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1.2.4
Reliability
(1)
MTBF
MTBF is defined as follows.
MTBF
=
operating time/the number of equipment failures
Operating time is the entire time at which the power is ON except during
maintenance work. Failure of the unit means trouble that requires, either
repairs, adjustments, or a replacement. Mishandling by the operator, power
failure, control unit problems, cable problems and failure due to unsuitable
environment are not included.
The MTBF of the M2301/M2302 shall exceed 10,000 hours (engineering
specification).
(2)
MTTR
MTTR is the average time a well-trained service technician should take to
diagnose and correct a failure to the sub-assembly level. The M2301/M2302 is
designed for a MTTR of 30 minutes or less.
(3)
Component Life
The M2301/M2302 need not be overhauled for the first five years.
(4)
Power Loss
Integrity of the data on the disk is guaranteed against all forms of abnormal DC
power loss. However, if the power failure occurs during a WR ITE operation,
the data is not guaranteed.
(5)
Error Rate
An error detected during initialization, and processed to be replaced by a spare
record is not included in the error rate.
(a)
Recoverable Error Rate
An error which is recoverable with one try of the RETRY command
should not exceed once per 10
10
bits read.
(b)
Non Recoverable Error Rate
Errors that cannot be recovered within 16 retries are included in the
MTBF.
(c)
Positioning Error Rate
The rate of positioning errors recoverable by one retry is one error or less
per 1 0
6
seeks.
(d)
Media Error
B03P-4605-0003A .... B
i) No error will be found at HO and Hl in cylinder 000 .
. ii) The following shows the number of defective spots in the M2301/
M2302.
M2301 B ..... Less than 10
M2302B ..... Less than 20
1-7
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