Apple Mac OS X Server manual Understanding Disks, Partitions, and the File System

Working with Disks and Volumes 7

In this chapter you will find commands that are used to initialize and test disks and volumes.

Computers use disks and partitions to store and organize data. This chapter covers the commands that are used to manage, configure, initialize, and test disks and volumes.

Understanding Disks, Partitions, and the File System

Like UNIX, Mac OS X uses special files called device files, located in /dev, to keep track of the devices (disks, keyboards, monitors, network connections, and so on) attached to the computer. Device files for a disk are named /dev/diskn, where n is the number of the disk. For example, a computer with one drive would have a device file called /dev/ disk0. If the computer has a second drive, the computer creates a second device file called /dev/disk1, and so on. Each drive that is divided into multiple partitions has a device file for each partition. The first partition on disk 0 would be called /dev/disk0s1, the second partition would be /dev/disk0s2, and so on.

Although Mac OS X Server assigns a device name to each device, the files on a particular device are not accessed in this way. A virtual file system is created where all files on all devices appear to exist under a single hierarchy. This sets one root folder and every file exisiting on the computer is under that folder. This is known as the Hierarchical File System (HFS+). The root folder can exist anywhere on a network as a shared resource.

Mounting and Unmounting Volumes

To gain access to files on a different device, you must first mount the device.

This process informs the operating system where in the folder tree you would like those files to appear. The folder given to the operating system is the mount point. Different volumes on a computer may have different file systems.

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