grub 目录下.mod文件解释
915resolution.mod crypto.lst gcry_md5.mod iso9660.mod multiboot2.mod raid6rec.mod ufs2.mod
acpi.mod crypto.mod gcry_rfc2268.mod jfs.mod nilfs2.mod read.mod uhci.mod
affs.mod cs5536.mod gcry_rijndael.mod jpeg.mod normal.mod reboot.mod usb.mod
afs.mod date.mod gcry_rmd160.mod kernel.img ntfs.mod regexp.mod usb_keyboard.mod
afs_be.mod datehook.mod gcry_seed.mod keylayouts.mod ntfscomp.mod reiserfs.mod usbms.mod
aout.mod datetime.mod gcry_serpent.mod keystatus.mod ntldr.mod relocator.mod usbserial_common.mod
at_keyboard.mod diskboot.img gcry_sha1.mod legacycfg.mod ohci.mod scsi.mod usbserial_ftdi.mod
ata.mod dm_nv.mod gcry_sha256.mod linux.mod part_acorn.mod search.mod usbserial_pl2303.mod
ata_pthru.mod drivemap.mod gcry_sha512.mod linux16.mod part_amiga.mod search_fs_file.mod usbtest.mod
befs.mod echo.mod gcry_tiger.mod lnxboot.img part_apple.mod search_fs_uuid.mod vbe.mod
befs_be.mod efiemu.mod gcry_twofish.mod loadenv.mod part_bsd.mod search_label.mod vga.mod
biosdisk.mod efiemu32.o gcry_whirlpool.mod locale part_gpt.mod sendkey.mod vga_text.mod
bitmap.mod efiemu64.o gettext.mod loopback.mod part_msdos.mod serial.mod video.lst
bitmap_scale.mod elf.mod gfxmenu.mod ls.mod part_sun.mod setjmp.mod video.mod
blocklist.mod example_functional_test.mod gfxterm.mod lsacpi.mod part_sunpc.mod setpci.mod video_bochs.mod
boot.img ext2.mod gptsync.mod lsapm.mod partmap.lst sfs.mod video_cirrus.mod
boot.mod extcmd.mod grldr.img lsmmap.mod parttool.lst sleep.mod video_fb.mod
bsd.mod fat.mod grub.cfg lspci.mod parttool.mod squash4.mod videoinfo.mod
btrfs.mod font.mod grubenv lvm.mod password.mod tar.mod videotest.mod
bufio.mod fs.lst gzio.mod mdraid09.mod password_pbkdf2.mod terminal.lst xfs.mod
cat.mod fshelp.mod halt.mod mdraid1x.mod pbkdf2.mod terminal.mod xnu.mod
cdboot.img functional_test.mod hashsum.mod memdisk.mod pci.mod terminfo.mod xnu_uuid.mod
chain.mod g2hdr.img hdparm.mod memrw.mod play.mod test.mod xzio.mod
cmostest.mod gcry_arcfour.mod hello.mod minicmd.mod png.mod test_blockarg.mod zfs.mod
cmp.mod gcry_blowfish.mod help.mod minix.mod probe.mod testload.mod zfsinfo.mod
command.lst gcry_camellia.mod hexdump.mod minix2.mod pxe.mod tga.mod
configfile.mod gcry_cast5.mod hfs.mod mmap.mod pxeboot.img trig.mod
core.img gcry_crc.mod hfsplus.mod moddep.lst pxecmd.mod true.mod
cpio.mod gcry_des.mod hwmatch.mod msdospart.mod raid.mod udf.mod
cpuid.mod gcry_md4.mod iorw.mod multiboot.mod raid5rec.mod ufs1.mod
这里有很多的以mod为后缀的文件，其具体意义为：
常规命令
---------------------------------------------------------
pxe.mod Driver to provide access to the pxe filesystem
pxecmd.mod Command to control the PXE device
cat.mod Show the contents of a file. 显示文件内容
cmp.mod Compare two files.
configfile.mod configure - Load another config file.
source - Load another config file without changing context.
. - Load another config file without changing context.
cpuid.mod Check for CPU features
crc.mod Calculate the crc32 checksum of a file.
echo.mod Display a line of text.
halt.mod halts the computer. This command does not work on all firmware.
suspend.mod Halt the system, if possible using APM
hello.mod Say hello
help.mod Show a help message.
hexdump.mod Dump the contents of a file or memory.
ls.mod List devices and files.
lspci.mod List PCI devices
normal.mod Grub2 的常规模式（于此对应的是安全模式，内置于 kernel 中）
pci.mod
play.mod 播放音频文件 (体验功能) Play a tune
read.mod Set variable with user input
reboot.mod Reboot the computer. 重启计算机
search.mod Search devices by file, filesystem label or filesystem UUID.
serial.mod
sleep.mod Wait for a specified number of seconds
terminal.mod Select a terminal.
terminfo.mod Set terminfo type.
test.mod test -
[ - Evaluate an expression
ieee1275_suspend Return to Open Firmware prompt
分区管理
---------------------------------------------------------
pc.mod pc 机上的分区类型（主分区、扩展分区）管理
sun.mod sun 机上的分区类型管理
gpt.mod Read GUID Partition Tables (GPT).
apple.mod 苹果机的分区管理
acorn.mod Linux/ADFS partition tables.
amiga.mod Amiga partition tables (RDB).
图形相关:
---------------------------------------------------------
vga.mod 字符终端
gfxterm.mod 图形终端
background_image - Load background image for active terminal.
font.mod Specify one or more font files to display.
vbe.mod pc 上图形核心库
vbeinfo.mod List compatible VESA BIOS extension video modes.
vbetest.mod Test VESA BIOS Extension 2.0+ support
video.mod
videotest.mod Test video subsystem
bitmap.mod 图片格式基类
jpeg.mod JPG 图片格式解码
tga.mod TGA 图片格式解码
png.mod PNG 图片格式解码
文件系统
---------------------------------------------------------
affs.mod Amiga Fast FileSystem.
afs.mod The native AtheOS file-system.
cpio.mod cpio and tar filesystem.
ext2.mod Second Extended filesystem
fat.mod FAT filesystem
hfs.mod HFS
hfsplus.mod HFS+ Filesystem.
iso9660.mod iso9660 implementation with extensions: SUSP, Rock Ridge. (光盘文件系统)
jfs.mod JFS
minix.mod The minix filesystem, version 1 and 2.
ntfs.mod NTFS filesystem
ntfscomp.mod compression support for the NTFS filesystem
reiserfs.mod ReiserFS versions up to 3.6
sfs.mod Amiga Smart FileSystem.
udf.mod Universal Disk Format filesystem. (光盘文件系统)
ufs.mod Unix File System
xfs.mod XFS
fshelp.mod Filesystem helper functions (查找文件、读取文件操作)
磁盘访问
---------------------------------------------------------
ata.mod ATA disk access.
fs_uuid.mod Access disks by their filesystem UUID.
host.mod Dummy disk driver to provide access to the hosts filesystem. (grub-emu 用以访问宿主文件系统)
loopback.mod Make a device of a file. (command to add loopback devices.)
biosdisk.mod BIOS 磁盘设备 (cdrom, hdd, cdrom 访问层)
lvm.mod module to read Logical Volumes. (加密卷)
memdisk.mod Access embedded memory disk
raid.mod module to read RAID arrays.
引导器
---------------------------------------------------------
appleloader.mod Boot legacy system. （apple legacy boot loader.）
multiboot.mod multiboot - Load a Multiboot kernel.
module - Load a Multiboot module.
linux.mod linux - Load a linux kernel.
initrd - Load an initrd.
loadenv.mod load_env - Load variables from environment block file.
save_env - Save variables to environment block file.
blocklist.mod Print a block list.
boot.mod Boot an operating system.
bsd.mod freebsd - load freebsd kernel
openbsd - load openbsd kernel
netbsd - load netbsd kernel
freebsd_loadenv
- load freebsd env
freebsd_module
- load freebsd module
chain.mod load another boot loader
其他 （未知）
---------------------------------------------------------
aout.mod
elf.mod
_bsd.mod
_chain.mod
_linux.mod
_multiboot.mod
IO hook
---------------------------------------------------------
bufio.mod buffered io access
gzio.mod decompression support for gzip