File_field original filename

Assume for I have a field on my form as follows:

<%= file_field ( “drawing”, “drawing” ) %>

the form has multipart set and the upload is occurring. I’m trying to
retrieve the original filename. Reading the documentation in "How to
upload Files, it appears that

<%= drawing[‘drawing’] %>

Would display the original filename. I don’t get anything from this,
however, so obviously I’m misreading something.
params[:drawing][:drawing] correctly has the file name uploaded, but I
also need to know something about the file on the user’s machine.

What am I missing? How do I find the original filenname?

thanks in advance
—Michael