An Express version is also available. This software runs on Windows servers and will backup both MacOS and Windows clients. Veritas also offers solutions for larger network environments. There are many other sites with good information that can be found with a quick trip through a search engine. Newsgroups can also be a good source of information.
Capacity is measured in units called bits, bytes, kilobytes, megabytes, gigabytes and terabytes.
All digital information is described as a string of ones and zeros called bits. Also see Hardware Compression and Software Compression. The duty cycle portion of an MTBF rating is the percentage of the time the unit is in use. The higher the duty cycle percentage, the greater number of hours of use. The Quantum web site covers MTBF and duty cycle more thoroughly.