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Re: Rereading A Partition Table
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Re: Rereading A Partition Table



--- At Thu, 16 Aug 2007 10:53:50 -0400, Dan Markarian wrote:

>Hey Duane,
>
>We do not detect live changes to a partition map in Tiger.

Thanks. Then I am back to my original question. When Disk Utility
(diskutil) partitions a drive it takes it off-line then puts it back on-
line. Clearly this causes everything to be re-read.

I'd like to do the same thing. Disk Arbitration doesn't seem quite the
right tool for doing this. In fact even Disk Utility does not fully
"eject" a firewire disk unless it is partitioning.

I surely don't want to request the user to restart just to re-read
changes to a disk.

Is there somewhere I should look for how to do this? Another mailing list?

Thanks for the help.

>On 15 Aug 2007, at 9:58 PM, Duane Murphy wrote:
>
>> --- At Wed, 15 Aug 2007 17:26:42 -0700, Chris Sarcone wrote:
>>
>>> Duane --
>>>
>>> I'm making changes to GUID partition disks partition table, and I
>>> would
>>> like the system to re-read the disk in order to recognize new
>>> partitions
>>> on the disk.
>>>
>>> What do I need to do to get the system to re-read the disk and
>>> recognize
>>> the changes?
>>>
>>> I've tried several disk util commands (unmountDisk, mountDisk, and
>>> eject) but they don't re-read the disk.
>>>
>>> Disk Utility->Eject does the same thing (ie nothing).
>>>
>>> I note that this is a FireWire drive, but it could also be an
>>> internal
>>> drive or any other non-network drive.
>>>
>>> For example, when Disk Utility partitions a disk, it fully unmounts
>>> and
>>> then remounts the disk. How can I do the same thing?
>>>
>>> Try opening and closing the raw disk node for the whole device.
>>>
>>
>> Hi Chris,
>> That's what I was told. In fact, I am editing the partition table
>> using /
>> dev/rdisk1
>> (or whatever number). But when it is closed it doesn't do anything.
>>
>> Here's how I open. inDisk is "/dev/rdisk1" (for example);
>> 	int diskDescriptor
>> 		= open( inDisk, O_RDWR | O_SHLOCK, S_IRUSR | S_IWUSR | S_IRGRP );
>>
>> later I just
>>
>> close( diskDescriptor );
>>
>> There's no errors and in fact, the disk is nicely edited. If I unplug
>> the drive and plug it back in the partitions looks exactly like what I
>> want, but it's hard to do that for internal disks. :-)

 ...Duane

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References: 
 >Re: Rereading A Partition Table (From: "Duane Murphy" <email@hidden>)
 >Re: Rereading A Partition Table (From: Dan Markarian <email@hidden>)



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