I tried to install calibre using synaptic but
it failed. I ran "dpkg ---configure -a" to fix problem. oddly, I get the error

dpkg: failed to write status record about "maxima" to '/var/lib/dpkg/status': No space left on device

When I do a df it appears that there is plenty of space.
So my question is, as I'm concerned about removing files that should
not be touched, where are some good places to look to
remove files to clear space for this installation?