Humidifiers

[Don Holmgren]

Another obscure reason for controlling the humidity of machine rooms is
that tape drives usually have RH specifications that should be honored.  
We found out about this on an experiment at a telescope at 10,000 feet
in New Mexico, where the humidity is usually very low.  DLT tape
cartridges have an RH specification of 20-80%.  The explanation from
Quantum was that the tape substrate takes up or releases moisture and
changes thickness.  Since high performance tape drives "fly" the tape
over the head (there's an air bearing), the thickness of the tape makes
a difference in error rate and also the life of the tape head.  Or so we
were led to believe.

Don Holmgren
Fermilab