It can copy a floppy on the fly, or by using archives with IMG file extension that store the content of the disk with a proprietary file format (whose first three bytes noted in hexadecimal will be FF 18, and its size will be anything[clarify]).
HD represents high density (floppy disks with capacity greater than 1.2 MB).
In the early 90s, when floppy diskettes for PCs were widely used, HDCopy was extremely popular in many places.
Its usage started to decline as floppy disks became less widely used.
The program can handle a large variety of non-standard formats and in many cases automatically recover bad sectors.