CygwinでCD-ROMをdd出来ない

$ dd if=/dev/scd0 of=hoge.iso
dd: opening `/dev/scd0': Invalid request code

$ cat /dev/scd0 >hoge.iso
cat: /dev/scd0: Invalid request code

$ dd if=//./h: of=hoge.iso
dd: opening `//./h:': No such host or network path

• http://kinshachi.ddo.jp/kurage/html/MT/comp/archives/000713.html
• http://blog.so-net.ne.jp/janus/2005-03-22