User`s manual

Dynamic C User’s Manual digi.com 165
Figure 3. High-Level View of an MBR
NOTE: Some devices are formatted without an MBR and, therefore, have no partition
table. This configuration is not currently supported in the Dynamic C FAT file system.
10.2.5.3 FAT Partitions
The first sector of a valid FAT file system partition contains the BIOS parameter block (BPB); this is fol-
lowed by the file allocation table (FAT), and then the root directory. The figure below shows a device with
two FAT partitions.
Figure 4. Two FAT Partitions on a Device
10.2.5.3.1 BPB
The fields of the BPB contain information describing the partition:
• the number of bytes per sector
• the number of sectors per cluster (see Table 13)
• the total count of sectors on the partition
• the number of root directory entries
• plus additional information not mentioned here
Entry
0x000
0x1BE
0x1CE
0x1DE
0x1EE
Boot Region
Partition 1
Partition 2
Partition 3
Signature
Partition Table
Master Boot Record (MBR)
Partition 0
0x1FE
BPB
FAT
ROOT
Data Area
Partition 0
Start of
Cluster 2
First Sector
of Partition 1
BPB
FAT
ROOT
Partition 1
Data Area
MBR
Start of
Cluster 2
First Sector
of Partition 2
Sector 0
of Device