Placement of Continuous Media in Multi-Zone Disks

IEEE Transactions on Knowledge and Data Engineering, 2000

AbstractÐThe problem of optimally placing data on disks (ODP) to maximize disk-access performance has long been recognized as important. Solutions to this problem have been reported for some widely available disk technologies, such as magnetic CAV and optical CLV disks. However, important new technologies such as multizoned magnetic disks, have been recently introduced. For such technologies no formal solution to the ODP problem has been reported. In this paper, we first identify the fundamental characteristics of disk-device technologies which influence the solution to the ODP problem. We develop a comprehensive solution to the problem that covers all currently available disk technologies. We show how our comprehensive solution can be reduced to the solutions for existing disk technologies, contributing thus a solution to the ODP problem for multizoned disks. Our analytical solution has been validated through simulations and through its reduction to the known solutions for particular disks. Finally, we study how the solution for multizoned disks is affected by the disk and data characteristics.

IEEE Distributed Systems Online, 2000

To meet multimedia servers' increasing performance and scalability requirements, researchers must design multimedia storage system components that adapt to various workloads and requirements. They must also develop strategies for combining components into a single highperformance system.

2002 IEEE Workshop on Multimedia Signal Processing.

2000

Lately, on-demand streaming multimedia applications have become very popular. Contemporary personal computers can handle the load imposed by such multimedia applications on the client side, but the potentially high number of concurrent users accessing a server represents a generic problem. The multimedia storage system is responsible for storage and retrieval of multimedia data from storage devices, and plays a vital role for the performance and scalability of multimedia servers. It deals with issues related to data placement, scheduling, file management, continuous data delivery, buffer management, prefetching, etc., and with the particular demands of multimedia applications, such as real-time characteristics, large file sizes, high data rates, and several data sources. Performing these tasks and supporting these requirements appropriately are burdened by an increasing speed mismatch between processors and the most prolific and affordable storage devices, -magnetic disks -, and by the introduction of new requirements in new multimedia scenarios.

Multimedia Tools and Applications, 1995

During the past decade, information technology has evolved to where it is economically viable to store and retrieve continuous media data types, e.g., audio and video objects. Systems that support this data type are expected to play a major role in many applications including library information systems, entertainment technology, and educational applications. The objects of this new data type should be retrieved at a pre-specified bandwidth. If an object is retrieved at a rate lower than its pre-specified bandwidth then its display will suffer from frequent disruptions and delays termed hiccups.

International Journal of Intelligent Systems, 1998

We describe the design and implementation of the RIO (Randomized I/O) multimedia object server which manages a set of parallel disks and supports real-time throughput and statistical delay guarantees. This storage subsystem was implemented as part of a multimedia information server which supports multiple concurrent applications such as video on demand and 3D interactive virtual worlds. We discuss the principal issues and innovations involved in the design and implementation of the RIO storage system, and present experimental performance results measured on a prototype implementation.

ACM SIGMETRICS Performance Evaluation Review, 1995

The past decade has witnessed a proliferation of repositories that store and retrieve continuous media data types, e.g., audio and video objects. These repositories are expected to play a major role in several emerging applications, e.g., library information systems, educational applications, entertainment industry, etc. To support the display of a video object, the system partitions each object into fixed size blocks. All blocks of an object reside permanently on the disk drive. When displaying an object, the system stages the blocks of the object into memory one at a time for immediate display. In the presence of multiple displays referencing different objects, the bandwidth of the disk drive is multiplexed among requests, introducing disk seeks. Disk seeks reduce the useful utilization of the disk bandwidth and result in a lower number of simultaneous displays (throughput).This paper characterizes the impact of disk seeks on the throughput of the system. It describes REBECA as a ...

Multimedia Technologies and Applications for the 21st Century, 1998

Mitra is a scalable storage manager that supports the display of continuous media data types, e.g., audio and video clips. It is a software based system that employs o -the-shelf hardware components. Its present hardware platform is a cluster of multi-disk workstations, connected using an ATM switch. Mitra supports the display of a mix of media types. To reduce the cost of storage, it supports a hierarchical organization of storage devices and stages the frequently accessed objects on the magnetic disks. For the number of displays to scale as a function of additional disks, Mitra employs staggered striping. It implements three strategies to maximize the number of simultaneous displays supported by each disk. First, the EVEREST le system allows di erent les (corresponding to objects of di erent media types) to be retrieved at di erent block size granularities. Second, the FIXB algorithm recognizes the di erent zones of a disk and guarantees a continuous display while harnessing the average disk transfer rate. Third, Mitra implements the Grouped Sweeping Scheme (GSS) to minimize the impact of disk seeks on the available disk bandwidth.

Recently, disk zoning techniques have been widely used for increasing disk drive capacity. As a side effect, data transfer rates for outer zones of a hard disk are much higher than those of inner zones. Without giving proper care to disk zoning features, disk bandwidth cannot be utilized effectively. In this paper, we propose a data placement scheme for VBR (Variable Bit Rate) video objects, called NCTT (Near Constant Transfer Time). NCTT considers the nature of the VBR, the MZR disk...

Future Generation Computer Systems, 2003

An integrated storage platform for open systems should be able to meet the requirements of deterministic applications, multimedia systems, and traditional best-effort applications. It should also provide a scheduling mechanism fitting all those types of applications. In this paper, we propose a two-level hierarchical disk scheduling scheme, named 2-Q, which can guarantee deterministic deadlines, maximize the number of statistic real-time streams processed by the disk system, and minimize the average latency for best-effort requests. The upper level of the scheduling architecture, server level, is divided into three queues: deterministic, statistic, and best-effort requests. Each server may have its own scheduling algorithm. The lower level, disk driver, chooses the ready streams using its own scheduling criteria. We also propose an adaptive admission control algorithm relying on worst and average values of disk server utilization. Only streams satisfying the admission algorithm criteria are accepted for further processing by the disk server. The solution is extended to a parallel disk system by using a third hierarchical level, named meta-scheduler, briefly described in the paper. The performance evaluations demonstrate that our scheduling architecture is adequated for handling stream sets with different deterministic, statistic, or best-effort requirements.