Hi, I'm trying to copy a QT movie to 2 flash drives on my new Retina - but I want them to accept the data at the same time. It seems like they just write the data to one drive - THEN the second, taking twice as long. And my processors are only working at 1% to 6% power!
How can I get my MacBook Pro to write to both drives concurrently?
Thanks,
Larry
Hi LowLuster,
I've tried everything! I have a 2 gig movie - I drag it to one flash drive and then immediately drag it to the other. It shows it copies to the first, and the second is waiting until the first has completed.
I've tried "Command C" to copy the file and then highlight both USB drives and "Comand V" to paste - doesn't work either. That just duplicates the QT on my desktop.
No matter how I highlight the USB drives and try to drag the QT movie to them- they only copy one drive at a time. I can't believe this is a limitation of Mac?
Larry Cohen wrote:
I have a program nemed "MenuMeters" - it shows each processor and what it's doing . . . and many other things.
Well if you believe it to acurate, then you have a serious hardware problem and should take your Mac to the Apple Store for repair.
Cheers
Pete
Hmmmm . . . we have 4 Mac computers. Our Office iMac (about a year old) 2 MacBook Pro Retina's and a regular MacBook Pro. None will write to 2 USB's at the same time. Anyway, thanks for your response.
Yes, I just plug two USB flash drives into my Retina. Then drag the QT movie to both - but it DOESN'T copy to both. First one, then another. Are you on Mountain LION?
Here's a post I found elsewhere describing this exact issue . . .
Thanks,
"For some bizarre reason, with Lion, this does not seem to be possible. Drag a single file to two separate drives, or a folder to two separate drives , or multiple items to two separate drives, and LION will only copy to ONE drive at a time. It will only copy to the first drive and the progress bar for the second drive says "Calculating time to transfer", but the OS will not begin copying to the second drive until the first drive is completely finished. SO, before, if you were for instance transferring 150GB of files to two drives for redundant backup, that would take approximately 11 hours or so, and now it takes nearly twice as long.
Am I missing out on something here? How can Apple consider taking the ability to this out of the OS to be progress? Something that every one of their OS's has been able to do for over a decade now."
Hmmm . . . and when you drag a large file to both drives, you'll see 2 progress bars (showing their copying progress) moving simultaneously? Very strange - I don't here.
You are copying a large file, right - so it takes a minute or so to copy - so you'll accurately see the status of both drives while it's copying?
If so, thanks - we're certainly not!
And my processors are only working at 1% to 6% power!
The CPUs are not using a lot of cycles because you are I/O bound. That is to say, you do not need a lot of CPU power to perform I/O.
The next issue is what kind of USB devices are you using? USB3 or USB2?
If you are using USB2, then unless there are 2 separate USB controllers being used, you will saturate the USB2 bus with just one transfer. Starting a 2nd transfer in parallel using the same USB2 bus will not make things go faster, it will just make each transfer go half as fast.
If the USB devices are USB3, then chances are the USB3 bus is sufficiently fast that you can support 2 concurrent transfers without saturating the USB3 bus.
Thank you, Bob. We're simply using standard Thumbdrives, or Flash Drives. They're USB2 (I'm pretty sure). We're going to want to make 30 or 40 of the same movie (about 2 gig) and I just thought if we could dub them directly from my MacBook Pro - 2 at a time - and we have 2 Retina's and an iMac - we could do this inhouse practically. Doing one at a time gets too bulky, and we'll buy a USB Flashdrive duplicater.
But I seem to remember when we'd copy to multiple firewire hard drives or USB drives - we would see the copy status bars all working simultaneously. We don't see that anymore - like the post above says.
You'd think we're not the only people in the world wanting to copy to two flash drives concurrently - certainly my computer is "fast" enough (I don't really know the mechanism here) but it seems you're saying it will only copy to ONE Flash Drive at a time. I guess we'll have to buy a duplicater then? Thanks very much.
Larry
We had the same problem this week... we had to make 25 copies of some videos we did along with some other materials and I put in a couple of 8GB thumb drives and only one would copy at a time. I kind of assumed this was an issue with having only one USB controller (like another responder said), I was wondering if putting one thumb drive in back of the machine and one up front would make any difference. We ended up copying the files to 4 different machines and doing copies 4-at-a-time.
The worst part is upper-management wanted 25 more today... and asked us to give them the drives because they can make multiples on their machines. That was horrible to hear, made it seem like we didn't know what we were doing.
I wonder if this is a Mac only issue? Like does this work on a PC? I never really had a reason to do it, so it's probably not really a common thing people do. But I imagine it will be soon.
-Francesco
iMacs and MacBooks tend to have 2 usb Buses 1 for Usb sockets and the other for keyboards, internal cameras etc so you can only copy to one bus at a time.
If you have a Mac Pro, at least the silver ones they have more Buses so you should be able to copy one to each at a time.
Hey everyone,
I ran into the same problem on my macbook pro 15" late 2013. im trying to copy a file to 2 USB flash drives (one is USB 3 and one is USB 2 and both are directly plugged into my macbook). It copies to one USB but the other one says estimating time remaining until the first USB is done and then copies the file to the other USB.
I also tested this with 2 USB 2.0 flash drives. Funny thing is that it can copy simultaneously to a external harddrive and a USB but not 2 USBs at the same time.
Any thoughts why this is the case? I haven't tested it on my windows partition yet to verify if it is something in OSX that prevents this from happening.
cheerio
Start the copy to one then to the other. Never tried this so I don't know if it will work or how you are now copying to both at the same time.
Larry Cohen wrote:
And my processors are only working at 1% to 6% power!
How are you being alerted to this?
Pete
I have a program nemed "MenuMeters" - it shows each processor and what it's doing . . . and many other things.
Getting back to our question, can you copy to both USB drives simultaneously?
Normally yes. But probably not if your Processors are faulty.
Pete
Copy to both USB flash drives at the same time?
