Safely remove an USB device... but why?

[leSLIe]

Since the beginning of the usb memory sticks i've been removing them without prior deactivation, (e.g. via the green arrow in windows) and i never had any problems, no data loss, no fried memory, i''ve even used that method on USB HDs. I only make sure no data is being read or written at the time i do that.

But when my friends use my PC or when i use some other PC, and insert their USB memory sticks, i also remove them just like that, and they keep telling me that that is not the "correct" way to do it, and well that really annoys me , some even said that by doing so they have ruined their USB memory sticks. I think they buy poor quality cheap stuff.

Anyways, could someone tell me an educated version of why or why not is it safe to remove USB Memory sticks without "properly" deactivation?

 

[SmokeRngs]

You can corrupt the data or even fry it, that's why. Do you think all the major OSes have a "safely remove" option just to make it look pretty? There's a reason for it being there. If you haven't messed anything up yet, then you're lucky.

You can't always tell when something has been completely written or read from the device. In some instances, the data will not be immediately written to the device. This will not happen until the device has begun being removed from they system via software and the safely remove command. Part of it depends on the OS you run and part of it depends on the settings in the OS.

I prefer not to take chances. I like keeping a piece of hardware working for a good long time.

 

[MooCow]

Of the hundreds of times of just pulling the plug on my USB drives, I only had memory corruption happen to me once. So yes it does happen. Should you keep a backup of all your USB data locally? Yes....

I only use mine to store trivial shit. So if you're working on a college paper, I suggest emailing it to yourself, or some off site storage, or perhaps using logmein.com. Your USB stick is not the safest place to store data.

 

[leSLIe]

You can corrupt the data or even fry it, that's why. Do you think all the major OSes have a "safely remove" option just to make it look pretty? There's a reason for it being there. If you haven't messed anything up yet, then you're lucky.

indeed there is a reason, that is exactly what i want to know
what i was looking is an answer from the electronic point of view, since these devices are NAND flash memory

well what i do know is that when u are running your memory sticks with the option of disk cache, then yes, you should use the remove safely option

 

[phaelinx]

Here's the reason.. XP is coded to make data transfer look fast.. Microsoft has admitted to this.. while you do a copy, the popup appears and then closes, but the transfer still happens in the background..

The reason why Vista appears so slow to copy data, is because MS admitted to doing the little trick in XP, but left it out of Vista.. so the reason Vista appears so slow, is because it copies the data as it's being actually copied, rather than cached and done in the background.

So, if you do data transfers with the USB then immediately yank it, you run the risk of losing the data that's in the cached memory.

 

[squares]

Oh wow that's interesting to hear, nice tidbit of info about xp, next time i'll wait a little longer before pulling out the usb.

 

[swatbat]

You can corrupt the data or even fry it, that's why. Do you think all the major OSes have a "safely remove" option just to make it look pretty? There's a reason for it being there. If you haven't messed anything up yet, then you're lucky.

What he said.

I've delt with at least 75 usb sticks when I was in retail where I had to try to recover data off them. Happens more then people think.

I've had 1 or 2 get messed up on me where for not doing it as well. Usualy on a screwed up system where it wasn't responding right. I never keep important data on a usb stick anyway. Always have a backup.

 

[phongus]

so that it doesn't corrupt the data. happens with ipods but mostly flash drives in my case i never had a problem with just pulling it in and out.

 

[bexamous]

Yea no one believed me at work about this so we tried it out... you can get corruption if you unplug it immediately after the copy dialog closes. If you wait at all we couldn't get corruption. The time is probably dependent on how fast the OS can write to the USB key... 1.1 might be more likely to fail than 2.0.... anyways not sure about that.

Also because its not been brought up:
"some even said that by doing so they have ruined their USB memory sticks"
Data corruption is the main problem, physical damage is not possible. Thats a physical propery of the usb connector. No matter how fast you yank out the USB key the ground will always be disconnected last.

We also have the same arguement at work over sata drives... claims are that you need a backplane to hotswap sata, or you need a controller that supports it to hotswap... I agree with netiehr. The grounds are slightly longer in the sata connector... therefore you can't physically damage the drive or controller. If hotswap isn't supported by the controller mabe it'll screw up or the driver in the OS will give some errors but physical daamge isn't a possibility.



And for the record, I've never damaged a IDE cdrom drive hotwapping them .... I never mean to do it but its happened a number of times... never broke anything. Even functioned under linux after plugging it in a couple times, no reboot needed. But yeah I can see how this could cause damage.

Anyways.

 

[leSLIe]

We also have the same arguement at work over sata drives...

if i remember correctly sata drives were designed to be hot swappable

Data corruption is the main problem, physical damage is not possible. Thats a physical propery of the usb connector. No matter how fast you yank out the USB key the ground will always be disconnected last.
.

that is what i wanted to know, indeed data corruption is likely to happen, but in the end your memory stick would not be damaged.

 

[sed8em]

I've used about 4 different USB memory key stick things, and of the hundreds of times I've written and read to them, I almost always rip it out of the USB slot after putting something on it in XP Pro SP2, and have never once last data or had a corrupted file result. YMMV I guess.
The files have ranged from mp3s to avi 700mb videos to office documents for school work.

 

[illuminate]

Here's the reason.. XP is coded to make data transfer look fast.. Microsoft has admitted to this.. while you do a copy, the popup appears and then closes, but the transfer still happens in the background..

The reason why Vista appears so slow to copy data, is because MS admitted to doing the little trick in XP, but left it out of Vista.. so the reason Vista appears so slow, is because it copies the data as it's being actually copied, rather than cached and done in the background.

So, if you do data transfers with the USB then immediately yank it, you run the risk of losing the data that's in the cached memory.

DO you have a link where i can read about it?

 

[somename]

Here's the reason.. XP is coded to make data transfer look fast.. Microsoft has admitted to this.. while you do a copy, the popup appears and then closes, but the transfer still happens in the background..

The reason why Vista appears so slow to copy data, is because MS admitted to doing the little trick in XP, but left it out of Vista.. so the reason Vista appears so slow, is because it copies the data as it's being actually copied, rather than cached and done in the background.

So, if you do data transfers with the USB then immediately yank it, you run the risk of losing the data that's in the cached memory.

Are you talking about write caching? If so, you can disable it per drives.

 

[leSLIe]

Are you talking about write caching? If so, you can disable it per drives.

no, i don't think he meant that, but yes u can disable the caching on the properties tab

 

[alphanumeric]

In the Windows XP device manager under disk drives select your USB drive and under policies you can select optimize for quick removal. This disables the write cache for the drive and you don't have to use the safe removal icon.