Quantum DLT 2000 Handbook page 138

last week's backups off-site, so that would mean a total of investment
of 20 DLTtape cartridges.
Archiving data presents a very different need. When you are con-
suming tapes on an ongoing basis, rather than rotating the same
tapes through the system, media costs are higher. This is another
case in which the high capacity DLTtape cartridges are more eco-
nomical than lower capacity cassettes.
In fact, the difference in cost over the long run can be dramatic.
One customer who uses both 4mm and the DLTtape system
describes going through as many as 100 4mm cartridges each week
to keep up with an archiving requirement. Using DLTtape car-
tridges would require many fewer cartridges, and would also cost
less, in spite of the big difference in unit cost.
Compatibility Can Save Money
When you are looking at media costs, you can't overlook the eco-
nomic impact of media compatibility. Or, to put it another way,
the high cost of incompatibility. As we discuss elsewhere in this
handbook, media incompatibility is a significant problem for users
of some tape technologies. You can't simply jump from one tech-
nology to another without a great deal of pain, and, even within
what look like related technologies, there are often critical incom-
patibility issues from one generation to the next.
DLTtape technology is the notable exception. Over the years, Quantum
has made a strong commitment to preserving its customers' invest-
ments in media and drives by maintaining a high level of compatibili-
ty across generations of DLTtape media and drives. One most com-
pelling example is the DLTtape IV media cartridge. DLTtape IV
cartridges run on the DLT1, DLT 4000, DLT 7000, and DLT 8000
drives, and are read-compatible with Super DLTtape drives. Thus,
this single cartridge can be used in a very high percentage of all the
12.4 EVALUATING THE COST OF A DLTtape BACKUP SOLUTION