Reliability Specifications; Read Error Rates; Bit Jitter; Media Defects - Seagate ST251R Product Manual

1.7 RELIABILITY SPECIFICATIONS
MTBF:
PM:
MTTR:
Service life:
1.7.1 READ ERROR RATES
Recoverable Read Errors:
Nonrecoverable Read Errors:
Seek Errors:
1.7.1.1 BIT JITTER
20,000 Power-on hours
(Sea level, 25°C ambient temp.)
Not required
30 minutes
5 years
1 per 10
10
bits read
1 per 10
12
bits read
1 per 10
6
seeks
Bit jitter reduction determines the relationship between the leading
edge of read data and the center of the data window.
The specified read error rates are based on the following bit jitter
specifications: the data separator must provide at least -40 dB of bit
jitter reduction at 2F with an offset error of less than 1.5 nsec. shift
from the center of the data window.
1.7.2 MEDIA DEFECTS
A media defect is a read error when the data, which has been correctly
written, cannot be recovered within 16 retries.
A printout will be provided with each drive shipped listing the locations
of any defect by head, cylinder, sector and byte. It will also specify
the number of bytes from index. For MFM this will be based on 1.6
psec.lbyte. RLL encodi ng is based on 1.056 psec.lbyte.
A single media defect may be up to 16 bits long. Cylinders 0,1,2 and
3 will be free of defects.
1-4
ST2511251 RI277R Product Manual, Rev.A