DASDRESP question

Document ID : KB000125040
Last Modified Date : 22/01/2019
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Question:
We have a question about DASDRESP that we couldn't find the answer on the manuals:
We have the MVS-DEVICES scheduled every 15 minutes;
Does the data shown on DASDRESP represent the average of those 15 mintues or a snapshot every 15 minutes.
If it's a snapshot, it's for how long? 
Answer:
The data in DASDRESP is coming from the CMB (Channel Measurement Block).
For each DASD device, the CMB contains a cumulative SSCH+RSCH count, a Sample count, Connect time, Pending time, Disconnect time, and Control-Unit Queueing time (all times are in 128-micro seconds).
Our MVS data collector obtains the CMB data roughly every 30 seconds and then takes the delta for each of these fields.
The SSCHSamp and SSCHCnt fields show the delta values
The time fields are converted to seconds, then averaged out using the interval length.
The interval is roughly 60 seconds and will usually contain two samples per interval.
So the times shown are the averages over the interval.