Force usb drive to /dev/sdb1 ?

[Gene Smith]

I have a permanently connected usb hard drive for backups and it is 
typically at /dev/sdb1. However, if I have other usb devices, such as a 
SD card reader connected at boot, the backup drive moves to /dev/sdb2. I 
do the backup by having cron run a script which mounts /dev/sdb1 and it 
fails when the backup devices is at /dev/sdb2 (or it might mount the 
card reader instead).

Is there a way to ensure that the backup usb drive is *always* /dev/sdb1 
even when other usb devices are attached during boot?

Thanks,
-gene