Ioedc During Write/Read Commands; Commands - Seagate ST3750641NS Product Manual

4.3.3

IOEDC during Write/Read commands

IOEDC during Write Commands
• IOEDC is checked when data is transferred from: A) FIFO to Buffer, B) FIFO to Disk, during the write operation.
• For A), Attribute 199 is incremented, no Critical Event Log entry is made, no ATA Error is returned, attribute 184
increments signaling a IOEDC error occurred and 51/84 (CRC Error) is reported to the host.
• For B), non-cached writes reports 51/10 (ID Not Found) to the host. Cached writes can only post an error to the host if a
Flush Cache Extended command is issued reporting a 51/04 with error location in Extended Task File, Critical Event is
logged and attribute 184 which counts IOEDC errors is incremented.
• If IOEDC is triggered during the transfer from FIFO to disc, the data will be re-transferred from buffer up to disc 4 times.
If IOEDC still fails the drive will write uncorrectable data to Media. When a subsequent read is issued to this located a
hard error (uncorrectable) will be returned to the host, not unnecessarily failing IOEDC, causing a host level retry.
IOEDC during Read Commands
• IOEDC is checked when data is transferred from : C) Buffer to FIFO and D) FIFO to Host Controller Interface, during the
read operation.
• For C and D), the drive will report 51/84 (Interface CRC Error), no Critical Event entry is made, SMART attributes 199
(CRC Error) and 184 (IOEDC error counter) will be incremented.
• IOEDC cannot be checked during the data transfer from disc to buffer during a read because the data sent to buffer is
not ECC-corrected. Thus the two bytes of IOEDC parity data are not available until all the data is in the buffer.
4.3.4 S.M.A.R.T. commands
S.M.A.R.T. provides near-term failure prediction for disc drives. When S.M.A.R.T. is enabled, the drive moni-
tors predetermined drive attributes that are susceptible to degradation over time. If self-monitoring determines
that a failure is likely, S.M.A.R.T. makes a status report available to the host. Not all failures are predictable.
S.M.A.R.T. predictability is limited to the attributes the drive can monitor. For more information on S.M.A.R.T.
commands and implementation, see the Draft ATA-5 Standard.
SeaTools diagnostic software activates a built-in drive self-test (DST S.M.A.R.T. command for D4
nates unnecessary drive returns. The diagnostic software ships with all new drives and is also available at:
http://seatools.seagate.com.
This drive is shipped with S.M.A.R.T. features disabled. You must have a recent BIOS or software package that
supports S.M.A.R.T. to enable this feature. The table below shows the S.M.A.R.T. command codes that the
drive uses.
Table 12: S.M.A.R.T. commands
Code in features register
D0
H
D2
H
D3
H
D4
H
D5
H
D6
H
D8
H
D9
H
DA
H
Note. If an appropriate code is not written to the Features Register, the command is aborted and 0x 04
(abort) is written to the Error register.
Barracuda ES+ Serial ATA Product Manual, Rev. B
S.M.A.R.T. command
S.M.A.R.T. Read Data
S.M.A.R.T. Enable/Disable Attribute Autosave
S.M.A.R.T. Save Attribute Values
S.M.A.R.T. Execute Off-line Immediate (runs DST)
S.M.A.R.T. Read Log Sector
S.M.A.R.T. Write Log Sector
S.M.A.R.T. Enable Operations
S.M.A.R.T. Disable Operations
S.M.A.R.T. Return Status
) that elimi-
H
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