Integrating a solid state drive (SSD) into a data store is expected to improve its I/O performance. However, there is still a large difference between the price of an SSD and a hard-disk drive (HDD). One of the methods to offset the increase in cost of consisting devices is to configure a hybrid system using both devices. In such a system, a common method to decide the placement of data records...

This paper presents a simple yet effective design solution to facilitate technology scaling for hard disk drives (HDDs) being deployed in data centers. Emerging magnetic recording technologies improve storage areal density mainly through reducing the track pitch, which however makes HDDs subject to higher read retry rates. More frequent HDD read retries could cause intolerable tail latency for ...

Abstract This paper presents a method to analyze the free vibration of a rotating disk–spindle system in a HDD with hydrodynamic bearings (HDBs) considering the flexibility of a complicated base structure by using finite element method. Finite element equations of each component of a HDD spindle system from the spinning flexible disk to the flexible base plate are consistently derived by satisf...

Due to the rapid development of flash memory, SSD is considered to be the replacement of HDD in the storage market. Although SSD retains several promising characteristics, such as high random I/O performance and nonvolatility, its high expense per capacity is the main obstacle in replacing HDD in all storage solutions. An alternative is to provide a hybrid structure where a small portion of SSD...

During 2006 and 2007, forages from 3 individual hay harvests were utilized to assess the effects of spontaneous heating on concentrations of fiber components, 48-h neutral detergent fiber (NDF) digestibility (NDFD), and in situ disappearance kinetics of NDF for large-round bales of mixed alfalfa (Medicago sativa L.) and orchardgrass (Dactylis glomerata L.). Over the 3 harvests, 96 large-round b...

I am a second-year Epidemic Intelligence Service (EIS) officer assigned to the Centers for Disease Control and Prevention’s (CDC’s) National Environmental Public Health Tracking Program (Tracking Program). EIS offcers, commonly referred to as “disease detectives,” have opportunities to apply our skills to many public health activities beyond outbreak investigations and emergency response. One o...

The infusion of new in-vehicle technologies (IVTs) into automobiles may have important implications for driver safety, especially to the extent that these devices interfere with the primary driving task. One important issue is the placement or location of in-vehicle displays—specifically, whether the spatial separation between the IVT and the outside world is reduced (as in the case of head-up ...

This paper discusses the optimal H∞ control synthesis via discrete Riccati equations for hard disk drives (HDDs) with an irregular sampling rate. A HDD servo system with an irregular sampling rate, caused by missing position error signal sampling data, is modeled as a linear periodically timevarying (LPTV) system. An optimal H∞ track-following control algorithm for HDD servo systems with irregu...