NetBSD/sys/msdosfs/bootsect.h

/*
 * Written by Paul Popelka (paulp@uts.amdahl.com)
 * 
 * You can do anything you want with this software, just don't say you wrote
 * it, and don't remove this notice.
 * 
 * This software is provided "as is".
 * 
 * The author supplies this software to be publicly redistributed on the
 * understanding that the author is not responsible for the correct
 * functioning of this software in any circumstances and is not liable for
 * any damages caused by this software.
 * 
 * October 1992
 * 
 *	$Id: bootsect.h,v 1.3 1993/12/01 22:42:29 cgd Exp $
 */

/*
 * Format of a boot sector.  This is the first sector on a DOS floppy disk
 * or the fist sector of a partition on a hard disk.  But, it is not the
 * first sector of a partitioned hard disk.
 */
struct bootsector33 {
	u_char bsJump[3];	/* jump instruction E9xxxx or EBxx90 */
	char bsOemName[8];	/* OEM name and version */
	char bsBPB[19];		/* BIOS parameter block */
	char bsDriveNumber;	/* drive number (0x80) */
	char bsBootCode[474];	/* pad so structure is 512 bytes long */
	u_short bsBootSectSig;
#define	BOOTSIG	0xaa55
};

struct bootsector50 {
	u_char bsJump[3];	/* jump instruction E9xxxx or EBxx90 */
	char bsOemName[8];	/* OEM name and version */
	char bsBPB[25];		/* BIOS parameter block */
	char bsDriveNumber;	/* drive number (0x80) */
	char bsReserved1;	/* reserved */
	char bsBootSignature;	/* extended boot signature (0x29) */
#define	EXBOOTSIG	0x29
	char bsVolumeID[4];	/* volume ID number */
	char bsVolumeLabel[11];	/* volume label */
	char bsFileSysType[8];	/* file system type (FAT12 or FAT16) */
	char bsBootCode[448];	/* pad so structure is 512 bytes long */
	u_short bsBootSectSig;
#define	BOOTSIG	0xaa55
};

union bootsector {
	struct bootsector33 bs33;
	struct bootsector50 bs50;
};

/*
 * Shorthand for fields in the bpb.
 */
#define	bsBytesPerSec	bsBPB.bpbBytesPerSec
#define	bsSectPerClust	bsBPB.bpbSectPerClust
#define	bsResSectors	bsBPB.bpbResSectors
#define	bsFATS		bsBPB.bpbFATS
#define	bsRootDirEnts	bsBPB.bpbRootDirEnts
#define	bsSectors	bsBPB.bpbSectors
#define	bsMedia		bsBPB.bpbMedia
#define	bsFATsecs	bsBPB.bpbFATsecs
#define	bsSectPerTrack	bsBPB.bpbSectPerTrack
#define	bsHeads		bsBPB.bpbHeads
#define	bsHiddenSecs	bsBPB.bpbHiddenSecs
#define	bsHugeSectors	bsBPB.bpbHugeSectors