What is nominal disk size?

Nominal disk size refers to the advertised or specified capacity of a disk drive, such as a hard disk or solid-state drive, typically measured in gigabytes (GB) or terabytes (TB). This size represents the total storage space available for data, but actual usable space may be less due to factors like file system formatting, reserved space, or system files. Additionally, manufacturers may use decimal (base 10) measurements, while operating systems often display sizes in binary (base 2), leading to discrepancies in reported capacity.