我刚刚格式化了 microSD 卡，并想运行dd命令。不幸的是dd命令失败：
$ sudo dd bs=1m if=2016-02-26-raspbian-jessie-lite.img of=/dev/rdisk2
dd: /dev/rdisk2: Resource busy
$
互联网上的每个人都说我需要先卸载磁盘。当然，可以做到这一点并继续前进。但我想了解 OS X 中的原因/到底是什么使设备繁忙？我该如何诊断这个问题？
到目前为止我尝试过：
列出打开的文件：
$ lsof /dev/disk2 $ lsof /dev/disk2s1 $还：
$ lsof /Volumes/UNTITLED $列出处理该文件的用户：
$ fuser -u /dev/disk2 /dev/disk2: $ fuser -u /dev/disk2s1 /dev/disk2s1: $还：
$ fuser -u /Volumes/UNTITLED $检查系统消息：
$ sudo dmesg | grep disk $还：
$ sudo dmesg | grep /Volumes/UNTITLED $
我的环境
操作系统：
Darwin Eugenes-MacBook-Pro-2.local 15.3.0 Darwin Kernel Version 15.3.0: Thu Dec 10 18:40:58 PST 2015; root:xnu-3248.30.4~1/RELEASE_X86_64 x86_64有关我的 microSD 的信息：
diskutil list disk2 /dev/disk2 (internal, physical): #: TYPE NAME SIZE IDENTIFIER 0: FDisk_partition_scheme *31.9 GB disk2 1: DOS_FAT_32 UNTITLED 31.9 GB disk2s1
PS 我使用的是 OS X 10.11。
更新 22/3/2016。弄清楚了。我使用上面重新运行了lsofand ，终于找到了问题的根源：fusersudo
$ sudo fuser /Volumes/UNTITLED/
/Volumes/UNTITLED/: 62 282
$
和：
$ sudo lsof /Volumes/UNTITLED/
COMMAND PID USER FD TYPE DEVICE SIZE/OFF NODE NAME
mds 62 root 8r DIR 1,6 32768 2 /Volumes/UNTITLED
mds 62 root 22r DIR 1,6 32768 2 /Volumes/UNTITLED
mds 62 root 23r DIR 1,6 32768 10 /Volumes/UNTITLED/.Spotlight-V100/Store-V2/A2D41CCB-48CC-45F3-B8D6-F3B383D91AAD
mds 62 root 25u REG 1,6 0 999999999 /Volumes/UNTITLED/.Spotlight-V100/Store-V2/A2D41CCB-48CC-45F3-B8D6-F3B383D91AAD/journalExclusion
mds_store 282 root txt REG 1,6 3277 17 /Volumes/UNTITLED/.Spotlight-V100/Store-V2/A2D41CCB-48CC-45F3-B8D6-F3B383D91AAD/0.indexGroups
mds_store 282 root txt REG 1,6 8 23 /Volumes/UNTITLED/.Spotlight-V100/Store-V2/A2D41CCB-48CC-45F3-B8D6-F3B383D91AAD/0.indexCompactDirectory
mds_store 282 root txt REG 1,6 312 19 /Volumes/UNTITLED/.Spotlight-V100/Store-V2/A2D41CCB-48CC-45F3-B8D6-F3B383D91AAD/0.indexTermIds
mds_store 282 root txt REG 1,6 3277 29 /Volumes/UNTITLED/.Spotlight-V100/Store-V2/A2D41CCB-48CC-45F3-B8D6-F3B383D91AAD/live.0.indexGroups
mds_store 282 root txt REG 1,6 1024 35 /Volumes/UNTITLED/.Spotlight-V100/Store-V2/A2D41CCB-48CC-45F3-B8D6-F3B383D91AAD/live.0.indexCompactDirectory
mds_store 282 root txt REG 1,6 312 21 /Volumes/UNTITLED/.Spotlight-V100/Store-V2/A2D41CCB-48CC-45F3-B8D6-F3B383D91AAD/0.indexPositionTable
mds_store 282 root txt REG 1,6 8192 31 /Volumes/UNTITLED/.Spotlight-V100/Store-V2/A2D41CCB-48CC-45F3-B8D6-F3B383D91AAD/live.0.indexTermIds
mds_store 282 root txt REG 1,6 2056 22 /Volumes/UNTITLED/.Spotlight-V100/Store-V2/A2D41CCB-48CC-45F3-B8D6-F3B383D91AAD/0.indexDirectory
mds_store 282 root txt REG 1,6 8192 33 /Volumes/UNTITLED/.Spotlight-V100/Store-V2/A2D41CCB-48CC-45F3-B8D6-F3B383D91AAD/live.0.indexPositionTable
mds_store 282 root txt REG 1,6 8224 34 /Volumes/UNTITLED/.Spotlight-V100/Store-V2/A2D41CCB-48CC-45F3-B8D6-F3B383D91AAD/live.0.indexDirectory
mds_store 282 root txt REG 1,6 16 16 /Volumes/UNTITLED/.Spotlight-V100/Store-V2/A2D41CCB-48CC-45F3-B8D6-F3B383D91AAD/0.indexIds
mds_store 282 root txt REG 1,6 65536 48 /Volumes/UNTITLED/.Spotlight-V100/Store-V2/A2D41CCB-48CC-45F3-B8D6-F3B383D91AAD/reverseDirectoryStore
mds_store 282 root txt REG 1,6 704 24 /Volumes/UNTITLED/.Spotlight-V100/Store-V2/A2D41CCB-48CC-45F3-B8D6-F3B383D91AAD/0.indexArrays
mds_store 282 root txt REG 1,6 65536 26 /Volumes/UNTITLED/.Spotlight-V100/Store-V2/A2D41CCB-48CC-45F3-B8D6-F3B383D91AAD/0.directoryStoreFile
mds_store 282 root txt REG 1,6 32768 28 /Volumes/UNTITLED/.Spotlight-V100/Store-V2/A2D41CCB-48CC-45F3-B8D6-F3B383D91AAD/live.0.indexIds
mds_store 282 root txt REG 1,6 65536 36 /Volumes/UNTITLED/.Spotlight-V100/Store-V2/A2D41CCB-48CC-45F3-B8D6-F3B383D91AAD/live.0.indexArrays
mds_store 282 root txt REG 1,6 65536 38 /Volumes/UNTITLED/.Spotlight-V100/Store-V2/A2D41CCB-48CC-45F3-B8D6-F3B383D91AAD/live.0.directoryStoreFile
mds_store 282 root 5r DIR 1,6 32768 10 /Volumes/UNTITLED/.Spotlight-V100/Store-V2/A2D41CCB-48CC-45F3-B8D6-F3B383D91AAD
mds_store 282 root 17u REG 1,6 8192 12 /Volumes/UNTITLED/.Spotlight-V100/Store-V2/A2D41CCB-48CC-45F3-B8D6-F3B383D91AAD/psid.db
mds_store 282 root 32r DIR 1,6 32768 10 /Volumes/UNTITLED/.Spotlight-V100/Store-V2/A2D41CCB-48CC-45F3-B8D6-F3B383D91AAD
mds_store 282 root 41u REG 1,6 28 15 /Volumes/UNTITLED/.Spotlight-V100/Store-V2/A2D41CCB-48CC-45F3-B8D6-F3B383D91AAD/indexState
$
从上面很容易看出进程被调用mds，mds_store已经创建，并且正在保持该卷上有很多文件。
答案1
苹果法庭，苹果裁决。尝试diskutil：
$ diskutil list
...
# if mounted somewhere
$ sudo diskutil unmount $device
# all the partitions (there's also a "force" option, see the manual)
$ sudo diskutil unmountDisk $device
# remember zip drives? this would launch them. good times!
$ sudo diskutil eject $device
（对于磁盘映像，该hdiutil命令也可能令人感兴趣。您也可以在 中单击Disk Utility.app。）
答案2
卸载子分区有帮助
/dev/disk2
#: TYPE NAME SIZE IDENTIFIER
0: FDisk_partition_scheme *8.0 GB disk2
1: Windows_FAT_16 wr_usb_efi 134.2 MB disk2s1
2: Linux 1.1 GB disk2s2
vgsprasad-mbp:~ vgsprasad$ diskutil umount /dev/disk2s1
Volume wr_usb_efi on disk2s1 unmounted
vgsprasad-mbp:~ vgsprasad$ diskutil umount /dev/disk2s2
disk2s2 was already unmounted