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Hard Disk Drives and How They Work

A hard disk drive (HDD), otherwise referred to as a hard drive, serves as the data storage device of a computer. HDDs are considered a “non-volatile” storage device, meaning that the data stored on them will not be lost when they are powered off. Since their advent in 1956 by IBM, HDDs have served as the main storage device for personal computers and servers. Recently, however, the growth of solid-state drive (SSD) technology has sought to disrupt this growth. In this blog, we will discuss how a hard disk drive works, as well as how hard disk drives and solid state drives compare to each other.

Every computer is designed to support HDD drives. For installation, the HDD is usually placed internally within the casing of the computer or system and then connected to the motherboard with either a SATA, ATA, or SCSI cable. Within the hard drive, disk platters are spun by a motor while read and write heads access or produce magnetically recorded information on the platters. The read and write head is the component of the HDD that transforms electrical currents and magnetic fields to store or read data on the drive. The speed at which HDDs can spin platters may range anywhere from 3,600 to 15,000 rotations per minute (RPM). The higher the rotation speed, the quicker the HDD is able to read and write.

Hard disk drives typically contain two motors that spin the disc and move the head to a desired position above the platter for reading and writing. With the use of a disk controller, the HDD’s read and write head can be directed by the CPU of the computer. As the average HDD nowadays has a spin speed of about 7,200 RPM, their data writing speeds may range anywhere from around 50 to 120 MB/s. For the longevity of HDD components, it is also important to note that HDDs can lose data if exposed to other magnets due to how their data is created and stored.

Unlike the magnetic data of hard drive disks, the solid-state drive utilizes flash memory to serve the same function as an HDD as a computer data storage device. While HDDs have spinning disks and moving read and write heads, the SSD has no moving parts, allowing them to have quicker read/write times and be less prone to mechanical failure. With semiconductor cells called “blocks”, data is stored with an electric charge. While this creates faster speeds, it also means that data integrity can be lost over time if the SSD is not supplied with power over longer durations of time. As most SSDs are either flash memory based or DRAM based, they have much higher reading and writing speeds, ranging from 200 to 550 MB/s. As SSDs are a much newer technology, they are currently more expensive than HDDs and max storage is usually less than that of available HDDs.

Altogether, when making a choice of which drive is best for you, it is important to think of your wants and needs for your system. The HDD has a long proven track record, is reliable, lasts a great amount of time, and holds a cheaper GB per dollar ratio. On the other hand, by utilizing semiconductor technology, solid state drives are much quicker and efficient, as well as are much less prone to mechanical failure with no moving parts. Due to their differences, if someone needs or requires top speeds and money is less of an issue, the SSD is a clear winner. Nevertheless, the HDD proves to be a perfect choice for those where speed is not a critical need and they desire great amounts of storage for a cheaper price. As time goes on, SSD technology continues to become cheaper and more powerful, slowly taking place as the data storage standard. Be that as it may, as HDD technology remains cheap and usable, it will continue to hold its place in the competition for a while longer.



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