Hard Disk Drives (HDD) and Solid State Drives (SSD) are both forms of data storage computing equipment. HDDs have been available for many decades while SSDs are a new, modern method of data storage. HDDs are generally less expensive and have high capacity than SSDs, but they are considered less reliable because they have moving parts such as rotating platters and a read-head. SSD’s don’t have moving parts but this makes them more expensive and since they are more modern technology capacities have not caught up to the efficiency of Hard Disk Drives.
The correct selection of storage technology really depends on your particular requirements and budget.