can be used for this purpose.
Advantages and Disadvantages of Solid State Drive vs Hard Drive
Within the past several years, Solid State Disk Drives have become a popular alternative to the standard hard drive. They are completely silent, less prone to mechanical malfunction and are able to write and rewrite data at more than 50 times the speed of the standard hard drive.
For those considering a switch from a standard hard drive to an SSD, there are several advantages and disadvantages for you to consider:
Advantages to Using a Solid State Hard Disk
The speed of an SSD is not constrained by its parts, because there are no moving parts to a Solid State Drive.
Only a series of wires that moves at the speed of electricity.
Many SSD require lower power and produce less heat, resulting in a decrease in electrical usage and a longer lifespan, especially in laptops that are prone to overheating.
Because there is no disk to spin, a Solid State Disk Drive can start up over 25 times faster than the standard hard drive.
There is no noise, except in the case of the higher capacity storage spaces that tend to have cooling fans attached.
Both flash and DRAM Solid State Drives run at faster speeds than hard drives and continue to run at those speeds regardless of the amount of data being accessed.
Any physical occurrences, such as vibration, high movements or temperature fluctuations, do not affect SSDs to the same degree because there are no moving parts to break.
Disadvantages to Using a Solid State Hard Disk
The Solid State Disk price per gigabyte is much higher than hard drives, so an upgrade to the same GB capacity can incur some considerable costs.
While they are able to withstand movement, they are vulnerable to power loss and electrical/magnetic currents much in the same way as flash cards.
Currently there are very few large capacity SSD models, though this is expected to change drastically over the course of the next few years.
Flash SSD have limited write cycles. It is estimated that these write cycles will last until long after the computer is still being used, it is possible that some files could use write cycles often enough that it affects the owner/user.
Despite requiring less power, many SSD still use more power than the standard hard drive, especially when idle. This can cause laptop batteries to use up more quickly.
Solid State Drives have a variety of benefits, especially for businesses and those that use their laptops regularly. Still, SSD are not for everyone, and some people may still prefer to use the standard hard drive until the capacity, power usage and write cycle lifespan has increase on the available Solid State Hard Disks. It is estimated, however, that these changes will occur sooner rather than later.
