Magnetic storage devices are a type of non-volatile storage that use a magnetic coating on some kind of surface to store data. Some common examples of magnetic storage devices are hard disk drives, floppy disks, and magnetic tapes. These devices use the magnetization of tiny magnetic particles to represent binary data. Magnetic storage has been used for data storage since the 1950s and continues to be used today alongside newer solid-state storage technologies.
In this article, we will provide an overview of magnetic storage, looking at what it is, how it works, common examples of magnetic storage devices, and the advantages and disadvantages of this type of data storage. We will compare magnetic storage to other data storage methods and examine its usage in modern times. The key points covered include the main types of magnetic storage devices, how data is stored and accessed using magnetization, and the capacity, speed, reliability and cost tradeoffs of magnetic storage.
What is Magnetic Storage?
Magnetic storage works by magnetizing materials in a certain pattern to store data bits. Early forms of magnetic storage media include magnetic tapes and floppy disks. These media contain magnetic particles that can be polarized to store bits – for example, magnetizing a section clockwise to represent a 1 or counterclockwise to represent a 0. The magnetic surface is able to retain the polarization even when power is removed, making magnetic storage non-volatile. To write data, a magnetic write head polarizes tiny sections on the media surface. To read data, a magnetic read head detects the polarization of each section as it moves over the media. In this way, different patterns of magnetism can be used to store audio, video, text, or any digital data.1
Hard Disk Drives
Hard Disk Drives (HDDs) store data on quickly rotating platters with magnetic surfaces. They utilize moving parts and electromagnetism to read/write data. The platters rotate on a spindle at high speeds while an actuator arm with read/write heads hovers above the surface of the platters. The read/write heads detect and modify the magnetism of the platter surfaces to store and retrieve data (TechTarget).
HDDs have high capacity storage, typically starting at 250GB for consumer models and ranging into the terabytes. But their moving parts lead to slower speed than solid state drives. The rate of rotation and density of platters helps determine the speed of a HDD. Top speeds range from 5,400 rpm on budget drives to 15,000 rpm on high performance models (Crucial). HDDs were once the primary storage device in computers, but have been increasingly supplanted by SSDs in newer systems.
Floppy Disks
The floppy disk is a data storage medium that first became commercially available in 1971. It uses a thin and flexible disk made of a type of plastic called mylar with a magnetic coating (Fujifilm, 2022). The earliest floppy disks were 8 inches in diameter, then 51⁄4 inches, and finally the 31⁄2 inch variety that became the standard and dominated from the mid-1980s until the late 1990s (Wikipedia, 2022).
The capacities of floppy disks evolved over the years as technologies improved. The very first 8 inch floppies stored just 80 kilobytes. The 51⁄4 inch disks in the late 1970s and early 1980s commonly stored anywhere from 100 kilobytes to 1.2 megabytes. The standard 31⁄2 inch floppies of the late 1980s and 1990s stored between 400 kilobytes to 4 megabytes (Heirloom Cloud, 2022).
Data is written and read on floppy disks via a magnetic head inside the disk drive. As the disk spins, the head hovers slightly above the surface and magnetizes or detects the magnetism of the material to read or write the binary data (Sony, 2022). Floppy disks became ubiquitous as a way to distribute software, transfer files between computers, and create backups until CDs and then USB drives largely replaced them in the late 1990s and early 2000s (Wikipedia, 2022).
Magnetic Tapes
Magnetic tape has been used for data storage and backup since the 1950s (https://en.wikipedia.org/wiki/Magnetic-tape_data_storage). It stores data as magnetic signals on plastic film and allows sequential access for recording and reading data. Magnetic tape offers very high capacities for data storage and backup. Modern tape cartridges can store up to 15 TB of compressed data, with a roadmap to up to 148 TB per cartridge (https://www.techtarget.com/searchdatabackup/definition/magnetic-tape). The linear access of tape makes it ideal for sequential data like video or genomic data, as well as for backup, archiving, and disaster recovery applications. Because of its high capacity, low cost, and reliability, magnetic tape continues to be used today alongside newer technologies like disk and flash storage.
Comparison
Hard disk drives (HDDs), floppy disks, and magnetic tapes all use magnetism for storing data, but have some key differences in capacity, speed, portability, and usage.
HDDs have very high storage capacity compared to floppy disks and tapes. Modern HDDs can store terabytes of data, while floppy disks max out at 1.44 MB and tapes at a few gigabytes per cartridge. However, HDDs are not very portable due to their physical size and need to be installed in a computer. Floppy disks and tapes are portable and can be removed/carried easily.
In terms of speed, HDDs provide much faster data access and transfer rates compared to floppies and tapes. HDDs can read/write data in milliseconds, while floppies and tapes are sequential access so reading/writing is much slower. Tapes are primarily used for archival storage and backups due to their capacity, portability, and durability.
While HDDs are common in desktop PCs and laptops, floppy disks have become obsolete for day-to-day usage. Tapes continue to be used for backups and archives where large amounts of data need to be stored at low cost. Overall, HDDs are best suited as primary storage while floppies and tapes are better for portable transfer and long-term archival respectively.
Advantages
Magnetic storage offers several key advantages, particularly in terms of storage capacity, cost efficiency, and durability. According to HelloVaiA, magnetic storage provides extremely high storage capacity at low cost per gigabyte. For instance, modern hard disk drives are able to store terabytes of data at just a few cents per gigabyte. This makes magnetic storage like HDDs a very cost-effective solution for large-scale, long-term data storage needs.
Additionally, as noted by CompSciStation, magnetic storage is nonvolatile, meaning it retains data even when power is removed. This makes it advantageous over volatile RAM storage for any data that needs to persist long-term. Magnetic tapes in particular are valued for offline, archival data storage due to their durability and longevity.
In summary, the high storage capacity, inexpensive cost per gigabyte, and nonvolatile nature of magnetic storage make it an efficient and reliable option for large-scale, offline data storage needs.
Disadvantages
Magnetic storage devices have some disadvantages compared to solid state storage. One disadvantage is that they are vulnerable to magnets, which can erase data stored on them. Strong magnets in close proximity can overwrite the magnetic orientation of the particles on the disk or tape, destroying the stored data. This vulnerability requires precautions to keep magnetic storage away from magnets.
Another downside is that magnetic storage devices are slower than solid-state devices like flash memory or SSDs. The movable heads used to read/write data are slower mechanically than accessing data electronically from solid-state chips. This makes solid-state faster for data access and transfer speeds.
Lastly, the mechanical and movable parts in magnetic storage like the platters and read/write heads have potential to break down and fail over time. Solid-state has no moving parts, making it more reliable and durable. The mechanical parts in magnetic storage have wear and tear over time, requiring replacement.
Usage in Modern Times
Despite the dominance of solid-state and cloud storage today, some magnetic storage devices are still widely used for niche purposes.
Magnetic tape remains popular for long-term data backup and archival storage. Tape has high capacity, low cost, and long durability compared to other storage media. Many companies and organizations rely on magnetic tape systems like Linear Tape-Open (LTO) drives for daily backup and disaster recovery. [1]
In contrast, usage of magnetic hard disk drives (HDDs) and floppy disks for primary data storage has rapidly declined. Most consumer desktops and laptops now use solid-state drives (SSDs) which have no moving parts and much faster read/write speeds. Solid-state storage has almost entirely replaced floppy disks. Cloud-based storage services provide abundant online capacity for home users and businesses. The portability, capacity, and speed benefits of SSDs and cloud storage have led to the phase out of magnetic HDDs and floppy disks in many applications. [2]
However, magnetic storage retains some unique advantages like high sequential read/write speeds on HDDs. Tape and HDDs remain cost-effective for high-capacity, infrequently accessed data. While the usage of magnetic devices continues to decline, they still serve vital roles in the modern data storage ecosystem.
Conclusion
In summary, the two main storage devices that use magnetics for storing data are hard disk drives and magnetic tapes. Both utilize magnetization to encode data on a spinning disk or magnetic tape. Hard disk drives have been the predominant form of computer data storage since the 1960s, though their use has declined recently in favor of solid state drives. Magnetic tapes were commonly used for backup and archiving but have been largely supplanted by cloud storage. While not as popular today, magnetic storage retains some advantages like large capacities and low cost. However, solid state drives continue displacing HDDs in most applications due to higher performance, robustness, power efficiency and size. The future of magnetic storage likely lies in cold storage and archival use cases where cost and capacity still outweigh other factors.
Going forward, magnetic storage will likely play a diminishing role in computing as solid state storage continues dominating across devices and use cases. However, magnetic drives still possess unique advantages that will sustain some ongoing usage for mass storage applications where cost and capacity are critical factors. So while no longer the primary storage medium, magnetic drives will continue serving an important archival role especially for large volume cold storage.
