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Please refer to http://grub4dos.sourceforge.net/wiki/ for DOCs on GRUB4DOS.
Main project page: https://gna.org/projects/grub4dos/
Download site: http://download.gna.org/grub4dos/
Download site: http://grub4dos.sourceforge.net/
Download site: http://sarovar.org/projects/grub4dos/
Download site: http://grub4dos.jot.com/
Download site: http://grub4dos.freespaces.com/
Get the source code by using anonymous svn in this way:
svn co svn://svn.gna.org/svn/grub4dos/trunk grub4dos
or in this way:
svn co http://svn.gna.org/svn/grub4dos/trunk grub4dos
View the source code online with your web browser at:
http://svn.gna.org/viewcvs/grub4dos/trunk/
------------------------------------------------------------------------------
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) (Changed 2006-12-23. See Update 3 below.)
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.
Update 3(2006-12-23): By default, GRUB.EXE will locate its
config file in the following order:
(DOS file) .\menu.lst, the MENU.LST in the current dir.
(DOS file) \menu.lst, the MENU.LST in the root dir of
the current drive.
(GRUB file) /menu.lst, the MENU.LST in the root dir of
the boot device.
The default boot device is still (hd0,0).
--------------------------------------------------------
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).
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
As an alternative, grldr can also 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.
The menu.lst file should be placed in the root dir of the CD.
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 almost exactly the same as the fifth sector of
grldr, with only the byte at offset 0x33 was changed from 0x90 to 0x99.
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 1 code for "cld"(0xFC).
31h 2 code for "xor ax,ax"(0x31, 0xC0).
33h 1 code for "nop"(0x90) or "cwd"(0x99)
34h 458 The rest of the 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 code for "cli".
3Fh 1 code for "cld".
40h 1 code 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 The rest of the 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 The rest of the 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.
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.
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.
3. From "http://heim.ifi.uio.no/~stanisls/helppc/make_codes.html":
INT 9 - Hardware Keyboard Make/Break Codes
Key Make Break Key Make Break
Backspace 0E 8E F1 3B BB
Caps Lock 3A BA F2 3C BC
Enter 1C 9C F3 3D BD
Esc 01 81 F4 3E BE
Left Alt 38 B8 F7 41 C1
Left Ctrl 1D 9D F5 3F BF
Left Shift 2A AA F6 40 C0
Num Lock 45 C5 F8 42 C2
Right Shift 36 B6 F9 43 C3
Scroll Lock 46 C6 F10 44 C4
Space 39 B9 F11 57 D7
Sys Req (AT) 54 D4 F12 58 D8
Tab 0F 8F
Keypad Keys Make Break
Keypad 0 (Ins) 52 D2
Keypad 1 (End) 4F CF
Keypad 2 (Down arrow) 50 D0
Keypad 3 (PgDn) 51 D1
Keypad 4 (Left arrow) 4B CB
Keypad 5 4C CC
Keypad 6 (Right arrow) 4D CD
Keypad 7 (Home) 47 C7
Keypad 8 (Up arrow) 48 C8
Keypad 9 (PgUp) 49 C9
Keypad . (Del) 53 D3
Keypad * (PrtSc) 37 B7
Keypad - 4A CA
Keypad + 4E CE
Key Make Break Key Make Break
A 1E 9E N 31 B1
B 30 B0 O 18 98
C 2E AE P 19 99
D 20 A0 Q 10 90
E 12 92 R 13 93
F 21 A1 S 1F 9F
G 22 A2 T 14 94
H 23 A3 U 16 96
I 17 97 V 2F AF
J 24 A4 W 11 91
K 25 A5 X 2D AD
L 26 A6 Y 15 95
M 32 B2 Z 2C AC
Key Make Break Key Make Break
1 02 82 - 0C 8C
2 03 83 = 0D 8D
3 04 84 [ 1A 9A
4 05 85 ] 1B 9B
5 06 86 ; 27 A7
6 07 87 ' 28 A8
7 08 88 ` 29 A9
8 09 89 \ 2B AB
9 0A 8A , 33 B3
0 0B 8B . 34 B4
/ 35 B5
Enhanced Keyboard Keys (101/102 keys)
Control Keys Make Break
Alt-PrtSc (SysReq) 54 D4
Ctrl-PrtSc E0 37 E0 B7
Enter E0 1C E0 9C
PrtSc E0 2A E0 37 E0 B7 E0 AA
Right Alt E0 38 E0 B8
Right Ctrl E0 1D E0 9D
Shift-PrtSc E0 37 E0 B7
/ E0 35 E0 B5
Pause E1 1D 45 E1 9D C5 (not typematic)
Ctrl-Pause (Ctrl-Break) E0 46 E0 C6 (not typematic)
- Keys marked as "not typematic" generate one stream of bytes
without corresponding break scan code bytes (actually the
break codes are part of the make code).
Normal Mode or
Shift w/Numlock
Key Make Break |----- Numlock on ------.
Make Break
Del E0 53 E0 D3 E0 2A E0 53 E0 D3 E0 AA
Down arrow E0 50 E0 D0 E0 2A E0 50 E0 D0 E0 AA
End E0 4F E0 CF E0 2A E0 4F E0 CF E0 AA
Home E0 47 E0 C7 E0 2A E0 47 E0 C7 E0 AA
Ins E0 52 E0 D2 E0 2A E0 52 E0 D2 E0 AA
Left arrow E0 4B E0 CB E0 2A E0 4B E0 CB E0 AA
PgDn E0 51 E0 D1 E0 2A E0 51 E0 D1 E0 AA
PgUp E0 49 E0 C9 E0 2A E0 49 E0 C9 E0 AA
Right arrow E0 4D E0 CD E0 2A E0 4D E0 CD E0 AA
Up arrow E0 48 E0 C8 E0 2A E0 48 E0 C8 E0 AA
Key |--Left Shift Pressed--. |--Right Shift Pressed--.
Make Break Make Break
Del E0 AA E0 53 E0 D3 E0 2A E0 B6 E0 53 E0 D3 E0 36
Down arrow E0 AA E0 50 E0 D0 E0 2A E0 B6 E0 50 E0 D0 E0 36
End E0 AA E0 4F E0 CF E0 2A E0 B6 E0 4F E0 CF E0 36
Home E0 AA E0 47 E0 C7 E0 2A E0 B6 E0 47 E0 C7 E0 36
Ins E0 AA E0 52 E0 D2 E0 2A E0 B6 E0 52 E0 D2 E0 36
Left arrow E0 AA E0 4B E0 CB E0 2A E0 B6 E0 4B E0 CB E0 36
PgDn E0 AA E0 51 E0 D1 E0 2A E0 B6 E0 51 E0 D1 E0 36
PgUp E0 AA E0 49 E0 C9 E0 2A E0 B6 E0 49 E0 C9 E0 36
Right arrow E0 AA E0 4D E0 CD E0 2A E0 B6 E0 4D E0 CD E0 36
Up arrow E0 AA E0 48 E0 C8 E0 2A E0 B6 E0 48 E0 C8 E0 36
/ E0 AA E0 35 E0 B5 E0 2A E0 B6 E0 35 E0 B5 E0 36
- The PS/2 models have three make/break scan code sets. The first
set matches the PC & XT make/break scan code set and is the one
listed here. Scan code sets are selected by writing the value F0
to the keyboard via the 8042 (port 60h). The following is a brief
description of the scan code sets (see the PS/2 Technical Reference
manuals for more information on scan code sets 2 and 3):
/ set 1, each key has a base scan code. Some keys generate
extra scan codes to generate artificial shift states. This
is similar to the standard scan code set used on the PC and XT.
/ set 2, each key sends one make scan code and two break scan
codes bytes (F0 followed by the make code). This scan code
set is available on the IBM AT also.
/ set 3, each key sends one make scan code and two break scan
codes bytes (F0 followed by the make code) and no keys are
altered by Shift/Alt/Ctrl keys.
/ typematic scan codes are the same as the make scan code
- Some Tandy 1000's do not handle Alt key combinations when multiple
shift keys are pressed. The Alt-Shift-H combination loses the Alt.
- extended keys like (F11, F12) can only be read with systems that
have extended keyboard BIOS support (or INT 9 extensions); to
read these special keys on these systems INT 16,10 must be used
******************************************************************************
*** !!!!!!!! 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.
5. Some USB BIOSes have a buggy int13/AH=08h function which returns incorrect
geometry in CX and DH registers. They will encounter various failure.
Note: The int13/AH=08h function call is very important for the normal
CHS-mode int13 disk access. If there is no other way to determine the
geometry, a USB BIOS programmer should probe the first sector of the
USB storage device and give a right geometry for the int13/AH=08h call.
A good BIOS programmer should implement EBIOS functions for USB storage
devices, especially functions 41h, 42h, 43h and 48h, which are very
important for BIOS-based programs or systems such as GRUB and DOS.
6. Reports say some newer Dell machines violently destroyed the int0d vector
and will cause failure or even hang the machine when running GRUB.EXE
from DOS.
******************************************************************************
*** 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).
4. A Chinese DOS system software, the TechWay SCS, will not work with
newer versions of GRUB.EXE. In general, TSRs that take antitracking
measures will not work with GRUB.EXE any more.
******************************************************************************
*** 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
<unload network drivers>
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 0.4.2 final. 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 earlier, 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.
******************************************************************************
*** New options for map were added ***
******************************************************************************
Along with 0.4.2 final, there are two new options for the map command. They
are --safe-mbr-hook=SMH and --int13-scheme=SCH. Both are related with disk
emulation for use(as smoothly as possible) in the Win9x environment.
SMH can take either of the two values 0 and 1. By default, SMH is 1. If you
encountered problems of disk emulation under Win9x, you may insert a line of
map --safe-mbr-hook=0
before the `boot' command and try again.
Also SCH may take either 0 or 1 at present. By default, SCH is 1. If you
encountered disk emulation problems under Win9x, you may insert a line of
map --int13-scheme=0
before the `boot' command and try again.
Note by the way. Like --safe-mbr-hook and --int13-scheme, the MAP command has
a few other options that are used for setting global variables. They are here:
map --floppies=M
M can be 0, 1, or 2. MAP will set a proper value at 0040:0010 by using M.
map --harddrives=N
N can be between 0 and 127(inclusive). MAP will set 0040:0075 to N.
map --memdisk-raw=RAW
RAW default to 1. If RAW=0, `int15/ah=87h' will be used to access memdrives.
map --ram-drive=RD
RD default to 0x7F which is a floppy. If the RAM DRIVE is a hard drive image
(with partition table in the first sector), you should set RD >= 0x80 and RD
< 0xFF.
map --rd-base=ADDR
map --rd-size=SIZE
ADDR specifies the physical base address of the ramdisk image. SIZE specifies
the size in bytes of the ramdisk image. ADDR default to 0. SIZE is also default
to 0, but a size of 0 means 4GB, not a zero-long disk. The RAM DRIVE can be
accessed in the GRUB environment using the (rd) device.
******************************************************************************
*** About the new map option --in-situ ***
******************************************************************************
--in-situ is used with hard drive images or hardrive partitions. With an
in-situ map, we can typically use a logical partition as a primary partition.
In-situ map is a whole drive map. It only virtualize the partition table and
the number of hidden sectors in the BPB of the DOS Boot Record.
While disk emulation may encounter various problems with win9x, the in-situ map
works fine with win9x.
If a partition or image is mapped in-situ, any real-mode software will see
only one primary partition entry (hdX,0) in the drive.
Note that this is virtual, so the real partition table on disk is not changed.
Example:
map --in-situ (hd0,4)+1 (hd0)
******************************************************************************
*** Newly implemented operators `&&' and `||' ***
******************************************************************************
This implementation is very simple. It does not handle operator nesting.
Usage of `&&':
command1 && command2
Description:
If command1 returns true, then command2 will be executed.
Usage of `||':
command1 || command2
Description:
If command1 returns false, then command2 will be executed.
Examples:
is64bit && default 0
is64bit || default 1
******************************************************************************
*** Three new commands is64bit, errnum and errorcheck ***
******************************************************************************
is64bit and errnum retrieve the value of is64bit and errnum respectively.
errorcheck controls whether or not the error will be handled. By default,
errorcheck is on, and menu script execution will stop on error. If errorcheck
is off, the script will continue to execute upto a boot command. A boot command
will turn the errorcheck on.
******************************************************************************
*** Loading GRUB4DOS in Windows Vista ***
******************************************************************************
First, you should copy GRLDR.MBR to C:\, and use the following commands:
bcdedit /create /d "Boot Manager" /application bootsector
bcdedit /set {id} device boot
bcdedit /set {id} path \grldr.mbr
bcdedit /displayorder {id} /addlast
Then copy GRLDR and menu.lst to the root directory of any FAT16/FAT32/EXT2/NTFS
partition.
Notice: These commands need elevated privileges, they should be used inside
cmd.exe which is started with "Run as administrator".
******************************************************************************
*** Use numeric keys to select a menu entry ***
******************************************************************************
If, for example, you intend to goto entry #25, you may press 2 followed by 5.
******************************************************************************
*** Use the INSERT key to debug step by step at startup ***
******************************************************************************
Some buggy machines could fail to enter grub4dos environment. They might hang
or reboot unexpectedly. Press INSERT as quickly as possible on startup, and
you can get the chance to single-step the boot process and see how far it can
go, and then report bugs.