From Seagate, but not specifically for Ubuntu: You can download "SeaTools" from
Seagate's web site. Nice set of diagnostics and tools. I run the
nondestructive tests once in a while, just as a health check.

You can download a .iso file and burn it to make a bootable CD. Or download the
.exe to make a bootable diskette, but you'll need a Windows PC for that.