ch10-storage

ch10-storage - Chapter 10: Storage and File Structure...

Info iconThis preview shows pages 1–8. Sign up to view the full content.

View Full Document Right Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: Chapter 10: Storage and File Structure Chapter 10: Storage and File Structure Silberschatz, Korth and Sudarshan 10.2 Database System Concepts - 6 th Edition Database System Internals Database System Internals Silberschatz, Korth and Sudarshan 10.3 Database System Concepts - 6 th Edition Chapter 10: Storage and File Structure Chapter 10: Storage and File Structure Overview of Physical Storage Media Magnetic Disks RAID --- skipping Tertiary Storage --- skipping Storage Access File Organization Organization of Records in Files Data-Dictionary Storage --- skipping Silberschatz, Korth and Sudarshan 10.4 Database System Concepts - 6 th Edition Classification of Physical Storage Media Classification of Physical Storage Media Speed with which data can be accessed Cost per unit of data Reliability data loss on power failure or system crash physical failure of the storage device Can differentiate storage into: volatile storage : loses contents when power is switched off non-volatile storage : Contents persist even when power is switched off. Includes secondary and tertiary storage, as well as batter- backed up main-memory. Silberschatz, Korth and Sudarshan 10.5 Database System Concepts - 6 th Edition Physical Storage Media Physical Storage Media Cache fastest and most costly form of storage; volatile; managed by the computer system hardware. Main memory : fast access (10s to 100s of nanoseconds; 1 nanosecond = 10 9 seconds) generally too small (or too expensive) to store the entire database capacities of up to a few Gigabytes widely used currently Capacities have gone up and per-byte costs have decreased steadily and rapidly (roughly factor of 2 every 2 to 3 years) Volatile contents of main memory are usually lost if a power failure or system crash occurs. Silberschatz, Korth and Sudarshan 10.6 Database System Concepts - 6 th Edition Physical Storage Media (Cont.) Physical Storage Media (Cont.) Flash memory Data survives power failure Data can be written at a location only once, but location can be erased and written to again Can support only a limited number (10K 1M) of write/erase cycles. Erasing of memory has to be done to an entire bank of memory Reads are roughly as fast as main memory But writes are slow (few microseconds), erase is slower Widely used in embedded devices such as digital cameras, phones, and USB keys Silberschatz, Korth and Sudarshan 10.7 Database System Concepts - 6 th Edition Physical Storage Media (Cont.) Physical Storage Media (Cont.) Magnetic-disk Data is stored on spinning disk, and read/written magnetically Primary medium for the long-term storage of data; typically stores entire database....
View Full Document

Page1 / 44

ch10-storage - Chapter 10: Storage and File Structure...

This preview shows document pages 1 - 8. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online