bootsect.h revision 72091 
1/* $FreeBSD: head/sys/fs/msdosfs/bootsect.h 72091 2001-02-06 11:21:58Z asmodai $ */
2/*	$NetBSD: bootsect.h,v 1.9 1997/11/17 15:36:17 ws Exp $	*/
3
4/*
5 * Written by Paul Popelka (paulp@uts.amdahl.com)
6 *
7 * You can do anything you want with this software, just don't say you wrote
8 * it, and don't remove this notice.
9 *
10 * This software is provided "as is".
11 *
12 * The author supplies this software to be publicly redistributed on the
13 * understanding that the author is not responsible for the correct
14 * functioning of this software in any circumstances and is not liable for
15 * any damages caused by this software.
16 *
17 * October 1992
18 */
19
20/*
21 * Format of a boot sector.  This is the first sector on a DOS floppy disk
22 * or the fist sector of a partition on a hard disk.  But, it is not the
23 * first sector of a partitioned hard disk.
24 */
25struct bootsector33 {
26	u_int8_t	bsJump[3];		/* jump inst E9xxxx or EBxx90 */
27	int8_t		bsOemName[8];		/* OEM name and version */
28	int8_t		bsBPB[19];		/* BIOS parameter block */
29	int8_t		bsDriveNumber;		/* drive number (0x80) */
30	int8_t		bsBootCode[479];	/* pad so struct is 512b */
31	u_int8_t	bsBootSectSig0;
32	u_int8_t	bsBootSectSig1;
33#define	BOOTSIG0	0x55
34#define	BOOTSIG1	0xaa
35};
36
37struct extboot {
38	int8_t		exDriveNumber;		/* drive number (0x80) */
39	int8_t		exReserved1;		/* reserved */
40	int8_t		exBootSignature;	/* ext. boot signature (0x29) */
41#define	EXBOOTSIG	0x29
42	int8_t		exVolumeID[4];		/* volume ID number */
43	int8_t		exVolumeLabel[11];	/* volume label */
44	int8_t		exFileSysType[8];	/* fs type (FAT12 or FAT16) */
45};
46
47struct bootsector50 {
48	u_int8_t	bsJump[3];		/* jump inst E9xxxx or EBxx90 */
49	int8_t		bsOemName[8];		/* OEM name and version */
50	int8_t		bsBPB[25];		/* BIOS parameter block */
51	int8_t		bsExt[26];		/* Bootsector Extension */
52	int8_t		bsBootCode[448];	/* pad so structure is 512b */
53	u_int8_t	bsBootSectSig0;
54	u_int8_t	bsBootSectSig1;
55#define	BOOTSIG0	0x55
56#define	BOOTSIG1	0xaa
57};
58
59struct bootsector710 {
60	u_int8_t	bsJump[3];		/* jump inst E9xxxx or EBxx90 */
61	int8_t		bsOEMName[8];		/* OEM name and version */
62	int8_t		bsPBP[53];		/* BIOS parameter block */
63	int8_t		bsExt[26];		/* Bootsector Extension */
64	int8_t		bsBootCode[418];	/* pad so structure is 512b */
65	u_int8_t	bsBootSectSig2;		/* 2 & 3 are only defined for FAT32? */
66	u_int8_t	bsBootSectSig3;
67	u_int8_t	bsBootSectSig0;
68	u_int8_t	bsBootSectSig1;
69#define	BOOTSIG0	0x55
70#define	BOOTSIG1	0xaa
71#define	BOOTSIG2	0
72#define	BOOTSIG3	0
73};
74#ifdef	atari
75/*
76 * The boot sector on a gemdos fs is a little bit different from the msdos fs
77 * format. Currently there is no need to declare a separate structure, the
78 * bootsector33 struct will do.
79 */
80#if 0
81struct bootsec_atari {
82	u_int8_t	bsBranch[2];		/* branch inst if auto-boot	*/
83	int8_t		bsFiller[6];		/* anything or nothing		*/
84	int8_t		bsSerial[3];		/* serial no. for mediachange	*/
85	int8_t		bsBPB[19];		/* BIOS parameter block		*/
86	int8_t		bsBootCode[482];	/* pad so struct is 512b	*/
87};
88#endif
89#endif /* atari */
90
91union bootsector {
92	struct bootsector33 bs33;
93	struct bootsector50 bs50;
94	struct bootsector710 bs710;
95};
96
97#if 0
98/*
99 * Shorthand for fields in the bpb.
100 */
101#define	bsBytesPerSec	bsBPB.bpbBytesPerSec
102#define	bsSectPerClust	bsBPB.bpbSectPerClust
103#define	bsResSectors	bsBPB.bpbResSectors
104#define	bsFATS		bsBPB.bpbFATS
105#define	bsRootDirEnts	bsBPB.bpbRootDirEnts
106#define	bsSectors	bsBPB.bpbSectors
107#define	bsMedia		bsBPB.bpbMedia
108#define	bsFATsecs	bsBPB.bpbFATsecs
109#define	bsSectPerTrack	bsBPB.bpbSectPerTrack
110#define	bsHeads		bsBPB.bpbHeads
111#define	bsHiddenSecs	bsBPB.bpbHiddenSecs
112#define	bsHugeSectors	bsBPB.bpbHugeSectors
113#endif
114