Turns out - having a swapfile and plugging the usb cable into the pc leads to this:

The device does NOT crash, like people said before.

The PC doesn't notice any difference, and treats the MMC as usual, but after unplugging you'll see that nothin can be written/removed from it.

Just wanted to share... Any ideas on why it may be so?

Were you stressing the memory at all on the Nokia 770? If you weren't actually using any of the swap space on the swap file, you could get away with unplugging the swap without crashing the system, until the kernel decided it wanted to use swap, in which case it might crash. Heck, even if you were using some of the swap space, you might still survive until you actually performed an action on the 770 that caused a swap read or write.

True... wasn't doing virtually anything... The work was done on the computer... I was just surprised, and wanted to bring it up here... Any ideas as to why the device became "read-only"? ("" because it seems like I could write to it from the pc, but not from the nokia)

This depends on how you have your swap configured, you can continue to safely use your 770 as a flash drive as long as you partition things intelligently. See the instructions for extending your root filesystem for the "best practice" in setting up swap and lots of other stuff.

If you fail to partition properly, you may not crash the 770 immediately but you can see erratic behavior up to and including crashes. As to what happened in your particular case, you'd need to examine the state of the kernel from a memory dump to know for sure... or partition your 770 safely and sleep soundly knowing that it won't be an issue again.

Mike