" Critics of so-called direct recording electronic, or DRE,
voting machines, most of which employ touch screens, are
particularly concerned about the lack of a paper trail. Although
the most widely used DRE machines can at day's end print out at a
record of ballots cast, detractors say this is insufficient.
"Because of the potential for memory glitches or even possible
tampering, critics such as Neumann advocate printing a paper record
that voters can examine immediately after casting their votes.
"A second concern is the voting machine companies' proprietary
control over the software that runs on their systems. Although
companies are required to allow election authorities to inspect
their software, the code is not open source and therefore not open
to public inspection..."