Understanding the Smart Card storage?

Good morning - last week I received my Encore Viewer software and have been successful reading my smart card.
I did, on several occassions, take a nap, read the card and re-insert it in the machine.
How is a "session" defined?
If I take a nap at 4PM, then sleep from 9PM to 5AM am I taking up two
"sessions"?
Assuming I use the machine and fill up the card; will old sessions be removed from the front and new data added to the end?
- Mike

Session is determined by how long a period exists between usgage ... I don't know tha exact amount of time but I have awaken to let the dogs out and do stuff in the morning and then gone back to sleep an hour later and it remains as one session.

I wouldn't worry about filling up the card ... holds a year or more of data. When it does fill, it begins to overwrite the oldest data ... I think Den (Wulfman) has determined how many days of data the card holds.

You should have a spare card anyway just in case the one you have becoems corrupted.

Thanks -
yesterday's nap wasn't recorded and last night's sleep wasn't either; I've read in the Forum about missing data and was wondering if this is what I' m seeing (or not seeing) - Mike

I have never lost any data on my M series but I have seen it reported here on the forum fairly common

There are some variations in the amount of data a card will hold. However, generally speaking, it holds around 320 days/nights of compliance information. Assuming there are no "nights off" (non-collected detail data) or days with multiple sessions, there should be 7 days/nights of detailed data (most current 7 days). The oldest detailed data then rolls into compliance and if you continue to use that card in in the machine, the oldest compliance rolls off of it at the point when it's reached the 300+ limit. In other words, it won't "fill up".

If there is more than a 60-minute break in the time the machine is turned off, it starts a new "session" (and chart).

By default, the "day" runs from noon on the first day to noon on the next day.


Den

For Respironics M series when the unit is running, if power is cut externally (pull the cord from the wall, turn of an extension strip into which the unit is plugged, ..) then there would be data loss. This repeatable behaviour here.