Types of Storage Technologies
Primary Types of Magnetic Storage
Diskettes (Floppy Disks)
High capacity floppy disks
Disk Cartridges
Hard Disks
Magnetic Tape
How Magnetic Storage Works
A magnetic disk's medium contains iron particles, which can be polarized when given a magnetic charge in one of two directions. Each particle's direction represents a 1 (on) or 0 (off) which in turn represent each bit of data that the CPU can recognize. A disk drive uses read/write heads containing electromagnets to create magnetic charges on the medium.
When no data is being stored, the particles in the medium are in random state. During the writing process, current passes from the write head to the particles which polarize them. Now the organized particles represent the data. And as the medium rotates, the head then writes the data.
Primary Types of Optical Storage
An optical disk is a high-capacity storage medium while an optical drive uses reflected light to read data.
Compact Disk Read-Only Memory (CD-ROM)
Digital Video Disk Read-Only Memory (DVD-ROM)
CD-Recordable (CD-R)
CD-Rewritable (CD-RW)
PhotoCD
How Optical Storage Works
To store data, the disk's metal surface is covered with tiny dents (pits) and flat spots (lands), which cause light to be reflected differently. When an optical drive shines light into a pit, the light cannot be reflected back. This represents a bit value of 0 (off). A land reflects light back to its source, representing a bit value of 1 (on).
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