Exabyte EXB-8505 8mm - Manual (Page 99)

Reliability Specifications
This section lists the reliability specifications for the tape drive.
Service Life
The tape drive has been designed to exceed a useful service life of five
years, during which time all performance and reliability specifications
are applicable.
Machine Reliability: Mean Time Between Failures
(MTBF)
The mean time between failures (MTBF) value for the EXB-8205,
EXB-8205XL, EXB-8505, and EXB-8505XL is 160,000 power-on hours.
The MTBF value for the tape drive is defined as follows:
MTBF =
Total Power-on Hours
Number of Relevant Equipment Failures
where:
Total Power-on Hours is the total time the tape drive is drawing
current from the input power supply system.
Relevant Equipment Failures are those failures that cannot be
corrected by the operating personnel and require the intervention
of maintenance personnel.
May 1994 EXB-8205 and EXB-8505 6-7
(Standard and XL)
6 Functional Specifications