1/* $NetBSD: bpb.h,v 1.8 2016/01/22 22:53:36 dholland Exp $ */ 2 3/* 4 * Written by Paul Popelka (paulp@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 */ 25struct bpb33 { 26 uint16_t bpbBytesPerSec; /* bytes per sector */ 27 uint8_t bpbSecPerClust; /* sectors per cluster */ 28 uint16_t bpbResSectors; /* number of reserved sectors */ 29 uint8_t bpbFATs; /* number of FATs */ 30 uint16_t bpbRootDirEnts; /* number of root directory entries */ 31 uint16_t bpbSectors; /* total number of sectors */ 32 uint8_t bpbMedia; /* media descriptor */ 33 uint16_t bpbFATsecs; /* number of sectors per FAT */ 34 uint16_t bpbSecPerTrack; /* sectors per track */ 35 uint16_t bpbHeads; /* number of heads */ 36 uint16_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 */ 43struct bpb50 { 44 uint16_t bpbBytesPerSec; /* bytes per sector */ 45 uint8_t bpbSecPerClust; /* sectors per cluster */ 46 uint16_t bpbResSectors; /* number of reserved sectors */ 47 uint8_t bpbFATs; /* number of FATs */ 48 uint16_t bpbRootDirEnts; /* number of root directory entries */ 49 uint16_t bpbSectors; /* total number of sectors */ 50 uint8_t bpbMedia; /* media descriptor */ 51 uint16_t bpbFATsecs; /* number of sectors per FAT */ 52 uint16_t bpbSecPerTrack; /* sectors per track */ 53 uint16_t bpbHeads; /* number of heads */ 54 uint32_t bpbHiddenSecs; /* # of hidden sectors */ 55 uint32_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 */ 61struct bpb710 { 62 uint16_t bpbBytesPerSec; /* bytes per sector */ 63 uint8_t bpbSecPerClust; /* sectors per cluster */ 64 uint16_t bpbResSectors; /* number of reserved sectors */ 65 uint8_t bpbFATs; /* number of FATs */ 66 uint16_t bpbRootDirEnts; /* number of root directory entries */ 67 uint16_t bpbSectors; /* total number of sectors */ 68 uint8_t bpbMedia; /* media descriptor */ 69 uint16_t bpbFATsecs; /* number of sectors per FAT */ 70 uint16_t bpbSecPerTrack; /* sectors per track */ 71 uint16_t bpbHeads; /* number of heads */ 72 uint32_t bpbHiddenSecs; /* # of hidden sectors */ 73 uint32_t bpbHugeSectors; /* # of sectors if bpbSectors == 0 */ 74 uint32_t bpbBigFATsecs; /* like bpbFATsecs for FAT32 */ 75 uint16_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 uint16_t bpbFSVers; /* filesystem version */ 79#define FSVERS 0 /* currently only 0 is understood */ 80 uint32_t bpbRootClust; /* start cluster for root directory */ 81 uint16_t bpbFSInfo; /* filesystem info structure sector */ 82 uint16_t bpbBackup; /* backup boot sector */ 83 uint8_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 92struct bpb_a { 93 uint16_t bpbBytesPerSec; /* bytes per sector */ 94 uint8_t bpbSecPerClust; /* sectors per cluster */ 95 uint16_t bpbResSectors; /* number of reserved sectors */ 96 uint8_t bpbFATs; /* number of FATs */ 97 uint16_t bpbRootDirEnts; /* number of root directory entries */ 98 uint16_t bpbSectors; /* total number of sectors */ 99 uint8_t bpbUseless1; /* meaningless on GEMDOS FS */ 100 uint16_t bpbFATsecs; /* number of sectors per FAT */ 101 uint16_t bpbUseless2; /* meaningless for harddisk fs */ 102 uint16_t bpbUseless3; /* meaningless for harddisk fs */ 103 uint16_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 */ 114 115#include <sys/endian.h> 116 117#define getushort(p) le16dec(p) 118#define getulong(p) le32dec(p) 119#define putushort(p, v) le16enc((p), (v)) 120#define putulong(p, v) le32enc((p), (v)) 121 122/* 123 * BIOS Parameter Block (BPB) for DOS 3.3 124 */ 125struct byte_bpb33 { 126 int8_t bpbBytesPerSec[2]; /* bytes per sector */ 127 int8_t bpbSecPerClust; /* sectors per cluster */ 128 int8_t bpbResSectors[2]; /* number of reserved sectors */ 129 int8_t bpbFATs; /* number of FATs */ 130 int8_t bpbRootDirEnts[2]; /* number of root directory entries */ 131 int8_t bpbSectors[2]; /* total number of sectors */ 132 int8_t bpbMedia; /* media descriptor */ 133 int8_t bpbFATsecs[2]; /* number of sectors per FAT */ 134 int8_t bpbSecPerTrack[2]; /* sectors per track */ 135 int8_t bpbHeads[2]; /* number of heads */ 136 int8_t bpbHiddenSecs[2]; /* number of hidden sectors */ 137}; 138 139/* 140 * BPB for DOS 5.0 The difference is bpbHiddenSecs is a short for DOS 3.3, 141 * and bpbHugeSectors is not in the 3.3 bpb. 142 */ 143struct byte_bpb50 { 144 int8_t bpbBytesPerSec[2]; /* bytes per sector */ 145 int8_t bpbSecPerClust; /* sectors per cluster */ 146 int8_t bpbResSectors[2]; /* number of reserved sectors */ 147 int8_t bpbFATs; /* number of FATs */ 148 int8_t bpbRootDirEnts[2]; /* number of root directory entries */ 149 int8_t bpbSectors[2]; /* total number of sectors */ 150 int8_t bpbMedia; /* media descriptor */ 151 int8_t bpbFATsecs[2]; /* number of sectors per FAT */ 152 int8_t bpbSecPerTrack[2]; /* sectors per track */ 153 int8_t bpbHeads[2]; /* number of heads */ 154 int8_t bpbHiddenSecs[4]; /* number of hidden sectors */ 155 int8_t bpbHugeSectors[4]; /* # of sectors if bpbSectors == 0 */ 156}; 157 158/* 159 * BPB for DOS 7.10 (FAT32). This one has a few extensions to bpb50. 160 */ 161struct byte_bpb710 { 162 uint8_t bpbBytesPerSec[2]; /* bytes per sector */ 163 uint8_t bpbSecPerClust; /* sectors per cluster */ 164 uint8_t bpbResSectors[2]; /* number of reserved sectors */ 165 uint8_t bpbFATs; /* number of FATs */ 166 uint8_t bpbRootDirEnts[2]; /* number of root directory entries */ 167 uint8_t bpbSectors[2]; /* total number of sectors */ 168 uint8_t bpbMedia; /* media descriptor */ 169 uint8_t bpbFATsecs[2]; /* number of sectors per FAT */ 170 uint8_t bpbSecPerTrack[2]; /* sectors per track */ 171 uint8_t bpbHeads[2]; /* number of heads */ 172 uint8_t bpbHiddenSecs[4]; /* # of hidden sectors */ 173 uint8_t bpbHugeSectors[4]; /* # of sectors if bpbSectors == 0 */ 174 uint8_t bpbBigFATsecs[4]; /* like bpbFATsecs for FAT32 */ 175 uint8_t bpbExtFlags[2]; /* extended flags: */ 176 uint8_t bpbFSVers[2]; /* filesystem version */ 177 uint8_t bpbRootClust[4]; /* start cluster for root directory */ 178 uint8_t bpbFSInfo[2]; /* filesystem info structure sector */ 179 uint8_t bpbBackup[2]; /* backup boot sector */ 180 uint8_t bpbReserved[12]; /* Reserved for future expansion */ 181}; 182 183/* 184 * FAT32 FSInfo block. 185 */ 186struct fsinfo { 187 uint8_t fsisig1[4]; 188 uint8_t fsifill1[480]; 189 uint8_t fsisig2[4]; 190 uint8_t fsinfree[4]; 191 uint8_t fsinxtfree[4]; 192 uint8_t fsifill2[12]; 193 uint8_t fsisig3[4]; 194 uint8_t fsifill3[508]; 195 uint8_t fsisig4[4]; 196}; 197#endif /* _MSDOSFS_BPB_H_ */ 198