Hard Drives are a necessary component to any computer or smartphone. They store information long term in a way that can be accessed even after the machine turns off. That being said, this ubiquitous piece of hardware comes in a couple different forms. This will be a quick primer about Solid-State Drives (SSD for short), Hard Disk Drives, how these two things work, and their relative strengths and weaknesses.
Disk Drives are an analog method of storing data long term. They have two basic components; a disk, and an arm. The disk rotates rapidly while the arm hovers above, reading and writing information mechanically onto the disk itself.
You can think about it like an old school record player that starts with a totally smooth vinyl. You put the record into the machine, and instead of the needle playing back already existing audio, it first has to scrape the disk to create an inscription that can later be read as sound.
Rather than physically scraping the disk, Disk Drives use magnets to mark certain slots with ones and zeros (not literally the symbol one and zero, but something that’s read as a one or zero.) Since those values are physically marked on the disk, it’s able to survive the machine being turned off and on, and can even be recovered separately if the rest of the drive breaks but the disk remains intact.
Alternatively, SSDs operate entirely differently. They utilize a technology called “Flash memory,” which has no relation to the defunct software platform. Essentially, it consists of a stack of transistors whose states of activation are read by the computer to be 1’s and 0’s. Just like the Disk Drive, these 1’s and 0’s are then interpreted as information by the computer.
However, if it were just this simple, then the state of the transistors, that is whether they’re a 1 or a 0, would be lost when the computer turns off and on. That means that SSDs must also come with their own, independent battery to keep the drive alive while its parent machine is disabled.
As you can probably already tell, Disk Drives are much more stable and safe than their SSD counterparts. This is because the information is mechanically, physically inscribed into a piece of metal, so will never simply vanish if its battery dies. However, because SSDs use transistors instead of having to actually read and write a 1 or a 0, that makes them much, much faster.
Traditionally, Disk Drives have also been able to store significantly more data; however, as SSD technology has improved over the last ten years, the differences are largely negligible for most consumers. Both SSDs and Disk Drives can hold more than enough storage for normal, commercial uses.
To find out whether you want to use an SSD or a Disk Drive, you need to analyze your situation. Is having more stable, long term storage important? Or is being able to load things quickly your priority? In almost every case, having both is the best option, but if that isn’t the option, consider the strengths and weaknesses.