Acronis Disk Director 11 Advanced Server - User Guide - Manual (Page 92)

92 Copyright © Acronis, Inc., 2000-2010
Physical disk
A disk (p. 85) that is physically a separate device. Thus, floppy disks, hard disks and CD-ROMs are
physical disks.
Primary partition
See Primary volume (p. 92).
Primary volume
A volume which is located on a portion of a basic disk (p. 83) and works as if it were on a separate
hard disk.
Primary volumes often store files that are necessary to start the machine or an operating system.
Many operating systems can start only from a primary volume.
The number of primary volumes on the disk is limited and depends on the partitioning scheme (p.
91).
A primary volume is also called a primary partition.
R
RAID-5 volume
A fault-tolerant volume (p. 94) whose data is striped in equally-sized blocks across an array of three
or more disks (p. 85).
Fault tolerance is achieved by using parity, a calculated value that can be used to reconstruct data in
case of a failure. Parity is also striped across the disk array. Parity is always stored on a different disk
than the data itself. If one of the hard disks fails, the portion of the RAID-5 volume that was on that
hard disk can be recreated from the remaining data and the parity.
A RAID-5 volume has a higher volume-size-to-disk-space ratio than a mirrored volume. For example,
suppose that you want to use 120 GB of disk space to create a fault-tolerant volume:

By using two 60-GB disks, you can create a 60-GB mirrored volume.

By using three 40-GB disks, you can create an 80-GB RAID-5 volume.
Root folder
The folder (p. 88) where the folder tree of a file system (p. 87) begins.
Starting from the root folder, you can uniquely describe the file (p. 87) position in the folder tree by
sequentially naming all the intermediate nested folders—for example:
\Windows\System32\Vmm32.vxd.
In this example, the Windows folder is a subfolder of the root folder, the System32 folder is a
subfolder of the Windows folder, and the Vmm32.vxd file is located in the System32 folder.