bpb.h revision 1.3
1 /* $NetBSD: bpb.h,v 1.3 2004/06/30 03:43:14 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 /* 20 * BIOS Parameter Block (BPB) for DOS 3.3 21 */ 22 struct bpb33 { 23 u_int16_t bpbBytesPerSec; /* bytes per sector */ 24 u_int8_t bpbSecPerClust; /* sectors per cluster */ 25 u_int16_t bpbResSectors; /* number of reserved sectors */ 26 u_int8_t bpbFATs; /* number of FATs */ 27 u_int16_t bpbRootDirEnts; /* number of root directory entries */ 28 u_int16_t bpbSectors; /* total number of sectors */ 29 u_int8_t bpbMedia; /* media descriptor */ 30 u_int16_t bpbFATsecs; /* number of sectors per FAT */ 31 u_int16_t bpbSecPerTrack; /* sectors per track */ 32 u_int16_t bpbHeads; /* number of heads */ 33 u_int16_t bpbHiddenSecs; /* number of hidden sectors */ 34 }; 35 36 /* 37 * BPB for DOS 5.0 The difference is bpbHiddenSecs is a short for DOS 3.3, 38 * and bpbHugeSectors is not in the 3.3 bpb. 39 */ 40 struct bpb50 { 41 u_int16_t bpbBytesPerSec; /* bytes per sector */ 42 u_int8_t bpbSecPerClust; /* sectors per cluster */ 43 u_int16_t bpbResSectors; /* number of reserved sectors */ 44 u_int8_t bpbFATs; /* number of FATs */ 45 u_int16_t bpbRootDirEnts; /* number of root directory entries */ 46 u_int16_t bpbSectors; /* total number of sectors */ 47 u_int8_t bpbMedia; /* media descriptor */ 48 u_int16_t bpbFATsecs; /* number of sectors per FAT */ 49 u_int16_t bpbSecPerTrack; /* sectors per track */ 50 u_int16_t bpbHeads; /* number of heads */ 51 u_int32_t bpbHiddenSecs; /* # of hidden sectors */ 52 u_int32_t bpbHugeSectors; /* # of sectors if bpbSectors == 0 */ 53 }; 54 55 /* 56 * BPB for DOS 7.10 (FAT32). This one has a few extensions to bpb50. 57 */ 58 struct bpb710 { 59 u_int16_t bpbBytesPerSec; /* bytes per sector */ 60 u_int8_t bpbSecPerClust; /* sectors per cluster */ 61 u_int16_t bpbResSectors; /* number of reserved sectors */ 62 u_int8_t bpbFATs; /* number of FATs */ 63 u_int16_t bpbRootDirEnts; /* number of root directory entries */ 64 u_int16_t bpbSectors; /* total number of sectors */ 65 u_int8_t bpbMedia; /* media descriptor */ 66 u_int16_t bpbFATsecs; /* number of sectors per FAT */ 67 u_int16_t bpbSecPerTrack; /* sectors per track */ 68 u_int16_t bpbHeads; /* number of heads */ 69 u_int32_t bpbHiddenSecs; /* # of hidden sectors */ 70 u_int32_t bpbHugeSectors; /* # of sectors if bpbSectors == 0 */ 71 u_int32_t bpbBigFATsecs; /* like bpbFATsecs for FAT32 */ 72 u_int16_t bpbExtFlags; /* extended flags: */ 73 #define FATNUM 0xf /* mask for numbering active FAT */ 74 #define FATMIRROR 0x80 /* FAT is mirrored (like it always was) */ 75 u_int16_t bpbFSVers; /* filesystem version */ 76 #define FSVERS 0 /* currently only 0 is understood */ 77 u_int32_t bpbRootClust; /* start cluster for root directory */ 78 u_int16_t bpbFSInfo; /* filesystem info structure sector */ 79 u_int16_t bpbBackup; /* backup boot sector */ 80 u_int8_t bpbReserved[12]; /* Reserved for future expansion */ 81 }; 82 83 #ifdef atari 84 /* 85 * BPB for gemdos filesystems. Atari leaves the obsolete stuff undefined. 86 * Currently there is no need for a separate BPB structure. 87 */ 88 #if 0 89 struct bpb_a { 90 u_int16_t bpbBytesPerSec; /* bytes per sector */ 91 u_int8_t bpbSecPerClust; /* sectors per cluster */ 92 u_int16_t bpbResSectors; /* number of reserved sectors */ 93 u_int8_t bpbFATs; /* number of FATs */ 94 u_int16_t bpbRootDirEnts; /* number of root directory entries */ 95 u_int16_t bpbSectors; /* total number of sectors */ 96 u_int8_t bpbUseless1; /* meaningless on gemdos fs */ 97 u_int16_t bpbFATsecs; /* number of sectors per FAT */ 98 u_int16_t bpbUseless2; /* meaningless for harddisk fs */ 99 u_int16_t bpbUseless3; /* meaningless for harddisk fs */ 100 u_int16_t bpbHiddenSecs; /* the TOS-BIOS ignores this */ 101 }; 102 #endif 103 #endif /* atari */ 104 105 /* 106 * The following structures represent how the bpb's look on disk. shorts 107 * and longs are just character arrays of the appropriate length. This is 108 * because the compiler forces shorts and longs to align on word or 109 * halfword boundaries. 110 * 111 * XXX The little-endian code here assumes that the processor can access 112 * 16-bit and 32-bit quantities on byte boundaries. If this is not true, 113 * use the macros for the big-endian case. 114 */ 115 #include <machine/endian.h> 116 #ifdef __STDC__ 117 #define __ICAST(q,a,x) ((q u_int ## a ## _t *)(q void *)(x)) 118 #else 119 #define __ICAST(q,a,x) ((q u_int/**/a/**/_t *)(q void *)(x)) 120 #endif 121 #if (BYTE_ORDER == LITTLE_ENDIAN) && defined(UNALIGNED_ACCESS) 122 #define getushort(x) *__ICAST(const,16,x) 123 #define getulong(x) *__ICAST(const,32,x) 124 #define putushort(p, v) (void)(*__ICAST(,16,p) = (v)) 125 #define putulong(p, v) (void)(*__ICAST(,32,p) = (v)) 126 #else 127 #define getushort(x) (__ICAST(const,8,x)[0] + (__ICAST(const,8,x)[1] << 8)) 128 #define getulong(x) (__ICAST(const,8,x)[0] + (__ICAST(const,8,x)[1] << 8) \ 129 + (__ICAST(const,8,x)[2] << 16) \ 130 + (__ICAST(const,8,x)[3] << 24)) 131 #define putushort(p, v) (__ICAST(,8,p)[0] = (v), \ 132 __ICAST(,8,p)[1] = (v) >> 8) 133 #define putulong(p, v) (__ICAST(,8,p)[0] = (v), \ 134 __ICAST(,8,p)[1] = (v) >> 8, \ 135 __ICAST(,8,p)[2] = (v) >> 16,\ 136 __ICAST(,8,p)[3] = (v) >> 24) 137 #endif 138 139 /* 140 * BIOS Parameter Block (BPB) for DOS 3.3 141 */ 142 struct byte_bpb33 { 143 int8_t bpbBytesPerSec[2]; /* bytes per sector */ 144 int8_t bpbSecPerClust; /* sectors per cluster */ 145 int8_t bpbResSectors[2]; /* number of reserved sectors */ 146 int8_t bpbFATs; /* number of FATs */ 147 int8_t bpbRootDirEnts[2]; /* number of root directory entries */ 148 int8_t bpbSectors[2]; /* total number of sectors */ 149 int8_t bpbMedia; /* media descriptor */ 150 int8_t bpbFATsecs[2]; /* number of sectors per FAT */ 151 int8_t bpbSecPerTrack[2]; /* sectors per track */ 152 int8_t bpbHeads[2]; /* number of heads */ 153 int8_t bpbHiddenSecs[2]; /* number of hidden sectors */ 154 }; 155 156 /* 157 * BPB for DOS 5.0 The difference is bpbHiddenSecs is a short for DOS 3.3, 158 * and bpbHugeSectors is not in the 3.3 bpb. 159 */ 160 struct byte_bpb50 { 161 int8_t bpbBytesPerSec[2]; /* bytes per sector */ 162 int8_t bpbSecPerClust; /* sectors per cluster */ 163 int8_t bpbResSectors[2]; /* number of reserved sectors */ 164 int8_t bpbFATs; /* number of FATs */ 165 int8_t bpbRootDirEnts[2]; /* number of root directory entries */ 166 int8_t bpbSectors[2]; /* total number of sectors */ 167 int8_t bpbMedia; /* media descriptor */ 168 int8_t bpbFATsecs[2]; /* number of sectors per FAT */ 169 int8_t bpbSecPerTrack[2]; /* sectors per track */ 170 int8_t bpbHeads[2]; /* number of heads */ 171 int8_t bpbHiddenSecs[4]; /* number of hidden sectors */ 172 int8_t bpbHugeSectors[4]; /* # of sectors if bpbSectors == 0 */ 173 }; 174 175 /* 176 * BPB for DOS 7.10 (FAT32). This one has a few extensions to bpb50. 177 */ 178 struct byte_bpb710 { 179 u_int8_t bpbBytesPerSec[2]; /* bytes per sector */ 180 u_int8_t bpbSecPerClust; /* sectors per cluster */ 181 u_int8_t bpbResSectors[2]; /* number of reserved sectors */ 182 u_int8_t bpbFATs; /* number of FATs */ 183 u_int8_t bpbRootDirEnts[2]; /* number of root directory entries */ 184 u_int8_t bpbSectors[2]; /* total number of sectors */ 185 u_int8_t bpbMedia; /* media descriptor */ 186 u_int8_t bpbFATsecs[2]; /* number of sectors per FAT */ 187 u_int8_t bpbSecPerTrack[2]; /* sectors per track */ 188 u_int8_t bpbHeads[2]; /* number of heads */ 189 u_int8_t bpbHiddenSecs[4]; /* # of hidden sectors */ 190 u_int8_t bpbHugeSectors[4]; /* # of sectors if bpbSectors == 0 */ 191 u_int8_t bpbBigFATsecs[4]; /* like bpbFATsecs for FAT32 */ 192 u_int8_t bpbExtFlags[2]; /* extended flags: */ 193 u_int8_t bpbFSVers[2]; /* filesystem version */ 194 u_int8_t bpbRootClust[4]; /* start cluster for root directory */ 195 u_int8_t bpbFSInfo[2]; /* filesystem info structure sector */ 196 u_int8_t bpbBackup[2]; /* backup boot sector */ 197 u_int8_t bpbReserved[12]; /* Reserved for future expansion */ 198 }; 199 200 /* 201 * FAT32 FSInfo block. 202 */ 203 struct fsinfo { 204 u_int8_t fsisig1[4]; 205 u_int8_t fsifill1[480]; 206 u_int8_t fsisig2[4]; 207 u_int8_t fsinfree[4]; 208 u_int8_t fsinxtfree[4]; 209 u_int8_t fsifill2[12]; 210 u_int8_t fsisig3[4]; 211 u_int8_t fsifill3[508]; 212 u_int8_t fsisig4[4]; 213 }; 214
Indexes created Mon Sep 29 21:09:56 GMT 2025