These days, the removable media you’ll most likely deal with are external hard drives, flash drives, and CDs. The CD is the simplest, because you know how to use
umount(8), and you know its device node and filesystem type will always be the same. But how do you identify the device name of a removable hard drive?
When you attach a drive to your machine, OpenBSD automatically assigns your drive a device node to your console and prints a message to the console. You can check the console as you attach the drive, or you can watch your messages log by running
tail -f /var/log/messages before attaching the drive.
If you frequently use a particular removable disk, you can simplify your routine by making an /etc/fstab entry ...