Attaching (vs. detaching) a USB disk with hdiutil?

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Level 1

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Attaching (vs. detaching) a USB disk with hdiutil?

For a very specific and very arcane reason, I need to be able to do this at the command line as opposed to physically plugging and unplugging.

So, if I can "hdiutil detach /dev/disk1s1" as an alternative to ejecting the disk icon, how do I do the reverse -- recreating at the command line what automount (I assume) does when I plug in the USB disk? (This is with the USB disk plugged in but not mounted.)

iBook G4 Mac OS X (10.3.9)

Posted on Jan 2, 2006 12:02 AM

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Answer 1

Camelot

Level 9

58,473 points

Jan 2, 2006 2:37 AM in response to jccc

The opposite of 'detach' is 'attach', so the logical answer would be:

hdiutil attach /dev/disk1s1 -mount required

The -mount option tells the OS to mount volumes on the specified volume.

man hdiutil lists more options supported by hdiutil.

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Answer 2

Jan 2, 2006 4:50 AM in response to jccc

Hi jccc,

I'll suggest you use hdiutil to manipulate disk images and use diskutil or disktool to mount or unmount hard disks. There isn't a manual for disktool. Use this command for instructions.

disktool -help

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Answer 3

jccc Author

Level 1

1 points

Jan 3, 2006 4:35 PM in response to Camelot

06:28 PM: ~ > hdiutil attach /dev/disk1s1 -mount required
Initializing...
Attaching...
Finishing...
hdiutil: attach failed - Operation not permitted

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Answer 4

jccc Author

Level 1

1 points

Jan 3, 2006 4:49 PM in response to Mark Jalbert

06:36 PM: ~ > diskutil mountDisk /dev/disk1s1
Disk Utility Tool ?2002-2003, Apple Computer, Inc.
Usage: diskutil [mount(Disk)|unmount(Disk)|eject] <force>
[Mount Point|Disk Identifier|Device Node]
Mount, unmount or eject disks or volumes.
force is only valid on unmount or unmountDisk.
Example: diskutil unmount /Volumes/SomeDisk

06:47 PM: ~ > disktool -m disk1s1
Cannot find device /dev/disk1s1

06:48 PM: ~ > disktool -m disk1
Cannot find device /dev/disk1

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Answer 5

jccc Author

Level 1

1 points

Jan 3, 2006 4:55 PM in response to jccc

Comments from "zeb" at the end of this thread relate the same problem:
http://forums.macosxhints.com/archive/index.php/t-34244.html

Zeb: "Any ideas about getting a readout [from disktool -l] that includes unmounted but still connected USB drives?"

Perhaps I just cannot do this with my particular USB gadget.

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Answer 6

jccc Author

Level 1

1 points

Jan 3, 2006 5:07 PM in response to jccc

Okay. I can unmount/remount at will, but not eject. Once I've done that, I have to unplug and replug if I want it back.

What I really wanted to do was get it back after ejecting without having to unplug/replug. I guess that's not possible.

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Answer 7

Jan 3, 2006 6:30 PM in response to jccc

Hi jccc,
I'm not sure from where "mountDisk" came but I gather that you figured out that the verb you want is simply "mount". Mounting and unmounting is the part of the process designed for user control so I think you have the most important information.

I don't think you're supposed to be able to eject and then remount. Eject and unmount are very different. Aside from doing everything unmount does ejecting also deletes the device file. Generally a device file is a prerequisite for mounting. While there may be some obscure command that tells the system (maybe diskarbitrationd) to rebuild the device tree, I've never heard of it. You might try sending diskarbitrationd a SIGHUP with "sudo killall -HUP diskarbitrationd". However, be ready with "sudo /sbin/SystemStarter start Disks" should diskarbitrationd die. Mac utilities don't always trap signals like their UNIX brethren. Of course I bet that causes the device tree to be rebuilt.

The simple "workaround" is to use it the way it was designed to be used. If you want to "forget about" the device for a while but not disconnect irreparably, unmount it. Ejecting should be reserved for the moment you actually wish to yank it out.
--
Gary
~~~~
Q. Doctor, Doctor, it hurts when I do this!
A. So don't do that.

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