[X-Unix] Running fsck on a target disk

[John Johnson]

There is a little info on it here:
http://tinyurl.com/7yvvw

Basically, /rdisk's are raw, unbuffered (character mode) access to  
the disk, whereas /disk's are buffered by the kernel.

Regards,
   JJ

On 11-Aug-2006, at 08:32, Alexandre Gauthier wrote:

> Hi Eric,
>
> I only asked since when you boot in single user mode and issue an  
> fsck on
> the root file system as per the instructions, it uses /dev/ 
> rdisk0sX, the raw
> block device...
>
> It's also what /etc/rc does, I believe... But thanks!
>
>
> On 27/07/06 15:49, "Eric F Crist" <ecrist at secure-computing.net> wrote:
>
>> Alexandre,
>>
>> According to all the documentation from Apple I've read, and my small
>> amount of experience, no.  You should use disk0s3, not rdisk0s3.
>> Don't know the particulars though.
>>
>> Eric
>>
>>
>> On Jul 27, 2006, at 6:09 AM, Alexandre Gauthier wrote:
>>
>>> Sorry for interrupting, but is that not supposed to be  
>>> "rdisk0s3"? As
>>> in, the raw block device? /etc/rc does this when fsck'ing...
>>>
>>> Eric F Crist wrote:
>>>> Thom,
>>>>
>>>> There is only one 'trick' to running fsck. You need to define the
>>>> mount point as one of the arguments, usually the last. On a typical
>>>> Mac system running Mac OS X, you could run fsck on the primary file
>>>> system by running:
>>>>
>>>> # fsck_hfs /dev/disk0s3
>>>>
>>>> To run the above command on an HFS formatted file system, type:
>>>>
>>>> # df -h
>>>>
>>>> This allows you to find out where your disk is mounted. When I
>>>> connect
>>>> a USB HFS formatted disk (an old startup volume, actually) I get:
>>>>
>>>> Filesystem Size Used Avail Capacity Mounted on
>>>> /dev/disk0s3 93G 34G 58G 37% /
>>>> devfs 100K 100K 0B 100% /dev
>>>> fdesc 1.0K 1.0K 0B 100% /dev
>>>> <volfs> 512K 512K 0B 100% /.vol
>>>> automount -nsl [201] 0B 0B 0B 100% /Network
>>>> automount -fstab [205] 0B 0B 0B 100% /automount/Servers
>>>> automount -static [205] 0B 0B 0B 100% /automount/static
>>>> /dev/disk1s3 74G 67G 7.2G 90% /Volumes/Macintosh HD 1
>>>>
>>>> I can see that my new mount, Macintosh HD 1, is filesystem
>>>> /dev/disk1s3 which means, 2nd hard disk, slice 3. Computers  
>>>> typically
>>>> start counting from 0, so 1 is actually 2. ;)
>>>>
>>>> Finally, to run fsck, we use Apple's fsck_hfs utility against the
>>>> above listed filesystem, NOT the mount point, /Volumes/Macintosh
>>>> HD 1.
>>>>
>>>> # fsck_hfs /dev/disk1s3
>>>>
>>>> I hope this helps!
>>>>
>>>> -----
>>>> Eric F Crist
>>>> Secure Computing Networks
>>>>
>>>>
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>>>>
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>>>
>>>
>>> -- 
>>> Alexandre Gauthier
>>> supernaut at underwares.org
>>>
>>> underwares.org
>>> Obscure IT knowledge Open Database
>>>
>>> The human brain operates at only 10% of its capacity. The rest is
>>> overhead for
>>> the operating system.
>>>
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>>> stuff:
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>>>
>>
>> -----
>> Eric F Crist
>> Secure Computing Networks
>>
>>
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>>
>> Listmom is trying to clean out his closets! Vintage Mac and random  
>> stuff:
>>          http://search.ebay.com/_W0QQsassZmacguy1984
>
>
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