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Leopard bug identified with moving data
If you're moving data from one Mac or PC to a Mac running Mac OS X Leopard, don't trip over the cord.
Tom Karpik, a computer science student at the British Columbia Institute of Technology, says he has identified a bug in Leopard that can cause you to lose data if problems occur while moving files between two different storage volumes, such as two different hard drives. Apparently, the problem is that if the source of the file crashes or is disconnected from the network while the move is under way, the contents of the file completely disappear from the source machine, and you're only left with whatever had already been copied to the destination machine.
Be careful when moving files from a Mac or PC to a Leopard machine.
(Credit: Apple)We're talking about moving files here, not copying them, which is a bit more dangerous way of getting a file from one place to another. When you opt to move a file, you're acknowledging that you want that file deleted from the source machine after the operation is completed. And you have to actually hold down the Command button when dragging the file from one volume to another to bypass the default way of doing this operation, which is to "copy" the file from source to destination when the icon is dragged across the screen.
Commenters on Karpik's blog, Slashdot, and others like Daring Fireball's John Gruber point out that you're asking for trouble if you opt to "move" files rather than copy them. An easy way to avoid any problems is to just drag the file from one volume to another without pressing any keys, and if you really want the file gone from the source machine, manually delete it after everything has been completed.
But Karpik's point is that Leopard shouldn't delete the source data until it has verified that the transfer was successfully completed. "Windows behaves differently in that it never deletes the source unless everything has been completely copied to the destination. This is just sane, to-be-expected behaviour," he wrote in an e-mail in response to asking for clarification on a couple of his findings. Some commenters on Karpik's blog said this is an issue that has existed since Panther (Mac OS X 10.3), but I haven't been able to confirm that.
I sent an e-mail to Apple earlier this morning asking if it had identified this as a bug or problem, and if any fix was anticipated. I'll update if I hear back.
Tom Krazit, a staff writer for CNET News, focuses on all things Apple. He has covered traditional PC companies such as Dell and Hewlett-Packard, chip companies such as Intel and Advanced Micro Devices, and mobile computers ranging from Research In Motion's to Palm's. E-mail Tom.
I am thinking about buying a new Mac and will continue to wait a little longer to see what else turns up...
exploit. You are exaggerating the seriousness.
It almost seems like your removing some of the blame from Apple. 'What you did was risky'.
No, what Apple did was not verify, simply delete.
This is staggering incompetence that never should have gotten by QA.
from backup disks when I noticed they weren't copied properly. I'd
discovered this behaviour when I moved from Windows to Mac. The
work round is "copy", "compare results" then "delete". This minor
inconvenience, however, still justifies the much more elegant and
productive OS X user interface.
I have always assumed a hardware failure or a disconnect during a move could result in data loss. ****, I get that alert whenever I prematurely disconnect my iPod.
Any number of things can happen during a move process from network interruptions, HDD failure, HDD Controller issues, NIC's failing/flaking, power disruptions, or even the cat stepping on your keyboard at a bad time.
I'm somewhat surprised that Leopard would do a move without confirmation before deletion but I'm sure Apple will implement a fix for this soon enough. Sounds like a simple oversight that can be quickly remedied.
At least Microsoft has had this working right since Windows 3.11.... A move algorythm designed properly will always COPY the file first and on acknowledgement of successful transfer back on the source, THEN and ONLY THEN delete the source file. Like, DUH!
So was this one of the 'benefits' they got by starting with a Unix core, or just one of those superb Apple designs we hear so much about?
I think readers might agree to this more if you note that this becomes more and more of a problem with larger files. Moving a 5KB document isn't probably going to have anything break the transfer. But if you're copying your latest iMovie creation that sizes 300MB, and over a wired network might a minute to five, and thats when a power failure or something might happen.
them is suicidal in any OS. The safest way is to copy/paste, confirm
the new copy is in order then go back and delete the original.
*example: a different hard drive, internal or external
I for one would not move ALL my files to a new OS, but eventually I can see this impacting me. For example, I often MOVE older files from my laptop to desktop to clean up the laptop. Sure I could copy and delete, but that's a hassle beyond compare, especially if the older files are in many different folders. What if something interferes with the laptop's wireless connection or it goes into sleep mode cutting the connection in medias res? It's not that unlikely that this will happen.
I hope Apple fixes this...of course personally I don't have to worry since I'm using Windows on one and Linux on the other (but could care LESS what OS is better so don't tell me what you use or why).
Code is designed by humans in an imperfect world and we just got reminded of that with this story. This will not be the last time this happens. Despite what the fanboys tell you, there is no such thing as a perfect operating system.
I have just read through everyone saying "You should copy, verify, delete; not move!"
They of course are right.
I have also just read "It should be a no brainer basic OS function!".
They are also right.
While most people that work in the IT industry ALWAYS copy/verify/delete, their spouses, loved ones, friends, and children have a tendancy to do the easiest thing possible. MOVE. One Command, not thinking..
It's a bug.. Just like all bugs that make the news, it will be fixed. My personal opinion is that it should not have slipped through, since it is so low level. But, there have been TONS of bugs in EVERY OS that should not have slipped through.
We know about it now, so until it is patched, inform your kids not to move a movie from HD to HD until it is fixed. Or simply tell them to copy and deleted, or... Wait till you get home and you will do it until the bug is fixed.
Simple bug, simple fix (most likely), potential to cause moderate damage, esecially in the Kid, Wife, friends how just want it to work department.
Not a big deal to IT pros, just annoying that it shouldn't be there.
J.G.
- I've done if for years...
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by b8375629
November 11, 2007 8:52 AM PST
- Basically, it's called "cut-and-paste" in Windows. Never had a problem doing it. Never lost data or anything.
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