> Did you stop it via ctrl-C or how?
Hmmm... I knew there was a keyboard command, but I couldn't remember it, so I ran sudo kill (dd process #).
FYI, if DD is in the middle of a block (per its BS), particularly if it's lagging on an IO error or slow disc block (512), it won't respond immediately to ctrl-c. It may not even be easily killable in activity monitor. DD operations are kernel level and CAN block. DD will only respond to ctrl-c (as buffered) when it completes one of its blocks. (BS)
I finally just bit the bullet and let "dd" run despite both the "apparent" time issue
You should try my disk verify script posted earlier, it will give periodic progress reports. I have a more advanced version available, I'm always tweaking things like that, let me know if you want.