$ drutil status
Vendor Product Rev
MATSHITA DVD-R UJ-8A8 HB14
Type: DVD-R Name: /dev/disk1
Sessions: 1 Tracks: 1
Overwritable: 00:00:00 blocks: 0 / 0.00MB / 0.00MiB
Space Free: 00:00:00 blocks: 0 / 0.00MB / 0.00MiB
Space Used: 411:49:41 blocks: 1853216 / 3.80GB / 3.53GiB
Writability:
Book Type: DVD-R (v5)
Media ID: CMC MAG. AM3
找到光盘的设备名/dev/disk1
卸载设备（为啥要卸载？linux下不用啊）：
$ diskutil unmountDisk /dev/disk1
最后就是用dd拷贝了：
dd if=/dev/disk1 of=~/iso.iso bs=2048k