How to write protect an USB pen drive ?

Forum: Other Help Topics
Topic: How to write protect an USB pen drive ?
started by: Key

Posted by Key on Mar. 18 2006,22:34

Is there an easy way to do this in DSL?
Maybe also, that you can choose the partiton, which you want to write protect?

I'm thinking about something like the "mount/unmount" - button, but with an unmounted drive, you can't read from it, right?

So is there any possibility to choose by your own, when you will allow the USB pen to write/change data?

What about the automatically generated backup-file? Will the system crash when the media is write protected?

I would like to have the complete control on the USB pen.

Posted by faroutscience on Mar. 19 2006,00:36

I have a 128MB Lexar Jump Drive. It has a small switch on the side that write protects the module.

Otherwise, I would go in as root and change the premissions to the desired state : user group other, rwx (read write execute) or not for each group per directory / file.

Jeff

Posted by Key on Mar. 19 2006,06:07

Thanks Jeff.

I read now, that TwinMos USB drives have such a mechanical switch as well. Costs around 20 Euros for 256 MB, no real big investment required

But however, what happens to the system when this USB drive is mechanical write protected and the automatic backup function of DSL wants to save the latest changes? Will there be an error? What will the system do then?

Unfortunately, I don't have any experience with adding different users and creating a password login. The system is only used by myself. Nevertheless, would there be an additional protection in an internet connected system, if you log in as user with reduced rights? I read somewhere, that in worst case, the drive can be erased by an executed command from an internet application. Can such things be prevented with installing special users with limited rights? Don't know what the standard booted system offers on rights. For special commands, you have to do a sudo but this is all I know on this yet. As which kind of user are I'm logged-in in a standard booted usb pen-drive installation?

Posted by faroutscience on Mar. 20 2006,02:22

I just ran DSL 2.2 with my Lexar 128MB key write protected by the switch.

DSL loaded and ran pretty much as expected. It did complain a couple of times about read/write errors but did run. I am able to surf the internet, play chess with eboard and do everything else that doesn't require writing to the key.

If you can mount and save data and files to something else such as a hard drive partition or floppy, you should be able to make it work.

When shutting down you do get errors when DSL tries to write backup files to the key. It still starts back up as originally configured before the write protect.

I guess with the key in write protect mode it is very similar to using a livecd version.

Jeff

Posted by Key on April 16 2006,17:55

@faroutscience @all, with write-protectable USB-pens.

I have a problem with my write protectable TwinMOS USB-pen. When I boot from an ordinary floppydisk first and in connection second from the write-protected USB-pen, the boot fails. If the USB-pen is write enabled, everything works fine.

Please finde more at:

< http://damnsmalllinux.org/cgi-bin....t=12689 >

Can you check this as well?
I don't understand where the problem is and how to solve it.

Thank you