//////// Decimal to Binary Conversion Function \\\\\\\\
Decimal_to_Binary(unsigned long input)
{
unsigned long i;
int count = 0;
int binary [32]; /* 32 Bit MAX only 32
elements total */
do
{
i = input%2; /* MOD 2 to get 1 or a 0*/
binary[count] = i; /* Load Elements into the
Binary Array */
input = input/2; /* Divide input by 2 to
decrement via binary */
count++; /* Count how many elements
are needed */
}while (input > 0);
/* Reverse and output binary digits */
do
{
printf ("%d", binary[count - 1]);
count--;
} while (count > 0);
return 0;
}
When the program is run to read the DBR of a large volume, The Output of the Program is displayed as follows:
Jump Instruction Code = EB5890 (H)
OEM name and version = MSWIN4.1
Bytes per sector = 512
Sectors per cluster = 8
Reserved sectors = 32
FAT copies = 2
Root directory entries = 0
No. of sectors on disk = 0
Media Descriptor Byte = F8 (H)
Sectors per FAT = 0
Sectors per track = 63
No. of sides = 255
No. of reserved (Hidden) sectors = 63
=========== For Large (>32MB) Disks ===========
No. of sectors, (if Volume is >32MB) = 11277567
Number of Sectors per FAT = 11003
Root Directory Starting Cluster = 2
File System Information Sector = 1
Sector Number of Backup Boot Sector = 6
Physical Drive Number = 80 (H)
Extended Boot Signature = 29 (H)
32-Bit Binary Volume ID = 110101010001100001110111100101 (B)
Volume Label = SAAYA
FAT name = FAT32
Magic Number = 55AA (H) |
In the output of the program we see that the following parameters are shown zero:
- Root Directory Entry
- Number of Sectors on Disk
- Number Sectors Per FAT
These parameters are so because these values are set to zero, if the partition volume is greater then 32MB in size and the actual information is found in the Extended Volume Information Block of the DBR.
For Example, in the initial part of the DBR information, the number of Sectors per FAT is 0 and in the Extended Volume Information Block of DBR the Number of Sectors per FAT is 11003, which is the Actual Value for this large Volume.
The DBR of the Volume has the important information about the disk parameters, which can be used to link the all data information for programming purpose. For Example, if you want to access the DBRs of other Partition volume on the disk, you can calculate it by number of sectors, written in DBR and other related information.
If you want to access the Disk with cluster approach, you can make calculations with the help of Sectors per cluster, sectors per FAT and other information.
If you are using the hard disk larger than 8.4 GB (See the chapter, “Logical Approach to Disks and OS”, Discussed earlier in this book), use extensions to access all the DBR’s of the disk beyond 8.4 GB. Refer the Extended read-write functions, given in the previous chapters
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