Mount (File System)

To mount a file system is to attach it to the operating system so its files become reachable at a particular path, called the mount point. On Linux and macOS, drives appear as folders in a single tree; Windows usually assigns a drive letter instead.

Why it matters

A disk can be physically connected yet unusable until it is mounted. Understanding mounting explains why a USB drive must be safely ejected (unmounted), how network shares such as NFS or SMB appear as local folders, and how an ISO file can be opened as a virtual disc. In Linux, /etc/fstab lists the file systems mounted at boot.

Example

sudo mount /dev/sdb1 /mnt/usb
ls /mnt/usb
sudo umount /mnt/usb

The first command attaches the partition to /mnt/usb, the second lists its files and the third detaches it safely. A matching fstab line would be UUID=1234-ABCD /mnt/usb exfat defaults 0 0.

Common mistakes

• Pulling a drive without unmounting, risking unwritten data and corruption.
• Mounting over a non-empty directory, which temporarily hides its contents.
• Using /dev/sdX names in fstab; these can change, so UUIDs are more reliable.

Related

• File system
• ISO file
• Disk partition
• File path

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