Hard disk drives and solid state drives are known first and foremost as storage media for PCs and other computer systems, for portable media players and navigation systems. But they are also finding increased use in industrial applications, because these technologies allow for unheard-of flexibility and new opportunities for service and production management. Which one to choose though – HDD or SSD? By Waldemar Batke, Senior Marketing Manager, Storage at Rutronik Elektronische Bauelemente GmbH.
A hard disk stores data by writing it to a rotating disk; data is then read back by probing the surface of the disk. The performance of a hard disk is therefore dependent on its mechanical properties, they require constant correction to maintain the position and movement speed, and the faster a mechanical component must react, the higher the force or energy needed to generate this movement.
SSDs, on the other hand, are an electronic storage medium and do not contain any moving mechanical parts. This eliminates the search time and rotation delay of HDDs and this speed, combined with a higher data transfer rate and more inputs/outputs per second (IOPS) are among the most important sales arguments of SSD technology. Another advantage of SSDs is their quietness in operation due to the lack of moving parts. This may be of benefit in applications where low noise levels are critical.
However, every read or write shortens the life of the memory cells of an SSD. In industrial use particularly, this is often an important counterargument, as the workloads are frequently extremely high and encompass large quantities of transaction data, where more write operations are needed than read operations. HDDs have the upper hand over SSDs when it comes to capacity too, even if SSD capacity will continue to grow considerably in the course of further development.
HDDs are also superior to SSDs in terms of cost per Gbyte and are therefore also currently the more successful technology. SSDs continue to be restricted to devices that are sensitive to acceleration or vibration, are small in size and lightweight, or for which high speeds are required. This is why both storage media technologies will continue to co-exist for the next few years. But SSD or HDD, some industrial applications impose special requirements that are not met by all products.
Harsh But Fair
Industrial hard disks are designed to provide outstanding performance in a wide variety of challenging situations. Even if the nature of industrial environments varies, a number of core characteristic requirements are always the same. The digital contact must always be supplied reliably and stored under extreme conditions, another requirement in industrial use is 24/7 operation. Unlike people, hard disk drives do not get to take breaks during high-performance storage applications; they must operate without any faults or interruptions, even though they operate with physically moving parts. This is why Toshiba has developed HDDs designed to operate 24/7. They can run 24 hours a day, seven days a week (depending on the hard disk model, level of usage and the environment in which it is used). They only shut down or switch to energy-saving mode if the workload permits.
For industrial systems with intensive write and read loads, Toshiba offers special high-durability hard disks that allow for more read/write cycles than conventional hard disks. They are also fitted with special anti-vibration technology. This provides them with an industry-leading tolerance to vibration, which in turn provides a previously unheard-of level of uptime and performance in systems with multiple drives.
The core features of an industrial hard disk include the possibility of their use under extreme environmental conditions. The Toshiba MK1060GSCX, for example, can be used at altitudes from -300m to 5,650m. In 24/7 operation (low-duty cycle), this hard disk works reliably under a temperature range unique to this design, namely -15 to +70°C (measured on the housing surface).
Many industrial systems are exposed to stronger vibrations than consumer or mobile applications. To enable the drives to operate smoothly and reliably even under these conditions, models are available that have a higher resistance to vibration. Reduced energy consumption and low noise levels are also frequent deal makers or breakers.
Solid And Reliable
If a decision is made in favour of an SSD due to speed or size requirements, there are also SSD models available that are specifically developed for the industrial sector. Toshiba, for example, introduced the world's first SSD with 19nm NAND process technology onto the market in the form of the THNSNFxxxGzzS series. This series of SSDs offers an extraordinary combination of capacity and performance, combining the capacity of up to 512Gbyte with a read speed of 524MB/sec and a write speed of 461MB/sec.
To prevent the increase in data transfer rates from compromising the data integrity, Toshiba has fitted the THNSNF SSDs with QSBC (Quadruple Swing-By Code). This internally developed, highly efficient error correction code procedure (ECC) protects against read errors by adding units. With the additional Data Corrupt Protection feature, the THNSNF series of SSDs also provide a protective mechanism which protects data during an internal data transfer in the event of an unexpected power failure or if write errors occur. The integrated read-only mode enables the user to access the data if even the ability to write to the drive fails.
This provides developers of industrial applications in any field, where high-quality specifications and unique functionality are critical, with storage solutions that provide high performance.