N7 and USB issue(s)

[cooch17]

Greetings --

Been using my Nexus 7 tablet for 3-4 weeks now, with no major issues, except...some 'flakiness' in terms of connecting it to a PC (running, say, Windows 7 Home Premium) as a USB device. Several questions related to this theme:

1\ tablet does not show up on the PC as a USB device if I connect it when tablet is powered down. It only shows up if I connect it powered on.

q: is this normal? If so, it is the only USB-device (out of *many* I own) that needs to be 'turned on' in order to be seen/mounted by the computer

2\ if I connect when the tablet is powered on, shows up as a 'portable device', not as a USB device. I'm sure because it is a MTP device by default. Fine - easy enough to access the device, and copy various files from PC -> tablet. The issue I'm having is with 'unmounting' the tablet. Since it is not showing up as a 'typical USB device', I can't right-click and safely disconnect the tablet from the PC. In a bit of reading, it seems that all I need to do is simply unplug the table from the PC. OK, easy enought to do 'mechanically', but most of the time when I do this, the table get's 'locked up'. It's on, but the screen stops responding to anything. I can 'get the tablet back' only by doing a hard power-down (i.e., hold power-button down for 10-15 seconds).

q: again, this can't be 'normal' - what is the preferred way to disconnect the tablet from the PC? In all my years of working with a *lot* of USB devices, the N7 is the only device I have which has this little 'issue'.


Thanks much in advance...

 

[Deleted User]

It is normal that the tablet must be powered on to be seen.

Despite your impression that this is the only device that requires this, in reality, ALL devices are required to be powered on before connecting to USB. It so happens that things like flash drives or keyboards or mice are capable of being powered by the USB port itself, but for any device that is not capable of being powered by USB (anything big, that draws a lot of power), those devices absolutely must have power before the computer will recognize them.

If you plug in a printer through USB, for instance, but do not turn it on - can you print? Nope. If you plug in a scanner, or a full sized hard drive, or any other large USB peripheral, they require power first.

In RE: your second question, I simply disconnect the tablet. Mass storage transfers do some caching of file transfer, which is why you must "safely remove" them - in case data is incompletely written. MTP doesn't do that, so when it's done transferring - it's done, and you can disconnect it. I'm afraid I don't have your disconnection problem, though, so I can't help you there.

 

[cooch17]

It is normal that the tablet must be powered on to be seen.

Despite your impression that this is the only device that requires this, in reality, ALL devices are required to be powered on before connecting to USB. It so happens that things like flash drives or keyboards or mice are capable of being powered by the USB port itself, but for any device that is not capable of being powered by USB (anything big, that draws a lot of power), those devices absolutely must have power before the computer will recognize them.

If you plug in a printer through USB, for instance, but do not turn it on - can you print? Nope. If you plug in a scanner, or a full sized hard drive, or any other large USB peripheral, they require power first.

Sure, makes sense. I have a number of USB ports on my computer that are 'souped up' to out out a bit more 'juice' than normal. I guess the N7 passes the threshold beyond which the port provided sufficient power, which is probably why I didn't think of that. Thanks!

In RE: your second question, I simply disconnect the tablet. Mass storage transfers do some caching of file transfer, which is why you must "safely remove" them - in case data is incompletely written. MTP doesn't do that, so when it's done transferring - it's done, and you can disconnect it. I'm afraid I don't have your disconnection problem, though, so I can't help you there.

Actually, after *much* trial and error, it is (likely) related to a similar issue. If I've been transferring large files (so 1-2 Gb video files), and if I unplug immediately after Windows 'tells me' the transfer is complete, I get the 'hanging issue' I mentioned in my OP. If however I wait 20-30 seconds (perhaps some back-side 'cache flush' to the device), no problem.

 

[JanComputerman]

Usually the N7 asks how you want to be mounted usb storage or charging only and also informs you to unmount it before you disconnect it first from pc and second from the N7. Make sure that other programs are not trying to access it when you want trying to disconnect. This would include anti virus programs.

 

[cooch17]

Usually the N7 asks how you want to be mounted usb storage or charging only and also informs you to unmount it before you disconnect it first from pc and second from the N7.

...which would imply that it was set up as an MSC device, which it isn't (by default, and I see no way to turn it into one).

I've never had the N7 'ask' me if its 'charge only, or mount'. I do have other Android-based devices ask me (e.g., my little Archos 32), but not the N7.

Make sure that other programs are not trying to access it when you want trying to disconnect. This would include anti virus programs.

Worth a try.

 

[rootbrain]

I'm having some storage mount issues depending on which device. I have a 16GB microSD that goes into an SD adapter, which I put into a USB adapter. When I plug it in, stickmount launces and gives it the /sdcard/usbstorage/sda mount point. But when I copy files, of any size, and then unplug the device, the mountpoint is still on the N7, with the files, and there are NO FILES ON THE DEVICE?

I'm stumped. Also when I connect a 180gb myPassport WD portable drive, there are some directories that show up but root explorer (3 different ones) will not let me open some directories, basically thinking they are emply. I know they are not because I look at them on the PC.

 

[cooch17]

...which would imply that it was set up as an MSC device, which it isn't (by default, and I see no way to turn it into one).

Moreover, if it has to be turned on to be detected by the PC, then it is clear that you can't choose between 'charge' and 'mount'.

 

[JanComputerman]

...which would imply that it was set up as an MSC device, which it isn't (by default, and I see no way to turn it into one).

I've never had the N7 'ask' me if its 'charge only, or mount'. I do have other Android-based devices ask me (e.g., my little Archos 32), but not the N7.



Worth a try.

Oops yeah was thinking of my Archos43 but there is a setting for media or camera mode if you pull down the status menu. The important thing is to not unplug it too soon after transferring files to the N7 because it does take a little while for it to be written to the flash memory.