This paper describes the operation of a demonstrator of the authentication/tamper detection system proposed in [1] for surveillance systems. The demonstrator consists of three parts. The first captures images, calculates and embeds authentication data, then compresses and records the images to hard disk. The second provides means to tamper a selection of recorded images, and the third checks th...

In this paper, we propose a new multi-rate state estimator for seeking control of hard disk drives, which has a proportional, integral, and discontinuous error feedback structure to improve robustness. Conventional state estimators do not have enough accuracy under the existence of external disturbances and model uncertainty. With the proposed estimator, the seeking control system of hard disk ...

A data-based approach is presented for modeling and controller design of a dual-stage servo actuator in a hard disk drive. The servo actuator in this hard disk drive consists of a conventional voice coil motor and a piezo-electrically actuated suspension. A weighted Hankel matrix based realization algorithm that uses frequency domain data is applied to estimate a discrete-time model of the voic...

We examine the possibility that Ultraluminous X-ray sources (ULXs) represent the extreme end of the black hole X-ray binary (XRB) population. Based on their X-ray properties, we suggest that ULXs are persistently in a high/hard spectral state and we propose a new disk–jet model that can accomodate both a high accretion rate and a hard X-ray spectrum. Our model predicts that the modified disk em...

We report on the formal functional verification of a simple device driver for an ATAPI hard disk in Isabelle/HOL. The proof is based on a functional model of the hard disk, which has been integrated into the instruction set architecture of a verified RISC processor as one of several memory-mapped devices. The result is an interleaved computational model, in which the devices and the processor t...

Disk scheduling is one of the main responsibilities of Operating System. OS manages hard disk to provide best access time. All major Disk scheduling algorithms incorporate seek time as the only factor for disk scheduling. The second factor rotational delay is ignored by the existing algorithms. This research paper considers both factors, Seek Time and Rotational Delay to schedule the disk. Our ...

Control Design and Implementation of Hard Disk Drive Servos

Problem statement: Abrasive is one of key influencing factors on the polished surface quality in Chemical Mechanical Polishing (CMP). Solid abrasives in CMP slurries are easy to cause polishing scratches. It is well known that reducing the hardness of abrasives would improve the polished surface quality. Therefore, the change in structure or shape of the abrasives means a change in polished sur...

In emerging database applications that deal with large sets of multidimensional data, the performance of the query system significantly depends on the performance of its access methods and the underlying disk system. In recent years, hard disks are manufactured with multiple physical zones, where seek times and data transfer rates vary significantly across the zones. However, there is a marked ...