I was trying to copy an iso of the windows installer onto a hard drive to avoid burning a disk. I first tried Disk Utility's restore function, however it didn't like the ISO for some reason. Then I tried using dd:
dd if=/path/to/image.iso of=/dev/disk3
I realized it was copying the file at a snail's pace, about 160 KB/sec. I rebooted into my linux installation and ran the command again, almost verbatim:
dd if=/path/to/image.iso of=/dev/sdc
This time the command executed in under a minute, with an average speed of 57 MB/sec. In both cases the source and destination were the same physical hard drives. What's going on?
I am running OSX 10.7.3 and Linux 2.6.38-13.