dd won't create an image of a floppy

[Reed Scarce]

Thanks for your work,

I wish to use the Cygwin dd command to read the contents of a floppy and
output an image file.

The command...  dd if=a: of=floppy1 ... yeilds the common result of my
various attempts, i.e. 'a: is a directory'

Is this a bug or am I looking at it the wrong way.

Thank you,
Reed Scarce