The SunOS release 5.7 fsck(1M) command differs significantly from the SunOS release 4 version of the command. In keeping with the virtual file-system (VFS) architecture, the fsck file-checking utility has two parts:
A generic command that is called first, regardless of the type of file system.
A specific command that is called by the generic command, depending on the type of the target file system (see "Generic File System Commands").
In addition, fsck accepts only names conforming to the SunOS release 5.7 device naming conventions. For more information, see "Device Naming Conventions".
The fsck command performs faster consistency checks at mount time. In addition, the SunOS release 5.7 software does not require you to reboot the system after running fsck on the root and /usr file systems. This results in faster system startup compared to previous SunOS releases. The fsck -m command enables you to skip checking for file systems that are clean. See fsck(1m) for additional details.