Contiguous Placement on Hierarchical Storage Systems

2011 ◽  
pp. 156-160
Author(s):  
Phillip K.C. Tse
Keyword(s):  
Storage Systems ◽  
Data File ◽  
Common Method ◽  
Storage Space ◽  
Storage Devices ◽  
Placement Method ◽  
Tertiary Storage ◽  
Hierarchical Storage ◽  
Data Files ◽  
The Media

The contiguous placement is the most common method to place traditional data files on tertiary storage devices. The storage space in the media units is checked. The data file is stored on a media unit with enough space to store the data file. When tertiary storage devices are used to store multimedia objects, the objects are stored and retrieved similar to traditional data files. Since the main application of the tertiary storage devices is to back up multimedia objects from computers, the objectives of the contiguous method are: 1. supporting back up of multimedia objects efficiently, and 2. reducing the number of separate media units that are used to store an object. We will describe in the next sections the simple contiguous placement method. Afterwards, the log structured placement method is explained before we summarize this chapter.

Tertiary Storage Devices

2011 ◽  
pp. 145-155
Author(s):  
Phillip K.C. Tse
Keyword(s):  
New Media ◽  
Computer System ◽  
Storage Capacity ◽  
Storage Systems ◽  
Low Cost ◽  
Storage Devices ◽  
Tertiary Storage ◽  
Hierarchical Storage ◽  
The Media ◽  
Optical Disks

The main objective of the tertiary storage level is to provide huge storage capacity at low cost. Several types of storage devices are available to be used at the tertiary storage level in Hierarchical Storage Systems (HSS). They include: • Magnetic tapes • Optical disks • Optical tapes These storage devices are composed of fixed storage drives and removable media units. The storage drives are fixed to the computer system. The removable media unit can be removed from the drives so that the storage capacity can be expanded with more media units. When data on a media are accessed, the media unit is accessed from their normal location. One of the storage drives on the computer system is chosen. If there is a media unit in the storage drive, the old media unit is unloaded and ejected. The new media unit is then loaded to the drive. Each type of storage drive may handle the storage drives and media units differently. The magnetic tapes are described below in the next section. Then, the optical tapes are presented. Afterwards, the optical disks are briefly described before this chapter is summarized.

Striping on Hierarchical Storage Systems

2011 ◽  
pp. 167-186
Author(s):  
Phillip K.C. Tse
Keyword(s):  
Storage Systems ◽  
Placement Method ◽  
Data Striping ◽  
Hierarchical Storage

The data striping technique has been successfully applied on disks to reduce the time to access objects from the disks as shown in Chapter VI. Similarly, the striping technique has been investigated to reduce the time to access objects from the tape libraries. Similar to the striping on disks, the objective of the parallel striping method is to reduce the time to access objects from the tape libraries. The parallel tape striping directly applies the striping technique to place data stripes on tapes. The triangular placement method changes the order in which data stripes are stored on tapes to further enhance the performance. In the next section, the parallel tape striping method will be described. The performance of the parallel tape striping follows. After that, the triangular placement method is explained, and it is followed by the performance of the triangular placement method.

Statistical Placement on Hierarchical Storage Systems

2011 ◽  
pp. 161-166
Author(s):  
Phillip K.C. Tse
Keyword(s):  
Storage Systems ◽  
Storage System ◽  
Access Time ◽  
Placement Method ◽  
Statistical Strategy ◽  
Hierarchical Storage ◽  
The Mean ◽  
Statistical Time ◽  
Strategy Changes

We have described the contiguous placement in the previous chapter and the statistical strategy to place objects on disks in Chapter IV. In this chapter, we describe the statistical strategy to place them on hierarchical storage systems. The objective of the data placement methods is to minimize the time to access object from the hierarchical storage system. The statistical strategy changes the statistical time to access objects so that the mean access time is optimal. The objective of the frequency based placement method is to differentiate objects according to their access frequencies. The objects that are more frequently accessed are placed in the more convenient locations. The objects that are less frequently accessed are placed in the less convenient locations. We will describe the frequency based placement method in the next section. Afterwards, we will analyze its performance. Last, we summarize this chapter.

Maintaining Redundancy in Peer-to-Peer Storage Systems

2010 ◽  
pp. 616-634
Author(s):  
Anwitaman Datta ◽  
Di Wu ◽  
Liu Xin ◽  
Adam Wierzbicki
Keyword(s):  
Quality Of Service ◽  
Storage Systems ◽  
End Users ◽  
Peer To Peer ◽  
Analytical Models ◽  
Storage Space ◽  
Storage Devices ◽  
Empirical Results ◽  
P2p Storage

Peer-to-Peer (P2P) storage systems leverage the combined storage capacity of a network of storage devices (peers) contributed typically by autonomous end-users as a common pool of storage space to store and share content. A major challenge in such a system comprising of autonomous participants is to guarantee quality of service in terms of persistence and availability of the stored content. This chapter focuses on the different possible design choices for maintaining redundancy in P2P storage systems, including algorithm details of maintenance mechanisms, analytical models to understand system’s dynamics, empirical results from simulation experiments as well as experiences from prototype deployments.

Constraint Allocation on Hierarchical Storage Systems

2011 ◽  
pp. 187-206
Author(s):  
Phillip K.C. Tse
Keyword(s):  
Storage Systems ◽  
Storage System ◽  
Data Migration ◽  
Access Time ◽  
Worst Case ◽  
Exchange Time ◽  
Multimedia Streams ◽  
Hierarchical Storage ◽  
The Media ◽  
Migration Method

Multimedia objects are stored on hierarchical storage systems (HSS). The objects are large in size but the access latency of HSS is high. It is necessary to provide high throughput in delivering data from the storage system. In addition to the statistical placement and striping methods in the two previous chapters, constraint allocation can also improve the throughput of HSS. Multimedia streams should be displayed with continuity. Depending on the data migration method, the whole object or only partial object is retrieved prior to the beginning of consumption. Thus, it may need to retrieve the parts of the object within guarantee times. The maximum access time depends on the storage locations of the object. If the parts of the object are freely stored on any media units, it may take the longest exchange time to exchange a media unit. If the parts of the object are freely stored on any locations of the media units, it may take the longest reposition time to reposition the media unit. The maximum access time needs to include both the longest exchange time and the longest reposition time. As a result, the guarantee times should not be shorter than the maximum access time in the worst case. The long guarantee time results in a small number of acceptable streams to the hierarchical storage system. The constraint allocation methods limit the freedom to place data on media units so that the worst case would never happen. They reduce the longest exchange time and/or the longest reposition time in accessing the objects. Two approaches to provide constraint allocations have been proposed on different types of media units. The interleaved contiguous placement limits the storage locations of data stripes on optical disks and it is described in the next section. The concurrent striping method that limits the storage locations of data stripes on tapes is described.

Prevention of suicide due to charcoal burning

2021 ◽  
pp. 743-748
Author(s):  
Ying-Yeh Chen ◽  
Jacky Wong ◽  
Paul Yip
Keyword(s):  
Suicide Prevention ◽  
East Asian ◽  
Common Method ◽  
The Internet ◽  
Specific Method ◽  
Charcoal Burning ◽  
Effective Strategies ◽  
The Media ◽  
Enclosed Space ◽  
Year 2000

Since the year 2000, suicide by combustion of barbecue charcoal in an enclosed space has become a common method of suicide in many East Asian countries. The spread of charcoal burning suicides was related to the pervasive media glamorization of the method to be a painless, peaceful, and effective way to end one’s life. Popularity of the internet accompanying its contagious effect further imposes challenges in suicide prevention, in particular, in the prevention of charcoal burning suicides. In areas where charcoal burning has already become a common method of suicide, effective strategies include working with the media to moderate the reporting of suicide news and creating barriers in the purchase of charcoal. In other areas where the method is still not widely known, muting the media reporting of this specific method of suicide to eliminate its ‘cognitive availability’ is key to prevent the seeding of charcoal burning suicides.

Time Slicing Method

2011 ◽  
pp. 272-279
Author(s):  
Phillip K.C. Tse
Keyword(s):  
High Throughput ◽  
Storage Capacity ◽  
Low Cost ◽  
Storage Devices ◽  
Access Latency ◽  
Tertiary Storage ◽  
Start Up ◽  
Slicing Method ◽  
Time Slicing

Tertiary storage devices provide huge storage capacity at low cost. Multimedia objects stored on the tertiary storage devices are accessed with high latency. Despite the high access latency, some tertiary storage devices are able to deliver data at high throughput. The time slicing method is designed to reduce the start-up latency in accessing multimedia objects from tertiary storage devices. The start-up latency is lowered by reducing the amount of data being migrated in stage one of the staging method being described in the last chapter. In order to support the time-slicing method, the tertiary storage devices should have the ability to deliver data at high throughput. The tertiary storage devices that cannot deliver data at sufficiently high throughput; the start-up latency cannot be reduced.

Sign in / Sign up

Export Citation Format

Share Document