升级到 Ubuntu 18.04 后，我的启动需要 3 分钟以上的时间，尝试执行软盘读取之类的操作（没有软盘存在）。
这是我在启动过程中粗略看到的摘录/var/log/boot.log，尽管在启动过程中似乎还有一些输出（包括一些关于放弃等待的注释），但我在启动完成后的日志中找不到这些输出：
[ 4.034457] ata2: SATA link down (SStatus 0 SControl 300)
[ 4.370680] ata3: SATA link down (SStatus 0 SControl 300)
[ 4.706681] ata4: SATA link down (SStatus 0 SControl 300)
[ 5.204035] ata5: SATA link up 3.0 Gbps (SStatus 123 SControl 300)
[ 5.227738] ata5.00: ATA-8: Hitachi HDS721010CLA332, JP4OA3MA, max UDMA/133
[ 5.249953] ata5.00: 1953525168 sectors, multi 0: LBA48 NCQ (depth 31/32), AA
[ 5.273709] ata5.00: configured for UDMA/133
[ 5.296052] scsi 4:0:0:0: Direct-Access ATA Hitachi HDS72101 A3MA PQ: 0 ANSI: 5
[ 5.318606] sd 4:0:0:0: Attached scsi generic sg0 type 0
[ 5.318752] sd 4:0:0:0: [sda] 1953525168 512-byte logical blocks: (1.00 TB/932 GiB)
[ 5.318812] sd 4:0:0:0: [sda] Write Protect is off
[ 5.318813] sd 4:0:0:0: [sda] Mode Sense: 00 3a 00 00
[ 5.318890] sd 4:0:0:0: [sda] Write cache: enabled, read cache: enabled, doesn't support DPO or FUA
[ 5.366205] sda: sda1 sda2 sda3 sda4
[ 5.366658] sd 4:0:0:0: [sda] Attached SCSI disk
[ 5.936034] ata6: SATA link up 1.5 Gbps (SStatus 113 SControl 300)
[ 5.959911] ata6.00: ATAPI: TSSTcorp DVDWBD SH-B123L, SB03, max UDMA/100
[ 5.985249] ata6.00: configured for UDMA/100
[ 6.010890] scsi 5:0:0:0: CD-ROM TSSTcorp DVDWBD SH-B123L SB03 PQ: 0 ANSI: 5
[ 6.098266] sr 5:0:0:0: [sr0] scsi3-mmc drive: 48x/48x writer dvd-ram cd/rw xa/form2 cdda tray
[ 6.121604] cdrom: Uniform CD-ROM driver Revision: 3.20
[ 6.144998] sr 5:0:0:0: Attached scsi CD-ROM sr0
[ 6.145208] sr 5:0:0:0: Attached scsi generic sg1 type 5
[ 60.388280] print_req_error: I/O error, dev fd0, sector 0
[ 60.412397] floppy: error 10 while reading block 0
[ 83.427787] print_req_error: I/O error, dev fd0, sector 0
[ 83.452049] floppy: error 10 while reading block 0
[ 106.380206] print_req_error: I/O error, dev fd0, sector 0
[ 106.404593] floppy: error 10 while reading block 0
[ 106.429281] random: crng init done
[ 129.368293] print_req_error: I/O error, dev fd0, sector 0
[ 129.392645] floppy: error 10 while reading block 0
[ 153.408135] print_req_error: I/O error, dev fd0, sector 0
[ 153.432814] floppy: error 10 while reading block 0
[ 176.423440] print_req_error: I/O error, dev fd0, sector 0
[ 176.448027] floppy: error 10 while reading block 0
[ 199.631450] print_req_error: I/O error, dev fd0, sector 0
[ 199.655318] floppy: error 10 while reading block 0
[ 222.659803] print_req_error: I/O error, dev fd0, sector 0
[ 222.683064] floppy: error 10 while reading block 0
[ 245.843419] print_req_error: I/O error, dev fd0, sector 0
[ 245.865876] floppy: error 10 while reading block 0
[ 268.856302] print_req_error: I/O error, dev fd0, sector 0
[ 268.878046] floppy: error 10 while reading block 0
[ 292.004186] print_req_error: I/O error, dev fd0, sector 0
[ 292.025434] floppy: error 10 while reading block 0
[ 315.024279] print_req_error: I/O error, dev fd0, sector 0
[ 315.045328] floppy: error 10 while reading block 0
[ 315.553949] EXT4-fs (sda4): mounted filesystem with ordered data mode. Opts: (null)
是什么原因导致了这种输出？我该如何消除这个问题？