IBM Midrange System DS4000 Series Hardware Manual page 430

ICRC
A sampling time of around 24 hours is normally sufficient to show any errors on a degraded
drive-side loop. In some cases, the pattern of errors will begin to emerge within minutes of
resetting the baseline. If the baseline has not been reset for an extended period, then the
values might be historic rather than reflecting the current status.
ITW is the key error count to be used when analyzing the error count data. In a switched
(SOC) ESM environment, a high ITW error count is likely to indicate a problem on the
associated device.
The Read Link Status file can be saved as a comma separated file. It is included within the
Collect all Support Data bundle.
SOC Statistics File (socStatistics.csv)
While RLSD error statistics are measured at the Fibre Channel port on the actual device, that
is, the controller port, ESM port or disk, the SOC statistics are measured by the
Switch-on-Chip (SOC) chip. Therefore, interpreting the differences between the two sets of
output can be vital to accurately determine the root cause of a degraded drive-side channel.
The SOC statistics file can be generated with the following script command:
save storageSubsystem SOCCounts file="c:\socStatistics.csv";
It is also included within the Collect all Support Data bundle.
The columns displayed in the socStatistics file include:
OPM
PS
PIC
LS
LUC
CRCEC
RFDEA
LCC
OSEC
PCAC
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IBM Midrange System Storage Hardware Guide
The total number of invalid cyclic redundancy check (ICRC) errors
detected on the Fibre Channel loop from the baseline time to the
current date and time.
This is the Operating Port Mode (OPM). Valid states include
non-cascade, tree, or string.
The state of the port (PS). Valid values could be inserted, loopback,
unknown, or various bypassed states.
Port Insertion Count (PIC) is the number of times the device has been
inserted into this port.
Loop State (LS) is the condition of the loop between the SOC and
component. Possible states include up, down, or various transition
states.
Loop Up Count (LUC) is the number of times the loop has changed
from Down to Up.
CRC Error Count (CRCEC) is the number of Cyclic Redundancy
Check errors that are detected in frames.
Relative Frequency Drift Error Average (RFDEA) is the difference
between the port-received data rate and the internal clock of the SOC.
A value in the 1,000s indicates a problem device.
Loop Cycle Count (LCC) is the number of LIPs seen by the reference
port.
Ordered Set Error Count (OSEC) is the number of invalid FC transmit
words seen at the receiver of the port.
Port Connections Attempted Count (PCAC) is the number of times the
port attempted to make a connection due to ARB connection requests.