You are very lucky then. I cannot tell you how many posts and PM I get from people that screw up because they exit incorrectly.

I also NEVER exit the application on my 2DIN either - and never have issues. Maybe the car radios are designed in a way that they don't suffer from this problem? Hell, the way the radio comes from the factory, you CAN'T exit the application (the iGO "power button" is disabled by default!).

jtrosky wrote:Do you have any details on the head-unit you have? As asked above, is it WindowsCE-based or Android-based? What is the screen resolution? etc, etc, etc... You can force a particular screen resolution in the sys.txt file.

But we should probably take a step back and find out what we're working with here first! :-)

It's an s160 Android head unit, branded Roadnav. Part no. 991-I042. I've just noticed that the box it arrived in says the screen resolution is 1024x600, whereas the website claims it's 800x480. I have checked a few times over the last few days what the resolution was set at in the .sys folder and was it 800x480. If I get chance tomorrow I'll try changing it to 1024x600 and let you all know how it goes.

jtrosky wrote:I also NEVER exit the application on my 2DIN either - and never have issues. Maybe the car radios are designed in a way that they don't suffer from this problem? Hell, the way the radio comes from the factory, you CAN'T exit the application (the iGO "power button" is disabled by default!).

I was starting to think I was missing something obvious in the menu because I couldn't find a way of shutting it down. The normal way of closing recent apps like on my Android phone didn't seem to make a difference.

In Primo (WinCE) the exit button is in the "Navigation Menu" and in the "Extra Setting Menu" you can set it so it skips completely the Navigation Menu so you will never see it. On my old Mio and on my 2Din (WinCE) I never Exit Primo before I shut them, If there is a problem it may be in Android.

Thanks for sharing the information. It used to a problem since it interfered with the save folder but it appears now that it's OK.

I guess if the power interruption to the GPS CPU is instantaneous then there may be a problem. Most units have fairly large storage capacitors on the power input to facilitate an orderly shut down sequence and to filter ignition noises. So when you turn off the ignition, the system really doesn't shut off instantaneously. On my 2Din unit (generic Chinese), it is fully functional at least 5 seconds after I turn off the ignition.

With my Rosen 2DIN, it comes from the factory with "show_exit=0" in the sys.txt (they purposely disable the exit button). I guess it all depends on the exact head-unit and how they set it up.

Obviously, I'm not using the stock version of Primo that came with it, but I do usually disable the exit button (usless I'm testing stuff) - the ONLY time I exit the app is if I'm testing though - normally, I NEVER exit the app before turning my car off. Being that it comes with the power button disabled from the factory, I think it's safe to say that it's not needed - at least not with my specific head-unit! :-)

Maybe it does cause issues with certain head-units though - who knows...

The reason to exit iGO before you turn off the power is the OS uses write caching to extend the life of the flash disk.

It will hold data that needs to be written to disk in a cache and will write several lots in go.

If you turn off the power in the middle of a write operation you will get corruption on FAT formatted disks.

However the write operation takes milliseconds so it's unlikely to happen. What you may see is any changes to settings or added favourites etc, made just before turning off the power are lost.

Exiting iGO will force the OS to write it's pending data to disk

Maybe automotive GPS units disable write caching in order to eliminate the possibility of this issue, since the amount/frequency of data being written is so little. I mean it's just not practical or user friendly to have to specifically exit a GPS application in an automotive application. Like I said, they even specifically disable the exit button on my Rosen. If not exiting were problem-prone, they certainly wouldn't do that.

I have a feeling that there are a lot of variables that play into this, so there probably isn't a "right" answer. All depends on the specific hardware, it's design and the way it's all integrated with the application.

Interesting discussion though!

Had a quick look through the sd card today. I was convinced I'd seen the screen resolution set to 800x480 in the .sys file (which I now know would be wrong, as I've confirmed via the Roadnav website that mine Is 1024x600), but it actually says "auto" in that file. So, I'm guessing then that this won't be the cause of the problem? If I navigate to config/devices/android it does have 800x480 in the resolution bit of there, that was obviously where I'd seen it. Is it worth me copy and pasting the two files on here for somebody to look at?

Another advantage not exiting the Primo (at least with my 2Din) is that next time I start the engine the GPS starts automatically. If I exit the GPS then next time I start the engine I have to manually restart it.

Sounds like your device goes to suspend when you turn off the ignition.

Suspend is ok, as the device effectively freezes, and resumes when next turned on.

Turning off the device completely is the problem.

Unfortunately it doesn't go into suspend, I wish it was, so I didn't have to wait for the software to reload and acquire satellites each time. The GPS actually shuts down and when I restart the engine it automatically reload the GPS software. My old C320 Mio however does go into suspend so I am familiar with the difference.

Same here - my unit actually has to restart from scratch each time as well - definitely not a suspend mode with mine either.