Ejecting usb drives without warning?

Discussion in 'macOS' started by EmbraceNext, May 17, 2011.

  1. EmbraceNext macrumors member

    Joined:
    Aug 17, 2007
    #1
    I am sorry if this has been talked about before.

    I really don't understand why this still happens. Is there a way to get rid of this warning or something. I have a script that I want to run that as soon as I plug in a drive that it copies an image to it. So i wanna just take it out, plug in, pull out, plug in. Not have to deal with anything else.

    Thanks
    Mark
     
  2. Mal macrumors 603

    Mal

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    #2
    No. Disabling a warning that tells you you just did something you shouldn't have is a bad idea anyways. You should always eject the drive properly, otherwise you're likely to run into problems.

    jW
     
  3. BiggAW macrumors 68020

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    #3
    I've always wondered if it's OK to yank a drive out. I rarely do on the Mac only because it yells at me so much. I know it's OK on Windows. What about on the Mac?
     
  4. Mal macrumors 603

    Mal

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    #4
    Actually, it's not ok on Windows either. The system won't yell at you, but it's bad for the disk regardless of the OS. That's why there's a "Safely Remove" command in the system tray on Windows.

    jW
     
  5. BiggAW macrumors 68020

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    #5
    It's fine in Windows, you just have to make sure it's not writing to the disk when you do it. I've done it literally hundreds of times, I rarely eject, except for HDD's.
     
  6. nizmoz macrumors 65816

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    #6
    It's completely safe to remove the usb flash drive or HD without ejecting it first. Just make sure it's done copying any data to or from it before you do that. It's the main reason it's there. It will not harm the machine or the O/S by just pulling it out on either Windows or MAC.
     
  7. Mal macrumors 603

    Mal

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    #7
    Umm, no. It's worse if it's writing to the disk, of course, but it's definitely a bad idea to just pull it out. This isn't rocket science, kids. This is something that anyone who's used a computer for more than a week should know. On the Mac, especially, you shouldn't even think about unplugging a drive that's mounted, because things like Spotlight can be accessing the drive when you don't realize it, but on either system, not unmounting the drive can and will cause problems in the long run.

    jW
     
  8. nizmoz macrumors 65816

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    #8
    Again it is FINE to just pull it out. You really have no computer background do you? 20 years here and I am a Network Administrator. So please stop misinforming people. Pulling it out is just fine as long as you know it isn't being accessed any more. Back in the day it was recommended you do that, but not anymore.

    Even microsoft says it's fine to just remove it now as long as you know there is no data being transfered to it at that time.

    http://windows.microsoft.com/en-US/windows7/Safely-remove-devices-from-your-computer
     
  9. wpotere Guest

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    Oct 7, 2010
    #9

    and you have no UNIX background. Windows has a service to monitor the device which is why you can. UNIX actually mounts the device directly as does OSX. Yanking the device can cause you to damage the partition of the device even if the data is not being written. I have screwed up a couple of drive by not ejecting.

    In windows, yank away but in OSX you need to eject it properly.
     
  10. Mal macrumors 603

    Mal

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    #10
    Yeah, yeah, stroke yourself all you want. I've been repairing Macs for a long time, and I've seen countless drives fail because of this exact issue. Guessing you haven't worked with a Mac or any UNIX system? (The poster above summed up the rest, no need to repeat it). Take your 20 years as a "Network Administrator" and shove it.

    jW
     
  11. nizmoz macrumors 65816

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    #11
    LOL No unix background? And you know that how? And no it won't cause damage to it on a MAC. The only way it can cause any corruption is if you pulled it while it was writing to or from the device and whatever file it was on will be corrupted. That is all.
     
  12. wpotere, May 19, 2011
    Last edited: May 19, 2011

    wpotere Guest

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    #12
    How do I know this? Because you are blatantly incorrect and don't even know how the device is actually mounted from OS to OS. Please feel free to explain how the partition is mount on OSx and what will prevent the partition from being damaged. As I mentioned in Windows (starting in windows 2000 SP2 if I remember correctly) there is a survive that basically soft ejects the thumb drive from the OS once any transfer is complete. It then initiates it if a transfer begins again while keeping a drive letter assigned to it. They did this because people were trashing devices early on. UNIX has never had this and I hate to hurt your feelings but Mac has nothing for it either. I have lost data on two thumb drives because I removed an external drive without ejecting it first. Transfers were complete and no activity was on happening. So, if you are so smart with your 20 years, then why would that happen? Just to let you know, both drives are still in use today and have never had the problem again. I was used to windows protecting me and forgot I was on a Mac when I did it. Bottom line, you are wrong...

    Believe what you want, but I recommend to all the folks out there that they USE the eject feature on OSX. It is there for the reasons posted above.
     
  13. hwojtek macrumors 65816

    hwojtek

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    #13
    Sure. Because your 20 years of network engineering experience tells you the exact time the mdworker process stops accessing the drive to index its contents and the exact time when finder.app stops updating .DS_Store files. Both of which happens asynchronously and continuously. You're truly a h4xx0r.
     
  14. Guiyon, May 19, 2011
    Last edited: May 20, 2011

    Guiyon macrumors 6502a

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    #14
    It depends on Windows. If you have the drive setup with the "Quick Removal" options then, assuming you are not in the middle of a copy/move/etc. operation, you can just pull the drive as the write cache is disabled. If the drive is configured for the "Better performance" option then you can't just pull the drive as all the latest writes are not guaranteed to be synced to the disk and there is a chance that you will corrupt the hell out of the allocation tables. This could result in anything from one (or more) corrupted files to a drive that will not mount.

    On Mac OS X, it is not safe to just pull the drive as all writes are cached by default and, AFAIK, there is no user-friendly way to disable this behavior. If you pull the drive before all the in-flight writes are synced to the disk then you will see some degree of corruption ranging from 'that file looks odd' to 'OMG, ALL MY DATA IS GONE'. Also, even if you don't write to the drive, there's no way to guarantee that nothing else did (metadata, spotlight, etc. are all constantly updated). There was a pretty good example of this when EXT4 was rolled out on a couple of Linux distros. EXT3 was setup by default so that, in the worse case scenario, it would be about 5 seconds before writing out any cached data. EXT4, on the other hand, implemented a delayed allocation algorithm which could delay the physical writes for a much longer period of time. As a result, there were several cases where users either had a system crash or a power loss and a significant number of files shows up as 0 bytes in size since, even though the metadata had been written, the actual file data was only in the cache when the system went down and was lost.

    In general, as long as write caching is enabled, it is NOT safe to remove any drive without following the proper un-mounting procedures. Just because a transfer finishes does not mean the data has actually been written to the drive.
     
  15. nizmoz macrumors 65816

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    #15
    You do it your way and I will continue to do it my way. I am done arguing with children on this site that really have no real tech experience.
     
  16. wpotere Guest

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    #16
    Just because I choose not to throw my resume in your face (like you did) does not mean I am not your senior in the industry. I have been working with it a lot longer than you and I am leaving it at that.

    Do it how you want, but you are wrong and several people have pointed this out. There is no need to be a jerk about it.
     
  17. mjsmke macrumors 6502a

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    UK
    #17
    Ive lost count the amount of USB sticks that have corupted due to people just pulling them out. You should always eject the correct way in OSX.

    I dont know about Windows as i dont use it.
     
  18. Mal macrumors 603

    Mal

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    Orlando
    #18
    I'm certainly no child, and you've yet to offer any evidence that "your way" won't harm the drives. We have significant technical explanations and anecdotal evidence proving that the correct way is the best way (go figure).

    If I believed your claim that you were a Network Administrator, I'd say I was really glad you didn't work in my company.

    jW
     
  19. nizmoz macrumors 65816

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    #19
    http://www.pcworld.com/article/116572/busting_the_biggest_pc_myths.html

    I will say it again. Many articles on the net you can read. I have never had a issue just pulling things out. But I WAIT for it to stop transferring any data. And make sure it's done. Most people who screw theirs up in OS-X or Windows do not and do it when something is being transferred and can get crap corrupted or screwed up. So they put that eject there to brain wash folks to learn to eject it so it makes them feel better than it isn't transferring anything.

    As long as you are tech savvy, you know when it's done transferring data and can pull it and you WILL NOT have problems.

    It's a MYTH to think it will screw stuff up when it's not transferring. Again this proves you have no tech background. Seriously stop posting.

    From the article:

    Myth: "If you don't 'stop' a USB device before unplugging it from a PC, you'll screw things up.

    When you unplug a USB device without first "stopping" it in Windows (accomplished by clicking the Remove Hardware icon in the taskbar), your PC makes a bing-bong sound and usually pops up a message scolding you for the move or warning that what you just did can delete data saved on USB storage devices or damage hardware.

    We're cautious about unplugging a device while it's still writing data (an action USB flash-drive makers always warn against) because doing so can cause major damage. Case in point: One PC World editor unplugged an external USB hard drive that was doing some activity in the background; he lost all his data and damaged the drive itself.

    If you wait until the device stops writing data and then pull the drive out, you're unlikely to experience serious problems. Although Windows takes you to task for such rashness, even Microsoft downplays the peril. The company told us that any damage will "depend on the USB device, but in general [unplugging a USB peripheral] shouldn't affect the system."

    To see if the task has negative effects, we unplugged and plugged a bunch of USB devices, including a camera, a printer, a USB flash drive, and a scanner, without first "stopping" them in Windows. The only problem was Windows' failure to recognize our USB flash drive after we had unplugged it and then immediately plugged it in again. If that happens to you, wait a few seconds between unplugging and plugging. If that doesn't work, reboot Windows. And if that doesn't work, run the Add Hardware wizard from the Control Panel to make Windows "see" the USB device. For more on USB devices, visit USBMan."
     
  20. Guiyon, May 20, 2011
    Last edited: May 20, 2011

    Guiyon macrumors 6502a

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    #20
    And every word of this is true, as long a write caching, or delayed allocation, or whatever you want to call it is disabled (or the filesystem is mounted RO)! You can't make a blanket claim that it is always safe unless you understand the underlying issue here, which you obviously don't.

    The whole point of write caching is to provide a speed boost to external devices by copying the data to RAM first and then, when it's convenient (for the OS, not you), write it to the disk. As long as write caching is enabled, ANY writes are asynchronous (with respect to the physical storage) unless they are made using either a function that makes an atomic guarantee (see rename(2)) or each and every write is immediately fsync'd (which you cannot guarantee if you are not doing the writes yourself) or you manually sync the disk using sync from the CLI to flush any pending writes.
     
  21. wpotere Guest

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    Oct 7, 2010
    #21
    Once again you fail and have only posted what we all have been saying. No problem with windows as there is a process in place to protect it. The article you posted covers WINDOWS, not OSX. :rolleyes:


    I think the one that needs to stop posting is you. ;)
     
  22. r0k, May 20, 2011
    Last edited: May 20, 2011

    r0k macrumors 68040

    r0k

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    #22
    Most thumb drives are formatted FAT32 which is not a fault tolerant file system. OS X likes to sit there and write dot underscore files and .ds_store files which clutter up the drive, can create problems later and add to the risk it is not safe to unplug when you want to. Normally I take a few extra seconds to click eject before popping out an SD card or a usb stick. If I were doing hundreds like the OP, I might be inclined to find a way to make sure the OS was never writing when I wanted to unplug. One method that occurs to me is to do the copying in a bash script that unmounted the drive as the last step in copying the files. Another method is to simply yank the thing out and never worry about data loss until after I saw evidence corruption could occur. I guess it depends on the value of the data. If these files are irreplaceable, it would be worth a few extra seconds to eject properly. If the files exist elsewhere and could be restored if there was ever a problem then yank away.

    OS X can sometimes bring the "best" of both worlds: a great gui over a stable unix where things are quick and easy to find thanks to a little thing called Spotlight. Sometimes OS X brings the worst of both worlds: processes running in the background meddling with files on a removable drive thanks to a little thing called Spotlight. If I have time I eject. When I'm in a hurry I yank. I have never had a problem either way. YMMV.

    BTW, telling other users not to post is not necessary. If the rudeness gets out of hand, there are mods to take care of things like that.
     
  23. nizmoz macrumors 65816

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    #23
    Again you fail because you aren't tech savvy.

    Like I said, Windows or OS-X, if data is being written, it can be corrupted or corrupt the device. But if it's not, then it will not period. You obviously can't get that through your head.

    Cache or not, there is a light on most devices, if it stops, and it doesn't showing the copy anymore or data action, it's safe to remove. Pull it.

    People with no experience will not know this like yourself and believe what they read instead. Over the past 3 years I have learned this site has a bunch of novice people on it that know very little about how computers work and that mainly might be due to the fact it is a Apple site and there isn't MUCH about a Apple to worry about.

    :rolleyes:
     
  24. wpotere Guest

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    Oct 7, 2010
    #24
    You know what, I give up, you are right. I guess I will just quit my job and find a new field because I'm not tech savvy. :rolleyes:

    You are still incorrect and I can't be bothered trying to educate you any further. You are one voice over many that have tried to correct you. As you said, keep on doing it your way but at least this thread shows that you are the only one that thinks this....
     
  25. nizmoz macrumors 65816

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    #25
    Funny I am incorrect per you, but I have the facts and you do not. Just an opinion.
     

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