User's Manual

1.2. Acronis True Image Home 2010 Netbook Edition
basic concepts
This section provides general information about basic concepts which could be useful for
understanding how the program works.
Backup
According to Wikipedia, "backup refers to making copies of data so that these additional copies may
be used to restore the original after a data loss event. Backups are useful primarily for two purposes.
The first is to restore a state following a disaster (called disaster recovery). The second is to restore
small numbers of files after they have been accidentally deleted or corrupted."
Acronis True Image Home 2010 Netbook Edition provides for both purposes by creating disk (or
partition) images and file-level backups respectively. By default, Acronis True Image Home 2010
Netbook Edition stores in an image only those hard disk parts that contain data (for supported file
systems). However, you may use an option that lets you include in an image all of the sectors of a
hard disk (so called sector-by-sector backup). When you back up files and folders, only the data, along
with the folder tree, is compressed and stored.
Backup archive components
Archive - Known as archive chain or archive group, it is the whole set of backup files managed by a
single backup task. The archive can consist of one or several slices.
Slice - It is a set of files created during each cycle of the task execution. The amount of slices created
is always equal to the amount of times the task is executed. A slice represents a point in time, to
which the system or data can be recovered.
Volume - It is a tib file associated with the slice. Usually there is only one volume per slice however,
each slice may consist of several volumes. If you have set archive splitting in the task options, the
resulting slice will be split into several files. In addition, Acronis True Image Home 2010 Netbook
Edition automatically splits a slice into several files of 4GB each (except the last file) when you make a
large backup to a FAT32 formatted hard disk. These files are the slice's volumes.
Snapshots
While creating disk images, Acronis True Image Home 2010 Netbook Edition uses "snapshot"
technology that allows creating even system partition backups while running Windows with files open
for reading and writing without the necessity to reboot the computer. Once the program starts the
partition backup process, it temporarily freezes all the operations on the partition and creates its
"snapshot". Snapshot creation usually takes just several seconds. After that the operating system
continues working as the imaging process is under way and you will not notice anything unusual in
the operating system functionality.
In its turn, the Acronis driver continues working to keep the point-in-time view of the partition.
Whenever the driver sees a write operation directed at the partition, it checks whether these sectors
are already backed up and if they are not, the driver saves the data on the sectors to be overwritten
to a special buffer, then allows overwriting. The program backs up the sectors from the buffer, so that
all the partition sectors of the point-in-time when the snapshot was taken will be backed up intact
and an exact "image" of the partition will be created.