bpb.h revision 1.4
1 /* $NetBSD: bpb.h,v 1.4 2005/12/03 17:34:43 christos Exp $ */ 2 3 /* 4 * Written by Paul Popelka (paulp (at) uts.amdahl.com) 5 * 6 * You can do anything you want with this software, just don't say you wrote 7 * it, and don't remove this notice. 8 * 9 * This software is provided "as is". 10 * 11 * The author supplies this software to be publicly redistributed on the 12 * understanding that the author is not responsible for the correct 13 * functioning of this software in any circumstances and is not liable for 14 * any damages caused by this software. 15 * 16 * October 1992 17 */ 18 19 #ifndef _MSDOSFS_BPB_H_ 20 #define _MSDOSFS_BPB_H_ 21 22 /* 23 * BIOS Parameter Block (BPB) for DOS 3.3 24 */ 25 struct bpb33 { 26 u_int16_t bpbBytesPerSec; /* bytes per sector */ 27 u_int8_t bpbSecPerClust; /* sectors per cluster */ 28 u_int16_t bpbResSectors; /* number of reserved sectors */ 29 u_int8_t bpbFATs; /* number of FATs */ 30 u_int16_t bpbRootDirEnts; /* number of root directory entries */ 31 u_int16_t bpbSectors; /* total number of sectors */ 32 u_int8_t bpbMedia; /* media descriptor */ 33 u_int16_t bpbFATsecs; /* number of sectors per FAT */ 34 u_int16_t bpbSecPerTrack; /* sectors per track */ 35 u_int16_t bpbHeads; /* number of heads */ 36 u_int16_t bpbHiddenSecs; /* number of hidden sectors */ 37 }; 38 39 /* 40 * BPB for DOS 5.0 The difference is bpbHiddenSecs is a short for DOS 3.3, 41 * and bpbHugeSectors is not in the 3.3 bpb. 42 */ 43 struct bpb50 { 44 u_int16_t bpbBytesPerSec; /* bytes per sector */ 45 u_int8_t bpbSecPerClust; /* sectors per cluster */ 46 u_int16_t bpbResSectors; /* number of reserved sectors */ 47 u_int8_t bpbFATs; /* number of FATs */ 48 u_int16_t bpbRootDirEnts; /* number of root directory entries */ 49 u_int16_t bpbSectors; /* total number of sectors */ 50 u_int8_t bpbMedia; /* media descriptor */ 51 u_int16_t bpbFATsecs; /* number of sectors per FAT */ 52 u_int16_t bpbSecPerTrack; /* sectors per track */ 53 u_int16_t bpbHeads; /* number of heads */ 54 u_int32_t bpbHiddenSecs; /* # of hidden sectors */ 55 u_int32_t bpbHugeSectors; /* # of sectors if bpbSectors == 0 */ 56 }; 57 58 /* 59 * BPB for DOS 7.10 (FAT32). This one has a few extensions to bpb50. 60 */ 61 struct bpb710 { 62 u_int16_t bpbBytesPerSec; /* bytes per sector */ 63 u_int8_t bpbSecPerClust; /* sectors per cluster */ 64 u_int16_t bpbResSectors; /* number of reserved sectors */ 65 u_int8_t bpbFATs; /* number of FATs */ 66 u_int16_t bpbRootDirEnts; /* number of root directory entries */ 67 u_int16_t bpbSectors; /* total number of sectors */ 68 u_int8_t bpbMedia; /* media descriptor */ 69 u_int16_t bpbFATsecs; /* number of sectors per FAT */ 70 u_int16_t bpbSecPerTrack; /* sectors per track */ 71 u_int16_t bpbHeads; /* number of heads */ 72 u_int32_t bpbHiddenSecs; /* # of hidden sectors */ 73 u_int32_t bpbHugeSectors; /* # of sectors if bpbSectors == 0 */ 74 u_int32_t bpbBigFATsecs; /* like bpbFATsecs for FAT32 */ 75 u_int16_t bpbExtFlags; /* extended flags: */ 76 #define FATNUM 0xf /* mask for numbering active FAT */ 77 #define FATMIRROR 0x80 /* FAT is mirrored (like it always was) */ 78 u_int16_t bpbFSVers; /* filesystem version */ 79 #define FSVERS 0 /* currently only 0 is understood */ 80 u_int32_t bpbRootClust; /* start cluster for root directory */ 81 u_int16_t bpbFSInfo; /* filesystem info structure sector */ 82 u_int16_t bpbBackup; /* backup boot sector */ 83 u_int8_t bpbReserved[12]; /* Reserved for future expansion */ 84 }; 85 86 #ifdef atari 87 /* 88 * BPB for gemdos filesystems. Atari leaves the obsolete stuff undefined. 89 * Currently there is no need for a separate BPB structure. 90 */ 91 #if 0 92 struct bpb_a { 93 u_int16_t bpbBytesPerSec; /* bytes per sector */ 94 u_int8_t bpbSecPerClust; /* sectors per cluster */ 95 u_int16_t bpbResSectors; /* number of reserved sectors */ 96 u_int8_t bpbFATs; /* number of FATs */ 97 u_int16_t bpbRootDirEnts; /* number of root directory entries */ 98 u_int16_t bpbSectors; /* total number of sectors */ 99 u_int8_t bpbUseless1; /* meaningless on gemdos fs */ 100 u_int16_t bpbFATsecs; /* number of sectors per FAT */ 101 u_int16_t bpbUseless2; /* meaningless for harddisk fs */ 102 u_int16_t bpbUseless3; /* meaningless for harddisk fs */ 103 u_int16_t bpbHiddenSecs; /* the TOS-BIOS ignores this */ 104 }; 105 #endif 106 #endif /* atari */ 107 108 /* 109 * The following structures represent how the bpb's look on disk. shorts 110 * and longs are just character arrays of the appropriate length. This is 111 * because the compiler forces shorts and longs to align on word or 112 * halfword boundaries. 113 * 114 * XXX The little-endian code here assumes that the processor can access 115 * 16-bit and 32-bit quantities on byte boundaries. If this is not true, 116 * use the macros for the big-endian case. 117 */ 118 #include <machine/endian.h> 119 #ifdef __STDC__ 120 #define __ICAST(q,a,x) ((q u_int ## a ## _t *)(q void *)(x)) 121 #else 122 #define __ICAST(q,a,x) ((q u_int/**/a/**/_t *)(q void *)(x)) 123 #endif 124 #if (BYTE_ORDER == LITTLE_ENDIAN) && defined(UNALIGNED_ACCESS) 125 #define getushort(x) *__ICAST(const,16,x) 126 #define getulong(x) *__ICAST(const,32,x) 127 #define putushort(p, v) (void)(*__ICAST(,16,p) = (v)) 128 #define putulong(p, v) (void)(*__ICAST(,32,p) = (v)) 129 #else 130 #define getushort(x) (__ICAST(const,8,x)[0] + (__ICAST(const,8,x)[1] << 8)) 131 #define getulong(x) (__ICAST(const,8,x)[0] + (__ICAST(const,8,x)[1] << 8) \ 132 + (__ICAST(const,8,x)[2] << 16) \ 133 + (__ICAST(const,8,x)[3] << 24)) 134 #define putushort(p, v) (__ICAST(,8,p)[0] = (v), \ 135 __ICAST(,8,p)[1] = (v) >> 8) 136 #define putulong(p, v) (__ICAST(,8,p)[0] = (v), \ 137 __ICAST(,8,p)[1] = (v) >> 8, \ 138 __ICAST(,8,p)[2] = (v) >> 16,\ 139 __ICAST(,8,p)[3] = (v) >> 24) 140 #endif 141 142 /* 143 * BIOS Parameter Block (BPB) for DOS 3.3 144 */ 145 struct byte_bpb33 { 146 int8_t bpbBytesPerSec[2]; /* bytes per sector */ 147 int8_t bpbSecPerClust; /* sectors per cluster */ 148 int8_t bpbResSectors[2]; /* number of reserved sectors */ 149 int8_t bpbFATs; /* number of FATs */ 150 int8_t bpbRootDirEnts[2]; /* number of root directory entries */ 151 int8_t bpbSectors[2]; /* total number of sectors */ 152 int8_t bpbMedia; /* media descriptor */ 153 int8_t bpbFATsecs[2]; /* number of sectors per FAT */ 154 int8_t bpbSecPerTrack[2]; /* sectors per track */ 155 int8_t bpbHeads[2]; /* number of heads */ 156 int8_t bpbHiddenSecs[2]; /* number of hidden sectors */ 157 }; 158 159 /* 160 * BPB for DOS 5.0 The difference is bpbHiddenSecs is a short for DOS 3.3, 161 * and bpbHugeSectors is not in the 3.3 bpb. 162 */ 163 struct byte_bpb50 { 164 int8_t bpbBytesPerSec[2]; /* bytes per sector */ 165 int8_t bpbSecPerClust; /* sectors per cluster */ 166 int8_t bpbResSectors[2]; /* number of reserved sectors */ 167 int8_t bpbFATs; /* number of FATs */ 168 int8_t bpbRootDirEnts[2]; /* number of root directory entries */ 169 int8_t bpbSectors[2]; /* total number of sectors */ 170 int8_t bpbMedia; /* media descriptor */ 171 int8_t bpbFATsecs[2]; /* number of sectors per FAT */ 172 int8_t bpbSecPerTrack[2]; /* sectors per track */ 173 int8_t bpbHeads[2]; /* number of heads */ 174 int8_t bpbHiddenSecs[4]; /* number of hidden sectors */ 175 int8_t bpbHugeSectors[4]; /* # of sectors if bpbSectors == 0 */ 176 }; 177 178 /* 179 * BPB for DOS 7.10 (FAT32). This one has a few extensions to bpb50. 180 */ 181 struct byte_bpb710 { 182 u_int8_t bpbBytesPerSec[2]; /* bytes per sector */ 183 u_int8_t bpbSecPerClust; /* sectors per cluster */ 184 u_int8_t bpbResSectors[2]; /* number of reserved sectors */ 185 u_int8_t bpbFATs; /* number of FATs */ 186 u_int8_t bpbRootDirEnts[2]; /* number of root directory entries */ 187 u_int8_t bpbSectors[2]; /* total number of sectors */ 188 u_int8_t bpbMedia; /* media descriptor */ 189 u_int8_t bpbFATsecs[2]; /* number of sectors per FAT */ 190 u_int8_t bpbSecPerTrack[2]; /* sectors per track */ 191 u_int8_t bpbHeads[2]; /* number of heads */ 192 u_int8_t bpbHiddenSecs[4]; /* # of hidden sectors */ 193 u_int8_t bpbHugeSectors[4]; /* # of sectors if bpbSectors == 0 */ 194 u_int8_t bpbBigFATsecs[4]; /* like bpbFATsecs for FAT32 */ 195 u_int8_t bpbExtFlags[2]; /* extended flags: */ 196 u_int8_t bpbFSVers[2]; /* filesystem version */ 197 u_int8_t bpbRootClust[4]; /* start cluster for root directory */ 198 u_int8_t bpbFSInfo[2]; /* filesystem info structure sector */ 199 u_int8_t bpbBackup[2]; /* backup boot sector */ 200 u_int8_t bpbReserved[12]; /* Reserved for future expansion */ 201 }; 202 203 /* 204 * FAT32 FSInfo block. 205 */ 206 struct fsinfo { 207 u_int8_t fsisig1[4]; 208 u_int8_t fsifill1[480]; 209 u_int8_t fsisig2[4]; 210 u_int8_t fsinfree[4]; 211 u_int8_t fsinxtfree[4]; 212 u_int8_t fsifill2[12]; 213 u_int8_t fsisig3[4]; 214 u_int8_t fsifill3[508]; 215 u_int8_t fsisig4[4]; 216 }; 217 #endif /* _MSDOSFS_BPB_H_ */ 218
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