Overview of Physical Storage Media

Overview of Physical Storage Media - Overview of Physical...

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Overview of Physical Storage Media 1. Several types of data storage exist in most computer systems. They vary in speed of access, cost per unit of data, and reliability. o Cache: most costly and fastest form of storage. Usually very small, and managed by the operating system. o Main Memory (MM): the storage area for data available to be operated on. General-purpose machine instructions operate on main memory. Contents of main memory are usually lost in a power failure or ``crash''. Usually too small (even with megabytes) and too expensive to store the entire database. o Flash memory: EEPROM ( electrically erasable programmable read-only memory ). Data in flash memory survive from power failure. Reading data from flash memory takes about 10 nano-secs (roughly as fast as from main memory), and writing data into flash memory is more complicated: write-once takes about 4-10 microsecs. To overwrite what has been written, one has to first erase the entire
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This note was uploaded on 10/25/2010 for the course CMPN SEM4 taught by Professor Thakur during the Spring '07 term at University of Mumbai.

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Overview of Physical Storage Media - Overview of Physical...

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