( 3) Other Storage media other than magnetic discs and optical discs are summarized below.
Storage device
Streamer( Magnetic
tape drive)
MO device( Magnetooptical disk drive)
Storage media
Magnetic tape
MO
* Approximate capacities as of May 2009.
DAT
Characteristics
A streamer continuously reads and writes data, whereas magnetic tapes typically used with general purpose computers are started and stopped as each block is read and written. Magnetic tape formats include“ DAT” and“ 8mm tape.” For computers, DAT tape is mainly used to perform operations such as backing up data.
Writes data using laser optics and magnetism, but only uses laser optics for reading data. Capable of repeated rewriting.
MO
Storage capacity
Several tens of to several hundred GB
Several hundred MB to several GB
Reference
Sequential access“ Sequential access” is a method of reading and writing data in sequence starting from the first position of a file.
Reference
Random access“ Random access” is a method of reading and writing from an arbitrary point in a file.
Reference
DAT Abbreviation for“ Digital Audio Tape.”
Reference
MO Abbreviation for“ Magneto-Optical disk.”
Chapter 8 Computer system
( 4) Flash memory“ Flash memory” is a non-volatile type of rewriteable memory that retains stored content after the power is turned off. Several types of flash memory are summarized below.
Storage media
USB memory
SD memory card
Characteristics
Reads and writes data using fl ash memory. Integrated with a connector for connecting to a computer, offering small size and excellent portability.
Reads and writes data using fl ash memory. Used in digital cameras and mobile phones.
* Approximate capacities as of May 2009.
Storage capacity
Several tens of MB to several tens of GB
Several tens of MB to several tens of GB
Reference
Compact flash memory card A“ compact flash memory card” is a type of storage media that reads and writes data using flash memory. They are used in digital cameras and portable laptop computers.
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