They exist when more than one directory entry references the same inode. Hence, when a hard link is opened by a user program, the directory entry that is opened points directly to the inode of the data to be provided. And, when a hard link is deleted using rm , the directory entry is removed. Only when one deletes the last remaining directory entry that points to an inode are the data deleted. Special Special files are also known as device files .
Device files contain information on location, type, and access mode for a specific device.
When a device file is opened, the kernel uses the information in it to determine which physical device to access and how to access it. Character device files are associated with character or raw device access. They are used for unbuffered data transfers to and from a device. Rather than transferring data in blocks the data is transfered character by character. One transfer can consist of multiple characters.