我有一个外部驱动器，我想用它来备份我的主目录，因为我的 Ubuntu 18.04 桌面安装最近出现了错误。最初，我将其插入桌面的 USB 端口，它被识别并自动安装。无论出于何种原因（我很累），我将其拔出并重新插入而没有卸载。随后，它现在给我带来了困扰，/dev 中没有弹出 sdc 文件，并且使用 lsusb、gparted、dmesg 或我尝试过的其他一些命令也没有找到它的踪迹。
我将它插入我的笔记本电脑（也是 Ubuntu 18.04），它立即被检测到并安装。我再次对其进行分区并添加了新的 ext4 文件系统，然后卸载设备并在桌面上再次尝试。仍然没有被发现。
我还多次重新启动系统并尝试了各种 USB 端口，结果表明它们都可以工作。更让我困惑的是，我的桌面正在识别 U 盘。
任何帮助将不胜感激，谢谢
编辑
fdisk -l 的输出仅显示我的内部驱动器
Disk /dev/sdb: 931.5 GiB, 1000204886016 bytes, 1953525168 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
Disk /dev/sda: 232.9 GiB, 250059350016 bytes, 488397168 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: gpt
Disk identifier: 001F511E-EAC4-4F52-A84C-E1DEA384BEC5
Device Start End Sectors Size Type
/dev/sda1 2048 1050623 1048576 512M EFI System
/dev/sda2 1050624 488396799 487346176 232.4G Linux filesystem
dmesg 的输出通过管道输送到 sd 的正则表达式中
[ 0.006822] ACPI: SSDT 0x000000008E1FEA98 003154 (v02 SaSsdt SaSsdt 00003000 INTL 20160422)
[ 0.006823] ACPI: SSDT 0x000000008E201BF0 0025E1 (v02 PegSsd PegSsdt 00001000 INTL 20160422)
[ 0.006831] ACPI: SSDT 0x000000008E204D98 000EDE (v02 CpuRef CpuSsdt 00003000 INTL 20160422)
[ 0.902360] ahci 0000:00:17.0: flags: 64bit ncq sntf led clo only pio slum part ems deso sadm sds apst
[ 1.284781] sd 1:0:0:0: Attached scsi generic sg0 type 0
[ 1.284906] sd 1:0:0:0: [sda] 488397168 512-byte logical blocks: (250 GB/233 GiB)
[ 1.284913] sd 1:0:0:0: [sda] Write Protect is off
[ 1.284914] sd 1:0:0:0: [sda] Mode Sense: 00 3a 00 00
[ 1.284926] sd 1:0:0:0: [sda] Write cache: enabled, read cache: enabled, doesn't support DPO or FUA
[ 1.285012] sd 3:0:0:0: Attached scsi generic sg1 type 0
[ 1.285040] sd 3:0:0:0: [sdb] 1953525168 512-byte logical blocks: (1.00 TB/932 GiB)
[ 1.285041] sd 3:0:0:0: [sdb] 4096-byte physical blocks
[ 1.285048] sd 3:0:0:0: [sdb] Write Protect is off
[ 1.285049] sd 3:0:0:0: [sdb] Mode Sense: 00 3a 00 00
[ 1.285058] sd 3:0:0:0: [sdb] Write cache: enabled, read cache: enabled, doesn't support DPO or FUA
[ 1.311685] sda: sda1 sda2
[ 1.312239] sd 1:0:0:0: [sda] supports TCG Opal
[ 1.312240] sd 1:0:0:0: [sda] Attached SCSI disk
[ 1.326145] sd 3:0:0:0: [sdb] Attached SCSI disk
[ 2.650657] EXT4-fs (sda2): mounted filesystem with ordered data mode. Opts: (null)
[ 2.931667] EXT4-fs (sda2): re-mounted. Opts: errors=remount-ro
[ 3.568905] EXT4-fs (sdb): mounted filesystem with ordered data mode. Opts: (null)