1.3.3 Magnetic Storage Flashcards
Storing a bit
The value of each bit of data (0 or 1) is represented as a positively or negatively charged magnetic particle.
These particles are part of a magnetic disk called the platter.
Accessing data
Data could be stored anywhere on the disk, and so to read/write data we first need to find the location on the disk.
A magnetic read/write head is used to access the data while the platter spins.
Reliability
The HDD has moving parts.
Although the HDD is generally reliable, any device with moving parts will be subject to wear-and-tear.
HDDs can also be damaged by shocks. They are not robust.
Properties of Magnetic Media - Low Speed
Magnetic media needs a high number of moving parts.
The high number of moving parts make magnetic media slow to access.
Properties of Magnetic Media - Low Cost
Magnetic media is very low cost per unit capacity.
This makes it an economical choice for storing large amounts of data.
Properties of Magnetic Media - High Capacity
Magnetic media can store a large quantity of data in a compact way.
This makes them a popular choice for archives as well as home computers.
Properties of Magnetic Media - Good Reliability
Magnetic media is reliable and tends to last for a long time.
Magnetic media is not robust, and tends to break on impact or during vibrations.
Examples of Magnetic Storage - Hybrid Drives
Some modern devices have both magnetic and solid state storage.
The combination of magnetic and solid state storage is known as a hybrid drive, and offers the benefits of both systems.
Examples of Magnetic Storage - Magnetic Tapes
Magnetic tape used to be popular for distributing content such as:
Audio.
Video.
Software.
Nowadays, tape is only used for:
Some video cameras.
Making backups.
Examples of Magnetic Storage - HDD
HDDs are often used as the main form of secondary storage in a computer system.
HDDs hold the operating system, applications, and user data.
