disk-utility interview questions
Top disk-utility frequently asked interview questions
This is out of interest rather then looking for a fix to a problem.
What actually causes permissions on Mac OS X Systems to become messed up? Its an easily fixed problem (i.e. there's a quick and easy fix via Disk Utility) but its something I'd encountered a few times doing support in a Mac-reseller store without actually understanding the causes.
I'd guess that part of it is due to some applications not playing nicely, but what else might be the source of this issue?
Source: (StackOverflow)
I already have Windows XP, During installing Ubuntu(dual boot) the disk drive just stuck up at one place and doesn't seem to move ahead..
Is there a disk bad sector mark utility that just marks these sectors so that the disk doesn't seek them later.
I tried running Seagate Seatools on the drive but both the short test and long test fail even before they start even chkdsk /f/r doesn't seem to work as the system locks up at stage four.
Source: (StackOverflow)
I've downloaded Mac OS X Mountain Lion today and wanted to backup the installation image to a USB drive for later.
I've created a new empty partition of at least 8 GB size on the external drive using Disk Utility, and tried to restore the InstallESD.dmg image to this new partition, via the Restore menu.
However, doing that, I get the following error message, right after it finishes copying:
Cannot Allocate Memory
What can I do now?
Source: (StackOverflow)
I tried a few utils and none of them worked. Either USB wasnt supported or the drive was 'recognized'. I am trying to figure out if i should dump the drive or not. Its only a year old but the warranty is only a year which is a pity.
Source: (StackOverflow)
According to the rasbery pi documentation, You can load your OS to a flash card with either /dev/disk or /dev/rdisk.
rdisk stands for raw disk.
/dev/disk is a block level device, why would rdisk be 20 times faster?
Using Mac OSX
Note: In OS X each disk may have two path references in /dev:
/dev/disk# is a buffered device, which means any data being sent
undergoes extra processing. /dev/rdisk# is a raw path, which is much
faster, and perfectly OK when using the dd program. On a Class 4 SD
card the difference was around 20 times faster using the rdisk path.
Source: (StackOverflow)
I've been looking around for a way to do this for a while, but I haven't been able to find the answer. I need to format my 2 GB SD card to FAT-32, but I don't see the option in Disk Utility.
If I select the SD drive (Apple SDXC Reader Media) and go to 'Erase,' I have the following format options:
- Mac OS extended (Journaled)
- Mac OS extended (Journaled, Encrypted)
- Mac OS extended (Case sensitive, Journaled)
- Mac OS extended (Case sensitive, Journaled, Encrypted)
- MS DOS (FAT)
- ExFAT
Doing the same, but selecting the SD card itself (in my case, NO NAME), I get all the same results, minus Mac OS X's with encryption.
I have read that selecting MS-DOS will chose between FAT-16 and -32, depending on the SD card's size. However, I have a 2 GB one.
Format: MS-DOS (FAT16)
Owners Enabled: No
Number of Folders: 0
Capacity: 1.98 GB (1,975,546,368 Bytes)
Available: 1.79 GB (1,789,296,640 Bytes)
Used: 186 MB (185,991,168 Bytes) --> (I have already backed up)
Number of Files: 512
Source: (StackOverflow)
I have a hard disk that I scanned with TechTool and it reports one bad block. As far as I can tell, TechTool only scans and reports a failure. It doesn't fix anything.
Back in the day, Norton Disk Doctor did the job of scanning and flagging (remapping) bad blocks on the Mac. Today we have various tools for fixing up HFS+ directory errors (Disk Utility, fsck, DiskWarrior, TechTool), but I don't know of any tool that will do a surface scan and fix the bad blocks too.
What software is available for this?
If I know the address of the bad block, is there a low-level terminal utility for marking it?
Source: (StackOverflow)
I am unable to expand my Mac's hard disk. diskutility reports this error:
MediaKit reports partition (map) too small
How can I resolve this?
Source: (StackOverflow)
I have a 10G encrypted volume bundle created with Disk Utility. I want to change it's encryption password. How can I do that?
Source: (StackOverflow)
My external USB drive failed. I made a .dmg image file of the drive using disk utility. Later I was not able to mount the .dmg image. I used terminal
hdiutil attach -noverify -nomount name.dmg
diskutil list
diskutil mountDisk /dev/disk4
then received the following message:
Volume(s) mounted successfully
However, I cant see the drive or access its contents through Finder. Disk Utility shows the drive as ghost but I still cant mount it using diskutility.
Terminal tells me that the drive is mounted and constantly shows it in the diskutil list.
pwd is not the mounted .dmg image. I don't know how to enter into the mounted image drive to see its contents. So in case what I said sounds like I see the files in the mounted image no this is not the case. I do not know how to access or even change the pwd within Terminal. I was hoping to see the mounted drive through Finder but I do not see that.
So I need help as to how to find a way to access the mounted image drive if it was really mounted.
Terminal says that it was and it shows it under diskutil list as a /dev/disk4.
Can someone please help me access the files on this drive?
Source: (StackOverflow)
There is some error reported when I run Disk Utility and verify the root volume on my OS X MacBook. So I boot and CMD-S into the shell mode and run /sbin/fsck -fy.
Errors are like:
** Checking catalog file.
Missing thread record (id = ...)
In correct number of thread records
** Checking catalog hierarchy.
Invalid volume file count
(It should be ... instead of ...)
** Repairing Volume
Missing directory record (id = ...)
I'd like to know what is the cause of the above errors? Hopefully I will be more careful in the future to prevent them from happening again.
p.s. I am using a SSD and so I assume mechanical hard disk error is less likely. Thanks!
Source: (StackOverflow)
I have a MacBook Air that has suddenly stopped booting at all. I booted into recovery mode and see the harddrive fine in Disk Utility. The partition is there as well marked: Mac OS X Base System. I can verify this partition with Verify Disk. The disk verifies just fine and appears to be ok.
However when I go to set it as the startup disk (in Choose startup disk), it doesn't show. I get a blank list.
What gives? How can the disk be seen by Disk Utility but not Choose startup disk?
Other things attempted:
- ⌥⌘RP to reset PRAM (reset the box)
- Shift on boot for safe mode (did nothing)
Source: (StackOverflow)
I'm using ZFS on OSX and I've zpool which is active and online:
NAME SIZE ALLOC FREE CAP DEDUP HEALTH ALTROOT
WD_1TB 931G 280G 651G 30% 1.00x ONLINE -
but I can't actually mount it.
$ sudo zfs mount WD_1TB
cannot open 'WD_1TB': pool I/O is currently suspended
cannot open 'WD_1TB': pool I/O is currently suspended
or unmount it:
$ sudo zfs unmount WD_1TB
cannot open 'WD_1TB': pool I/O is currently suspended
cannot open 'WD_1TB': pool I/O is currently suspended
or even destroy it:
$ sudo zpool destroy -f WD_1TB
cannot open 'WD_1TB': pool I/O is currently suspended
When doing zpool export WD_1TB it just freezes.
When clearing device errors in a pool, there is an error as well:
$ sudo zpool clear WD_1TB
cannot clear errors for WD_1TB: I/O error
Above happening whatever the disk is connected via USB or not.
What's interesting that zpool status points zpool to /dev/disk1, but diskutil list points to /dev/disk3.
I've enabled debug messages via: sysctl -w zfs.vnops_osx_debug=1 and run sudo dmesg | tail which shows something like:
0 [Level 3] [Facility com.apple.system.fs] [ErrType IO] [ErrNo 6] [IOType Read] [PBlkNum 0] [LBlkNum 0]
0 [Level 3] [Facility com.apple.system.fs] [DevNode devfs] [MountPt /dev] [Path /dev/disk1s2]
disk1s2: media is not present.
0 [Level 3] [Facility com.apple.system.fs] [ErrType IO] [ErrNo 6] [IOType Read] [PBlkNum 512] [LBlkNum 512]
0 [Level 3] [Facility com.apple.system.fs] [DevNode devfs] [MountPt /dev] [Path /dev/disk1s2]
zfs_vnop_write(vp 0xffffff804f6303c0, offset 0x12b00000 size 0x10000
zfs_vnop_write(vp 0xffffff804f6303c0, offset 0x12b10000 size 0x10000
zfs_vnop_write(vp 0xffffff804f6303c0, offset 0x12b20000 size 0x10000
zfs_vnop_write(vp 0xffffff804f6303c0, offset 0x12b30000 size 0x10000
zfs_vnop_write(vp 0xffffff8051b031e0, offset 0x1f0000 size 0x10000
Connecting or disconnecting HDD doesn't help.
Any way of simply mounting the HDD on OSX in above circumstances?
Related:
Source: (StackOverflow)
I have a long, complicated password for an external drive encrypted with FileVault that I have securely stored, but OS X doesn’t allow pasting into the password unlock GUI dialog (argh!). How can I unlock it via the terminal so I can paste the password in there?
Source: (StackOverflow)