This paper researches a programmable signal device by an improved direct digital frequency synthesis technology on DSP and FPGA to simulate servo signal for read-write channel of micro hard disk. This device has wide ...
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ISBN:
(纸本)0769526519
This paper researches a programmable signal device by an improved direct digital frequency synthesis technology on DSP and FPGA to simulate servo signal for read-write channel of micro hard disk. This device has wide frequency range from 1Hz to 10MHz, high frequency resolution of 0.001Hz, high precision of frequency, phase and amplitude of output wave, good reliability, little distortion. Compared with general devices, this device can generate all kinds of servo signal, and circuit is simply, reliable, and programmable.
Storage systems represent a growing market. In recent years there has been an explosion of applications that use enormous amounts of data. Disk arrays are today's standard solution for enterprise class storage sys...
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ISBN:
(纸本)0769526519
Storage systems represent a growing market. In recent years there has been an explosion of applications that use enormous amounts of data. Disk arrays are today's standard solution for enterprise class storage systems. One of the most crucial parameters in designing a disk array is the size of the striping unit. The paper presents and validates a performance model for RAID level 5. The model is created as a closed fork-join queue network (CFJQN) under synchronous I/O workloads. It can be used to compute the optimal strip unit size for disk arrays.
The security of multimedia data in digital network is commonly provided by encryption. Nevertheless, most current modern encryption algorithms, which only transform a plaintext message that is the simplest form of mul...
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ISBN:
(纸本)0769526519
The security of multimedia data in digital network is commonly provided by encryption. Nevertheless, most current modern encryption algorithms, which only transform a plaintext message that is the simplest form of multimedia data into unintelligible ciphertext, are not appropriate for higher forms such as images and video with very large file sizes. Selective encryption of MPEG video streams has been proposed to reduce encryption requirements, saving in complexity and facilitating new system functionality. In this paper, a two-way selective encryption algorithm (TWAEA) for MPEG video is proposed to compromise the security and speed in the process of encryption.
In this paper a new approach for building networked embedded software is presented. The approach is based on the composition of reusable components with the addition of a perspective contract principle for modeling no...
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In this paper a new approach for building networked embedded software is presented. The approach is based on the composition of reusable components with the addition of a perspective contract principle for modeling non-functional properties. Nonfunctional properties are an important aspect of networked embedded software, and this is why they are modeled separately. As such, the component view presented here differs from traditional component based views, where focus is laid on the functional part. The ideas discussed in the paper have been implemented in a tool. This tool enables the construction of networked embedded software by means of components and perspective contracts. Currently, a queuing network based algorithm that considers all non-functional properties together performs a static analysis on the perspective contracts before execution of the application
This paper extends the environment for open distributed real-time systems, where hard or soft real-time applications may run concurrently with non-real-time applications. We replace the top-level improved constant uti...
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This paper extends the environment for open distributed real-time systems, where hard or soft real-time applications may run concurrently with non-real-time applications. We replace the top-level improved constant utilization server scheduler of the open system architecture in with variable utilization server scheduler. The proposed open real-time environment in this paper allows tasks in each application to share local and global nonpreemptive resources, which accommodates a much broader spectrum of real-time applications. Additionally, the extended environment assigns CPU bandwidth to each server in a more flexible and more adaptive way. The evaluation results show the performance of the open system is also improved considerably
Storage systems represent a growing market. In recent years there has been an explosion of applications that use enormous amounts of data. Disk arrays are today's standard solution for enterprise class storage sys...
详细信息
Storage systems represent a growing market. In recent years there has been an explosion of applications that use enormous amounts of data. Disk arrays are today's standard solution for enterprise class storage systems. One of the most crucial parameters in designing a disk array is the size of the striping unit. The paper presents and validates a performance model for RAID level 5. The model is created as a closed fork-join queue network (CFJQN) under synchronous I/O workloads. It can be used to compute the optimal strip unit size for disk arrays
This paper researches a programmable signal device by an improved direct digital frequency synthesis technology on DSP and FPGA to simulate servo signal for read-write channel of micro hard disk. This device has wide ...
详细信息
This paper researches a programmable signal device by an improved direct digital frequency synthesis technology on DSP and FPGA to simulate servo signal for read-write channel of micro hard disk. This device has wide frequency range from 1 Hz to 10MHz, high frequency resolution of 0.001 Hz, high precision of frequency, phase and amplitude of output wave, good reliability, little distortion. Compared with general devices, this device can generate all kinds of servo signal, and circuit is simply, reliable, and programmable
This paper researches a programmable signal generator by an high integrated direct digital frequency synthesis (DDFS) technology on FPGA to simulate servo signal for read-write channel of micro hard disk. This device ...
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This paper researches a programmable signal generator by an high integrated direct digital frequency synthesis (DDFS) technology on FPGA to simulate servo signal for read-write channel of micro hard disk. This device use very large-scale integrated circuit FPGA (field-programmable logic) to integrate PDSP (programmable digital signal processor) for look-up table and integrate DDFS design, use 16 bit high resolution DAC (digital to analog converter) .This device has high precision of frequency, phase and amplitude of output wave, good reliability, little distortion. Compared with general devices, this device can generate all kinds of servo signal, and circuit is simply, reliable, and programmable.
Referring to the concept of "distributed virtual disks" in cluster file system, this paper proposes a new storage architecture for mid/large-scale RAID-ESS, which consists of several different-structure SubR...
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Referring to the concept of "distributed virtual disks" in cluster file system, this paper proposes a new storage architecture for mid/large-scale RAID-ESS, which consists of several different-structure SubRAIDs. Clients data can migrate into optimal SubRAID dynamically according to their access characteristics; the number of SubRAIDs and the structure of each SubRAID can also be adjusted to the evolution of system load, thus the whole ESS system can always provide a virtual disk for each client to satisfy its I/O need. Simulation results demonstrate significant I/O performance advantage in ESS, compared with the traditional mid/large-scale RAID5 or RAID1 of the same storage space.
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