Continuous display using heterogeneous disk-subsystems

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.

2002 IEEE Workshop on Multimedia Signal Processing.

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.

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 Tools and …, 2005

Multimedia presentations (e.g., lectures, digital libraries) normally include discrete media objects such as text and images along with continuous media objects such as video and audio. Objects composing a multimedia presentation need to be delivered based on the temporal relationships specified by the author(s). Hence, even discrete media objects (that do not normally have any real-time characteristics) have temporal constraints on their presentations. Composition of multimedia presentations may be light (without any accompanying video or large multimedia data) or heavy (accompanied by video for the entire presentation duration). The varying nature of the composition of multimedia presentations provides some flexibility for scheduling their retrieval. In this paper, we present a min-max skip round disk scheduling strategy that can admit multimedia presentations in a flexible manner depending on their composition. We also outline strategies for storage of multimedia presentations on an array of disks as well as on multi-zone recording disks.

Proceeding of 13th IEEE Annual International Phoenix Conference on Computers and Communications

Th e ad r.e ii t of in ultiiii edzn z n form citzo 11 processing has brought a lot of rnformatzon inaiicigfmenf issues anfo attentzon in the past few years Promineitt among fhem anclude the eficicnt storage and refrzeifal of multzmedia objects When handling digital continuous media, these ~ssiies herome more critacal. An eficreiit storage and retrtevnl process bcconics usefiil aiid nteaniitgfd when combined wzth efictrnt bii~flcr inanagement The buffer ncquzsatian and rettniioii mechanzsnis 90 a long luny to achzeciang the display reqniremeizis. In this pnpfr. UY preseiit a iecbntque for cow tanuous rnedra di5plays lhal str.ri>t to mntiifaav some degree of datcl ararlnhility through efirienf hiiffer managenlent. nltdia drsp/@y factors are dcrcbpcd for dala acquasztion and hiifer releniion to satasfy media dtsplay reqiiircm e ti t 5

Computing the Brain, 2001

The past decade has witnessed a proliferation of repositories whose workload consists of queries that retrieve information. These repositories provide on-line access to vast amount of data and serve as an integral component of many applications, e.g., library information systems, scientific applications, and the entertainment industry. Their storage subsystems are expected to be hierarchical, consisting of memory, magnetic disk drives, optical disk drives, and tape libraries. The database itself resides permanently on the tape. Objects are swapped onto either the magnetic or optical disk drives on demand, and later deleted when the available space of a device is exhausted. This behavior will generally cause fragmentation of the disk space over a period of time, resulting in a non-contiguous layout of diskresident objects. As a consequence, the disk is required to reposition its read head multiple times (incurring seek operations) whenever a resident object is retrieved. This may reduce the overall performance of the system. This study investigates four alternative techniques to manage the available space of mechanical device in such hierarchical storage systems. Conceptually, these techniques can be categorized according to how they optimize several quantities, including: (1) the fragmentation of disk-resident objects, (2) the amount of wasted space, and (3) adaptation to the evolving access pattern of an application. For each of these alternative strategies, we identify the fundamental factors that impact the performance of the system and develop analytical models that quantify each factor. These models can be employed by a Shahram Ghandeharizadeh, Douglas J. Ierardi, Roger Zimmermann April 99 2 system designer to choose among competing strategies based on the physical characteristics of both the system and the target application.

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.

Proceedings Twenty-First Annual International Computer Software and Applications Conference (COMPSAC'97), 1997

With the increasing processing speeds, there is a shift away from the paradigm of centralized, sequential storage systems towards distributed and network based storage systems. Further, with the new imaging and real time multimedia applications, it is becoming more than ever important to design powerful, efficient and scaleable U 0 systems. In this paper, the requirements of storage subsystems in multimedia environment were presented. The storage system components relating to those requirements were analyzed. Current solutions were surveyed and classified. Then we proposed approaches to improve storage subsystem performance for multimedia. The first approach applies constrained layout currently used for single disk model to multi-disk system. The second calls for using a striping unit that meets both media and storage system optimization criteria. The third uses a pool of buffers instead of single buffer per stream.

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.