Project Name: GRUB for DOS Definition: A GRUB build for DOS with extensions for disk drive emulation. Current Version: 0.4.2 Author: Tinybit(tinybit@tom.com) File Format: DOS EXE executable, Linux kernel Purpose: Launch GRUB boot loader from within DOS Circumstanced Use: in CONFIG.SYS or AUTOEXEC.BAT Ability: Boot any installed operating system on your PC Limitations: GRUB.EXE may run in real mode DOS. It cannot run from a DOS BOX inside Windows, nor if some TSR programs are running. Currently runs on MS-DOS 3.30, 4.0, 5.0, 6.0, 6.20. 6.21, 6.22, 7.0(Win95), 7.10(Win98), 8.0(WinME/NT/2000/XP), and FreeDOS(build 2029 and hopefully more future builds). Limited support for returning to DOS from GRUB.EXE, see below. Copyright(C): Tinybit(tinybit@tom.com) License: GNU GPL(see file COPYING) source available as diff patches to the GNU GRUB release. See the shell script COMPILE for more info. WARRANTY: NO WARRANTY(see file COPYING) TO DO: Let GRLDR.MBR support more filesystems. Usage: GRUB [--bypass] [--time-out=T] [--hot-key=K] [--config-file=FILE] The FILE, for example, can be (hd0,0)/menu.lst In CONFIG.SYS, the line looks like: install=c:\some\where\grub.exe --config-file=FILE If no options present, GRUB.EXE simply uses (hd0,0)/menu.lst as the configure file, if it exists. (Notice! We finally changed the default file from (hd0,0)/boot/grub/menu.lst to (hd0,0)/menu.lst) The partition (hd0,0) can be of a Windows partition or a Linux partition, or any other partition type supported by GRUB. Only GRUB-style filename is acceptable here for FILE. A DOS filename won't work(it is certain we should use GRUB-style filenames because DOS-filenames won't access a file in a Linux ext2 partition for example).(See Update 2 below) Update: FILE can be the contents of a menu. Use semi-colon to delimitate the embedded commands here in FILE. The FILE can be enclosed with a pair of double-quotes. For example: GRUB --config-file="root (hd0,0);chainloader +1" This command will boot the system in (hd0,0). Another example: GRUB --config-file="reboot" This command will reboot the machine. One more example: GRUB --config-file="halt" This command will halt the machine. if --bypass is specified, GRUB will exit to DOS when timeout reached. The option `--time-out=T' specifies the timeout value in seconds. T defaults to 5 if --bypass is specified and defaults to 0 if --bypass is not specified. The default hot key value is 0x3920(for space bar). If this key is pressed, GRUB will boot normally. If another key is pressed, GRUB will terminate immediately and return back to DOS. See "int 16 keyboard scan codes" below. Each option can be specified only once at most. Update 2: DOS filenames have been supported(patched by John Cobb). If the beginning two characters of FILE are "#@", then the rest of FILE is taken as a DOS filename. Example: GRUB --config-file="#@c:\menu.lst" Only the beginning 4KB of the DOS file will be used. The file should be an uncompressed text file. Note: You may also use the `direct DOS file access' with the SHELL or INSTALL line in CONFIG.SYS, but should not use it with the DEVICE line. The DOS document said that a DOS device driver should not call the `open file' DOS call. Compile: You should unzip the package under Linux in this way: unzip grub_for_dos-*.zip then cd into the grub_for_dos-* dir and do a make. -------------------------------------------------------- Web site: http://sarovar.org/projects/grub4dos/ Web site: http://grub4dos.jot.com/ Web site: http://grub4dos.freespaces.com/ Web site: http://grub4dos.sourceforge.net/ (WinGRUB by bean123) Web site: http://grub.linuxeden.com/ (scratchpad, mainly in Chinese) Update 1: Version 0.2.0 also brings out a new thing, GRUB for NTLDR, which could be used to boot into GRUB from the boot menu of Windows NT/2000/XP. Copy GRLDR to the root directory of drive C: of Windows NT/2000/XP and append to C:\BOOT.INI this line: C:\GRLDR="Start GRUB" That will be done. The GRLDR should be in the same directory as BOOT.INI and NTLDR. Note that BOOT.INI is usually hidden and you must unhide it before you can see it. The filename GRLDR shouldn't be changed. If GRLDR is in a NTFS partition, it should be copied to the root directory of another non-NTFS partition(and likewise should the menu.lst file be). If GRLDR is compressed, e.g., in a NTFS partition, it will not work. Even if the drive letter of this disk has been changed to other than C by the Windows device manager, it seems you still have to use the letter C here in BOOT.INI, otherwise, NTLDR will fail to locate the GRLDR file. And what's more, if you are booting NTLDR from a floppy, you will have to write the GRLDR line in A:\BOOT.INI like this: C:\GRLDR="Start GRUB" and shouldn't use the letter A like this: A:\GRLDR="Start GRUB" (Note that in the case when BOOT.INI is on floppy A, the notation "C:\GRLDR" actually refer to the file A:\GRLDR). Notice! In the future, we will remove NTFS support. For Windows users, please create an FAT partition and place GRLDR and menu.lst there. From now on, please don't report bugs relevant to NTFS. Someone reports that Windows XP with newer SPs and Windows Vista have intentionally broken the compatiblity with many things(including GRLDR). So you will get into trouble with these systems. Update 2: GRUB for Linux is also introduced along with 0.2.0. You can boot grub using a linux loader KEXEC, LILO, SYSLINUX or another GRUB. (GRUB4LIN has merged into GRUB.EXE) To boot GRUB off Linux, use this pair of commands: kexec -l grub.exe kexec -e To boot GRUB via GRUB, use commands like the following: kernel (hd0,0)/grub.exe boot To boot GRUB via LILO, use these lines in lilo.conf: image=/boot/grub.exe label=grub.exe To boot GRUB via SYSLINUX, use these lines in syslinux.cfg: label grub.exe kernel grub.exe LOADLIN may encounter problems when loading grub.exe, because grub.exe requires some unchanged original BIOS interrupt vectors, but DOS has destroyed them, and loadlin does not recover them before it transfers control to grub.exe. Update 3: Beginning at version 0.4.0, GRUB for DOS supports memdrives. Example: # boot into a floppy image map --mem (hd0,0)/floppy.img (fd0) map --hook chainloader (fd0)+1 rootnoverify (fd0) map --floppies=1 boot Because the image will be copied to a memory area, the image itself can be non-contiguous and even gzipped. Another Example: map --mem=-2880 (hd0,0)/floppy.img (fd0) This memdrive (fd0) will occupy at least 1440 KB of memory. This is useful when the size of a 1.44M-floppy image is less than 1440 KB. One more example: map --mem --read-only (hd0,0)/hd.img (hd1) This memdrive is a hard drive, and read-only. That means you will not be able to write data to the memdrive (hd1). You can use many memdrives and many ordinary virtual emulated disk-based drives at the same time. If the BIOS does not support int15/EAX=e820h, you will not be able to use any memdrives. Update 4: For memdrive emulation, a single-partition image can be used instead of a whole-harddrive image. Example: map --mem (hd0,7)/win98.img (hd0) map --hook chainloader (hd0)+1 rootnoverify (hd0) map --harddrives=1 boot Here win98.img is a partition image without the leading MBR and partition table in it. Surely GRUB for DOS will build an MBR and partition table for the memdrive (hd0). Update 5: Now GRLDR can be used as a no-emulation-mode bootable CD-ROM boot image. Example for Linux users: mkdir iso_root cp grldr iso_root mkisofs -R -b grldr -no-emul-boot -boot-load-seg 0x1000 -o bootable.iso iso_root Note: There are quite a lot of buggy BIOSes that cannot boot the CD-ROM made with bootable.iso. The boot image of bootable.iso is the whole GRLDR file, not solely the first 2048 bytes of GRLDR. Buggy BIOSes only load the beginning 2048 bytes of the boot image, and will hang the machine. For Those buggy BIOSes, please use stage2_eltorito instead. Do a compilation, and the stage2_eltorito will be created in the grub-0.97/stage2/ directory. For detailed usage about stage2_eltorito, google the Internet, please. Don't use the above `mkisofs' line on stage2_eltorito. The line only works for GRLDR. The stage2_eltorito has a different `mkisofs' line as in the following: mkdir iso_root cp stage2_eltorito iso_root mkisofs -R -b stage2_eltorito -no-emul-boot -boot-load-size 4 -boot-info-table -o stage2.iso iso_root The option -boot-info-table should not be used with the GRLDR line, while it must be used with stage2_eltorito. Update 2006-12-03: Now grldr can be used the same way as stage2_eltorito. The -boot-info-table option is allowed but you can omit it: mkdir iso_root cp grldr iso_root mkisofs -R -b grldr -no-emul-boot -boot-load-size 4 -o grldr.iso iso_root Also note that the bootable.iso above must be created with the -boot-load-seg 0xHHHH option where HHHH is greater than or equal to 1000(hex). If HHHH < 1000(hex), QEMU will hang. This is a bug in QEMU. The grldr.iso can be created with or without -boot-load-seg 0xHHHH option. Update 6: The Chinese special build is in the "chinese" subdirectory. (patched by Gandalf, 2005-06-27) The Chinese special build also has scdrom builtin. (update: scdrom has been dropped since 2006-07-20) Update 7: Added memory drive (md). Like (nd) for network drive and (cd) for CD-ROM drive, a new drive (md) is implemented for accessing the whole memory as a disk drive. (md) only works for systems with BIOS int15/EAX=E820h support. The cat command now has a few new options: --hex for hexdump, and --locate=STRING for string search in file. Typical examples: cat --hex (hd0)+1 It will display the MBR sector in hex form. cat --hex (md)+2 It will display 1KB of your memory(in fact, it is the real-mode IDT table), also in hexdump form. cat --hex (md)0x800+1 It will display 1 sector of your extended memory. cat --hex (hd0,0)+1 It will display the first sector of partition (hd0,0). Usually this sector contains the boot record of an operating system. Update 8: Added ram drive (rd). The (md) device accesses the memory starting at physical address 0. But (rd) accesses memory starting at any base address. The base and length of the ram drive can be specified through the map command. "help map" for details. You can even specify the BIOS drive number used for the (rd) drive, e.g., map --ram-drive=0xf0. The default drive number for (rd) is 0x7F which is a floppy. If (rd) is a hard drive image, you should change the drive number to a value greater than or equal to 0x80(but should avoid using 0xff, because 0xff is for the (md) device). Update 9: Directly boot NTLDR of WinNT/2K/XP and IO.SYS of Win9x/ME and KERNEL.SYS of FreeDOS. Examples: chainloader --edx=0xPPYY (hd0,0)/ntldr boot chainloader --edx=0xYY (hd0,0)/io.sys boot chainloader --ebx=0xYY (hd0,0)/kernel.sys boot Hex YY specifies the boot drive number, and hex PP specifies the boot partition number of NTLDR. If the boot drive is floppy, PP should be the hex value ff, i.e., decimal 255. For KERNEL.SYS of FreeDOS, the --edx won't work, use --ebx please. The option --edx ( --ebx ) can be omitted if the file is in its normal place. But in some cases, those options are needed. If, e.g., the ntldr file is in an ext2 partition called (hd2,8) while you want it to think of the Windows partition (hd0,7) as the boot partition, then --edx is required: chainloader --edx=0x0780 (hd2,8)/ntldr For DOS kernels(i.e., IO.SYS and KERNEL.SYS), the boot partition number is meaningless, so you only need to specify the correct boot drive number YY(but specifying the boot partition number is harmless). The above PPYY can also be specified by using a root or rootnoverify command after the chainloader command. Examples: chainloader (hd2,6)/kernel.sys rootnoverify (hd0) <-------- YY=80 boot chainloader (hd0,0)/ntldr rootnoverify (hd0,5) <-------- YY=80, PP=05 boot Tip: CMLDR (the ComMand LoaDeR, which is used to load the Windows Fault Recovery Console) can be chainloaded as well as NTLDR. Bean has successfully decompressed and booted IO.SYS of WinME. Thanks for the great job! -------------------------------------------------------- There is no full documentation in English at present. Here are some examples showing the usage of disk emulation commands: 1. Emulates HD partition C: as floppy drive A: and boot win98 from C: map --read-only (hd0,0)+1 (fd0) chainloader (hd0,0)+1 rootnoverify (hd0) boot In the above example, (hd0,0) is drive C: with win98 on it. After win98 boot complete, you will find that A: contains all files of C:, and if you delete files in A:, the files in C: will also disappear. At the map command line, the notation (hdm,n)+1 is interpreted to represent the whole partition (hdm,n), not just the first sector of the partition. 2. Emulates HD partition C: as floppy drive A: and boot win98 from A: map --read-only (hd0,0)+1 (fd0) map --hook chainloader (fd0)+1 rootnoverify (fd0) map --floppies=1 boot After the "map --hook" command, the emulation takes effect instantly even in the GRUB command line. Note that the (fd0) in "chainloader (fd0)+1" is the emulated virtual floppy A:, not the real floppy diskette(because map is hooked now). 3. Emulates an image file as floppy drive A: and boot win98 from C: map --read-only (hd0,0)/floppy.img (fd0) chainloader (hd0,0)+1 rootnoverify (hd0) map --floppies=1 map --harddrives=1 boot 4. Emulates an HD partition as the first hard disk and boot DOS from it: map --read-only (hd2,6)+1 (hd0) map --hook chainloader (hd0,0)+1 rootnoverify (hd0) map --harddrives=1 boot In this example, (hd2,6)+1 represents an extended logical DOS partition of the third BIOS hard disk (hd2). If a DOS partition is used to emulate a hard disk, GRUB for DOS will first try to locate the partition table, usually 63 sectors ahead of the DOS partition. GRUB for DOS will refuse the emulation if the partition table is not there. 5. Emulates an image file as the first hard disk and boot DOS from it: map --read-only (hd0,0)/harddisk.img (hd0) chainloader --load-length=512 (hd0,0)/harddisk.img rootnoverify (hd0) map --harddrives=1 boot If an image file is used to emulate a hard disk, the image file must contain an MBR. In other word, the first sector of HARDDISK.IMG must contain the partition table of the emulated virtual hard disk. Note: Counters for floppies and harddrives in the BIOS Data Area remain unchanged during the mapping. You should manually set them to proper values with `map --floppies=' and/or `map --harddrives=', especially, e.g., when there is no real floppy drive attached to the mother board. If not doing so, DOS might fail to start. `map --status' can report the values. Note also that `map --floppies=' and `map --harddrives=' can be used independently without the appearance of mappings. 0.4.2 has introduced a new variable, memdisk_raw, to simulate the memdisk-like raw mode. If the BIOS has no int15/87h, or if it has buggy int15/87h support, you should set this variable before any memdrives are used. Here is an example: map --memdisk-raw=1 map --mem (hd0,0)/floppy.img (fd0) map --hook chainloader (fd0)+1 rootnoverify (fd0) boot If you encountered a memdrive failure without using map --memdisk-raw=1, you should have a try with `map --memdisk-raw=1'. If you `map --memdisk-raw=0' later, you should afterwards do a `map --unhook'(and followed by a `map --hook' if needed). Update: memdisk_raw now defaults to 1. You should `map --memdisk-raw=0' if you want to use int15/87h to access memdrives. -------------------------------------------------------- Floppies/harddisks of any size can be emulated with GRUB for DOS 0.2.0. Image file must be contiguous, or else GRUB for DOS will refuse it. The `blocklist' command can list fragments or pieces of a file. Type "help map" at the GRUB prompt to get a brief description of the command. The form map ... (fd?) is a floppy emulation, and the form map ... (hd?) is a hard disk emulation. When a HARD DISK emulation is used, better not start Windows for security reasons. Windows may even destroy all data and all information on all your real hard disks!!!!!!!! Update for --mem: when --mem is used, it seems rather safe even after entering Windows. Win98 can operate the memdrive normally. Windows NT/2000/XP does not recognize the emulated drives no matter whether the --mem option is present. ****************************************************************************** *** Explanation of the grldr-bootable floppies or harddisk partitions *** ****************************************************************************** 1. Ext2 Boot Sector/Boot Record Layout (for loading grldr) ------------------------------------------------------------------------------ A sample floppy image is ext2grldr.img within the GRUB for DOS release. Copy grldr and an optional menu.lst to the root dir of the filesystem inside this image, and it is then a GRUB-bootable floppy image. Note that the first sector of ext2grldr.img is exactly the same as the fifth sector of grldr. Offset Length Description ====== ====== ============================================================== 00h 2 Machine code for short jump over the data. 02h 1 LBA indicator. Valid values are 0x02 for CHS mode, or 0x42 for LBA mode. If the BIOS int13 supports LBA, this byte can be safely set to 0x42. Some USB BIOSes might have bugs when using CHS mode, so the format program should set this byte to 0x42. It seems that (generally) all USB BIOSes have LBA support. If the format program does not know whether the BIOS has LBA support, it may operate this way: if (partition_start + total_sectors_in_partition) exceeds the CHS addressing ability(especially when it is greater than 1024*256*63), the caller should set this byte to 0x42, otherwise, set to 0x02. Note that Windows98 uses the value 0x0e as the LBA indicator. Update: this byte of LBA indicator is ignored. The boot record can probe the LBA support of BIOS. 03h 10 OEM name string (of OS which formatted the disk). 0Dh 1 Sectors per block. Valid values are 2, 4, 8, 16 and 32. 0Eh 2 Bytes per block. Valid values are 0x400, 0x800, 0x1000, 0x2000 and 0x4000. 10h 4 Pointers in pointers-per-block blocks, that is, number of blocks covered by a double-indirect block. Valid values are 0x10000, 0x40000, 0x100000, 0x400000 and 0x1000000. 14h 4 Pointers per block, that is, number of blocks covered by an indirect block. Valid values are 0x100, 0x200, 0x400, 0x800, 0x1000. 18h 2 Sectors per track. 1Ah 2 Number of heads/sides. 1Ch 4 Number of hidden sectors (those preceding the boot sector). Also referred to as the starting sector of the partition. For floppies, it should be 0. 20h 4 Total number of sectors in the filesystem(or in the partition). 24h 1 BIOS drive number of the boot device. Actually this byte is ignored for read. The boot code will write DL onto this byte. The BIOS or the caller should set drive number in DL. We assume all BIOSes pass correct drive number in DL. Buggy BIOSes are not supported!! 25h 1 Partition number of this partition on the boot drive. 0, 1, 2, 3 are primary partitions. 4, 5, 6, ... are logical partitions in the extended partition. 0xff is for whole drive. So for floppies, it should be 0xff. 26h 2 reserved. 28h 4 Number of inodes per group. Normally a 1.44M floppy has only one group, and the total number of inodes is 184. So the value should be 184 or greater. 2Ch 4 The block number for group descriptors. Valid values are 2 for 1024-byte blocks, and 1 otherwise. The value here is equal to (s_first_data_block + 1). 30h 462 Machine code. 1FEh 2 Boot Signature AA55h. 2. FAT12/FAT16 Boot Sector/Boot Record Layout (for loading grldr) ------------------------------------------------------------------------------ A sample floppy image is fat12grldr.img within the GRUB for DOS release. Copy grldr and an optional menu.lst to the root dir of the filesystem inside the image, and the image is then a GRUB-bootable floppy image. Note that the first sector of fat12grldr.img is exactly the same as the fourth sector of grldr. Offset Length Description ====== ====== ============================================================== 00h 2 Machine code for short jump over the data. 02h 1 LBA indicator. Valid values are 0x90 for CHS mode, or 0x0e for LBA mode. If the BIOS int13 supports LBA, this byte can be safely set to 0x0e. Some USB BIOSes might have bugs when using CHS mode, so the format program should set this byte to 0x0e. It seems that (generally) all USB BIOSes have LBA support. If the format program does not know whether the BIOS has LBA support, it may operate this way: if (partition_start + total_sectors_in_partition) exceeds the CHS addressing ability(especially when it is greater than 1024*256*63), the caller should set this byte to 0x0e, otherwise, set to 0x90. Update: this byte of LBA indicator is ignored. The boot record can probe the LBA support of BIOS. Update(2006-07-31): Though GRLDR won't use this LBA-indicator byte, Windows 98 uses it. Usually this byte should be 0x90 for CHS mode(especially for floppies). If this byte is not set properly, Windows 98 will not recognize the floppy or partition. This problem was reported by neiljoy. Many thanks! 03h 8 OEM name string (of OS which formatted the disk). 0Bh 2 Bytes per sector. Must be 512. 0Dh 1 Sectors per cluster. Valid values are 1, 2, 4, 8, 16, 32, 64 and 128. But a cluster size larger than 32K should not occur. 0Eh 2 Reserved sectors(number of sectors before the first FAT, including the boot sector), usually 1. 10h 1 Number of FATs(nearly always 2). 11h 2 Maximum number of root directory entries. 13h 2 Total number of sectors (for small disks only, if the disk is too big this is set to 0 and offset 20h is used instead). 15h 1 Media descriptor byte, pretty meaningless now (see below). 16h 2 Sectors per FAT. 18h 2 Sectors per track. 1Ah 2 Total number of heads/sides. 1Ch 4 Number of hidden sectors (those preceding the boot sector). Also referred to as the starting sector of the partition. For floppies, it should be 0. 20h 4 Total number of sectors for large disks. 24h 1 BIOS drive number of the boot device. Actually this byte is ignored for read. The boot code will write DL onto this byte. The BIOS or the caller should set drive number in DL. We assume all BIOSes pass correct drive number in DL. Buggy BIOSes are not supported!! 25h 1 Partition number of this filesystem in the boot drive. This byte is ignored for read. The boot code will write partition number onto this byte. See offset 41h below. 26h 1 Signature (must be 28h or 29h to be recognised by NT). 27h 4 Volume serial number. 2Bh 11 Volume label. 36h 8 File system ID. "FAT12 ", "FAT16 " or "FAT ". 3Eh 1 opcode for "cli". 3Fh 1 opcode for "cld". 40h 1 opcode for "mov dh, imm8". 41h 1 Partition number of this partition on the boot drive. 0, 1, 2, 3 are primary partitions. 4, 5, 6, ... are logical partitions in the extended partition. 0xff is for whole drive. So for floppies, it should be 0xff. 42h 442 Machine code. 1FCh 4 Boot Signature AA550000h. (Win9x uses 4 bytes as magic value) 3. FAT32 Boot Sector/Boot Record Layout (for loading grldr) ------------------------------------------------------------------------------ A FAT32 partition can be GRUB-bootable. Copy grldr and an optional menu.lst to the root dir of the FAT32 partition, and build the boot sector based on the third sector of grldr(some fields need to be changed as detailed in the following table). That is ok, the FAT32 partition is then GRUB-bootable. Offset Length Description ====== ====== ============================================================== 00h 2 Machine code for short jump over the data. 02h 1 LBA indicator. Valid values are 0x90 for CHS mode, or 0x0e for LBA mode. If the BIOS int13 supports LBA, this byte can be safely set to 0x0e. Some USB BIOSes might have bugs when using CHS mode, so the format program should set this byte to 0x0e. It seems that (generally) all USB BIOSes have LBA support. If the format program does not know whether the BIOS has LBA support, it may operate this way: if (partition_start + total_sectors_in_partition) exceeds the CHS addressing ability(especially when it is greater than 1024*256*63), the caller should set this byte to 0x0e, otherwise, set to 0x90. Update: this byte of LBA indicator is ignored. The boot record can probe the LBA support of BIOS. Update(2006-07-31): Though GRLDR won't use this LBA-indicator byte, Windows 98 uses it. Usually this byte should be 0x90 for CHS mode(especially for floppies). If this byte is not set properly, Windows 98 will not recognize the floppy or partition. This problem was reported by neiljoy. Many thanks! 03h 8 OEM name string (of OS which formatted the disk). 0Bh 2 Bytes per sector. Must be 512. 0Dh 1 Sectors per cluster. Valid values are 1, 2, 4, 8, 16, 32, 64 and 128. But a cluster size larger than 32K should not occur. 0Eh 2 Reserved sectors(number of sectors before the first FAT, including the boot sector), usually 1. 10h 1 Number of FATs(nearly always 2). 11h 2 (Maximum number of root directory entries)Must be 0. 13h 2 (Total number of sectors for small disks only)Must be 0. 15h 1 Media descriptor byte, pretty meaningless now (see below). 16h 2 (Sectors per FAT)Must be 0. 18h 2 Sectors per track. 1Ah 2 Total number of heads/sides. 1Ch 4 Number of hidden sectors (those preceding the boot sector). Also referred to as the starting sector of the partition. For floppies, it should be 0. 20h 4 Total number of sectors for large disks. 24h 4 FAT32 sectors per FAT. 28h 2 If bit 7 is clear then all FATs are updated, otherwise bits 0-3 give the current active FAT, all other bits are reserved. 2Ah 2 High byte is major revision number, low byte is minor revision number, currently both are 0. 2Ch 4 Root directory starting cluster. 30h 2 File system information sector. 32h 2 If non-zero this gives the sector which holds a copy of the boot record, usually 6. 34h 12 Reserved, set to 0. 40h 1 BIOS drive number of the boot device. 80h is first HDD, 00h is first FDD. Actually this byte is ignored for read. The boot code will write DL onto this byte. The BIOS or the caller should set drive number in DL. We assume all BIOSes pass correct drive number in DL. Buggy BIOSes are not supported!! 41h 1 Partition number of this filesystem in the boot drive. This byte is ignored for read. The boot code will write partition number onto this byte. See offset 5Dh below. 42h 1 Signature (must be 28h or 29h to be recognised by NT). 43h 4 Volume serial number. 47h 11 Volume label. 52h 8 File system ID. "FAT32 ". 5Ah 1 opcode for "cli". 5Bh 1 opcode for "cld". 5Ch 1 opcode for "mov dh, imm8". 5Dh 1 Partition number of this partition on the boot drive. 0, 1, 2, 3 are primary partitions. 4, 5, 6, ... are logical partitions in the extended partition. 0xff is for whole drive. So for floppies, it should be 0xff. 5Eh 414 Machine code. 1FCh 4 Boot Signature AA550000h. (Win9x uses 4 bytes as magic value) ------------------------------------------------------------------------------ Appendix A: File System Information Sector of FAT32(not used by grldr) Offset Length Description ====== ====== ============================================================== 0h 4 Leading Signature 41615252h. 4h 480 Reserved, set to 0. 1E4h 4 FSI structure signature 61417272h. 1E8h 4 Contains the last known count of free clusters, if this is equal to FFFFFFFFh, then the count is unknown. 1ECh 4 Cluster number at which you should begin a search for a free cluster, if this is equal to FFFFFFFFh then the field has not been set. 1F0h 12 Reserved, set to 0. 1FCh 4 Trailing Signature AA550000h. ------------------------------------------------------------------------------ Appendix B: Media Descriptor Byte(not used by grldr) The Media descriptor byte is meaningless because of the duplications, F0h for example. Byte Type of disk Sectors Heads Tracks Capacity ---- ------------ ------- ----- ------ -------- FFh 5 1/4" 8 2 40 320KB FEh 5 1/4" 8 1 40 160KB FDh 5 1/4" 9 2 40 360KB FCh 5 1/4" 9 1 40 180KB FBh both 9 2 80 640KB FAh both 9 1 80 320KB F9h 5 1/4" 15 2 80 1200KB F9h 3 1/2" 9 2 80 720KB F0h 3 1/2" 18 2 80 1440KB F0h 3 1/2" 36 2 80 2880KB F8h hard disk NA NA NA NA ****************************************************************************** *** grldr.mbr - How to write it to Master Boot Track of the hard disk *** ****************************************************************************** grldr.mbr contains code that can be used as Master Boot Record. The code is responsible for searching all partitions for grldr and when found, loading it. Currently supported partition types are: FAT12/FAT16/FAT32, NTFS, EXT2/EXT3. Logical partitions in the extended partition are supported, provided that the extended partition type is Microsoft-compatible. In fact, the Linux extended partition type(0x85) is not fully tested for the search mechanism. Notice! In the future, we will remove NTFS support. For Windows users, please create an FAT partition and place GRLDR and menu.lst there. From now on, please don't report bugs relevant to NTFS. Someone reports that Windows XP with newer SPs and Windows Vista have intentionally broken the compatiblity with many things(including GRLDR). So you will get into trouble with these systems. How to write GRLDR.MBR to the Master Boot Track of a hard disk? First, read the Windows disk signature and partition information bytes (72 bytes in total, from offset 0x01b8 to 0x01ff of the MBR sector), and put them on the same range from offset 0x01b8 to 0x01ff of the beginning sector of GRLDR.MBR. Optionally, if the MBR in the hard disk is a single sector MBR created by Microsoft FDISK, it may be copied onto the second sector of GRLDR.MBR. The second sector of GRLDR.MBR is called "previous MBR". When GRLDR not found, "previous MBR" will be started. No other steps needed, after all necessary changes stated above have been made, now simply write GRLDR.MBR on to the Master Boot Track. That's all. Note: The Master Boot Track means the first track of the hard drive. Note: The bootstrap code of GRLDR.MBR only finds GRLDR file in the root dir of a partition. You'd better place menu.lst file accompanying with GRLDR(i.e., in the same root dir of the same partition as GRLDR). The filename "grldr" in an ext2 partition must be in lower case letters, and the file type of grldr must be plain regular. Other types, e.g., a symbolic link, won't work. Update: bootlace.com is a DOS/Linux utility for installing grldr.mbr to MBR. The whole grldr.mbr is embedded in the body of the bootlace.com utility, so bootlace.com can be used independently. See below. ****************************************************************************** *** grldr.mbr - Details about the control bytes *** ****************************************************************************** Six bytes can be used to control the boot process of GRLDR.MBR. Offset Length Description ====== ====== ============================================================== 02h 1 bit0=1: disable the search for GRLDR on floppy bit0=0: enable the search for GRLDR on floppy bit1=1: disable the boot of PREVIOUS MBR with invalid partition table(usually an OS boot sector) bit1=0: enable the boot of PREVIOUS MBR with invalid partition table(usually an OS boot sector) bit2=1: disable the feature of unconditional entrance to the command-line(See below `--duce') bit2=0: enable the feature of unconditional entrance to the command-line(See below `--duce') bit3 - bit6: reserved bit7=1: try to boot PREVIOUS MBR after the search for GRLDR bit7=0: try to boot PREVIOUS MBR before the search for GRLDR 03h 1 timeout in seconds to wait for a key press. 0xff stands for waiting all the time(endless). 04h 2 hot-key code. high byte is scan code, low byte is ASCII code. the default value is 0x3920, which stands for the space bar. if this key is pressed, GRUB will be started prior to the boot of previous MBR. See "int 16 keyboard scan codes" below. 06h 1 preferred boot drive number, 0xff for no-drive 07h 1 preferred partition number, 0xff for whole drive if the preferred boot drive number is 0xff, the order of the search for GRLDR will be: (hd0,0), (hd0,1), ..., (hd0,L),(L=max partition number) (hd1,0), (hd1,1), ..., (hd1,M),(M=max partition number) ... ... ... ... ... ... ... ... (hdX,0), (hdX,1), ..., (hdX,N),(N=max partition number) (X=max harddrive number) (fd0) otherwise, if the preferred boot drive number is Y(not equal to 0xff) and the preferred partition number is K, then the order of the search for GRLDR will be: (Y) if K=0xff; or (Y,K) otherwise (hd0,0), (hd0,1), ..., (hd0,L),(L=max partition number) (hd1,0), (hd1,1), ..., (hd1,M),(M=max partition number) ... ... ... ... ... ... ... ... (hdX,0), (hdX,1), ..., (hdX,N),(N=max partition number) (X=max harddrive number) (fd0) Note: if Y < 0x80, then (Y) is floppy, else (Y) is harddrive, and (Y,K) is partition number K on harddrive (Y). ****************************************************************************** *** bootlace.com - Install GRLDR.MBR bootstrap code to MBR *** ****************************************************************************** BOOTLACE.COM installs GRLDR.MBR boot record to the MBR of a harddrive or of a harddrive image file, or to the boot sector of a floppy or a floppy image. Usage: bootlace.com [OPTIONS] DEVICE_OR_FILE OPTIONS: --read-only do everything except the actual write to the specified DEVICE_OR_FILE. --no-backup-mbr do not copy the old MBR to the second sector of DEVICE_OR_FILE. --force-backup-mbr force the copy of old MBR to the second sector of DEVICE_OR_FILE. --mbr-enable-floppy enable the search for GRLDR on floppy. --mbr-disable-floppy disable the search for GRLDR on floppy. --mbr-enable-osbr enable the boot of PREVIOUS MBR with invalid partition table(usually an OS boot sector). --mbr-disable-osbr disable the boot of PREVIOUS MBR with invalid partition table(usually an OS boot sector). --duce disable the feature of unconditional entrance to the command-line. Normally one can unconditionally get the command-line console by a keypress of `C', bypassing all config-files(including the preset-menu). This is a security hole. So we need this option to disable the feature. DUCE is for Disable Unconditional Command-line Entrance. --boot-prevmbr-first try to boot PREVIOUS MBR before the search for GRLDR. --boot-prevmbr-last try to boot PREVIOUS MBR after the search for GRLDR. --preferred-drive=D preferred boot drive number, 0 <= D < 255. --preferred-partition=P preferred partition number, 0 <= P < 255. --time-out=T wait T seconds before booting PREVIOUS MBR. if T is 0xff, wait forever. The default is 5. --hot-key=K if the desired key K is pressed, start GRUB before booting PREVIOUS MBR. K is a word value, just as the value in AX register returned from int16/AH=1. The high byte is the scan code and the low byte is ASCII code. The default is 0x3920 for space bar. See "int 16 keyboard scan codes" below. --floppy if DEVICE_OR_FILE is floppy, use this option. --floppy=N if DEVICE_OR_FILE is a partition on a hard drive, use this option. N is used to specify the partition number: 0,1,2 and 3 for the primary partitions, and 4,5,6,... for the logical partitions. --sectors-per-track=S specifies sectors per track for --floppy. 1 <= S <= 63, default is 63. --heads=H specifies number of heads for --floppy. 1 <= H <= 256, default is 255. --start-sector=B specifies hidden sectors for --floppy=N. --total-sectors=C specifies total sectors for --floppy. default is 0. --lba use lba mode for --floppy. If the floppy BIOS has LBA support, you can specify --lba here. It is assumed that all floppy BIOSes have CHS support. So you would rather specify --chs. If neither --chs nor --lba is specified, then the LBA indicator(i.e., the third byte of the boot sector) will not be touched. --chs use chs mode for --floppy. You should specify --chs if the floppy BIOS does not support LBA. We assume all floppy BIOSes have CHS support. So it is likely you want to specify --chs. If neither --chs nor --lba is specified, then the LBA indicator(i.e., the third byte of the boot sector) will not be touched. --fat12 FAT12 is allowed to be installed for --floppy. --fat16 FAT16 is allowed to be installed for --floppy. --fat32 FAT32 is allowed to be installed for --floppy. --vfat FAT12/16/32 are allowed to be installed for --floppy. --ntfs NTFS is allowed to be installed for --floppy. --ext2 EXT2 is allowed to be installed for --floppy. --install-partition=I Install the boot record onto the boot area of partition number I of the specified hard drive or harddrive image DEVICE_OR_FILE. DEVICE_OR_FILE: Filename of the device or the image file. For DOS, a BIOS drive number(hex 0xHH or decimal DDD) can be used to access the drive. BIOS drive number 0 is for the first floppy, 1 is for the second floppy; 0x80 is for the first hard drive, 0x81 is for the second hard drive, etc. Note: BOOTLACE.COM writes only the boot code to MBR. The boot code needs to load GRLDR as the second(and last) stage of the GRUB boot process. Therefore GRLDR should be copied to the root directory of one of the supported partitions, either before or after a successful execution of BOOTLACE.COM. Currently only partitions with filesystem type of FAT12, FAT16, FAT32, NTFS, EXT2 or EXT3 are supported. Note 2: If DEVICE_OR_FILE is a harddisk device or a harddisk image file, it must contain a valid partition table, otherwise, BOOTLACE.COM will fail. If DEVICE_OR_FILE is a floppy device or a floppy image file, then it must contain a supported filesystem(i.e., either of FAT12/FAT16/FAT32/NTFS/EXT2/EXT3). Note 3: If DEVICE_OR_FILE is a floppy device or a floppy image file, and it was formated EXT2/EXT3, then you should specify --sectors-per-track and --heads explicitly. Notice! In the future, we will remove NTFS support. For Windows users, please create an FAT partition and place GRLDR and menu.lst there. From now on, please don't report bugs relevant to NTFS. Important!! If you install GRLDR Boot Record to a floppy or a partition, the floppy or partition will boot solely grldr, and your original IO.SYS(DOS/Win9x/Me) and NTLDR(WinNT/2K/XP) will become unbootable. This is because the original boot record of the floppy or partition was overwritten. There is no such problem when installing GRLDR Boot Record onto the MBR. Update: Some NTLDR/IO.SYS/KERNEL.SYS files can be directly chainloaded in the latest GRUB4DOS. Tip: If the filename begins in a dash(-) or a digit, you may prefix a dirname (./) or (.\) to it. Examples: Installing GRLDR boot code to MBR under Linux: bootlace.com /dev/hda Installing GRLDR boot code to MBR under DOS: bootlace.com 0x80 Installing GRLDR boot code to a harddisk image under DOS or Linux: bootlace.com hd.img Installing GRLDR boot code to floppy under Linux: bootlace.com --floppy --chs /dev/fd0 Installing GRLDR boot code to floppy under DOS: bootlace.com --floppy --chs 0x00 Installing GRLDR boot code to a floppy image under DOS or Linux: bootlace.com --floppy --chs floppy.img BOOTLACE.COM cannot function well under Windows NT/2000/XP/2003. It is expected (and designed) to run under DOS/Win9x and Linux. Update: For image FILES, bootlace.com function well under Windows NT/2000/XP/2003. For devices, bootlace.com will not work under Windows NT/2000/XP/2003 because bootlace.com is a DOS utility and Windows NT/2000/XP/2003 does not allow bootlace.com to access devices. ****************************************************************************** *** kexec-tools should be patched for the 1.101 release *** ****************************************************************************** The file kexec-tools-1.101-patch is a patch to the kexec-tools-1.101 release. Kexec might fail to load grub.exe without this patch. The home page of kexec-tools is: http://www.xmission.com/~ebiederm/files/kexec/ Note: The Linux kernel should be KEXEC enabled before kexec can be run. !! Important Update !! The patch `kexec-tools-1.101-patch' is not needed now and has been deleted. Even worse, it fails in `kexec -l grub.exe --initrd=imgfile'. So please do not use it any more. ****************************************************************************** *** Direct transition to DOS/Win9x from within Linux *** ****************************************************************************** By using kexec, we can easily boot into DOS/Win9x from a running Linux system. If WIN98.IMG is a bootable hard-disk image, do as follows: kexec -l grub.exe --initrd=WIN98.IMG --command-line="--config-file=map (rd) (hd0); map --hook; chainloader (hd0)+1; rootnoverify (hd0)" kexec -e If DOS.IMG is a bootable floppy image, do this way: kexec -l grub.exe --initrd=DOS.IMG --command-line="--config-file=map (rd) (fd0); map --hook; chainloader (fd0)+1; rootnoverify (fd0)" kexec -e Note that in this manner, we can boot DOS/Win9x without using a real DOS/Win9x disk. We need no FAT partition but an image file. We have noticed that Linux itself can act as a big boot manager by using kexec and grub.exe. This may be convenient to developers who write installation or bootstrap or initialization programs. Certainly, grub.exe and the bootable disk image can also be loaded by a running GRUB or LILO or syslinux. Examples: 1. Loaded by GRUB: kernel (hd0,0)/grub.exe --config-file="map (rd) (fd0); map --hook; chainloader (fd0)+1; rootnoverify (fd0)" initrd (hd0,0)/DOS.IMG boot 2. Loaded by LILO: image=/boot/grub.exe label=grub.exe initrd=/boot/DOS.IMG append="--config-file=map (rd) (fd0); map --hook; chainloader (fd0)+1; rootnoverify (fd0)" 3. Loaded by SYSLINUX: label grub.exe kernel grub.exe append initrd=DOS.IMG --config-file="map (rd) (fd0); map --hook; chainloader (fd0)+1; rootnoverify (fd0)" Note: If the above `map (rd) (...)' failed, you may use `map (rd)+1 (...)' instead and try again. ****************************************************************************** *** Keyboard BIOS Scan Code/ASCII code tables *** ****************************************************************************** Keyboard bios scan code and ascii character code tables can be obtained from the web by, for example, googling for "3920 372A 4A2D 4E2B 352F". Here are 2 main results: 1. From "http://heim.ifi.uio.no/~stanisls/helppc/scan_codes.html": INT 16 - Keyboard Scan Codes Key Normal Shifted w/Ctrl w/Alt A 1E61 1E41 1E01 1E00 B 3062 3042 3002 3000 C 2E63 2E43 2E03 2E00 D 2064 2044 2004 2000 E 1265 1245 1205 1200 F 2166 2146 2106 2100 G 2267 2247 2207 2200 H 2368 2348 2308 2300 I 1769 1749 1709 1700 J 246A 244A 240A 2400 K 256B 254B 250B 2500 L 266C 264C 260C 2600 M 326D 324D 320D 3200 N 316E 314E 310E 3100 O 186F 184F 180F 1800 P 1970 1950 1910 1900 Q 1071 1051 1011 1000 R 1372 1352 1312 1300 S 1F73 1F53 1F13 1F00 T 1474 1454 1414 1400 U 1675 1655 1615 1600 V 2F76 2F56 2F16 2F00 W 1177 1157 1117 1100 X 2D78 2D58 2D18 2D00 Y 1579 1559 1519 1500 Z 2C7A 2C5A 2C1A 2C00 Key Normal Shifted w/Ctrl w/Alt 1 0231 0221 7800 2 0332 0340 0300 7900 3 0433 0423 7A00 4 0534 0524 7B00 5 0635 0625 7C00 6 0736 075E 071E 7D00 7 0837 0826 7E00 8 0938 092A 7F00 9 0A39 0A28 8000 0 0B30 0B29 8100 Key Normal Shifted w/Ctrl w/Alt - 0C2D 0C5F 0C1F 8200 = 0D3D 0D2B 8300 [ 1A5B 1A7B 1A1B 1A00 ] 1B5D 1B7D 1B1D 1B00 ; 273B 273A 2700 ' 2827 2822 ` 2960 297E \ 2B5C 2B7C 2B1C 2600 (same as Alt L) , 332C 333C . 342E 343E / 352F 353F Key Normal Shifted w/Ctrl w/Alt F1 3B00 5400 5E00 6800 F2 3C00 5500 5F00 6900 F3 3D00 5600 6000 6A00 F4 3E00 5700 6100 6B00 F5 3F00 5800 6200 6C00 F6 4000 5900 6300 6D00 F7 4100 5A00 6400 6E00 F8 4200 5B00 6500 6F00 F9 4300 5C00 6600 7000 F10 4400 5D00 6700 7100 F11 8500 8700 8900 8B00 F12 8600 8800 8A00 8C00 Key Normal Shifted w/Ctrl w/Alt BackSpace 0E08 0E08 0E7F 0E00 Del 5300 532E 9300 A300 Down Arrow 5000 5032 9100 A000 End 4F00 4F31 7500 9F00 Enter 1C0D 1C0D 1C0A A600 Esc 011B 011B 011B 0100 Home 4700 4737 7700 9700 Ins 5200 5230 9200 A200 Keypad 5 4C35 8F00 Keypad * 372A 9600 3700 Keypad - 4A2D 4A2D 8E00 4A00 Keypad + 4E2B 4E2B 4E00 Keypad / 352F 352F 9500 A400 Left Arrow 4B00 4B34 7300 9B00 PgDn 5100 5133 7600 A100 PgUp 4900 4939 8400 9900 PrtSc 7200 Right Arrow 4D00 4D36 7400 9D00 SpaceBar 3920 3920 3920 3920 Tab 0F09 0F00 9400 A500 Up Arrow 4800 4838 8D00 9800 - Some key combinations are not available on all systems. The PS/2 includes many that aren't available on the PC, XT and AT. - To retrieve the character from a scan code logical AND the word with 0x00FF. - see INT 16 MAKE CODES 2. From "http://www.hoppie.nl/ivan/keycodes.txt": Keystroke Keypress code -------------------------------------------------- Esc 011B 1 0231 2 0332 3 0433 4 0534 5 0635 6 0736 7 0837 8 0938 9 0A39 0 0B30 - 0C2D = 0D3D Backspace 0E08 Tab 0F09 q 1071 w 1177 e 1265 r 1372 t 1474 y 1579 u 1675 i 1769 o 186F p 1970 [ 1A5B ] 1B5D Enter 1C0D Ctrl ** a 1E61 s 1F73 d 2064 f 2166 g 2267 h 2368 j 246A k 256B l 266C ; 273B ' 2827 ` 2960 Shift ** \ 2B5C z 2C7A x 2D78 c 2E63 v 2F76 b 3062 n 316E m 326D , 332C . 342E / 352F Gray * 372A Alt ** Space 3920 Caps Lock ** F1 3B00 F2 3C00 F3 3D00 F4 3E00 F5 3F00 F6 4000 F7 4100 F8 4200 F9 4300 F10 4400 F11 8500 F12 8600 Num Lock ** Scroll Lock ** White Home 4700 White Up Arrow 4800 White PgUp 4900 Gray - 4A2D White Left Arrow 4B00 Center Key 4C00 White Right Arrow 4D00 Gray + 4E2B White End 4F00 White Down Arrow 5000 White PgDn 5100 White Ins 5200 White Del 5300 SysReq ** Key 45 [1] 565C Enter (number keypad) 1C0D Gray / 352F PrtSc ** Pause ** Gray Home 4700 Gray Up Arrow 4800 Gray Page Up 4900 Gray Left Arrow 4B00 Gray Right Arrow 4D00 Gray End 4F00 Gray Down Arrow 5000 Gray Page Down 5100 Gray Insert 5200 Gray Delete 5300 Shift Esc 011B ! 0221 @ 0340 # 0423 $ 0524 % 0625 ^ 075E & 0826 * (white) 092A ( 0A28 ) 0B29 _ 0C5F + (white) 0D2B Shift Backspace 0E08 Shift Tab (Backtab) 0F00 Q 1051 W 1157 E 1245 R 1352 T 1454 Y 1559 U 1655 I 1749 O 184F P 1950 { 1A7B } 1B7D Shift Enter 1C0D Shift Ctrl ** A 1E41 S 1F53 D 2044 F 2146 G 2247 H 2348 J 244A K 254B L 264C : 273A " 2822 ~ 297E | 2B7C Z 2C5A X 2D58 C 2E43 V 2F56 B 3042 N 314E M 324D < 333C > 343E ? 353F Shift Gray * 372A Shift Alt ** Shift Space 3920 Shift Caps Lock ** Shift F1 5400 Shift F2 5500 Shift F3 5600 Shift F4 5700 Shift F5 5800 Shift F6 5900 Shift F7 5A00 Shift F8 5B00 Shift F9 5C00 Shift F10 5D00 Shift F11 8700 Shift F12 8800 Shift Num Lock ** Shift Scroll Lock ** Shift 7 (number pad) 4737 Shift 8 (number pad) 4838 Shift 9 (number pad) 4939 Shift Gray - 4A2D Shift 4 (number pad) 4B34 Shift 5 (number pad) 4C35 Shift 6 (number pad) 4D36 Shift Gray + 4E2B Shift 1 (number pad) 4F31 Shift 2 (number pad) 5032 Shift 3 (number pad) 5133 Shift 0 (number pad) 5230 Shift . (number pad) 532E Shift SysReq ** Shift Key 45 [1] 567C Shift Enter (number pad) 1C0D Shift Gray / 352F Shift PrtSc ** Shift Pause ** Shift Gray Home 4700 Shift Gray Up Arrow 4800 Shift Gray Page Up 4900 Shift Gray Left Arrow 4B00 Shift Gray Right Arrow 4D00 Shift Gray End 4F00 Shift Gray Down Arrow 5000 Shift Gray Page Down 5100 Shift Gray Insert 5200 Shift Gray Delete 5300 Ctrl Esc 011B Ctrl 1 -- Ctrl 2 (NUL) 0300 Ctrl 3 -- Ctrl 4 -- Ctrl 5 -- Ctrl 6 (RS) 071E Ctrl 7 -- Ctrl 8 -- Ctrl 9 -- Ctrl 0 -- Ctrl - 0C1F Ctrl = -- Ctrl Backspace (DEL) 0E7F Ctrl Tab 9400 Ctrl q (DC1) 1011 Ctrl w (ETB) 1117 Ctrl e (ENQ) 1205 Ctrl r (DC2) 1312 Ctrl t (DC4) 1414 Ctrl y (EM) 1519 Ctrl u (NAK) 1615 Ctrl i (HT) 1709 Ctrl o (SI) 180F Ctrl p (DEL) 1910 Ctrl [ (ESC) 1A1B Ctrl ] (GS) 1B1D Ctrl Enter (LF) 1C0A Ctrl a (SOH) 1E01 Ctrl s (DC3) 1F13 Ctrl d (EOT) 2004 Ctrl f (ACK) 2106 Ctrl g (BEL) 2207 Ctrl h (Backspace) 2308 Ctrl j (LF) 240A Ctrl k (VT) 250B Ctrl l (FF) 260C Ctrl ; -- Ctrl ' -- Ctrl ` -- Ctrl Shift ** Ctrl \ (FS) 2B1C Ctrl z (SUB) 2C1A Ctrl x (CAN) 2D18 Ctrl c (ETX) 2E03 Ctrl v (SYN) 2F16 Ctrl b (STX) 3002 Ctrl n (SO) 310E Ctrl m (CR) 320D Ctrl , -- Ctrl . -- Ctrl / -- Ctrl Gray * 9600 Ctrl Alt ** Ctrl Space 3920 Ctrl Caps Lock -- Ctrl F1 5E00 Ctrl F2 5F00 Ctrl F3 6000 Ctrl F4 6100 Ctrl F5 6200 Ctrl F6 6300 Ctrl F7 6400 Ctrl F8 6500 Ctrl F9 6600 Ctrl F10 6700 Ctrl F11 8900 Ctrl F12 8A00 Ctrl Num Lock -- Ctrl Scroll Lock -- Ctrl White Home 7700 Ctrl White Up Arrow 8D00 Ctrl White PgUp 8400 Ctrl Gray - 8E00 Ctrl White Left Arrow 7300 Ctrl 5 (number pad) 8F00 Ctrl White Right Arrow 7400 Ctrl Gray + 9000 Ctrl White End 7500 Ctrl White Down Arrow 9100 Ctrl White PgDn 7600 Ctrl White Ins 9200 Ctrl White Del 9300 Ctrl SysReq ** Ctrl Key 45 [1] -- Ctrl Enter (number pad) 1C0A Ctrl / (number pad) 9500 Ctrl PrtSc 7200 Ctrl Break 0000 Ctrl Gray Home 7700 Ctrl Gray Up Arrow 8DE0 Ctrl Gray Page Up 8400 Ctrl Gray Left Arrow 7300 Ctrl Gray Right Arrow 7400 Ctrl Gray End 7500 Ctrl Gray Down Arrow 91E0 Ctrl Gray Page Down 7600 Ctrl Gray Insert 92E0 Ctrl Gray Delete 93E0 Alt Esc 0100 Alt 1 7800 Alt 2 7900 Alt 3 7A00 Alt 4 7B00 Alt 5 7C00 Alt 6 7D00 Alt 7 7E00 Alt 8 7F00 Alt 9 8000 Alt 0 8100 Alt - 8200 Alt = 8300 Alt Backspace 0E00 Alt Tab A500 Alt q 1000 Alt w 1100 Alt e 1200 Alt r 1300 Alt t 1400 Alt y 1500 Alt u 1600 Alt i 1700 Alt o 1800 Alt p 1900 Alt [ 1A00 Alt ] 1B00 Alt Enter 1C00 Alt Ctrl ** Alt a 1E00 Alt s 1F00 Alt d 2000 Alt f 2100 Alt g 2200 Alt h 2300 Alt j 2400 Alt k 2500 Alt l 2600 Alt ; 2700 Alt ' 2800 Alt ` 2900 Alt Shift ** Alt \ 2B00 Alt z 2C00 Alt x 2D00 Alt c 2E00 Alt v 2F00 Alt b 3000 Alt n 3100 Alt m 3200 Alt , 3300 Alt . 3400 Alt / 3500 Alt Gray * 3700 Alt Space 3920 Alt Caps Lock ** Alt F1 6800 Alt F2 6900 Alt F3 6A00 Alt F4 6B00 Alt F5 6C00 Alt F6 6D00 Alt F7 6E00 Alt F8 6F00 Alt F9 7000 Alt F10 7100 Alt F11 8B00 Alt F12 8C00 Alt Num Lock ** Alt Scroll Lock ** Alt Gray - 4A00 Alt Gray + 4E00 Alt 7 (number pad) # Alt 8 (number pad) # Alt 9 (number pad) # Alt 4 (number pad) # Alt 5 (number pad) # Alt 6 (number pad) # Alt 1 (number pad) # Alt 2 (number pad) # Alt 3 (number pad) # Alt Del -- Alt SysReq ** Alt Key 45 [1] -- Alt Enter (number pad) A600 Alt / (number pad) A400 Alt PrtSc ** Alt Pause ** Alt Gray Home 9700 Alt Gray Up Arrow 9800 Alt Gray Page Up 9900 Alt Gray Left Arrow 9B00 Alt Gray Right Arrow 9D00 Alt Gray End 9F00 Alt Gray Down Arrow A000 Alt Gray Page Down A100 Alt Gray Insert A200 Alt Gray Delete A300 ------------------------------------------------------------------------- Footnotes [1] In the United States, the 101/102-key keyboard is shipped with 101 keys. Overseas versions have an additional key sandwiched between the left Shift key and the Z key. This additional key is identified by IBM (and in this table) as "Key 45." [**] Keys and key combinations marked ** are used by the ROM BIOS but do not put values into the keyboard buffer. [--] Keys and key combinations marked -- are ignored by the ROM BIOS. Note by Tinybit: Someone reported F11 key and F12 key do not work. I suspect there is something wrong with that BIOS. ****************************************************************************** *** !!!!!!!! NTFS Will No Longer Be Supported !!!!!!!! *** ****************************************************************************** Notice! In the future, we will remove NTFS support. For Windows users, please create an FAT partition and place GRLDR and menu.lst there. From now on, please don't report bugs relevant to NTFS. Someone reports that Windows XP with newer SPs and Windows Vista have intentionally broken the compatiblity with many things(including GRLDR). So you will get into trouble with these systems. Note 1: Although bug reports on NTFS will be ignored, patches on NTFS and/or Windows are welcome. Note 2: Microsoft will continue to block GRLDR on its newer OSes. If so, don't report it. But (again) patches are acceptable. Note 3: NTFS support will be dropped at the time when most people wouldn't like to use it. ****************************************************************************** *** GRLDR Error messages *** ****************************************************************************** 1. Missing MBR-helper. The helper function in the sectors that immediately follow the MBR is not present, or it has been erased by a virus or by Windows XP/Vista. Run the bootlace.com utility to fix the problem. 2. Buggy BIOS! Your BIOS is too buggy. It even has no support for INT13/AH=8. No solution except flashing your BIOS. Buggy BIOSes will encounter more and more problems with grub4dos in the future. 3. This partition is NTFS but with unknown boot record. Please install Microsoft NTFS boot sectors to this partition correctly, or create an FAT12/16/32 partition and place the same copy of GRLDR and MENU.LST there. The boot record was changed or erased by Microsoft Windows XP Service Pack 2. You may install the old boot record introduced with the original clean Windows 2K/XP. As another solution, you may create an FAT partition for your system, and copy GRLDR and your MENU.LST to its root dir. While the startup code of grldr might fail to load GRLDR in NTFS partitions, it always successfully loads GRLDR in FAT partitions(and even in ext2/ext3 partitions). Note that NTLDR only loads the startup code of grldr(i.e., the leading 16 sectors of grldr), not the whole grldr file. Thus, C:\GRLDR must exist(here C: can be NTFS), since it is used for BOOT.INI and NTLDR. If C: is NTFS, X:\GRLDR should exist as well, where X: stands for a certain FAT partition. ****************************************************************************** *** Known BIOS bugs *** ****************************************************************************** 1. Some newer Dell machines have no int13/AH=43h support. You may encounter failure when trying to write-access an emulated disk. Note: This bug is serious! The old "root+setup" installation method (in real mode grub environment) uses INT13 to write the first sector of stage2. It will fail for the buggy DELL machine when stage2 is accessed with LBA mode. 2. Some newer machines have no int15/AH=87h support. You may encounter failure when accessing a memdrive. 3. Some buggy BIOSes won't boot bootable.iso(See above).(qemu can boot it fine) 4. Some BIOSes have no int15/AH=24h(gate A20 control) support. It will encounter problems with GRUB4DOS in the future. ****************************************************************************** *** Known Problems *** ****************************************************************************** 1. Running GRUB.EXE from a DOS box of Windows 9x/Me could hang the machine, especially for some systems with USB support. You may encounter the same problem when running GRUB.EXE through KEXEC under Linux. Note: You don't have to run GRUB.EXE from protected mode of Win9x, which could hang the machine; Instead, you usually want to run GRUB.EXE after you have done a "Restart the computer in MS-DOS mode", which is safe enough. 2. The default chainloader action will keep A20 on. Some buggy DOS XMS memory managers could hang the machine. You may use the --disable-a20 option in the chainloader line and try again. Anyway, you should avoid using those buggy memory managers. 3. THTF BIOS L4S5M Ver 1.1a(dated 2002-1-10) has a buggy int15 which causes hang at the boot of a multi boot kernel(memdisk for example). ****************************************************************************** *** List of binary files and their corresponding source files *** ****************************************************************************** binary file main source file other included source or binary files ------------- ---------------- ------------------------------------- bootlace.com bootlacestart.S bootlace.inc, grldrstart.S grldr grldrstart.S pre_stage2(binary, See note below) grldr.mbr mbrstart.S grldrstart.S grub.exe dosstart.S pre_stage2(binary, See note below) ----------------------------------------------------------------------------- Note: pre_stage2 is the main body of GNU GRUB and it is simply appended to grldrstart/dosstart in binary format to form our grldr/grub.exe. Note: The GRUB file(WITHOUT .EXE suffix) is a static-linked ELF executable program for Linux, normally called the GRUB Shell. The GRUB Shell is a boot- manager, but not a boot-loader(the "boot" command won't work in GRUB Shell). GRUB.EXE(with KEXEC) can be used as a bootloader running directly under Linux. ****************************************************************************** *** Memory Layout for Quiting to DOS from GRUB.EXE *** ****************************************************************************** The quit command is implemented to return to DOS in the instance that GRUB.EXE is started off DOS. 1. Before GRUB.EXE transfers control to pre_stage2, it will copy 640KB of conventional memory to physical address 0x200000(i.e., 2MB), and write 4 long integers immediately follows the backup copy of the conventional memory: At 0x2A0000: 0x50554B42, it is the "BKUP" signature. At 0x2A0004: Gate A20 status under DOS: non-zero means A20 on; zero means A20 off. Update: A20 always on, see below. At 0x2A0008: high word is boot-CS, low word is boot-IP. The quit command uses this entry point to return to DOS. At 0x2A000C: CheckSum: the sum of all long integers in the memory range from 0x200000 to 0x2A000F is 0. 2. If the above memory structure is corrupted by a grub command, the quit command will issue an error message and refuse to exit from grub. 3. Because GRUB may corrupt extended memory, you should better avoid using extended memory under DOS before running GRUB.EXE. 4. Gate A20 will be enabled by GRUB.EXE. Hopefully this would hurt nothing. ****************************************************************************** *** Command-line Length about GRUB.EXE *** ****************************************************************************** GRUB.EXE now can be started in CONFIG.SYS with the **DEVICE** command: DEVICE=grub.exe [--config-file="FILENAME_OR_COMMANDS"] 1. If GRUB.EXE is invoked with DEVICE command and FILENAME_OR_COMMANDS is a collection of some GRUB commands separated by semi-colon, then the length of FILENAME_OR_COMMANDS can be nearly 4KB ----Supprise? But true! MS-DOS 7+ even allows a much longer line, but 4KB seems enough for our use of GRUB.EXE. This is very useful when we want to embed a big menu into the command line. Note that GRLDR hasn't yet supported any command-line arguments. 2. If GRUB.EXE is invoked with INSTALL command, the option length has a limit of 80 characters(including the leading "--config-file=" part). An overflow may hang up MS-DOS immediately. 3. If GRUB.EXE is invoked with SHELL command, the option length has a limit of 126 characters(including the leading "--config-file=" part). Overflow won't hang up MS-DOS, but the line will be cut short. This limit is the same as that in the console-DOS-prompt or in a BAT file. 4. The DOS editor EDIT does not allow to create a line of 4KB long. So use another editor, for example, vi for Linux, please. 5. The DEVICE=GRUB.EXE line can be used together with other DEVICE commands such as DEVICE=HIMEM.SYS and DEVICE=EMM386.EXE. The GRUB.EXE line should occur before the EMM386.EXE line in order to avoid the rejection by EMM386. Update: Since 0.4.2, GRUB.EXE works well even after EMM386.EXE is loaded. 6. In any case mentioned above, you can return back to DOS by quit command. 7. Memory usage about command-line menu: The 4KB command-line menu starts at physical address 0x0800 and ends at 0x17FF. ****************************************************************************** *** New Syntax for the DEFAULT/SAVEDEFAULT Commands *** ****************************************************************************** In addition to the original usage of "default NUM" and "default saved", now there is a new usage of "default FILE", like this: default (hd0,0)/default Note that FILE must have a valid DEFAULT file format. A sample DEFAULT file is included in the release. You may copy it to wherever you like, but you should avoid modifying its content manually. The DEFAULT file may be used in this way: (1) First, you should copy a default file with valid format to somewhere in your operating system. (2) Secondly, you should use the "default FILE" command of GRUB to announce the use of FILE as our new default file for being written by "savedefault". (3) Then, you may use "savedefault" command to save the desired entry number into this new default file. (4) OK, at next boot, you may read the saved entry number by using the same "default FILE" command as mentioned in above (2). And the SAVEDEFAULT command now accept an options `--wait=T', like this: savedefault --wait=5 If `--wait=T' is specified and T is non-zero, savedefault will prompt the user with a message just before it writes to disk. The write operation will be cancelled in T seconds if the `Y' key was not pressed. Here is a sample menu.lst file: #--------------------begin menu.lst--------------------------------------- color black/cyan yellow/cyan timeout 30 default /default title find and load NTLDR of Windows NT/2K/XP find --set-root /ntldr chainloader /ntldr savedefault --wait=2 title find and load CMLDR of Windows NT/2K/XP find --set-root /cmldr chainloader /cmldr savedefault --wait=2 title find and load IO.SYS of Windows 9x/Me find --set-root /io.sys chainloader /io.sys savedefault --wait=2 title floppy (fd0) chainloader (fd0)+1 rootnoverify (fd0) savedefault --wait=2 title find and boot Linux with menu.lst already installed find --set-root /sbin/init savedefault --wait=2 configfile /boot/grub/menu.lst title find and boot Mandriva with menu.lst already installed find --set-root /etc/mandriva-release savedefault --wait=2 configfile /boot/grub/menu.lst title back to dos savedefault --wait=2 quit title commandline savedefault --wait=2 commandline title reboot savedefault --wait=2 reboot title halt savedefault --wait=2 halt #--------------------end menu.lst--------------------------------------- Note 1: The file DEFAULT must exist and have a proper format as stated above. Or else, the default/savedefault commands won't function well. Note 2: The file DEFAULT which is in the same dir as a certain MENU.LST file is called associated with the MENU.LST file. Note 3: The associated DEFAULT file will take effect automatically if there are no `default' commands present. Note 4: Just before a menu file gains control(e.g., it is the associated MENU.LST of a GRLDR file, or it was specified via `grub.exe --config-file=(DEVICE)/PATH/YOUR_MENU_FILE', or it was specified by the `configfile' command of grub), its associated DEFAULT file will be used if present, until an explicit `default' command is encountered. ****************************************************************************** *** The New `cdrom' Command Syntax *** ****************************************************************************** 1. Initialize the ATAPI CDROM devices: grub> cdrom --init This will display the number of atapi cdroms found: atapi_dev_count 2. Stop the ATAPI CDROM devices: grub> cdrom --stop This will set atapi_dev_count to 0. 3. Add IO ports for searching the atapi cdrom devices. For example: grub> cdrom --add-io-ports=0x03F601F0 After running `cdrom --init' and `map --hook', the cdroms can be accessed through devices (cd0), (cd1), ... Note 1: If the system does not fully support the ATAPI CD-ROM specifications, you will encounter failure when trying to access the (cdX) devices. Note 2: After doing a `cdrom --stop', you should do a `map --unhook'. Of course you may `map --hook' again if there are mapped drives. Note 3: After adding IO ports, you should do a `map --unhook' followed by a `cdrom --init' and then followed by a `map --hook'. By default, these ports are used for searching cdroms(so they needn't be added): 0x03F601F0, 0x03760170, 0x02F600F0, 0x03860180, 0x6F006B00, 0x77007300. Note 4: The BIOS might have offered a cdrom interface. It would be (cd). After `cdrom --init' and `map --hook', we might have our (cd0), (cd1), ... available. It is likely that one of them could access the same media as the BIOS-offered (cd). Note 5: You may access the (cd) and (cdX)'es in the blocklist way. Example: cat --hex (cd0)16+2 The cdrom sectors are big sectors with a size of 2048 bytes. Note 6: The iso9660 filesystem driver has Rock-Ridge extension support, but has no Joliet extension support. So you may encounter failure when you attempt to read files on a Joliet CD. Note 7: The (cd) or (cdX)'es can be booted now. Examples: chainloader (cd) boot chainloader (cd0) boot chainloader (cd1) boot You should already have access to the CD sectors before you can chainload it. ****************************************************************************** *** About the New `setvbe' Command *** ****************************************************************************** Gerardo Richarte contributed the `setvbe' code and the following comment: New command is `setvbe', and can be used to change the video mode before executing the kernel. For example, you can do setvbe 1024x768x32 this will scan the list of available modes and set it, and automatically append a `video=' option to each subsequent kernel command-line. The appended `video=' option is like this: video=1024x768x32@0xf0000000,4096 where 0xf0000000 is the video framebuffer address as reported by vbe, and 4096 is the size of a scanline in bytes (also as reported by vbe). This is really useful if you want to give some graphics support to your OS, but you don't want to implement any video functionality other than writing a pixel to video memory. ****************************************************************************** *** About the DOS utility `hmload' *** ****************************************************************************** This program was written by John Cobb (Queen Mary, University of London). John Cobb's note: To make use of the ram drive feature I wrote a program `hmload' to load an arbitrary file to an arbitrary address in high memory. The program is not very sophisticated and relies on XMS to turn on the A20 line. (Also one must be very careful to steer clear of any areas of memory already in use). Under Linux we generated a disk image `dskimg' (with the kernel and Initrd and a partition table). Using this our boot procedure looked something like this: hmload -fdskimg -a128 fixrb grub map --ram-drive=0x81 map --rd-base=0x8000000 map --rd-size=0x400000 root (rd,0) kernel /kernel root=/dev/ram0 rw ip=bootp ramdisk_size=32768 ... initrd /initrd boot See http://sysdocs.stu.qmul.ac.uk/sysdocs/Comment/GrubForDOS.html for details. ****************************************************************************** *** Notes on the use of stack *** ****************************************************************************** The protected-mode and real-mode stack are merged at physical address 0x2000. All functions should use at most 2K stack space(0x1800-0x2000). So each subfunction should use as little stack as possible to avoid stack-overflow. Don't use recursive functions because they could expend too much stack space. The original protected mode stack at 0x68000(expand-down) is free now and can be reused for any purposes. ****************************************************************************** *** A bug was found in the CDROM driver *** ****************************************************************************** It seems the cdrom must be connected as the master device of an IDE controller. If cdrom is slave, the driver will fail to read the cdrom sectors. Hope someone could fix this problem. ****************************************************************************** *** BIOS and the (cd) drive *** ****************************************************************************** When BIOS boots a no-emulation-mode bootable CD-ROM, it allocates a BIOS drive number to the CD. If the boot image of the CD-ROM is grldr or stage2_eltorito, then GRUB can access the CD-ROM media through the drive number allocated by BIOS. The device name of the CD-ROM is (cd). BIOS can allocate a BIOS drive number to a no-emulation-mode CDROM even when the CDROM is not bootable. QEMU has done so. At boot time, GRUB4DOS will search drives 0x80-0xFE for a possible no-emulation-mode CDROM drive allocated by BIOS. So if BIOS offered a CDROM interface of int13 EBIOS functions 41h-4Eh, then the (cd) device will be automatically available in GRUB4DOS. ****************************************************************************** *** The way of disk emulation changed greatly *** ****************************************************************************** The way of disk emulation has changed greatly since 0.4.2pre10. Please don't mix newer versions with older versions when disk emulation features are used. The newer versions won't automatically unhook emulations established in a previous grub4dos environment. The GRUB.EXE of an older version will automatically dismiss emulations established previously, before transferring control to the main grub program(i.e., pre_stage2). ****************************************************************************** *** FreeDOS EMM386 v2.26 (2006-08-27) VCPI problem *** ****************************************************************************** The VCPI function "AX=DE0Ch - Switch From Protected Mode to V86 Mode" of FreeDOS EMM386 v2.26 was not implemented properly(it always hangs). As an alternative, you can use Microsoft's EMM386 instead. Even while emm386 is running, grub.exe can be started. But if you try to quit to DOS from grub4dos by using the `quit' command, the VCPI function DE0C will be called. If EMM386 is of Microsoft, everything goes ok. If EMM386 is of FreeDOS, the machine will hang.