Magnetic Storage Devices

Introduction

For many long years computer have been used for millions of persons in the world.
One of the most important characteristics of them have been their capacity of data storage. Nowadays there are a lot of devices we can use for storage information with a lot of space on it, and there are also many kinds of devices we can use for storage:

But still in this assignment we will onlysee one of this kinds of storage devices, magnetic storage devices.

Magnetic storage

What it’s a magnetic storage device?
A magnetic storage is a medium for holding information (data, voice, video, etc.), such as tape and disk. They can be erased and reused over and over again.
Magnetic storage and magnetic recording are terms from engineering referring to the storage of data on amagnetized medium. Magnetic storage uses different patterns of magnetization in a magnetizable material to store data and is a form of non-volatile memory. The information is accessed using one or more read/write heads. Magnetic storage media, primarily hard disks, are widely used to store computer data as well as audio and video signals. In the field of computing, the term magnetic storage is preferredand in the field of audio and video production, the term magnetic recording is more commonly used. The distinction is less technical and more a matter of preference.

 What are the Magnetic recording classes?
Analog recording
Analog recording is based on the fact that remnant magnetization of a given material depends on the magnitude of the applied field. The magnetic material is normally inthe form of tape, with the tape in its blank form being initially demagnetized. Analog recording was very popular in audio and video recording. In the past 20 years, however, tape recording has been gradually replaced by digital recording.
Digital recording
Instead of creating a magnetization distribution in analog recording, digital recording only need two stable magnetic states, which arethe +Ms and -Ms on the hysteresis loop. Examples of digital recording are floppy disks and HDDs.
What is their method for Access?

Magnetic storage media can be classified as either sequential access memory or random access memory although in some cases the distinction is not perfectly clear. In the case of magnetic wire, the read/write head only covers a very small part of the recording surfaceat any given time. Accessing different parts of the wire involves winding the wire forward or backward until the point of interest is found. The time to access this point depends on how far away it is from the starting point. The case of ferrite-core memory is the opposite. Every core location is immediately accessible at any given time. Hard disks and modern linear serpentine tape drives do notprecisely fit into either category. Both have many parallel tracks across the width of the media and the read/write heads take time to switch between tracks and to scan within tracks. Different spots on the storage media take different amounts of time to access. For a Hard
Disk is typically less than 10 ms, but tapes might take as much as 100 s.

What are the magnetic storage devices types?Tapes

One of the first types of magnetic storage was the tape.  This uses magnetically coated ribbon, wrapped around two reels. There are two common forms of Magnetic Tape.  Either reel-to-reel or cartridge.  The cartridge type usually has several hundred feet of magnetic tape, and was most often used in personal computers.  A reel-to-reel system is much larger, maybe several thousand feet oftape, and is on large spools.  They were usually used on large mainframes.
A tape drive is basically like a cassette tape player/recorder.  It has two heads: one read, one write.  As the tape passes the head, the data is read or written, as the case may be.
Tapes have the advantage of being inexpensive, and rather reliable.  But they are slow, because they are sequential access devices.  This...