RA7x Error Rates
E.3 Loss-of-Positioner Errors
E.3 Loss-of-Positioner Errors
A loss-of-positioner error is a recoverable error attributed to a disruption or
failure of the servo position control mechanism within the drive. Loss-of-
positioner errors include:
• Write and off-track errors (drive error code 39)
• Off-track errors (drive error code 25)
• Positioner errors (drive error code E8, E9)
• Controller detected positioning errors (MSCP status/event code 6B)
E.4 Soft Errors
A soft error is any recoverable error
except
:
• Type I data errors
• Type II data and header errors
• Loss-of-positioner errors
• Any recoverable fault causing a BBR
Soft errors include ‘‘soft uncorrectable’’ data errors. These are data errors that
were first detected as uncorrectable, but with controller retry operations and/or
hardware error recovery techniques, the data was subsequently recovered.
E.5 Unrecoverable Error (Hard Data Error)
An unrecoverable error is defined as an error which results in loss of data. A
single error involves the loss of one logical block (sector) of data. These errors
cannot be corrected by ECC and the retry/error recovery sequences cannot recover
the data.
E.6 Bad Block Replacement Rate
Each block of data replaced during BBR is counted against the BBR rate.
Recoverable errors causing BBR are only counted against the BBR rate and are
not counted against any recoverable error rate.
The recoverable errors causing BBR are counted against both the BBR rate and
the unrecoverable error rate.
E.7 RA7x System Error Rates
When using an RA7x drive a combination of factors, including track density, it is
possible that the system may occasionally report recoverable disk errors in the
host error log. The rate of these errors depends upon specific applications and the
resulting I/O rates. If error rates are no more than those listed in Table E–2, the
RA7x drive is performing within specifications.
E–2 RA7x Error Rates
