Operation Manual

Hard Disk And Operating System
112
Copyright © Acronis, Inc., 2000–2005
Table 2. Linux file systems.
File system Ext2 Ext3 ReiserFS
Operating systems Linux Linux Linux
Max. partition size
16 TB 16 TB 16 TB
Max. file size Limited by
partition size
Limited by partition
size
Limited by partition
size
Max. filename length
255 255 255
Restoration (logging) No
Y
es
Y
es
Max. files in root Unlimited Unlimited Unlimited
Max. clusters/blocks
~2
32
~2
32
~2
32
Cluster/block size
1–4 KB 1–4 KB 4 KB
File record table/I-node Set at formatting Set at formatting Dynamic
In case you've forgotten your computer engineering units: 1 Kbyte = 1024 Bytes,
1 Mbyte = 1024 Kbytes, 1 Gbyte = 1024 Mbytes, 1 Tbyte = 2
10
Gbytes= 1024
Gbytes, 1 Pbyte = 2
10
Tbytes= 1024 Tbytes, 1 Ebyte = 2
10
Pbytes= 1024 Pbytes.
A.9.2 FAT16
The FAT16 file system is widely used by DOS (DR-DOS, MS-DOS, PC-DOS, etc.),
Windows 95/98/Me, Windows NT/2000/XP operating systems and is supported
by most other systems.
Main features of FAT16 are the file allocation table (FAT) and clusters. The FAT is
the core of the file system. To increase data safety, it is possible to have several
instances of the FAT (there are usually two of them). A cluster is a minimum data
storage unit in the FAT16 file system. One cluster contains a fixed number (some
power of 2) of sectors. The FAT stores information about what clusters are free,
what clusters are bad, and also defines in what clusters files are stored.
Maximum size of a FAT16 file system is 4 Gigabytes, and the maximum number
of clusters is 65,525, the largest cluster being 128 sectors. Usually the smallest
possible cluster size is selected so that the resulting number of clusters is less
than 65,526. The larger the partition size, the larger the cluster has to be. Most
operating systems incorrectly perform with 128-sector clusters, thus reducing the
maximum FAT16 partition size to 2 Gigabytes.
Usually the larger the cluster size, the more disk space is wasted.