I'm trying to follow intructions found here (http://www.jeremymorgan.com/tutorials/raspberry-pi/how-to-raspberry-pi-file-server/) on how to set up a file server with the Raspberry pi, but cannot mount my drive. The error I get is cannot find /dev/sda1. When I look into /dev, I see that I have no folders /DEV/SDA. Why is that and how can I create them?
lsusb and see if you see the device listed. Do not bother with mknod, if udev does not create the node you won't be able to.
As mentioned in my comment, do not plug the device into the pi after boot. Plug it in before you power up or use a hub.
I had the same problem, nod /sda or sdb or anything. It was a USB 3.0 and the raspberry pi was seeing it but not able to access it. I changed it to USB 2.0 and worked perfectly fine