今天，我的主要 USB 密钥出现了一个奇怪的问题，我希望有办法从中提取一些数据。在 Linux 系统上，USB 正在工作，但过了一会儿就变成了只读模式。所以我卸载了它，无法再次安装它。
当我插入 USB 时，我在 dmesg 输出中看到：
[ 130.015152] usb 2-1.1: USB disconnect, device number 4
[ 148.668176] usb 2-1.1: new high-speed USB device number 5 using ehci-pci
[ 148.778233] usb 2-1.1: New USB device found, idVendor=0c76, idProduct=0005
[ 148.778237] usb 2-1.1: New USB device strings: Mfr=1, Product=2, SerialNumber=0
[ 148.778240] usb 2-1.1: Product: USB Mass Storage
[ 148.778242] usb 2-1.1: Manufacturer: GENERIC
[ 148.778786] usb-storage 2-1.1:1.0: USB Mass Storage device detected
[ 148.778997] scsi host4: usb-storage 2-1.1:1.0
[ 149.805608] scsi 4:0:0:0: Direct-Access GENERIC USB Mass Storage 1.00 PQ: 0 ANSI: 4 CCS
[ 149.806163] sd 4:0:0:0: Attached scsi generic sg2 type 0
[ 149.808241] sd 4:0:0:0: [sdb] Attached SCSI removable disk
lsusb 命令显示它是 Transcend Flash Disk：
Bus 002 Device 003: ID 05c6:9204 Qualcomm, Inc.
Bus 002 Device 005: ID 0c76:0005 JMTek, LLC. Transcend Flash disk
Bus 002 Device 002: ID 8087:0020 Intel Corp. Integrated Rate Matching Hub
Bus 002 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 001 Device 004: ID 17ef:480f Lenovo Integrated Webcam [R5U877]
Bus 001 Device 003: ID 0a5c:217f Broadcom Corp. BCM2045B (BDC-2.1)
Bus 001 Device 002: ID 8087:0020 Intel Corp. Integrated Rate Matching Hub
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
lsscsi 显示它附加为 ID 4：
[0:0:0:0] disk ATA SanDisk SDSSDA24 30RL /dev/sda
[1:0:0:0] cd/dvd Optiarc DVD RW AD-7930H 1.D0 /dev/sr0
[4:0:0:0] disk GENERIC USB Mass Storage 1.00 /dev/sdb
该设备在 /dev 中显示为块设备，但没有分区：
% ls -l /dev/sdb* /dev/disk/by-id/usb-GENERIC_USB_Mass_Storage-0:0
lrwxrwxrwx 1 root root 9 ott 23 14:52 /dev/disk/by-id/usb-GENERIC_USB_Mass_Storage-0:0 -> ../../sdb
brw-rw---- 1 root disk 8, 16 ott 23 14:52 /dev/sdb
Now, whatever I try to execute on the device I got a Medium not found or cannot open file error:
% sudo fdisk -l /dev/sdb
fdisk: cannot open /dev/sdb: No medium found
% sudo testdisk /dev/sdb
TestDisk 7.0, Data Recovery Utility, April 2015
Christophe GRENIER <[email protected]>
http://www.cgsecurity.org
Unable to open file or device /dev/sdb: No medium found
```
% sudo dd if=/dev/sdb of=/tmp/disk.img
dd: failed to open '/dev/sdb': No medium found
% sudo gpart /dev/sdb
*** Fatal error: open(/dev/sdb): No medium found.
我怀疑分区表已经消失了，我能否从该设备中获取数据？
更新：我注意到磁盘未列在下面，/dev/disk/by-uuid而它有指向/dev/disk/by-id和朋友的链接。这证实了主要问题是存储似乎处于非活动状态，而板载控制器处于活动状态（猜测）。