Which type of storage technology uses platters and read/write heads to store and retrieve data?

In todays era, every computing devices have some kind of storage memory that they use for storing informations. There are basically two types of storage, one is static or non-volatile storage and the other is Dynamic or volatile storage as I already discussed about these in the previous blog of RAM. Now lets talk about the storage technologies that we use to store data. There are basically three kinds of storage technologies which are

• Magnetic Storage
• Optical Storage
• Solid State Storage

1. Magnetic Storage

Magnetic storage encodes data in patterns of positive and negative magnetic polarity on some magnetic medium like organic metal. Devices like floppy disks, tape recorder cassettes and Hard disks are all using magnetic storage technology. Inside hard disks, there are round platters which are made of metal oxide material and they rotate around the spindle in a high speed. Similarly they have mechanical part i.e. armature and its head which read/ write the patterns of magnetic polarities on the platters. The patterns are stored in the form of bits through magnetizing the platters in positive and negative polarities. The hard disk drives’ storage capacities ranges from simply Mbs (Mega bytes) to hundreds of TB (Tera-bytes). The inside of hard disk is shown in the figure below.

The following video shows about how the hard disk works in order to read and write data.

2. Optical Storage

Optical storage technology use laser/optical reflection phenomenon to read or write data. Two things are required for optical storage technology, one is the optical media which are circular discs and the other is optical drives which have the laser beam source for lightening and the photo diodes for generating the voltages patterns when the reflection beam hit on these.

There are three types of Discs using nowadays

• CD (Compact Disc) which was firstly discovered and it is used for storage the music files and some programs. These have low storage capacity of about 700 MB. These use the red color laser rays.
• DVD (Digital versatile Disc): These storing media are used for storing standard definition movies. These are available in two layers like DVD-DL (Double Layer). These use the red color laser rays.
• BD (Blue-Ray Disc): These are used for storing high definition movies and these have larger capacities than both the CD and DVD. These uses the blue color rays laser.

Similarly, these all types of discs have further two categories, one is ROM (CD-ROM etc.) which are used for permanently storage while the other is RAM (CD RAM etc.) which can be used for temporary storages like the discs used in camcorders.

These all disc types can single sided (SS) or Double Sided (DS) as well as single layer or multi layers.

Following figure shows the above three disc types and notice the difference in colors.

The other main thing in the optical storage is the optical drives like CD drive, DVD drive and BD drive. These are also have different categories which are discussed below

• Read only Drives: which can only read the discs but cannot write
• Write only Drives: Which can only write the discs but cannot read
• Read and Write Drives: which can read as well as write the discs.

3. Solid State storage

Solid-state storage uses nonvolatile (or flash) memory that can retain data when power is off. This technology has no moving parts. Solid-state storage is more expensive but it is lighter, faster, quieter, and more efficient than the previous ones. Here are the most common forms of solid state storage:

• USB flash drive is a stick of highly portable storage that plugs into a USB port. These are mostly used nowadays because they have small sizes and good speed.

• Flash memory cards are used in digital cameras, smartphones, and navigation devices. The most common formats are CompactFlash, Secure Digital (SD), MemoryStick, and MicroSD.
• Flash Hard drives also called solid-state drives (SSDs) are mostly used in the laptops, tablets and many portable devices. These are same in shapes as the mechanical hard drives but in smaller size than those. These are mostly used today.

The following figure shows different kinds of solid-state devices.

This was all about the different technologies used for storing the data.

Thanks for Reading…!!!

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