(08-02-2014, 08:57 PM)justMongo Wrote:
(08-02-2014, 08:24 PM)PaytonA Wrote: ... I guess it is probably the flow rate data that makes the larger file
I would assume so.
I am wondering if instead of discard, I should be clicking overwrite when DL'ing for the SD card.
The S9 VPAP machines record two "High Rate" (20 samples per second, I think) data streams ("Flow" and "High Rate Pressure", plus the other slower (1 or 2 samples per second, I think) data streams.
My computer is down for repair these days, so I can't check how large my downloaded files are in ResScan.
I don't know how much data is needed for each sample, but it is likely that at least several bytes of data is used per sample, especially if the data contains time stamps and other identifiers for each sample.
If the data format per sample required 32 bytes, for example, this would result in large data files, and the file size for a 10 hour session would be:
32 bytes/sample times 20 samples/sec times 3600 sec/hour times 10 hrs , or about 23MB per 10 hr "High Rate" file, which would be about the same as the largest size file you mentioned.
I think the size of the files downloaded for a night would not be affected by selecting Overwrite versus Discard. If I wanted to find out, I would create a new or dummy patient and experiment as a new patient, so I would not risk losing any of my previously downloaded high rate data.
I have intermittently lost high rate data from my ResScan Patient folder by selecting Overwrite instead of Discard. I say "intermittently" because sometimes data is lost but other times it is not. A few months ago, using ResScan 4.1 or 4.2, I mistakenly selected Overwrite and did not notice any data missing from previous weeks or months, but I did lose most of my previously downloaded detailed data (or maybe just high rate data) when I selected Discard a year or two ago.
Within the past couple months at least one forum member has reported losing some previously downloaded data when Overwrite was selected. So I will continue to select only Discard.