Originally Posted by Greasemonkey
I see two possibilities for this. One is that the data was retained during the cold boot and was dropped in afterwards. The second is the DVR+ is able to scan for PSIP data while in standby, or has an intermittent state between standby and being fully on that allows it to scan for PSIP data. To test which theory is correct, I will have to wait until many/most of the channels I don't watch are showing "Unknown event", then reboot the DVR+ and shut it off immediately after rebooting. This last time I never checked the status of the channels before doing the cold boot.
Further experimentation has yielded additional data. This afternoon I checked the Guide to see what was going on. I noticed that two series of channels were displaying the dreaded "Unknown Event" message. One was the local Ion affiliate. The other was what I believe is an LP station that broadcasts Vietnamese programming on two of their subchannels. The LP station broadcasts 6 subchannels in addition to their primary channel. The Guide displays program titles for these channels, but I don't recall ever seeing program descriptions. The Ion affiliate has 4 subchannels in addition to their primary channel, and does display program descriptions in addition to the titles. But both were blank this afternoon, making it a perfect day to test some theories.
I set my DVR+ to the local Fox affiliate so that it wouldn't reboot into one of the channels I was testing. I unplugged the power cord from the back of the DVR+ and waited approximately 30 seconds before plugging it back in. As soon as I saw broadcast images I powered it down. Then the waiting began. I downloaded and ran BleachBit on my laptop, which netted me almost 3GB of reclaimed space. But after 2 hours it began wiping the free space, and when it displayed a message telling me that it had about 600 minutes remaining I killed the program and got back to science.
I hit the power button on the DVR+, and as soon as it displayed channel images I used the Guide and switched to the Ion affiliate (because it would be the one to show program descriptions), Sure enough, both titles and program descriptions had been collected and populated into the Guide. I then arrowed up the Guide to the LP station. It also had program titles for its channels, but of course no program descriptions. A quick flip through the rest of the Guide showed program titles for all the channels that usually display them.
Given that I have no reason to distrust the data, I can now draw some conclusions:
1. Since the two observed channels didn't display program titles or descriptions before the reboot, it seems clear that existing Guide data is not saved during a reboot and set back in place when it is finished.
2. That leaves the other two possibilities I mentioned in my earlier post: The DVR+ is scanning simultaneously while rebooting, or it runs a scan following a reboot.
3. While I have no proof, I tend to doubt that it is scanning during a reboot and do have one piece of evidence to support that belief. After a cold reboot I have seen channels with no program titles or descriptions in the Guide, with the same channels displaying program titles and descriptions 30 seconds later. It still could be that the DVR+ is scanning during the reboot, but doesn't finish until some time after it is completed.
4. That leaves running a scan following a reboot as the only remaining possibility. What is still unclear however, is whether the DVR+ runs this scan while in standby, or if there is an intermediate state between standby and fully on that is initiated to run a scan. Either way, it tends toward the positive regarding using a programmable timer to initiate reboots as a way to keep the Guide up to date. At some point I will probably pursue this possibility, but with Salvation coming back on Monday evening it will have to wait. I like the idea of being able to reclaim 20 recording slots and eliminating the manual recordings. But for maximum effectiveness a reboot rescan would need to be programmed on the timer to run every 6 hours. Programming it every 12 hours would replicate what I get with dummy recordings, but I still have blind spots on some channels that only provide 6 - 9 hours of Guide data.
Something else should be considered in all this. I seem to remember from past cold boots that if the DVR+ is on when the reboot is initiated, it remains on when completed. But if the DVR+ is off when the cold boot is initiated, it powers down when completed. Unfortunately, either method turns the power on for my TV during the process. I don't know if this is true for all TV's, or just mine because it is a Samsung. The DVR+ power button will frequently power on my TV when I turn on the DVR+, but it has never turned it off. The downside as it relates to the DVR+ is that if it stays on, it's going to stay on for a minimum of 4 hours because of the Power Options choices. 4 hours is the minimum, with Off, 5 hours and 6 hours being the others.
EDIT: My evening dummy recordings just finished up, so I decided to test the power question. The results are bad for me, but quite possibly great for others. I first did a cold boot from standby mode with the TV off. The DVR+ went through its routine, then promptly powered down to standby when finished. Unfortunately (for me anyway), my TV powered up as soon as the DVR+ power cord was plugged in to the unit. I then performed a warm boot with both the DVR+ and TV powered down. I had inverse results. While my TV didn't turn on during the process, the DVR+ didn't return to standby when it completed. The conclusion here is that if your TV doesn't turn on when performing a cold boot (with the DVR+ in standby), using a programmable timer is a potentially great way to keep your PSIP data up to date. I'd suggest programming it to reboot between 3 and 4 times a day. But definitely when you know you aren't going to be recording anything. The fact that my TV turns on during a cold boot pretty much kills it for me, though I might at least be able to live vicariously through the success of others.
There is also one final and disappointing conclusion. Finding out about a reboot scan just adds one more item to the list of Lost Opportunities for Channel Master. If the DVR+ can scan following a reboot, it wouldn't have been hard for CM/E* to program it to scan at set intervals, or give the user the ability to set those intervals. How much time and labor did CM waste when users complained about PSIP quality, and were told to change the Zip Code or do other things that didn't help? Maybe they didn't care, or maybe the actually wanted to herd people to the Internet guide because Rovi collected data or for some other reason. I don't know, and it's water under the bridge now. But that list of Lost Opportunities is a fairly long list, and it's really disappointing because it didn't have to end like that.