It is best to demonstrate this point via an example. On a modern hard drive, the head assembly floats barely above the surface of the platter. Its performance is affected by vibration, created by fans and power supplies and transmitted to the drive casing and then to the heads.

When such a drive is being tested by the manufacturer, the drive must be isolated from such vibrations so that the test equipment itself does not become the source of performance errors, which would be reported in the test results.

Each of the links in the supply chain may perform such tests to screen or otherwise validate the required performance and quality. However, at the end point, when the OEM installs the drive into the product ( eg. a storage array system, set-top box, server), the drive must be able to operate in the not-so-perfect environment of the end product.

So, for example, an OEM vendor of enterprise SAN/NAS products would likely test the drives again, inside the vibrational environment of the system within which it will operate.

However, SSDs are impervious to vibration. Therefore, they can be tested once and only once, at the manufacturing source, and we would posess the knowledge that they will operate the same when they are eventually working inside the end product. This aspect of SSD’s allows for further process efficiencies by making it possible to outsource the testing process to a third party (refer to sidebar).

In order to achieve the benefits of the above scenario, there must be agreed upon standards in place. For instance, before anyone else will accept a supplier’s results, the test procedures need to follow an industry standard which guarantees repeatability, consistency, comparability and relevancy.

Indeed, there are industry groups (e.g. SNIA, IDEMA) already working on the development of such standards, focusing initially on performance measures. But “testing” is not just about performance - there is also reliability, endurance, margin, etc. to consider. Standardizing on all these attributes requires that a “test platform” be defined and agreed upon, that is to say a common hardware/software and climatic environment test system.

In the HDD world, it has always been challenging to compare the performance and quality among the products of different suppliers. Without standards, this problem will be exacerbated in the world of SSDs, since there will be many more vendors, each with their own claimed area of differentiation. Standardization would minimize testing costs and facilitate accurate comparisons between products.

End users (e.g. OEMs, CMs) could then select the product with the best attributes to meet their requirement without an exhaustive test procedure. Even the laborious process of product qualification may reduce itself to an analysis of a manufacturer’s output test data.

Much more can be said about the test procedures required for SSDs, since they are the same as HDDs in terms of providing storage services to the main computer system, but very different in that they have different failure points, performance, error characteristics, reliability, and endurance. This is an interesting but lengthy topic, for another time.

So, when will SSDs become a replacement for HDDs? I believe it is a matter of “if” not “when”. Another way to state Grove’s Law is this: “Technology always wins”.

SSDs Change The Face Of Testing

It is not surprising that the SSD sector attracts a crowd of hopeful vendors. Relative to the manufacturing of HDDs, which requires a fortune in capital equipment and infrastructure, making SSDs has “garage business” requirements. At the risk of oversimplification, the latter consists of assembling off-the-shelf semiconductor components (e.g. Flash chips and a controller microprocessor), and melding them into a storage system through the magic of software.

Therefore, it is not surprising that many of these would-be “Seagates” are in startup situations; i.e. money is tight, milestone functionality must be demonstrated to investors, and credibility is paramount. Further exacerbating the situation is that most such companies come to the SSD sector from a history of memory or microprocessor technology, with little experience or skill in storage systems. Additionally, they generally lack test engineering know-how.

There are many varieties of test equipment, from bench-top testers which operate at room temperature, to environmental chambers which can stress SSDs at extreme temperatures, humidity, and even atmospheric pressure.

Different types of testers are required at different phases of testing, and for different types of OEM qualifications - depending on the ultimate application. Purchasing all of the different types of testing equipment would necessitate spending a daunting amount of capital expenditure for a small company.

It makes great financial sense to be able to buy “testing” in small bits, only when needed, and without having to build out an infrastructure of capital equipment and staff. It is tantalizing to imagine the idyllic scenario, whereby a company’s resources are fully focused on creating competitive differentiation and accelerated market entry.

In this process, the client would compile the test scripts which would be executed by the testing company on their equipment, and the test results would be provided to the client for analysis and product validation.

In fact, the test process could be done interactively with the client, by providing a real time link to the testing system and a live link for uploading output data as it is being produced. It allows the client to stay engaged and focused on the “forest”, without getting lost in the details of the “trees” – the test machinery and process itself.

Lastly is the issue of credibility. A newcomer to storage, who does not have a history within this sector, needs an extra measure of conviction among their potential clients. Nothing inspires belief like a “seal of approval” from an industry recognized testing company using standard and reproducible procedures.

For more information visit www.flexstar.com.

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