How many bus-powered usb external drives per hub?

I'd like to have two bus-powered USB hard drives (to be used as backups with Time Machine) connected to one powered USB hub. Would that work, or would a powered hub be likely to support only one bus-powered external hard disk? (In that case I could get a self-powered hard drive for my second backup drive.)
Thank you.

Works for me, I just connected both my WD Passport and Seagate GoFlex to my Belkin Hub.
Hub: Belkin
Product ID: 0x2507
Vendor ID: 0x0424 (SMSC)
Version: 0.00
Speed: Up to 480 Mb/sec
Location ID: 0x26200000 / 2
Current Available (mA): 500
Current Required (mA): 2
FreeAgent GoFlex:
Product ID: 0x5021
Vendor ID: 0x0bc2 (Seagate LLC)
Version: 1.48
Serial Number: NA03N18Y
Speed: Up to 480 Mb/sec
Manufacturer: Seagate
Location ID: 0x26270000 / 4
Current Available (mA): 500
Current Required (mA): 100
Capacity: 320.07 GB (320,072,932,864 bytes)
Removable Media: Yes
Detachable Drive: Yes
BSD Name: disk2
Partition Map Type: GPT (GUID Partition Table)
S.M.A.R.T. status: Not Supported
Passport WD:
Product ID: 0x0704
Vendor ID: 0x1058 (Western Digital Technologies, Inc.)
Version: 1.05
Serial Number: 5758453830384E4A30333634
Speed: Up to 480 Mb/sec
Manufacturer: Western Digital
Location ID: 0x26250000 / 3
Current Available (mA): 500
Current Required (mA): 2
Capacity: 160.04 GB (160,041,885,696 bytes)
Removable Media: Yes
Detachable Drive: Yes
BSD Name: disk1
Partition Map Type: MBR (Master Boot Record)
S.M.A.R.T. status: Not Supported
Likewise it your needing another External Hard Drive, I would recommend spending a little more for a more rugged Desktop drive to use for storage or backup.
Go with an OWC Mercury Elite Pro or a LaCie Little Big Disk and stay away from those cheap-o WD MyBooks.

Similar Messages

Wiebetech bus-powered FW800 external & daisy chaining...

Please, only people that ALREADY OWN & USE the Wiebetech drive reply. Thanks.
I just bought one - the 500GB. I have three questions:
1) From your experience in running this unit, can I use it on only bus power, in a daisy chain with another FW800 drive if the other drive has a power adapter?
2) What if I have a FW400 drive also plugged in, and the FW400 is connected to the FW400 port and has it's own power adapter?
3) Also, does including a FW400 drive in the loop AFTER the FW800 Wiebetech have any adverse affect on the FW800 speed or it's bus-power?
It sounds like the draw for the 500GB on us power will be running questionably close to the max output on the port. So I'm trying to do some homework ahead of time to see if I might run into any anomalies. Thanks.

tommmy wrote:
Most portable external drives are now bus powered, many don't even have a power input.
I wonder how many bus powered Firewire driives I can daisy-chain.
Use a powered Firewire/USB hub so there is enough power to power the port powered devices.
What happened is port powered devices are cheaper and many people opt for the lower price than the ones with their own power supplies, so it creates a problem and computer makers had to turn off ports drawing too much power from the comptuer, so people have to run out and get powered hubs.

Why won't my 2011 MBP boot from bus-powered USB devices?

In the past, I have often made use of OS X's ability to boot from an external USB device. Before installing major OS updates, or new productivity software, I usually clone my system drive onto an external USB drive using Superduper or CarbonCopyCloner. Once the clone is complete, I can then boot from the external drive (by holding Option at startup, and choosing the cloned image from the boot disk menu). This has been incedibly useful in the past when I've had hard disk problems, or when I've upgraded to a new Mac.
My issue is with my new 2011 model 17" MBP. I am only able to boot from an external USB drive if the drive isn't bus-powered. If I try to boot from an OS X image located on a bus-powered USB flash drive or pocket hard drive, the drive seems to power down upon choosing it from the boot menu and I'm greeted by a blank gray screen. I've also tested this technique using a bus-powered DVD drive containing the Snow Leopard retail DVD (and a Windows 7 install DVD for what it's worth) and the problem remains. The optical drive will spin up upon startup, but power down as soon as I choose to boot from the DVD.
This issue only seems to affect my 2011 MBP. I've had no issues getting the same technique to work on my old 2007 MBP or a 2008 model MacBook.
Any help would be much appreciated.

Fair enough. I'll give that a try as a last resort.
I used my wife's MacBook Pro, Target Disk Mode and a Firewire 800 cable to install Snow Leopard on my MacBook Pro as I don't have an internal optical drive any more--just the standard HD and the SSD.
I did use the retail disc, and I'm wondering if the issue might be that since my machine is fairly new, I might have had to use the stock install disk--which I seem to have lost. I have the Applications DVD, but not the OS disc.
To that end, do you know of a way to get a replacement disc? I bought my machine at the store, I wonder if they'd be willing to copy one for me...

USB External Drive Backup & Erase Woes

I have been using a Lacie 500GB USB external drive allocated as a backup disk for time machine. Over the last couple of weeks, the disk has been spontaneously ejecting itself from the desktop. This could happen when not backing up to time machine, or during the backup.
I am not a daily time machine backup-er, as I don't have much to backup on a daily basis (and I weekly backup to an alternative disk using Super Duper). What I had noticed with the time machine disk, is that the preparation prior to the backup beginning was a massive 40+GB, certainly not the amount of data which would have been 'new'.
To try to resolve this, I have used disk utility to verify the disk, and the snow leopard disc to check my boot disk on the Macbook Pro... there has not been a problem identified with either.
Today, I decided to erase the time machine disk, zero the data, and re-allocate the drive for time machine backup. After setting these preferences in disk utility, and clicking 'erase', the disk again erased itself, with the error message :
'Disk erase failed with the error: Assert: internal error, or unimplemented'
I then had an external disk which was not present on the desktop, and apparently in some sort of limbo between erased and mounted!
I was able to do a simpler format function on the disk via disk utility, the disk will mount, but the allocated disk space previously used by time machine is still present, and the format has only done that remaining space on the disk.
Anyone know what the above error message refers to, am I able to reformat the disk using the 'zero function', or has the disk failed and become unrecoverable?
Answers / suggestions kindly welcomed.

Welcome to Apple Discussions.
When you use Disk Utility to erase totally you need to click on the LaCie drive name not the name that appears on the desktop. Select how many partitions you want and give each partition the name you want it to have and perhaps also the partitioning scheme and other options that are available, then erase.
Doing this will of course make all that is on the drive unavailable to you.
These are LaCie's directions for their drives.
Some LaCie drives might also have firmware updates available - worth a check on their website.
Note that LaCie seem to have 2 yr warranty on their drives, at least the one I looked at on their website. If the drive is younger than this you might have a warranty claim.

MDT 2012 deploy OS from USB external drive failed - need to unplug and plug it once again

We are using MDT 2012 and deploying Windows 7 using media (USB external hard drive). We can successfully deploy Windows 7 32 bit using this method but there is a problem with deploying Windows 7 64bit. This problem appears only on HP EliteBook 840. We can
boot into WinPE 64 bit and can start proper task sequence, all image is applied then after restart, before logon screen appears there is an error saying that cannot find litetouch.vbs script. After clicking ok, I can logon to Windows and there is no usb external
drive recognized. But when I unplug and plug usb drive once again it is recognized by Windows and can be used. I can see that Windows install some drivers just after plug it again
I checked BIOS looking for some USB power options - there is no such settings. And 32 bit deployment works ok. So this is not a case. Looks for me like a problem with proper usb drivers for 64 bit. I download all drivers from HP website (driver pack and
drivers only for USB 3.0). We are using make and model matching in MDT - works ok for all the rest hardware models. Any idea how to troubleshoot it?

Not sure what's going on here. Is this a USB "Flash" drive or a USB "Hard Drive". There *Is* a distinction.
I *thought* that MDT would copy itself to the c:\minint\scripts folder to continue installation.
Next time, when you see this error, Press Shift-F10 to get into a cmd.exe prompt. Can you find litetouch.vbs on any of the drives? Does the USB Drive appear?
IF in fact, the USB Drive is not appearing after the 1st reboot, then you have a problem. Why did the USB 3.0 driver not install. Check the Driver Installation Logs to verify.
Keith Garner - keithga.wordpress.com

Using a usb external drive with logic

I have a 500 GB Lacie usb hard drive which I'm currently using just to backup my system. (Still on Tiger by the way.) I'm in an older intel iMac (1.83. 2 gigs ram, 250 gig internal hard drive). After installing LP 8 and all the bells and whistles on the internal drive I now have less than half of my internal drive space available. My logic project files are there as well. Not a big problem but I'm trying to look further down the road... Usb drives are slower than firewire but my projects are relatively simple. I don't record more than 2 tracks simultaneously and rarely exceed 24 tracks total for a song. Two questions. First can I get by with my usb external drive? And second how do I move my projects onto and external drive and still have logic know where they are? Thanks

I have the oldest macbook (1.83. 2 gigs ram, 60 gig internal hard drive)
I have all my logic content on my external maxtor firewire 400 drive (usb 2.0 is actually faster than firewire 400) and everything is fine. the good thing is if your external drive has 7200rpm, but the ones with 5600rpm should do as well.
Once you drag your apple loops to logic from your external drive, logic will remember for the next visit. And when you are opening a project which is on the external drive , just find it with logic finder and all should be fine.

Problem mapping USB external drive connected to Airport Extreme on my PC

I am having a problem mapping my USB external drive in my PC running WIndows Vista. Here is what I have so far:
USB External Drive connected to my AirPort Extreme which is connected to my Century Link modem/router.
I have installed the USB drive using the Airport Utility. In the Disks section the Enable File Sharing is checked, Secure Shared Disks is set to With a Disk Password, I have entered the password in the next 2 rows, and finally AirPort Disks Gues Access is set to Not Allowed. The section below named These Settings Configure Windows File Sharing is empty. Am I supposed to put something here?
I was also told I need to map the drive in my PC, but when I go to do that via the Computer and the Map Network Drive, I get stuck where it asks me to enter a folder name. I read many of the posts which tell me I need to enter among other things the disk's ip address, but I am unable to find it anywhere. Where do I find what to put here?
Can someone please help this frustrated user?

I had my USB drive on my APE working with Time Machine under 10.5.1 very reliably. A few days ago however, I needed to suspend a backup operation, and when I came back to restart it, time machine refused to mount the disk image on the drive. After several attempts to get it to connect with no luck I decided to delete the image (the sparce image file) and start over. Now TM refuses to create a new image.
BTW, on the Mac OSX hints site there have been suggestions to start a backup with the drive directly connected, then stop the backup, move the sparce image file to the root of the drive, reconnect the drive to the APE base station to get it working. I tried this again, but I think Apple has changed something in 10.5.2, because when directly connected TM no longer creates a sparce image file.
Anybody else seen this behavior after upgrading to 10.5.2?

How to re-format an external drive?

I had a G3 iMac with a 160 GB internal drive that was running an earlier version of OS-X. When I installed that drive, there was a limitation that only allowed it to recognize about 120 GB of that drive.
I now have an iMac G5 and want to use the 160 GB drive from the G3 iMac as an external USB drive. When I connect it to the G5 iMac, the drive is recognized, but only shows a total of 120 GB of total space.
How can I reformat this external drive to allow it to recognize the entire 160 GB of space which the newer versions of OS-X now can do?
Thanks,
Bart

Thanks! My problem is solved. When I was in Disk Utility, I had been clicking on the partition name in the list on the left side of the window. It wasn't until I clicked on the level above the partition name (which I assume represents the actual hard drive) that the Partition tab became available. Once I could get to the partition window, it was quick and easy to delete the old partition and create a newer one that recognized the whole amount of space on the drive.
Thanks!

Imovie9, 13"macbook aluminum and USB external drive

I know firewire is better, but is it totally impossible to use USB. Others have said its ok. Tom Wolsky on the FCE forum said that many people are returning the macbooks without firewire. I did a search on other discussions and some say its ok, while others say no.
Please do i really need a macbook pro or a white macbook. I will be editing HDV and eventually AVCHD.

Thank you! Yes. I have HDV today with an imac. I am deciding between the new macbook and the new white macbook. I really want the small form factor. I should really just buy the white one since it has firewire, but I don't want plastic and i like the new touchpad. I also want to get a flash drive HD camera that uses USB. I got concerned using a USB External drive for the AVCHD because of file sizes and making the USB drive unstable. I think i will ensure that i keep enough hard drive space on the macbook to do all editing and then move as much as I can to the external drive.

GRUB hangs when booting Oracle VM Server via USB External Drive

I installed Oracle VM Server 2.1 on USB external drive (/dev/sde - 80gb) with First Sector Boot Partion (/dev/sde1) as /dev/sda1 (MBR) is already occupied. After a successful installation, I changed the hard-disk device sequence (not boot order) so that USB drive is found as first C: drive. All I got was the word 'GRUB' displayed (hangs) and nothing else. How do I get Oracle VM Server to boot? Should I reinstall now that the hard drive sequence has been changed?
Thank you.

Not Oracle VM-related, so I would say: "Google is your friend!".
Search for "grub change boot sequence": http://www.google.com/search?q=grub%20change%20boot%20sequence

How to boot from USB flash drive - Portege R500

Hi,
I have a Portege R500 running Windows XP, brought about 2 years ago, and recently contracted a worm virus that has infected some of the start up files as the minute I log in it logs out again, even in safe mode! Quickest way I can think of sorting it is to reformat it with the XP recovery disc and reinstall windows.
Problem!! The CD/DVD drive on the laptop stopped working a while ago, have tried pretty much everything in the thread on this site but had no luck.
So my plan was to boot from a USB flash drive and do it that way. However in the boot settings I only have the options of HDD / FDD / CD-ROM / LAN, neither of these will work. Does anyone know how to boot from USB flash drives?
Any help would be really appreciated

Hi
As far as I know it should be possible to boot from USB FDD
Im not sure if you would be able to boot from USB flash drive but its definitely worth a try
Generally you could try to press F12 button when notebook powers up.
Then a boot menu should appear on the display and you should see all bootable devices.
PS: As far as I know the USB booting was available in ToshibaHWSetup (Toshiba tool which changes the BIOS settings in windows OS.) Therefore I assume booting from USB should be possible.
Greets

How to install (using usb flash drive) os x snow leopard on 10.5?

i have a version 10.5 (leopard), but i would like to install snow leopard (10.6). i tried using bootable usb flash drive using the "utility drive". However, it did not quite work as i expected. Does anyone know how to use bootable usb flash drive to install snow leopard on leopard?

How to Install OS X Updates Successfully
A. Repair the Hard Drive and Permissions:
Boot from your current Leopard installer DVD. After the installer loads select your language and click on the Continue button. Then select Disk Utility from the Utilities menu. After DU loads select your hard drive entry (mfgr.'s ID and drive size) from the the left side list. In the DU status area you will see an entry for the S.M.A.R.T. status of the hard drive. If it does not say "Verified" then the hard drive is failing or failed. (SMART status is not reported on external Firewire or USB drives.) If the drive is "Verified" then select your OS X volume from the list on the left (sub-entry below the drive entry,) click on the First Aid tab, then click on the Repair Disk button. If DU reports any errors that have been fixed, then re-run Repair Disk until no errors are reported. If no errors are reported click on the Repair Permissions button. Wait until the operation completes, then quit DU and return to the installer. Now restart normally.
If DU reports errors it cannot fix, then you will need Disk Warrior (4.0 for Tiger) and/or TechTool Pro (4.5.2 for Tiger) to repair the drive. If you don't have either of them or if neither of them can fix the drive, then you will need to reformat the drive and reinstall OS X.
B. Make a Bootable Backup Using Restore Option of Disk Utility:
Open Disk Utility from the Utilities folder.
Select the destination volume from the left side list.
Click on the Restore tab in the DU main window.
Check the box labeled Erase destination.
Select the destination volume from the left side list and drag it to the Destination entry field.
Select the source volume from the left side list and drag it to the Source entry field.
Double-check you got it right, then click on the Restore button.
Destination means the external backup drive. Source means the internal startup drive.
C. Important: Please read before installing:
If you have a FireWire hard drive connected, disconnect it before installing the update unless you will boot from this drive and install the update on it. Reconnect it and turn it back on after installation is complete and you've restarted.
You may experience unexpected results if you have installed third-party system software modifications, or if you have modified the operating system through other means. (This does not apply to normal application software installation.)
The installation process should not be interrupted. If a power outage or other interruption occurs during installation, use the standalone installer (see below) from Apple Downloads to update. While the installation is in progress do not use the computer.
D. To upgrade:
Insert the USB flash drive.
Restart the computer.
Immediately after the chime press and hold down the "OPTION" key.
Release the key when the boot manager screen appears.
Select the icon of the USB flash drive and click on the arrow button below the icon.
When the installer finishes loading follow the onscreen instructions.

MacBook Air USB external drive power source

I have a LaCie 250GB USB external drive on my MacBook Air and the computer is not being able to power the drive without me connecting the hard drive to an external power source. when the drive was had about 80GB of data it would do it, now that the drive has about 180GB of data, it does not work. Can anybody recommend a solution or an external drive that can hold at least 250GB that can be powered by the MacBook Air without need for external power source?

I have the same time of problem. Although, it's mentioned a using a self powered hub. However, I find this did not work. Apple states that the single usb port on the MBA is high powered to give the ext. super drive they sell the power it needs to connect to the MBA. What I have noticed is no matter which USB self powered hub I use I get the same results. The MBA reports that one or more devices is drawing too much power. Although, the powered hub is supposed to provide power to those devices that require power over USB. I should also mention, all I am connecting are two USB devices. 1 ext. Verbatim 500 Gig Drive. and my iPhone. Since the MBA has only 120 gig drive I had to move all of my movies etc. to the Ext. 500 now if I want to sync my phone or move a movie to the phone I get the errors.

USB External Drive Trouble

Back in April, I hooked a 500 GB USB external drive to my iMac in order to run time machine. All worked fine until October 17. Yesterday Time Machine popped up with a message telling me it had not backed up in 10 days and I should figure this out. At this point, I noticed that the external drive was no longer mounted on the desktop, although I could see it in Disk Utility. The POSIX error came up. After a long search on the forum and fighting with a PC in the house, I was able to reformat the drive and let Time Machine do its thing.
The initial backup went great and it seemed to back up every hour until 12 am or so it says. Once again, I came down this am and the drive is not mounted and not showing in Disk Utility. I turned it off and on again and now the computer tells me it needs to be initialized.
What in the world is going on? Is it related to USB control and SL? Is it a Time Machine issue? Should I reformat the drive and see if I can simply copy files to the drive and see if it stays mounted that way?
I do not know how to tell an external drive when to unmount or if it should upon the computer going to sleep.
Any help would be greatly appreciated before I spend more money on a new drive.
Debbioe

Thanks, that one's not on my suspect list... yet
Good luck with the replacement, I'm sure it will be fine. When you get it remember to format for Mac OS X.
1. Launch Disk Utility
2. Click the "Erase" tab
3. Select your entire external drive on the sidebar (the uppermost icon).
4. Format: "Mac OS Extended Journaled"
5. Name the Disk (Time Machine, or whatever) only the name of the volume will show in Finder.
-mj

Having troubles reading usb external drives.

I have a macbook pro, mid 2010 is when I got it. The issue I've ran into for about 6 months now is my usb external drives are not currently being recognized. It's only external drives and thumb drives though. My mac recognizes my iphone, charges my camera usb, lets me use a usb midi controller. About six months ago I was having trouble connecting a usb dmx lighting interface. I called the company and they sent me to a workaround and it worked. http://groups.google.com/group/dmxis_users/browse_thread/thread/c5746c10c618bf19 ?hl=en_US
Ever since then, it's never been the same my external drives don't work. I even took it to an apple store and replaced the internal boards. (Sorry for not knowing specifics) Any suggestions or ideas would be greatly appreciated!

That would explain your problem! If you have a backup then see if it's on your backup. Otherwise, you will need to restore it from your installer DVD using Pacifist:
How Restore Deleted or Missing OS X Components
A few of the basic OS X installed applications can be restored from the Optional Installs installer located in the Optional installs folder on your Installer DVD. However, if what you need is not there then follow the instructions below.
How to Use Pacifist to Restore Deleted or Missing OS X Components
Insert the OS X Installer DVD into the optical drive. Use a simple utility like TinkerTool to toggle invisibility so you can see invisible items. Alternatively, open the Terminal application in your Utilities folder and at the prompt enter the following:
defaults write com.apple.finder AppleShowAllFiles Yes Press RETURN.
To turn off the display of invisible files repeat the above command substituting No for Yes.
The install packages are located in the /System/Installation/ folder on the DVD.
Download the shareware utility Pacifist from VersionTracker or MacUpdate. Use it to extract a fresh copy of the missing item(s) from the file archives on your OS X installation DVD. The file archives are in the /System/Installations/ folder (use Go to Folder option in the Go menu of the Finder.)
Here are Four Basic ways to use Pacifist (courtesy of George Orville.)
A. Drag a .pkg icon onto the Pacifist window .....proceed to step 7.
B. Click on “Open Package ....” and navigate to package desired and click “Open” in the open/save window.....proceed to step 7.
C. Insert Mac OS X installer CD and when it mounts, navigate to .... Menu->Go->Go to Folder. In the path field enter or paste ....
/Volumes/disc name/System/Installation/Packages (where disc name is the name of the CD/DVD that you inserted.
• Click on the "Go" button ..... • Drag a .pkg to Pacifist..... proceed to step 7.
The package you'll need will have to be discovered by trial and error, but for most applications you should start with the Essentials.pkg and/or Additional Essentials.pkg.
D. Insert your Mac OS X install disk 1 .... and open Pacifist.
1. In Pacifist, select "Open Mac OS X Install Packages" ... dialog may appear asking for disk 2, then disk 3 and finally disk 1 again.... {if DVD is not used)...If “Stop Loading” is selected...the procedure will stop!!!
2a. When loading is complete, a new window appears, click the triangle to display contents of each package...Select item and proceed to step 7.
2b. or click the “Find” icon in the Pacifist window and type the name of the software you need.
3. In the list that comes back, click the top most entry for the item that you want. ..... that is the one for the English language.
4. On the top of the Pacifist window, click “verify” .... you will probably be prompted for your password.
>5. Enter checks for.... “verify permissions” and “verify file contents.” and click “verify” ....enter password when prompted.... you will get back output which may look like this:
20 files were scanned. 20 of 20 files were present on the hard disk. 0 of 20 files had file permissions that did not match those specified in the package. 0 of 20 files had checksums that did not match those specified in the package.
6. Click “close”. Go to step 7.
Extract or Install........
7. In the Toolbar (upper left), you now have the option to extract or install. Click a file in the lower list and those two icons will be enabled.
8. If “Extract to...” is selected.... navigate to the location where the file will be placed, select “choose”, select “extract” in new dialog that appears,authenicate , if prompted, click “OK”.
9. In the next dialog, click “Extract”.
10. If “Install” is selected... dialog will appear with the location/path of the installed software. Click “Install”
11. Type in your password, click “OK”
Pacifist will begin to extract files.
12. In steps 8/10ß.... you also have the choice to “cancel”
Notes.....
Pacifist may find that a file it is installing already exists on the hard disk. Pacifist will present you with an alert panel....
Stop Leave original alone Update ..... Default selection Replace .... Replace option should only be used on full install packages

How many bus-powered usb external drives per hub?

Similar Messages

Maybe you are looking for