From LedHed's Wiki
Overview
If you install Ubuntu as an ESXi VM and remove the Floppy virtual hardware Ubuntu will boot slower and throw this error:
blk_update_request: I/O error, dev fd0, sector 0 op 0x0:(READ) flags 0x0 phys_seg 1 prio class 0
How to Fix
Login to your Ubuntu VM and run the following:
sudo rmmod floppy echo "blacklist floppy" | sudo tee /etc/modprobe.d/blacklist-floppy.conf sudo dpkg-reconfigure initramfs-tools
Reboot.
Reference
https://askubuntu.com/questions/719058/blk-update-request-i-o-error-dev-fd0-sector-0