Drive-filtering suggestion

After https://github.com/resin-io-modules/drivelist/issues/98 has been implemented (i.e. we can get info about all the mountpoints which are used by each physical drive), we could filter out the drive on which the image we’re going to be flashing is stored on.

Currently, this scenario is possible (which would be prevented if this issue is implemented) :

1. User has a USB Flash drive (e.g. /dev/sdb) and a USB SD-reader (e.g. /dev/sdc) connected to their computer
2. User is running out of space on their computer’s HDD, so they download e.g. 2016-09-23-raspbian-jessie-lite.zip to their USB Flash drive
3. User launches Etcher, and selects the 2016-09-23-raspbian-jessie-lite.zip file they’ve stored on their USB Flash drive
4. User accidentally selects /dev/sdb as the drive they want to flash to
5. User clicks Flash!
6. ??? (I didn’t actually try this myself to see what happens)

If this issue was fixed, /dev/sdb would automatically be filtered out (until the user selects an image not stored on their USB Flash drive), and Etcher would auto-select /dev/sdc.

[WasabiFan]

Side-note: It would be great if labels like this “locked” one explained why the device is locked. I could easily imagine a user looking at this and thinking that Etcher locked it as opposed to the device being locked by the OS/hardware. Is there a tooltip already there that serves this purpose?

[jviotti]

@konmouz What do you think of https://github.com/resin-io/etcher/pull/1066?