User Guide

• Root folder item, Total sectors, FAT16 size – fields used by FAT16 file
system;
•
Media ID – Media (disk) identifier;
•
Sectors per track – the number of sectors per track;
•
Number of heads – the number of heads;
•
Big total sectors – the number of disk sectors available to partition file
system (for partitions > 32 Mb);
•
FAT size – the size of File Allocation Table in disk sectors;
•
Active FAT – four low bits of this field contain the number of active FAT
copy used for reading and writing if copy duplication is switched off;
•
File System Version – always 0 for FAT32;
•
First Cluster of Root – the first cluster of the root folder (FAT32 stores
the root folder as all other folders and files; FAT16 used a special disk
area for it);
•
FAT32 FS Info sector – the relative number of information sectors of
FAT32 file system;
•
Backup sector – the sector containing a copy of bootsector;
•
Hard Drive – disk’s BIOS number;
•
Extension signature – the signature of extended bootsector;
•
Serial number – volume serial number (set at formatting);
•
Volume label – a char line;
•
File system name – file system char identifier (FAT32);
•
Bootsector signature – a bootsector signature.
Some bootsector fields are reserved for further use.
We have described this structure above. A hard disk partition also begins
with the sector containing the operating system loader program. Primary
loader and partition loader are bound as follows: the purpose of primary
loader is to locate the first (boot) sector of active partition, to load its code to
memory, and to pass controls to it. Further actions concerning operating
system loading are performed by the active partition loader.
To view instructions contained in the primary loader (partition loader) code, you can
use DEBUG utility supplied both with DOS and Windows. DEBUG allows to read any
disk sector and disassemble its code, i.e. to translate the machine code to assembler
language. Your understanding of these instructions will depend on your knowled
g
e
of assembler language.
24 Chapter 3 : Main Window View Modes