What Determines the Capacity of a Hard Drive?

Hard drives are pieces of computer hardware used to store data. As sizes of hard drives steadily increase, it's important to know what factors determine the capacity of a hard drive.

Technology

Hard drives use plates made of various metals and ceramics for data storage, and the data are interpreted by manipulating magnetic signals over conductive materials to produce a 1 or a 0 that corresponds to binary.

Computer's Age

The age of a computer can determine hard drive capacity. If a computer is past a certain age, it may not support the full capacity of a new hard drive.

Rounding

Hard drive manufacturers sometimes round the data amounts for kilobytes, megabytes and gigabytes, resulting in hard drive capacities that are actually smaller than advertised.

FAT Limits

FAT (File Access Table) technology, used in older Windows computer hard drives, caps sizes at 2 terabytes.

Operating System

Without creating a manual dynamic volume, the Windows Vista operating system caps hard drive size at 2 terabytes.