The solid-state drive (SSD) is another storage technology that is considered to be secondary storage. Unlike HDDs, SSDs are memory chips with no moving parts. They use less voltage (5V) than HDDs (12V for spinning the platters), are noiseless, are more physically reliable, and provide faster data access. SSDs are behind HDDs in capacity and cost. However, based on current development trends in storage technologies, things might turn in favor of SSDs over HDDs. These days, many manufacturers offer their PCs and laptops with SSD disks that hold the operating system and applications, as well as HDD disks to be used for data storage. Additionally, SSD drives are also encountered on servers, including NAS and SAN devices too.
You can learn more about SSDs at https://www.lifewire.com/solid-state-drive-833448.