Safe to Remove? USB devices

bozotheclown138 · Post by **bozotheclown138** » 27 Sep 2009, 23:15

Yes, let the light on is a new feature of Vista, probably
part of the 'Wow effect', as 'Wow, it's save to remove
while the light is still on'.

this is what i hear from google

Post by **bad_brain** » 28 Sep 2009, 07:07

hm, well, it's generally better to "safely remove" it.....I have to admit I also almost never do it, but 2 times files I had transfered to the USB device disappeared after simply unplugging it, but of course I don't really now if the "nonsafe" removal was really the reason.

as long as the LED is on there is power on the device, unplugging it in that state can (at least in theory) cause electric sparks which always also cause an electromagnetic field....which might corrupt stored data (again, at least in theory).

Post by **floodhound2** » 28 Sep 2009, 07:54

USB devices are hot swappable - meaning unplug and plug at will. No damage will happen.

Wiki puts it like this

The connector construction always ensures that the external sheath on the plug makes contact with its counterpart in the receptacle before any of the four connectors within make electrical contact. The external metallic sheath is typically connected to system ground, thus dissipating any potentially damaging static charges (rather than via delicate electronic components). This enclosure design also means that there is a (moderate) degree of protection from electromagnetic interference afforded to the USB signal while it travels through the mated connector pair (this is the only location when the otherwise twisted data pair must travel a distance in parallel). In addition, because of the required sizes of the power and common connections, they are made after the system ground but before the data connections. This type of staged make-break timing allows for electrically safe hot-swapping and has long been common practice in the design of connectors in the aerospace industry.

Post by **DNR** » 28 Sep 2009, 08:36

P4 I noticed the same thing - on my XP laptop - and desktop - I use the "safely Remove" right click option to shut down the USB stick. It also has a light on it too - when you shut down the stick on XP, the light goes off and the icon is gone. On Vista - the icon goes away, but the light is still on the stick!

Now, I still have those warnings in my head about shutting down anything plugged in the USB ports before removing them. My USB modem, the manual tells me to shut off the power to the device before removing it. I have seen the same warning for USB sticks. Floodie is right about the technical aspect of the USB port - the metal box the stick plugs into, as long as the usb stick is in contact with that - the metal will absorb the stray electrical charge as it is the ground.

Bad news about Vista? I run both - a USB memory stick and a USB modem (another port). If you shutdown the USB stick - you can get a BSOD. SO the work around I have is to shut down the laptop then remove the stick (I didnt try shutting down the USB modem, then the stick)

I just don't like to take the risk of damaging my sticks or the data on them.

DNR

Post by **lilrofl** » 28 Sep 2009, 16:02

Like previously mentioned I very rarely safely remove my USB devices, and I very rarely have problems with currupted data, but it has happened a few times. One of note, I disconnected a 250GB external hard drive, and the next time I plugged it in all of my data was gone.

I recovered it like you would any other media, but it made me think a bit. I'm not sure if unsafely removing the device caused the corruption, or if it was some other reason. A friend of mine told me that safe removal just stops data transfer so that you don't corrupt transitioning data... son't know how accurate it is, but it's a thought.

I have never had USB stick trouble by unsafely removing one, however after an unsafe removal my linux machine wouldn't mount the drive saing I had an active unsupported file system. A problem that was solved by reconnecting it to Windows and safely removing it.

Hope this babble helps.

Post by **ph0bYx** » 28 Sep 2009, 18:12

There is an option for quick removal:

I've been using it for quite a while now (disconnecting USB without safe removal) and haven't experienced any problems. Although it's only a 1GB USB stick where I rarely store anything important enough to safely remove it before disconnecting, while on the other hand I've always used the safe removal tool for my external HDD, don't know if it makes any difference but can't be to careful, I'd hate the data to get lost.

Oh, and I had / am having the same problem with Linux (not mounting quickly removed USB, although only the external, not the stick, must be because of that quick removal option I think.)

IceDane · Post by **IceDane** » 30 Sep 2009, 05:15

FYI, you can mount disks that need to be "safely removed" in Windows, in Linux without going into windows to "safely remove them." There is an option for mount that forces linux to mount it(It really doesn't do any damage as far as I can see). Don't remember what it is exactly, just man it.