1 ; **************************************************************************** 2 ; mbsave.s (MBSAVE.COM) - TRDOS 386 Harddisk MBR Saving/Backup Utility 3 ; (for MSDOS/WINDOWS) 4 ; **************************************************************************** 5 ; Last Update: 11/10/2020 6 ; ---------------------------------------------------------------------------- 7 ; Beginning: 03/10/2020 8 ; ---------------------------------------------------------------------------- 9 ; Assembler: NASM version 2.15 10 ; ---------------------------------------------------------------------------- 11 ; Turkish Rational DOS 12 ; Operating System Project v2.0 by ERDOGAN TAN (Beginning: 04/01/2016) 13 ; ---------------------------------------------------------------------------- 14 ; Purpose: To save masterboot sector (MBR) to a file before modifying it. 15 ; **************************************************************************** 16 ; nasm mbsave.s -l mbsave.lst -o MBSAVE.COM 17 ; ---------------------------------------------------------------------------- 18 ; Derived from: bssave.s (BSSAVE.COM) by Erdogan Tan, 03/10/2020 19 20 ; DTA (PSP+80h= Offset 128) 21 DTA_Attrib equ 149 ; PDP+21 22 DTA_Time equ 150 ; PSP+22 23 DTA_Date equ 152 ; PSP 24 24 DTA_FileSize equ 154 ; PSP + 26 25 DTA_FileName equ 158 ; PSP + 30 26 27 ; Masterboot / Partition Table at Beginning+1BEh 28 ptBootable equ 0 29 ptBeginHead equ 1 30 ptBeginSector equ 2 31 ptBeginCylinder equ 3 32 ptFileSystemID equ 4 33 ptEndHead equ 5 34 ptEndSector equ 6 35 ptEndCylinder equ 7 36 ptStartSector equ 8 37 ptSectors equ 12 38 39 ; BIOS INT 13h Extensions (LBA extensions) 40 ; Just After DP Data (DPDiskNumber+) 41 DAP_PacketSize equ 10h ; If extensions present, this byte will be >=10h 42 DAP_Reserved1 equ 11h ; Reserved Byte 43 DAP_NumOfBlocks equ 12h ; Value of this byte must be 0 to 127 44 DAP_Reserved2 equ 13h ; Reserved Byte 45 DAP_Destination equ 14h ; Address of Transfer Buffer as SEGMENT:OFFSET 46 DAP_LBA_Address equ 18h ; LBA=(C1*H0+H1)*S0+S1-1 47 ; C1= Selected Cylinder Number 48 ; H0= Number Of Heads (Maximum Head Number + 1) 49 ; H1= Selected Head Number 50 ; S0= Maximum Sector Number 51 ; S1= Selected Sector Number 52 ; QUAD WORD 53 ; DAP_Flat_Destination equ 20h ; 64 bit address, if value in 4h is FFFF:FFFFh 54 ; QUAD WORD (Also, value in 0h must be 18h) 55 ; TR-DOS will not use 64 bit Flat Address 56 57 pTableOffset equ 1BEh ; 446 58 59 60 ; Known partition types 61 62 ;FileSys_Names: ; 2003-2017 63 ;; (Valid FileSystems for TRDOS 386, SINGLIX, RETRO UNIX OS projects in 2017) 64 FS_FAT12 equ 1 ; 01h = FAT12 65 FS_XENIX equ 2 ; 02h , XENIX System V root 66 FS_XENIX_USR equ 3 ; 03h , XENIX System V user 67 FS_FAT16 equ 4 ; 04h = FAT16 < 32MB 68 FS_EXT_CHS equ 5 ; 05h = Extended DOS Partition 69 FS_FAT16_BIG equ 6 ; 06h = FAT16 > 32MB, CHS mode 70 FS_NTFS equ 7 ; 07h , WINDOWS NTFS Partition 71 FS_FAT32_CHS equ 11 ; 0Bh = FAT32, CHS mode 72 FS_FAT32_LBA equ 12 ; 0Ch = FAT32, LBA mode 73 FS_FAT16_LBA equ 14 ; 0Eh = FAT16, LBA mode 74 FS_EXT_LBA equ 15 ; 0Fh = Extented Partition, LBA mode 75 FS_UNIX_SYSV equ 99 ; 63h , SCO UNIX, UNIXWARE, OPENSERVER 76 FS_RETROUNIX equ 113 ; 71h , Retro UNIX 386 v2 Partition 77 FS_UNIX_V7 equ 114 ; 72h , UNIX v7 x86 Partition 78 FS_LINUXSWAP equ 139 ; 82h , LINUX SWAP Partition 79 FS_LINUX equ 131 ; 83h , LINUX NATIVE (ext2) Partition 80 FS_LINUXEXT equ 133 ; 85h , LINUX EXTENDED Partition 81 FS_TRDD equ 160 ; A0h , (Random Data Disk) LBA 82 FS_TRFS equ 161 ; A1h , (32 bit, 512 bytes per sector) 83 84 [BITS 16] 85 [ORG 100h] 86 87 ;;cli 88 ;;cld 89 ;;push cs 90 ;;pop ss 91 ;;mov sp, 0FFFEh 92 ;;sti 93 ; 94 ;;mov bx, SizeOfFile+100 95 ; 96 ;mov bx, bss_end 97 ; 98 ;add bx, 15 99 ;shr bx, 1 100 ;shr bx, 1 101 ;shr bx, 1 102 ;shr bx, 1 103 ;mov ah, 4Ah ; modify memory allocation 104 ;;push cs 105 ;;pop es 106 ;int 21h 107 108 ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 109 ; clear BSS 110 ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 111 112 ;mov cx, bss_clear_end 113 ; 114 ;mov di, bss_start 115 ;sub cx, di 116 ;;inc cx 117 ;shr cx, 1 118 ;xor ax, ax 119 ;rep stosw 120 121 ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 122 ; get command arguments (command tail) 123 ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 124 125 00000000 BE8000 mov si, 80h ; PSP command tail 126 00000003 AC lodsb 127 00000004 08C0 or al, al ; command tail length 128 00000006 7421 jz short _03 ; jump if zero 129 _01: 130 00000008 AC lodsb 131 00000009 3C20 cmp al, ' ' ; is it SPACE ? 132 0000000B 74FB je short _01 133 0000000D 721A jb short _03 134 135 ; check disk name 136 137 0000000F 3C68 cmp al, 'h' 138 00000011 7516 jne short _03 139 00000013 803C64 cmp byte [si], 'd' 140 00000016 7511 jne short _03 141 00000018 46 inc si 142 00000019 AC lodsb 143 0000001A 3C30 cmp al, '0' 144 0000001C 7406 je short _02 145 0000001E 7209 jb short _03 146 00000020 3C33 cmp al, '3' 147 00000022 7705 ja short _03 148 _02: 149 00000024 803C20 cmp byte [si], ' ' 150 00000027 7409 je short _04 151 _03: 152 00000029 BE[C901] mov si, TrDOS_Welcome 153 0000002C E87701 call print_msg 154 155 0000002F E92F01 jmp _29 156 _04: 157 00000032 46 inc si 158 00000033 0450 add al, 80h - '0' 159 00000035 A2[C801] mov [DrvNum], al ; 80h .. 83h 160 _05: 161 00000038 AC lodsb 162 00000039 3C20 cmp al, ' ' 163 0000003B 74FB je short _05 164 0000003D 72EA jb short _03 165 166 ; check backup file name 167 _06: 168 0000003F BF[8C04] mov di, mbr_file_name 169 00000042 AA stosb 170 _07: 171 00000043 AC lodsb 172 ;cmp al, 0Dh ; ENTER (CR) key 173 00000044 3C20 cmp al, 20h ; ' ' 174 00000046 760C jna short _08 175 00000048 AA stosb 176 00000049 81FF[9804] cmp di, mbr_file_name + 12 177 0000004D 72F4 jb short _07 178 0000004F 803C20 cmp byte [si], 20h 179 00000052 7742 ja short _14 180 _08: 181 00000054 28C0 sub al, al 182 00000056 AA stosb 183 184 ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 185 ; File name capitalization 186 ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 187 188 00000057 BE[8C04] mov si, mbr_file_name 189 0000005A 89F7 mov di, si 190 0000005C 89F3 mov bx, si 191 _09: 192 0000005E AC lodsb 193 0000005F 3C61 cmp al, 'a' 194 00000061 730D jnb short _11 195 00000063 20C0 and al, al 196 00000065 7412 jz short _12 197 00000067 3C2E cmp al, '.' 198 00000069 7502 jne short _10 199 0000006B 89FB mov bx, di ; dot position 200 _10: 201 0000006D AA stosb 202 0000006E EBEE jmp short _09 203 _11: 204 00000070 3C7A cmp al, 'z' 205 00000072 77F9 ja short _10 206 00000074 24DF and al, 0DFh ; NOT 32 207 00000076 AA stosb 208 00000077 EBE5 jmp short _09 209 _12: 210 00000079 8805 mov [di], al 211 0000007B 4F dec di 212 0000007C 39FB cmp bx, di 213 0000007E 7316 jnb short _14 214 00000080 29DF sub di, bx 215 00000082 81EB[8C04] sub bx, mbr_file_name 216 00000086 83FF03 cmp di, 3 217 00000089 7606 jna short _13 218 0000008B 21DB and bx, bx 219 0000008D 7507 jnz short _14 220 0000008F EB0E jmp short _15 221 _13: 222 00000091 83FB08 cmp bx, 8 223 00000094 7609 jna short _15 224 _14: 225 00000096 BE[2103] mov si, msg_inv_file_name 226 00000099 E80A01 call print_msg 227 0000009C E9C200 jmp _29 228 229 ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 230 ; Find masterboot record/sector (MBR) backup file 231 ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 232 233 _15: 234 0000009F BA[8C04] mov dx, mbr_file_name 235 000000A2 B93F00 mov cx, 3Fh ; File Attributes 236 000000A5 B44E mov ah, 4Eh ; MS-DOS Function = Find First File 237 000000A7 CD21 int 21h 238 000000A9 725D jc short _20 239 240 ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 241 ; Check mbr backup file features 242 ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 243 244 000000AB BE9500 mov si, DTA_Attrib 245 000000AE 8A04 mov al, [si] 246 000000B0 241F and al, 1Fh ; directory, volume label, system, hidden, read only 247 000000B2 753A jnz short _17 248 000000B4 BE9A00 mov si, DTA_FileSize 249 000000B7 AD lodsw 250 000000B8 8B14 mov dx, [si] 251 000000BA 09C2 or dx, ax 252 000000BC 744A jz short _20 ; zero file size (do not display owr question) 253 254 ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 255 ; Display file overwrite question and get the answer (Y/N/ESC) 256 ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 257 258 000000BE BE[A903] mov si, msg_overwrite_question1 259 000000C1 E8E200 call print_msg 260 261 000000C4 BE[8C04] mov si, mbr_file_name 262 000000C7 E8DC00 call print_msg 263 264 000000CA BE[C603] mov si, msg_overwrite_question2 265 000000CD E8D600 call print_msg 266 267 _16: 268 000000D0 31C0 xor ax, ax 269 000000D2 CD16 int 16h ; wait for keyboard command 270 000000D4 3C79 cmp al, 'y' 271 000000D6 7424 je short _19 ; retry 272 000000D8 3C59 cmp al, 'Y' 273 000000DA 7420 je short _19 274 000000DC 3C6E cmp al, 'n' 275 000000DE 7414 je short _18 ; exit 276 000000E0 3C4E cmp al, 'N' 277 000000E2 7410 je short _18 278 000000E4 3C03 cmp al, 'C'-40h 279 000000E6 7479 je _29 280 000000E8 3C1B cmp al, 27 281 000000EA 75E4 jne short _16 282 000000EC EB73 jmp _29 283 284 ; invalid backup file ! 285 _17: 286 000000EE BE[4F04] mov si, msg_inv_backup_file 287 000000F1 E9A200 jmp _32 288 _18: 289 000000F4 BE[D403] mov si, _NO 290 000000F7 E8AC00 call print_msg 291 000000FA EB65 jmp _29 292 _19: 293 000000FC BE[D003] mov si, _YES 294 000000FF E8A400 call print_msg 295 296 ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 297 ; Next line 298 ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 299 300 00000102 BE[EF03] mov si, CRLF 301 00000105 E89E00 call print_msg 302 303 _20: 304 305 ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 306 ; Read masterboot sector (MBR) 307 ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 308 309 00000108 BF0500 mov di, 5 310 311 ;mov ax, 0201h ; read disk 312 0000010B BB[9A04] mov bx, MasterBootBuff ; location of masterboot code 313 314 0000010E B90100 mov cx, 1 ; cylinder = 0 315 ; sector = 1 316 00000111 B600 mov dh, 0 ; head = 0 317 00000113 8A16[C801] mov dl, [DrvNum] ; drive number, 80h .. 83h 318 _21: 319 00000117 B80102 mov ax, 0201h 320 0000011A CD13 int 13h 321 0000011C 730C jnc short _22 ; read masterboot sector, OK 322 323 ; reset hard disk(s) 324 0000011E 30E4 xor ah, ah 325 ;mov dl, [drv] 326 00000120 CD13 int 13h 327 328 ;dec byte [RetryCount] 329 00000122 4F dec di 330 00000123 75F2 jnz short _21 331 332 ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 333 ; write disk error message and terminate 334 ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 335 336 00000125 BE[2504] mov si, msg_disk_not_ready_error 337 00000128 EB6C jmp _32 338 339 _22: 340 341 ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 342 ; Check MBR if it is valid and it contains a known partition 343 ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 344 345 0000012A 813E[9806]55AA cmp word [MBIDCode], 0AA55h 346 00000130 7405 je short _23 ; Valid MBR 347 348 ; invalid MBR ! 349 350 00000132 BE[9603] mov si, msg_inv_mbr 351 00000135 EB5F jmp short _32 352 353 _23: 354 ; check if MBR contains a known type of partition or not 355 356 00000137 BE[5806] mov si, MasterBootBuff+pTableOffset 357 _24: 358 0000013A BB[B401] mov bx, known_partitions 359 0000013D B91300 mov cx, kpc-known_partitions 360 _25: 361 00000140 8A4404 mov al, [si+ptFileSystemID] 362 00000143 08C0 or al, al 363 00000145 740A jz short _27 364 _26: 365 00000147 3A07 cmp al, [bx] 366 00000149 741B je short _30 367 0000014B 49 dec cx 368 0000014C 7403 jz short _27 369 0000014E 43 inc bx 370 0000014F EBF6 jmp short _26 371 _27: 372 00000151 81FE[9806] cmp si, MasterBootBuff+pTableOffset+64 373 00000155 7305 jnb short _28 374 00000157 83C610 add si, 16 375 0000015A EBDE jmp short _24 376 _28: 377 ; MBR does not contain a known partition type 378 0000015C BE[6303] mov si, msg_kp_notfound 379 0000015F EB35 jmp short _32 380 _29: 381 00000161 BE[EF03] mov si, CRLF 382 00000164 EB30 jmp short _32 383 384 ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 385 ; Create new file or overwrite/truncate existing file 386 ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 387 388 _30: 389 00000166 31C9 xor cx, cx ; 0 ; Regular file with write permission 390 00000168 BA[8C04] mov dx, mbr_file_name 391 0000016B B8003C mov ax, 3C00h ; create a file 392 0000016E CD21 int 21h 393 00000170 722E jc short _34 394 395 ;mov [bs_file_handle], ax 396 00000172 89C1 mov cx, ax 397 398 ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 399 ; Writing MBR to the backup file 400 ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 401 402 00000174 BE[D703] mov si, msg_writing_file 403 00000177 E82C00 call print_msg 404 405 ;mov bx, [bs_file_handle] 406 0000017A 89CB mov bx, cx 407 0000017C B90002 mov cx, 512 ; MBR size in bytes 408 0000017F BA[9A04] mov dx, MasterBootBuff 409 00000182 B440 mov ah, 40h ; write to file 410 00000184 CD21 int 21h 411 412 00000186 9C pushf 413 00000187 B43E mov ah, 3Eh ; close file 414 ;mov bx, [bs_file_handle] 415 00000189 CD21 int 21h 416 0000018B 9D popf 417 0000018C 7305 jnc short _31 418 419 ; Masterboot sector backup file writing error ! 420 0000018E BE[0C04] mov si, msg_file_write_error 421 00000191 EB03 jmp short _32 422 _31: 423 00000193 BE[EB03] mov si, msg_OK 424 _32: 425 00000196 E80D00 call print_msg 426 427 ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 428 ; Exit 429 ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 430 431 00000199 B8004C mov ax, 4C00h ; terminate 432 0000019C CD21 int 21h 433 _33: 434 0000019E EBFE jmp short _33 435 _34: 436 000001A0 BE[F203] mov si, msg_file_create_error 437 000001A3 EBF1 jmp short _32 438 439 ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 440 ; print message 441 ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 442 443 _35: 444 000001A5 C3 retn 445 446 print_msg: 447 000001A6 AC lodsb ; Load byte at DS:SI to AL 448 000001A7 20C0 and al, al 449 000001A9 74FA jz short _35 450 000001AB B40E mov ah, 0Eh 451 000001AD BB0700 mov bx, 07h 452 000001B0 CD10 int 10h ; BIOS Service func ( ah ) = 0Eh 453 ; Write char as TTY 454 ; AL-char BH-page BL-color 455 000001B2 EBF2 jmp short print_msg 456 457 ;============================================================================= 458 ; initialized data 459 ;============================================================================= 460 461 known_partitions: 462 000001B4 0102030405 db FS_FAT12, FS_XENIX, FS_XENIX_USR, FS_FAT16, FS_EXT_CHS 463 000001B9 06070B0C db FS_FAT16_BIG, FS_NTFS, FS_FAT32_CHS, FS_FAT32_LBA 464 000001BD 0E0F6371 db FS_FAT16_LBA, FS_EXT_LBA, FS_UNIX_SYSV, FS_RETROUNIX 465 000001C1 728B8385 db FS_UNIX_V7, FS_LINUXSWAP, FS_LINUX, FS_LINUXEXT 466 000001C5 A0A1 db FS_TRDD, FS_TRFS 467 468 000001C7 00 kpc: db 0 469 470 DrvNum: 471 000001C8 00 db 0 472 473 ;align 2 474 475 ;bs_file_handle: 476 ; dw 0 477 478 ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 479 ; Messages 480 ;- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 481 482 TrDOS_Welcome: 483 000001C9 0D0A db 0Dh, 0Ah 484 000001CB 4D6173746572426F6F- db "MasterBoot Record/Sector Backup Utility for TR-DOS 386" 484 000001D4 74205265636F72642F- 484 000001DD 536563746F72204261- 484 000001E6 636B7570205574696C- 484 000001EF 69747920666F722054- 484 000001F8 522D444F5320333836 485 00000201 0D0A db 0Dh, 0Ah 486 00000203 76312E302E31313130- db "v1.0.111020 (c) Erdogan TAN 2020" 486 0000020C 323020286329204572- 486 00000215 646F67616E2054414E- 486 0000021E 2032303230 487 00000223 0D0A db 0Dh, 0Ah 488 00000225 0D0A db 0Dh, 0Ah 489 00000227 55736167653A206D62- db "Usage: mbsave " 489 00000230 73617665203C646973- 489 00000239 6B206472697665206E- 489 00000242 616D653E203C626163- 489 0000024B 6B75702066696C6520- 489 00000254 6E616D653E 490 00000259 0D0A db 0Dh, 0Ah 491 0000025B 0D0A db 0Dh, 0Ah 492 0000025D 4469736B2064726976- db "Disk drive names: " 492 00000266 65206E616D65733A20 493 0000026F 0D0A db 0Dh, 0Ah 494 00000271 0D0A db 0Dh, 0Ah 495 00000273 20686430202E2E666F- db " hd0 ..for MBR of 1st hard disk " 495 0000027C 72204D4252206F6620- 495 00000285 317374206861726420- 495 0000028E 6469736B20 496 00000293 0D0A db 0Dh, 0Ah 497 00000295 20686431202E2E666F- db " hd1 ..for MBR of 2nd hard disk " 497 0000029E 72204D4252206F6620- 497 000002A7 326E64206861726420- 497 000002B0 6469736B20 498 000002B5 0D0A db 0Dh, 0Ah 499 000002B7 20686432202E2E666F- db " hd2 ..for MBR of 3rd hard disk " 499 000002C0 72204D4252206F6620- 499 000002C9 337264206861726420- 499 000002D2 6469736B20 500 000002D7 0D0A db 0Dh, 0Ah 501 000002D9 20686433202E2E666F- db " hd3 ..for MBR of 4th hard disk " 501 000002E2 72204D4252206F6620- 501 000002EB 347468206861726420- 501 000002F4 6469736B20 502 000002F9 0D0A0D0A db 0Dh, 0Ah, 0Dh, 0Ah 503 000002FD 4578616D706C653A20- db "Example: mbsave hd0 mbsector.bin " 503 00000306 6D6273617665206864- 503 0000030F 30206D62736563746F- 503 00000318 722E62696E20 504 0000031E 0D0A00 db 0Dh, 0Ah, 0 505 506 msg_inv_file_name: 507 00000321 0D0A db 0Dh, 0Ah 508 00000323 496E76616C69642066- db "Invalid file name !", 0Dh, 0Ah 508 0000032C 696C65206E616D6520- 508 00000335 210D0A 509 00000338 2846696C65206E616D- db "(File name must fit to 8.3 DOS format) !" 509 00000341 65206D757374206669- 509 0000034A 7420746F20382E3320- 509 00000353 444F5320666F726D61- 509 0000035C 74292021 510 00000360 0D0A00 db 0Dh, 0Ah, 0 511 512 msg_kp_notfound: 513 00000363 0D0A db 0Dh, 0Ah 514 00000365 4D425220646F657320- db 'MBR does not contain a known partition type ! ' 514 0000036E 6E6F7420636F6E7461- 514 00000377 696E2061206B6E6F77- 514 00000380 6E2070617274697469- 514 00000389 6F6E20747970652021- 514 00000392 20 515 00000393 0D0A db 0Dh, 0Ah 516 00000395 00 db 0 517 518 msg_inv_mbr: 519 00000396 0D0A db 0Dh, 0Ah 520 00000398 496E76616C6964204D- db 'Invalid MBR ! ' 520 000003A1 4252202120 521 000003A6 0D0A00 db 0Dh, 0Ah, 0 522 523 msg_overwrite_question1: 524 000003A9 0D0A db 0Dh, 0Ah 525 000003AB 446F20796F75207761- db 'Do you want to overwrite ' 525 000003B4 6E7420746F206F7665- 525 000003BD 72777269746520 526 000003C4 27 db 27h 527 000003C5 00 db 0 528 529 msg_overwrite_question2: 530 000003C6 27 db 27h 531 000003C7 2066696C65203F20 db ' file ? ' 532 000003CF 00 db 0 533 534 000003D0 594553 _YES: db 'YES' 535 ;db 0Dh, 0Ah, 0 536 000003D3 00 db 0 537 538 000003D4 4E4F _NO: db 'NO' 539 ;db 0Dh, 0Ah, 0 540 000003D6 00 db 0 541 542 msg_writing_file: 543 000003D7 0D0A db 0Dh, 0Ah 544 000003D9 57726974696E672066- db 'Writing file ... ' 544 000003E2 696C65202E2E2E20 545 000003EA 00 db 0 546 msg_OK: 547 000003EB 204F4B2E db ' OK.' 548 CRLF: 549 000003EF 0D0A00 db 0Dh, 0Ah, 0 550 551 msg_file_create_error: 552 000003F2 0D0A db 0Dh, 0Ah 553 000003F4 46696C652063726561- db "File creating error !" 553 000003FD 74696E67206572726F- 553 00000406 722021 554 00000409 0D0A00 db 0Dh, 0Ah, 0 555 556 msg_file_write_error: 557 0000040C 0D0A db 0Dh, 0Ah 558 0000040E 46696C652077726974- db "File writing error !" 558 00000417 696E67206572726F72- 558 00000420 2021 559 00000422 0D0A00 db 0Dh, 0Ah, 0 560 561 msg_disk_not_ready_error: 562 00000425 0D0A db 0Dh, 0Ah 563 00000427 4469736B2072656164- db "Disk read error or drive not ready ! " 563 00000430 206572726F72206F72- 563 00000439 206472697665206E6F- 563 00000442 742072656164792021- 563 0000044B 20 564 0000044C 0D0A00 db 0Dh, 0Ah, 0 565 566 msg_inv_backup_file: 567 0000044F 0D0A db 0Dh, 0Ah 568 00000451 496E76616C69642062- db "Invalid backup file name !", 0Dh, 0Ah 568 0000045A 61636B75702066696C- 568 00000463 65206E616D6520210D- 568 0000046C 0A 569 0000046D 28496D70726F706572- db "(Improper file attributes) !" 569 00000476 2066696C6520617474- 569 0000047F 726962757465732920- 569 00000488 21 570 00000489 0D0A00 db 0Dh, 0Ah, 0 571 572 SizeOfFile equ $-100 573 574 ;============================================================================= 575 ; uninitialized data 576 ;============================================================================= 577 578 bss_start: 579 580 ABSOLUTE bss_start 581 582 alignb 2 583 584 mbr_file_name: 585 0000048C resb 13 586 00000499 ?? resb 1 ; word alignment 587 588 bss_clear_end: 589 590 ;alignb 2 591 592 ; Masterboot sector (MBR) 593 594 MasterBootBuff: 595 MasterBootCode: 596 0000049A resb 446 597 PartitionTable: 598 00000658 resb 64 599 MBIDCode: 600 00000698 ???? resw 1 601 602 bss_end: