HP NonStop G-Series - Manual (Page 17)

5157/5157 ACL S-Series DLT Subsystems Installation/Users Guide
Overview and Features of the 5157/5157 ACL S-series Subsystem
1-6
1.10 Embedded Diagnostics
The DLT 5157/5157 ACL tape drives have embedded
diagnostics software that tells the user when head cleaning
is required, indicates diagnostics results, and tells the
operating status. The drives have embedded data logging of
errors for failure analysis.