故事背景：
一个朋友说他的移动硬盘在有的电脑有打的开，在有的上面打不开。我问是不是在win7上打的开，但在单位的windows xp上打不开？
把盘拿来一看，的确是这个问题。应该是在win7上分的GTP分区，windows xp不识别。
目标：
将GPT分区转为MBR
步骤：
先查看当前盘的分区：
➜ ~ sudo fdisk /dev/sdb Welcome to fdisk (util-linux 2.30.1). Changes will remain in memory only, until you decide to write them. Be careful before using the write command. Command (m for help): p Disk /dev/sdb: 465.7 GiB, 500074283008 bytes, 976707584 sectors Units: sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disklabel type: gpt Disk identifier: ED2D2D22-4506-436C-9D95-9AF27790A8B1 Device Start End Sectors Size Type /dev/sdb1 2048 245762047 245760000 117.2G Microsoft basic data /dev/sdb2 245762048 491522047 245760000 117.2G Microsoft basic data /dev/sdb3 491522048 737282047 245760000 117.2G Microsoft basic data /dev/sdb4 737282048 976703487 239421440 114.2G Microsoft basic data
fdisk显示Disklabel type: gpt，即是GPT分区没错。记住分区表的各Start End地址，这个是重建分区表的基础。
对原分区数据进行备份， 可以用rsync将数据同步到其它地方，支持中断续传。
数据备份完后，使用parted将盘的分区格式转为msdos，也即MBR格式。
(parted) select /dev/sdb Using /dev/sdb (parted) print Model: WD Elements 25A2 (scsi) Disk /dev/sdb: 500GB Sector size (logical/physical): 512B/512B Partition Table: gpt Disk Flags: Number Start End Size File system Name Flags 1 1049kB 126GB 126GB ntfs Basic data partition msftdata 2 126GB 252GB 126GB ntfs Basic data partition msftdata 3 252GB 377GB 126GB ntfs Basic data partition msftdata 4 377GB 500GB 123GB ntfs Basic data partition msftdata (parted) help mklabel mklabel,mktable LABEL-TYPE create a new disklabel (partition table) LABEL-TYPE is one of: atari, aix, amiga, bsd, dvh, gpt, mac, msdos, pc98, sun, loop (parted) mklabel msdos Warning: The existing disk label on /dev/sdb will be destroyed and all data on this disk will be lost. Do you want to continue? Yes/No? Yes (parted) print Model: WD Elements 25A2 (scsi) Disk /dev/sdb: 500GB Sector size (logical/physical): 512B/512B Partition Table: msdos Disk Flags: Number Start End Size Type File system Flags (parted) quit Information: You may need to update /etc/fstab.
下面再使用fdisk对硬盘进行分区，start,end地址与之前保持一致。分完区再将分区类型改为 7 HPFS/NTFS/exFAT
由于没有保存操作log，并且朋友的盘也拿走了，这里只做关键点提示，以当前系统盘为例子：
➜ ~ sudo fdisk -l /dev/sda [sudo] password for hyang0: Disk /dev/sda: 223.6 GiB, 240057409536 bytes, 468862128 sectors Units: sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disklabel type: dos Disk identifier: 0xcf138318 Device Boot Start End Sectors Size Id Type /dev/sda1 * 2048 468862127 468860080 223.6G 83 Linux ➜ ~ sudo fdisk /dev/sda Welcome to fdisk (util-linux 2.30.1). Changes will remain in memory only, until you decide to write them. Be careful before using the write command. Command (m for help): p Disk /dev/sda: 223.6 GiB, 240057409536 bytes, 468862128 sectors Units: sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disklabel type: dos Disk identifier: 0xcf138318 Device Boot Start End Sectors Size Id Type /dev/sda1 * 2048 468862127 468860080 223.6G 83 Linux Command (m for help): d Selected partition 1 Partition 1 has been deleted. Command (m for help): p Disk /dev/sda: 223.6 GiB, 240057409536 bytes, 468862128 sectors Units: sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disklabel type: dos Disk identifier: 0xcf138318 Command (m for help): n Partition type p primary (0 primary, 0 extended, 4 free) e extended (container for logical partitions) Select (default p): p Partition number (1-4, default 1): First sector (2048-468862127, default 2048): Last sector, +sectors or +size{K,M,G,T,P} (2048-468862127, default 468862127): 468862127 Created a new partition 1 of type 'Linux' and of size 223.6 GiB. Partition #1 contains a ext4 signature. Do you want to remove the signature? [Y]es/[N]o: N Command (m for help): p Disk /dev/sda: 223.6 GiB, 240057409536 bytes, 468862128 sectors Units: sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disklabel type: dos Disk identifier: 0xcf138318 Device Boot Start End Sectors Size Id Type /dev/sda1 2048 468862127 468860080 223.6G 83 Linux Command (m for help): m Help: DOS (MBR) a toggle a bootable flag b edit nested BSD disklabel c toggle the dos compatibility flag Generic d delete a partition F list free unpartitioned space l list known partition types n add a new partition p print the partition table t change a partition type v verify the partition table i print information about a partition Misc m print this menu u change display/entry units x extra functionality (experts only) Script I load disk layout from sfdisk script file O dump disk layout to sfdisk script file Save & Exit w write table to disk and exit q quit without saving changes Create a new label g create a new empty GPT partition table G create a new empty SGI (IRIX) partition table o create a new empty DOS partition table s create a new empty Sun partition table Command (m for help): t Selected partition 1 Hex code (type L to list all codes): L 0 Empty 24 NEC DOS 81 Minix / old Lin bf Solaris 1 FAT12 27 Hidden NTFS Win 82 Linux swap / So c1 DRDOS/sec (FAT- 2 XENIX root 39 Plan 9 83 Linux c4 DRDOS/sec (FAT- 3 XENIX usr 3c PartitionMagic 84 OS/2 hidden or c6 DRDOS/sec (FAT- 4 FAT16 <32M 40 Venix 80286 85 Linux extended c7 Syrinx 5 Extended 41 PPC PReP Boot 86 NTFS volume set da Non-FS data 6 FAT16 42 SFS 87 NTFS volume set db CP/M / CTOS / . 7 HPFS/NTFS/exFAT 4d QNX4.x 88 Linux plaintext de Dell Utility 8 AIX 4e QNX4.x 2nd part 8e Linux LVM df BootIt 9 AIX bootable 4f QNX4.x 3rd part 93 Amoeba e1 DOS access a OS/2 Boot Manag 50 OnTrack DM 94 Amoeba BBT e3 DOS R/O b W95 FAT32 51 OnTrack DM6 Aux 9f BSD/OS e4 SpeedStor c W95 FAT32 (LBA) 52 CP/M a0 IBM Thinkpad hi ea Rufus alignment e W95 FAT16 (LBA) 53 OnTrack DM6 Aux a5 FreeBSD eb BeOS fs f W95 Ext'd (LBA) 54 OnTrackDM6 a6 OpenBSD ee GPT 10 OPUS 55 EZ-Drive a7 NeXTSTEP ef EFI (FAT-12/16/ 11 Hidden FAT12 56 Golden Bow a8 Darwin UFS f0 Linux/PA-RISC b 12 Compaq diagnost 5c Priam Edisk a9 NetBSD f1 SpeedStor 14 Hidden FAT16 <3 61 SpeedStor ab Darwin boot f4 SpeedStor 16 Hidden FAT16 63 GNU HURD or Sys af HFS / HFS+ f2 DOS secondary 17 Hidden HPFS/NTF 64 Novell Netware b7 BSDI fs fb VMware VMFS 18 AST SmartSleep 65 Novell Netware b8 BSDI swap fc VMware VMKCORE 1b Hidden W95 FAT3 70 DiskSecure Mult bb Boot Wizard hid fd Linux raid auto 1c Hidden W95 FAT3 75 PC/IX bc Acronis FAT32 L fe LANstep 1e Hidden W95 FAT1 80 Old Minix be Solaris boot ff BBT Hex code (type L to list all codes): 7 Changed type of partition 'Linux' to 'HPFS/NTFS/exFAT'. Command (m for help): p Disk /dev/sda: 223.6 GiB, 240057409536 bytes, 468862128 sectors Units: sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disklabel type: dos Disk identifier: 0xcf138318 Device Boot Start End Sectors Size Id Type /dev/sda1 2048 468862127 468860080 223.6G 7 HPFS/NTFS/exFAT Command (m for help): q ➜ ~
fdisk 命令简介
Command (m for help): m Help: DOS (MBR) a toggle a bootable flag b edit nested BSD disklabel c toggle the dos compatibility flag Generic d delete a partition F list free unpartitioned space l list known partition types n add a new partition p print the partition table t change a partition type v verify the partition table i print information about a partition Misc m print this menu