Performance Measurements of Tertiary Storage Devices
tape-based tertiary storage devices. Applications that generate and use massive data sets drive the use of and research into tertiary storage. For example
Database Systems for E cient Access to Tertiary Memory 1 Introduction
Abstract. Tertiary storage devices have long been in use for storing massive amounts of data in le-oriented mass storage systems.
A brief survey of tertiary storage systems and research
A more detailed version of the paper is available in [9]. 2 Tertiary Devices - Current Technology. The most common tertiary storage devices are mag- netic
A BRIEF SURVEY OF TERTIARY STORAGE SYSTEMS AND
A more detailed version of the paper is available in 9]. 2 Tertiary Devices - Current Technology. The most common tertiary storage devices are mag- netic
Tertiary Storage: An Evaluation of New Applications
Below RAM is solid state memory and then magnetic disk devices commonly called sec- ondary storage. At the bottom of the hierarchy are tertiary storage devices
Query Processing in Tertiary Memory Databases
Two tertiary memory storage devices { a Sony opti- cal jukebox and an HP magneto-optical jukebox have already been interfaced with the postgres's storage.
EFFICIENT ORGANIZATION AND ACCESS OF MULTI
Characterization of Tertiary Storage Devices. The optimal partitioning depends also on the characteristics of the tertiary storage devices. Because we do not
Chapter 5 Storage Devices
Storage Devices. Types of Storage. There are four type of storage: • Primary Storage. • Secondary Storage. • Tertiary Storage. • Off-line Storage. Page 5. 5.
Scheduling Queries for Tape-resident Data ?
Tertiary storage devices have traditionally been used as archival storage. The new resides on automated tertiary storage containing multiple storage devices.
Chapter 5 Storage Devices
A storage device is used in the computers to store the data. Tertiary Storage. • Off-line Storage ... data storage device in a computer.
Performance Measurements of Tertiary Storage Devices
information about tertiary storage devices has been published. In this paper we present de- tailed measurements of several tape drives and robotic storage
Module 14: Tertiary-Storage Structure
Operating System Concepts. Silberschatz and Galvin 1999. 14.1. Module 14: Tertiary-Storage Structure. • Tertiary Storage Devices. • Operating System Issues.
A Study on the Use of Tertiary Storage in Multimedia Systems
Tape media is still two orders of magnitude less expensive than magnetic disk storage; although tape drives exhibit access latencies two to four orders of
TERTIARY STORAGE DEVICES
May 30 2017 Tertiary storage or tertiary memory
Chapter 5 Storage Devices
A storage device is used in the computers to store the data. Tertiary Storage. • Off-line Storage ... data storage device in a computer.
1 10: Storage and File System Basics Storage Hierarchy Example
Jun 15 2004 Tertiary Storage Devices. ? Used primarily as backup and archival storage. ? Low cost is the defining characteristic.
Query Processing in Tertiary Memory Databases
database systems to handle tertiary storage devices. The characteristics of tertiary mem- ory devices are very di erent from secondary.
Tertiary Storage: An Evaluation of New Applications
including increased tape capacities less expensive tape drives and optical disk drives
Chapter 14: Mass-Storage Systems
Swap-Space Management. ? RAID Structure. ? Disk Attachment. ? Stable-Storage Implementation. ? Tertiary Storage Devices. ? Operating System Issues.
Tertiary Storage - an overview ScienceDirect Topics
TertiaryStorageDevices OperatingSystemIssues PerformanceIssues 14 1 StructureTertiary thedefining Storage characteristic Lowcostis Generallytertiarystorage Commonexamplesof Devices of isbuiltusing removable CD-ROMs; othertypesaremedia tertiarystorage removablemedia arefloppydisksand available 14 2•Floppydisk— thin emovableD flexiblediskcoated
Chapter 5 Storage Devices - FTMS
Storage Devices Tertiary Storage • Typically it involves a robotic mechanism which will mount (insert) and dismount removable mass storage media into a storage device • It is a comprehensive computer storage system that is usually very slow so it is usually used to archive data that is not accessed frequently
Storage Systems - Department of Computer Science
Tertiary Storage Devices • Low cost is the defining characteristic of tertiary storage • Tradeoff between cost and access time • Tradeoff between data stability and access time • Generally tertiary storage is built using removable media • Floppy disks • ZIP drives • CD-ROMs • CD-RWs • DVDs • Magneto-optical storage • MEMS
Hierarchy and Characteristic of Storage Devices
a second storage tertiary storage and off-line storage Primary storage is the main memory or internal memory of the computer Second storage is an external memory or auxiliary memory Tertiary storage is a third level storage such as cloud storage Off-line storage is computer data storage on a medium or a device Primary storage is the only
What are tertiary storage devices?
For large-scale servers, economics will dictate the use of large tertiary storage devices such as tape and optical jukeboxes. Tertiary storage devices are highly cost-effective and offer enormous storage capacities by means of robotic arms that serve removable tapes or disks to a few reading devices (see Table 3 ).
Are tertiary storage devices suitable for cm playback?
Tertiary storage devices are highly cost-effective and offer enormous storage capacities by means of robotic arms that serve removable tapes or disks to a few reading devices (see Table 3 ). However, their slow random access—due to long seeking and loading times—and relatively low data transfer rates make them inappropriate for CM playback.
What is an example of secondary storage device?
An example of the secondary storage device is a hard disk The hard disk drive is the primary, and usually most considerable, data storage apparatus in a computer. It can stow from 160 gigabytes to 2 terabytes. Hard disk pace is the swiftness at which content can be read and documented on a hard disk.
What is a storage device?
A storage device is utilized in the computers to store, preserve accumulated data. The storage device is one of the most vital parts of the computer. It is capable of providing the crude and core functions of the system. The computer is incomplete without the storage device.
Module 14: Tertiary-Storage Structure
Tertiary Storage Devices
Operating System Issues
Performance Issues
Operating System ConceptsSilberschatz and Galvin?1999 14.2Tertiary Storage Devices
Low cost is the defining characteristic of tertiary storage. Generally, tertiary storage is built using removable media Common examples of removable media are floppy disks andCD-ROMs; other types are available.
Operating System ConceptsSilberschatz and Galvin?1999 14.3Removable Disks
Floppy disk - thin flexible disk coated with magnetic material, enclosed in a protective plastic case. - Most floppies hold about 1 MB; similar technology is used for removable disks that hold more than 1 GB. - Removable magnetic disks can be nearly as fast as hard disks, but they are at a greater risk of damage from exposure. Operating System ConceptsSilberschatz and Galvin?1999 14.4Removable Disks (Cont.)
A magneto-optic disk records data on a rigid platter coated with magnetic material. - Laser heat is used to amplify a large, weak magnetic field to record a bit. - Laser light is also used to read data (Kerr effect). - The magneto-optic head flies much farther from the disk surface than a magnetic disk head, and the magnetic material is covered with a protective layer of plastic or glass; resistant to head crashes. Optical disks do not use magnetism; they employ special materials that are altered by laser light. Operating System ConceptsSilberschatz and Galvin?1999 14.5WORM Disks
The data on read-write disks can be modified over and over.WORM ("Write Once, Read Many Times") disks can be
written only once. Thin aluminum film sandwiched between two glass or plastic platters. To write a bit, the drive uses a laser light to burn a small hole through the aluminum; information can be destroyed by not altered.Very durable and reliable.
Read Only disks, such ad CD-ROM and DVD, com from the factory with the data pre-recorded. Operating System ConceptsSilberschatz and Galvin?1999 14.6 Tapes Compared to a disk, a tape is less expensive and holds more data, but random access is much slower. Tape is an economical medium for purposes that do not require fast random access, e.g., backup copies of disk data, holding huge volumes of data. Large tape installations typically use robotic tape changers that move tapes between tape drives and storage slots in a tape library. - stacker - library that holds a few tapes - silo - library that holds thousands of tapes A disk-resident file can be archived to tape for low cost storage; the computer can stage it back into disk storage for active use. Operating System ConceptsSilberschatz and Galvin?1999 14.7Operating System Issues
Major OS jobs are to manage physical devices and to present a virtual machine abstraction to applicationsFor hard disks, the OS provides two abstraction:
- Raw device - an array of data blocks. - File system - the OS queues and schedules the interleaved requests from several applications. Operating System ConceptsSilberschatz and Galvin?1999 14.8Application Interface
Most OSs handle removable disks almost exactly like fixed disks - a new cartridge is formatted and an empty file system is generated on the disk. Tapes are presented as a raw storage medium, i.e., and application does not not open a file on the tape, it opens the whole tape drive as a raw device. Usually the tape drive is reserved for the exclusive use of that application. Since the OS does not provide file system services, the application must decide how to use the array of blocks. Since every application makes up its own rules for how to organize a tape, a tape full of data can generally only be used by the program that created it. Operating System ConceptsSilberschatz and Galvin?1999 14.9Tape Drives
The basic operations for a tape drive differ from those of a disk drive. locate positions the tape to a specific logical block, not an entire track (corresponds to seek). The read position operation returns the logical block number where the tape head is.The space operation enables relative motion.
Tape drives are "append-only" devices; updating a block in the middle of the tape also effectively erases everything beyond that block. An EOT mark is placed after a block that is written. Operating System ConceptsSilberschatz and Galvin?1999 14.10File Naming
The issue of naming files on removable media is especially difficult when we want to write data on a removable cartridge on one computer, and then use the cartridge in another computer. Contemporary OSs generally leave the name space problem unsolved for removable media, and depend on applications and users to figure out how to access and interpret the data. Some kinds of removable media (e.g., CDs) are so well standardized that all computers use them the same way. Operating System ConceptsSilberschatz and Galvin?1999 14.11Hierarchical Storage Management (HSM)
A hierarchical storage system extends the storage hierarchy beyond primary memory and secondary storage to incorporate tertiary storage - usually implemented as a jukebox of tapes or removable disks. Usually incorporate tertiary storage by extending the file system. - Small and frequently used files remain on disk. - Large, old, inactive files are archived to the jukebox. HSM is usually found in supercomputing centers and other large installaitons that have enormous volumes of data. Operating System ConceptsSilberschatz and Galvin?1999 14.12 Speed Two aspects of speed in tertiary stroage are bandwidth and latency.Bandwidth is measured in bytes per second.
- Sustained bandwidth - average data rate during a large transfer; # of bytes/transfer time. Data rate when the data stream is actually flowing. - Effective bandwidth - average over the entire I/O time, including seek or locate, and cartridge switching.Drive's overall data rate.
Operating System ConceptsSilberschatz and Galvin?1999 14.13Speed (Cont.)
Access latency - amount of time needed to locate data. - Access time for a disk - move the arm to the selected cylinder and wait for the rotational latency; < 35 milliseconds. - Access on tape requires winding the tape reels until the selected block reaches the tape head; tens or hundreds of seconds. - Generally say that random access within a tape cartridge is about a thousand times slower than random access on disk. The low cost of tertiary storage is a result of having many cheap cartridges share a few expensive drives. A removable library is best devoted to the storage of infrequently used data, because the library can only satisfy a relatively small number of I/O requests per hour. Operating System ConceptsSilberschatz and Galvin?1999 14.14Reliability
A fixed disk drive is likely to be more reliable than a removable disk or tape drive. An optical cartridge is likely to be more reliable than a magnetic disk or tape. A head crash in a fixed hard disk generally destroys the data, whereas the failure of a tape drive or optical disk drive often leaves the data cartridge unharmed. Operating System ConceptsSilberschatz and Galvin?1999 14.15 Cost Main memory is much more expensive than disk storage The cost per megabyte of hard disk storage is competitive with magnetic tape if only one tape is used per drive. The cheapest tape drives and the cheapest disk drives have had about the same storage capacity over the years. Tertiary storage gives a cost savings only when the number of cartridges is considerably larger than the number of drives.quotesdbs_dbs14.pdfusesText_20[PDF] tesco 2014 annual report
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