Functie om de Parameters van DBR te veranderen

/* Functie om de Parameters van DBR te veranderen */

Recover_with_values()
{
int val =0;

/* Jump Code of 3 Bytes For Floppy */
b.code[0] = 0xEB;
b.code[1]= 0x3E;
b.code[2]= 0x90 ;

/* System Id of 8 Bytes */
strcpy(b.system_id, "+05PSIHC");

/* Bytes Per Sector = 512 */
b.bytes_per_sec = 512;

/* Sector per Cluster for 1.44M 3.5" Floppy = 1 */
b.sec_per_clus = 1;

/* Number of Reserved Sectors = 1 */
b.res_sec =1;

/* Number of FAT Copies = 2 */
b.fat_copies =2;
/* Number of Root Directory Entry = 224 */
b.root_dir_entry =224;

/* Number of Sectors on Disk = 2880 */
b.no_sects =2880;

/* Media Descriptor Byte For Floppy = F0 (H) */
b.format_id =0xF0;

/* Sectors Per FAT = 9 */
b.sec_per_fat =9;

/* Sectors Per Track = 18 */
b.sec_per_trk =18;

/* Number of Sides = 2 */
b.no_sides =2;

/* Number of Special Reserved Sectors (or Hidden
Sectors) = 0 */
b.no_sp_res_sect =0;

/* Use For Floppy Disk*/
val = abswrite ( 0, 1, 0, &b ) ;

if ( val == -1 )
{
printf ( "\n Disk Write Error...bad sector\n" ) ;
printf ( " Disk was not Recovered." ) ;
exit ( 1 ) ;
}

return 0;
}

display_info()
{
printf ( "\n Jump Code (Hex) = %X%X%X (H)\n",
b.code[0],b.code[1],b.code[2]);
printf ( " System ID = %s\n", b.system_id ) ;
printf ( " Bytes per sector = %d\n", b.bytes_per_sec ) ;

printf ( " Sectors per cluster = %d\n", b.sec_per_clus ) ;

printf ( " Reserved sectors = %d\n", b.res_sec ) ;

printf ( " FAT copies = %d\n", b.fat_copies ) ;

printf ( " Root directory entries = %d\n", b.root_dir_entry ) ;

printf ( " No. of sectors on disk = %u\n", b.no_sects ) ;

printf ( " Media Descriptor Byte = %X\n", b.format_id ) ;

printf ( " Sectors per FAT = %d\n", b.sec_per_fat ) ;

printf ( " Sectors per track = %d\n", b.sec_per_trk ) ;

printf ( " No. of sides = %d\n", b.no_sides ) ;

printf ( " No. of reserved sectors = %d\n", b.no_sp_res_sect ) ;
return 0;
}

Commentaren op codage:

De structuurlaars wordt gebruikt om tot DBR, aan lees-schrijf toegang te hebben de parameters van de schijf. Functiedisplay_info (), toont de diverse parameters van de schijf, lezend van DBR. De functie Recover_with_values () wordt gebruikt om de parameters van DBR van Floppy te wijzigen en terug te krijgen.

De waarden die door de functie Recover_with_values () worden gebruikt, zijn voor parameters van 1.44MB, 3 ½ DBR van de duim floppy disk. De beschrijving van deze waarden is gegeven in de daarna gegeven lijst:

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