Many HDD production facilities and procedures involve performing one or more tests on HDDs, often following, or as part of, the servo track writing (STW) procedure. Such tests can be used for one or more of a number of purposes, including detecting flaws or anomalies, preferably, while obtaining information about the severity and/or location of the flaws or anomalies, obtaining disk characterization information (such as characterization of disk runout, fly height, read/write head operating characteristics) and the like. The results of such testing can be used for any of a number of purposes. Such testing can be used as a basis for deciding whether to fail an anomalous drive (take it out of the production stream, e.g., for repair, rebuild, scrap or the like). Testing can be used to obtain statistical information for process control, such as identifying suboptimal procedures or equipment. Testing can be used for obtaining and storing information, typically on the HDD, for use in normal read/write operation (such as sector remap information, runout correction information, fly height adjustment information and the like).
In many situations, some or all of the procedures used during such testing are specified in programming stored on the HDD. Thus, such tests are often called “self-test,” although, generally, at least some control (such as selecting the timing, order and/or number of tests to be performed), along with power for the HDD, is provided from external circuitry.
In many, if not most, self-test situations, at least some self-tests are performed before the HDD is sealed, and/or are otherwise performed in circumstances where it is advisable that the self-tests be conducted in a controlled environment. Typically, there are a number of HDDs undergoing self-tests, at any one time in such an environment. Typically, there are a number of HDDs undergoing self-tests, at any one time in such an environment, typically while each HDD is positioned in a slot of a “test rack,” where each slot not only supports an HDD but also provides power and, in some cases, control signals to the HDD. If viewed on an (average) per-HDD, which can be of significance to the final production cost of the product, particularly when test rack space is positioned in the (relatively expensive, per square foot) controlled environment. Accordingly, it would be useful to provide an apparatus, system and method which can effectively decrease the per HDD capital cost associated with test track slot space.
The production costs associated with test rack use is also related to the length of time, allocatable to individual HDDs, spent in the test rack, as needed to perform the self-testing. Accordingly, it would be useful to provide an apparatus, system and method which can reduce the average length of time, allocated to each HDD, spent in the test rack.
Some HDD testing involves performing tests while the HDD is at certain specified temperatures, or within specified temperature ranges. Some test protocols involve cooling to temperatures below ambient and/or heating to temperatures above ambient. Many previous systems involve changing the temperature of the entire clean room or other test rack area, leading to testing inefficiencies, e.g., when not all HDDs need to be tested at the same temperature for the same periods of time. Even if the temperatures within individual test rack slots were independently controlled, there is a potential for inefficiency if temperature control with a granularity smaller than test rack slots is useful. Accordingly, it would be useful to provide apparatuses, systems and methods which can reliably provide two (or more) different temperatures within a single test rack slot.