Grub Modules

The GRUB bootloader has many modules that provide extra capabilities (similar to the modules used by Linux). To active/load a GRUB module while in the GRUB command-line (CLI mode), type "insmod MODULE". The modules are typically stored under /boot/grub/i386-pc/ or some similarly name directory. To list the available modules, type "ls /boot/grub/i386-pc/*.mod" (if your system supports that command).

$ ls /boot/grub/i386-pc/*.mod
/boot/grub/i386-pc/915resolution.mod
/boot/grub/i386-pc/acpi.mod
/boot/grub/i386-pc/adler32.mod
/boot/grub/i386-pc/affs.mod
/boot/grub/i386-pc/afs.mod
/boot/grub/i386-pc/ahci.mod
/boot/grub/i386-pc/all_video.mod
/boot/grub/i386-pc/aout.mod
/boot/grub/i386-pc/archelp.mod
/boot/grub/i386-pc/ata.mod
/boot/grub/i386-pc/at_keyboard.mod
/boot/grub/i386-pc/backtrace.mod
/boot/grub/i386-pc/bfs.mod
/boot/grub/i386-pc/biosdisk.mod
/boot/grub/i386-pc/bitmap.mod
/boot/grub/i386-pc/bitmap_scale.mod
/boot/grub/i386-pc/blocklist.mod
/boot/grub/i386-pc/boot.mod
/boot/grub/i386-pc/bsd.mod
/boot/grub/i386-pc/btrfs.mod
/boot/grub/i386-pc/bufio.mod
/boot/grub/i386-pc/cat.mod
/boot/grub/i386-pc/cbfs.mod
/boot/grub/i386-pc/cbls.mod
/boot/grub/i386-pc/cbmemc.mod
/boot/grub/i386-pc/cbtable.mod
/boot/grub/i386-pc/cbtime.mod
/boot/grub/i386-pc/chain.mod
/boot/grub/i386-pc/cmdline_cat_test.mod
/boot/grub/i386-pc/cmosdump.mod
/boot/grub/i386-pc/cmostest.mod
/boot/grub/i386-pc/cmp.mod
/boot/grub/i386-pc/configfile.mod
/boot/grub/i386-pc/cpio_be.mod
/boot/grub/i386-pc/cpio.mod
/boot/grub/i386-pc/cpuid.mod
/boot/grub/i386-pc/crc64.mod
/boot/grub/i386-pc/cryptodisk.mod
/boot/grub/i386-pc/crypto.mod
/boot/grub/i386-pc/cs5536.mod
/boot/grub/i386-pc/datehook.mod
/boot/grub/i386-pc/date.mod
/boot/grub/i386-pc/datetime.mod
/boot/grub/i386-pc/diskfilter.mod
/boot/grub/i386-pc/disk.mod
/boot/grub/i386-pc/div_test.mod
/boot/grub/i386-pc/dm_nv.mod
/boot/grub/i386-pc/drivemap.mod
/boot/grub/i386-pc/echo.mod
/boot/grub/i386-pc/efiemu.mod
/boot/grub/i386-pc/ehci.mod
/boot/grub/i386-pc/elf.mod
/boot/grub/i386-pc/eval.mod
/boot/grub/i386-pc/exfat.mod
/boot/grub/i386-pc/exfctest.mod
/boot/grub/i386-pc/ext2.mod
/boot/grub/i386-pc/extcmd.mod
/boot/grub/i386-pc/fat.mod
/boot/grub/i386-pc/file.mod
/boot/grub/i386-pc/font.mod
/boot/grub/i386-pc/freedos.mod
/boot/grub/i386-pc/fshelp.mod
/boot/grub/i386-pc/functional_test.mod
/boot/grub/i386-pc/gcry_arcfour.mod
/boot/grub/i386-pc/gcry_blowfish.mod
/boot/grub/i386-pc/gcry_camellia.mod
/boot/grub/i386-pc/gcry_cast5.mod
/boot/grub/i386-pc/gcry_crc.mod
/boot/grub/i386-pc/gcry_des.mod
/boot/grub/i386-pc/gcry_dsa.mod
/boot/grub/i386-pc/gcry_idea.mod
/boot/grub/i386-pc/gcry_md4.mod
/boot/grub/i386-pc/gcry_md5.mod
/boot/grub/i386-pc/gcry_rfc2268.mod
/boot/grub/i386-pc/gcry_rijndael.mod
/boot/grub/i386-pc/gcry_rmd160.mod
/boot/grub/i386-pc/gcry_rsa.mod
/boot/grub/i386-pc/gcry_seed.mod
/boot/grub/i386-pc/gcry_serpent.mod
/boot/grub/i386-pc/gcry_sha1.mod
/boot/grub/i386-pc/gcry_sha256.mod
/boot/grub/i386-pc/gcry_sha512.mod
/boot/grub/i386-pc/gcry_tiger.mod
/boot/grub/i386-pc/gcry_twofish.mod
/boot/grub/i386-pc/gcry_whirlpool.mod
/boot/grub/i386-pc/gdb.mod
/boot/grub/i386-pc/geli.mod
/boot/grub/i386-pc/gettext.mod
/boot/grub/i386-pc/gfxmenu.mod
/boot/grub/i386-pc/gfxterm_background.mod
/boot/grub/i386-pc/gfxterm_menu.mod
/boot/grub/i386-pc/gfxterm.mod
/boot/grub/i386-pc/gptsync.mod
/boot/grub/i386-pc/gzio.mod
/boot/grub/i386-pc/halt.mod
/boot/grub/i386-pc/hashsum.mod
/boot/grub/i386-pc/hdparm.mod
/boot/grub/i386-pc/hello.mod
/boot/grub/i386-pc/help.mod
/boot/grub/i386-pc/hexdump.mod
/boot/grub/i386-pc/hfs.mod
/boot/grub/i386-pc/hfspluscomp.mod
/boot/grub/i386-pc/hfsplus.mod
/boot/grub/i386-pc/http.mod
/boot/grub/i386-pc/hwmatch.mod
/boot/grub/i386-pc/iorw.mod
/boot/grub/i386-pc/iso9660.mod
/boot/grub/i386-pc/jfs.mod
/boot/grub/i386-pc/jpeg.mod
/boot/grub/i386-pc/keylayouts.mod
/boot/grub/i386-pc/keystatus.mod
/boot/grub/i386-pc/ldm.mod
/boot/grub/i386-pc/legacycfg.mod
/boot/grub/i386-pc/legacy_password_test.mod
/boot/grub/i386-pc/linux16.mod
/boot/grub/i386-pc/linux.mod
/boot/grub/i386-pc/loadenv.mod
/boot/grub/i386-pc/loopback.mod
/boot/grub/i386-pc/lsacpi.mod
/boot/grub/i386-pc/lsapm.mod
/boot/grub/i386-pc/lsmmap.mod
/boot/grub/i386-pc/ls.mod
/boot/grub/i386-pc/lspci.mod
/boot/grub/i386-pc/luks.mod
/boot/grub/i386-pc/lvm.mod
/boot/grub/i386-pc/lzopio.mod
/boot/grub/i386-pc/macbless.mod
/boot/grub/i386-pc/macho.mod
/boot/grub/i386-pc/mda_text.mod
/boot/grub/i386-pc/mdraid09_be.mod
/boot/grub/i386-pc/mdraid09.mod
/boot/grub/i386-pc/mdraid1x.mod
/boot/grub/i386-pc/memdisk.mod
/boot/grub/i386-pc/memrw.mod
/boot/grub/i386-pc/minicmd.mod
/boot/grub/i386-pc/minix2_be.mod
/boot/grub/i386-pc/minix2.mod
/boot/grub/i386-pc/minix3_be.mod
/boot/grub/i386-pc/minix3.mod
/boot/grub/i386-pc/minix_be.mod
/boot/grub/i386-pc/minix.mod
/boot/grub/i386-pc/mmap.mod
/boot/grub/i386-pc/morse.mod
/boot/grub/i386-pc/mpi.mod
/boot/grub/i386-pc/msdospart.mod
/boot/grub/i386-pc/multiboot2.mod
/boot/grub/i386-pc/multiboot.mod
/boot/grub/i386-pc/nativedisk.mod
/boot/grub/i386-pc/net.mod
/boot/grub/i386-pc/newc.mod
/boot/grub/i386-pc/nilfs2.mod
/boot/grub/i386-pc/normal.mod
/boot/grub/i386-pc/ntfscomp.mod
/boot/grub/i386-pc/ntfs.mod
/boot/grub/i386-pc/ntldr.mod
/boot/grub/i386-pc/odc.mod
/boot/grub/i386-pc/offsetio.mod
/boot/grub/i386-pc/ohci.mod
/boot/grub/i386-pc/part_acorn.mod
/boot/grub/i386-pc/part_amiga.mod
/boot/grub/i386-pc/part_apple.mod
/boot/grub/i386-pc/part_bsd.mod
/boot/grub/i386-pc/part_dfly.mod
/boot/grub/i386-pc/part_dvh.mod
/boot/grub/i386-pc/part_gpt.mod
/boot/grub/i386-pc/part_msdos.mod
/boot/grub/i386-pc/part_plan.mod
/boot/grub/i386-pc/part_sun.mod
/boot/grub/i386-pc/part_sunpc.mod
/boot/grub/i386-pc/parttool.mod
/boot/grub/i386-pc/password.mod
/boot/grub/i386-pc/password_pbkdf2.mod
/boot/grub/i386-pc/pata.mod
/boot/grub/i386-pc/pbkdf2.mod
/boot/grub/i386-pc/pbkdf2_test.mod
/boot/grub/i386-pc/pcidump.mod
/boot/grub/i386-pc/pci.mod
/boot/grub/i386-pc/plan9.mod
/boot/grub/i386-pc/play.mod
/boot/grub/i386-pc/png.mod
/boot/grub/i386-pc/priority_queue.mod
/boot/grub/i386-pc/probe.mod
/boot/grub/i386-pc/procfs.mod
/boot/grub/i386-pc/progress.mod
/boot/grub/i386-pc/pxechain.mod
/boot/grub/i386-pc/pxe.mod
/boot/grub/i386-pc/raid5rec.mod
/boot/grub/i386-pc/raid6rec.mod
/boot/grub/i386-pc/read.mod
/boot/grub/i386-pc/reboot.mod
/boot/grub/i386-pc/regexp.mod
/boot/grub/i386-pc/reiserfs.mod
/boot/grub/i386-pc/relocator.mod
/boot/grub/i386-pc/romfs.mod
/boot/grub/i386-pc/scsi.mod
/boot/grub/i386-pc/search_fs_file.mod
/boot/grub/i386-pc/search_fs_uuid.mod
/boot/grub/i386-pc/search_label.mod
/boot/grub/i386-pc/search.mod
/boot/grub/i386-pc/sendkey.mod
/boot/grub/i386-pc/serial.mod
/boot/grub/i386-pc/setjmp.mod
/boot/grub/i386-pc/setjmp_test.mod
/boot/grub/i386-pc/setpci.mod
/boot/grub/i386-pc/sfs.mod
/boot/grub/i386-pc/signature_test.mod
/boot/grub/i386-pc/sleep.mod
/boot/grub/i386-pc/sleep_test.mod
/boot/grub/i386-pc/spkmodem.mod
/boot/grub/i386-pc/squash4.mod
/boot/grub/i386-pc/syslinuxcfg.mod
/boot/grub/i386-pc/tar.mod
/boot/grub/i386-pc/terminal.mod
/boot/grub/i386-pc/terminfo.mod
/boot/grub/i386-pc/test_blockarg.mod
/boot/grub/i386-pc/testload.mod
/boot/grub/i386-pc/test.mod
/boot/grub/i386-pc/testspeed.mod
/boot/grub/i386-pc/tftp.mod
/boot/grub/i386-pc/tga.mod
/boot/grub/i386-pc/time.mod
/boot/grub/i386-pc/trig.mod
/boot/grub/i386-pc/tr.mod
/boot/grub/i386-pc/truecrypt.mod
/boot/grub/i386-pc/true.mod
/boot/grub/i386-pc/udf.mod
/boot/grub/i386-pc/ufs1_be.mod
/boot/grub/i386-pc/ufs1.mod
/boot/grub/i386-pc/ufs2.mod
/boot/grub/i386-pc/uhci.mod
/boot/grub/i386-pc/usb_keyboard.mod
/boot/grub/i386-pc/usb.mod
/boot/grub/i386-pc/usbms.mod
/boot/grub/i386-pc/usbserial_common.mod
/boot/grub/i386-pc/usbserial_ftdi.mod
/boot/grub/i386-pc/usbserial_pl2303.mod
/boot/grub/i386-pc/usbserial_usbdebug.mod
/boot/grub/i386-pc/usbtest.mod
/boot/grub/i386-pc/vbe.mod
/boot/grub/i386-pc/verify.mod
/boot/grub/i386-pc/vga.mod
/boot/grub/i386-pc/vga_text.mod
/boot/grub/i386-pc/video_bochs.mod
/boot/grub/i386-pc/video_cirrus.mod
/boot/grub/i386-pc/video_colors.mod
/boot/grub/i386-pc/video_fb.mod
/boot/grub/i386-pc/videoinfo.mod
/boot/grub/i386-pc/video.mod
/boot/grub/i386-pc/videotest_checksum.mod
/boot/grub/i386-pc/videotest.mod
/boot/grub/i386-pc/xfs.mod
/boot/grub/i386-pc/xnu.mod
/boot/grub/i386-pc/xnu_uuid.mod
/boot/grub/i386-pc/xnu_uuid_test.mod
/boot/grub/i386-pc/xzio.mod
/boot/grub/i386-pc/zfscrypt.mod
/boot/grub/i386-pc/zfsinfo.mod
/boot/grub/i386-pc/zfs.mod

• 915resolution - This module is used to change the video resolution.
• acpi - Advanced Configuration and Power Interface (ACPI) is used to perform various power-related functions.
• adler32 - This is a cryptography module that contains the tools needed to use the Adler-32 checksum.
• affs - Support for the AFFS filesystem is provided by this module.
• afs - Support for the AFS filesystem is provided by this module.
• ahci - AHCI stands for "Advanced Host Controller Interface" and this is a special hard-drive format (like IDE or SATA). This module offers the needed code for GRUB to recognize such devices.
• all_video - Additional video and graphics support can be gained when the "all_video" module is loaded.
• ata - This module provides support for ATA computer buses.
• at_keyboard - This module is used to support the 84-key keyboards.
• backtrace - This module gets the list of functions that are running in an active thread.
• bfs - This module provides support for the Be FileSystem which is used by BeOS.
• biosdisk - This module provides GRUB with the ability to boot off of LiveDisks.
• blocklist - This module displays the list of blocks used by the specified file.
• bsd - This module provides support for loading BSD kernels.
• btrfs - This module provides support for the B-tree Filesystem.
• bufio - This module supports buffer reads and writes.
• cat - The "cat" command is provided by this module.
• cbfs - This module provides GRUB with support for the Callback Filesystem (CBFS).
• cbls - This module lists the coreboot tables.
• cbmemc - This module displays the contents of the CBMEM console.
• cbtable - This module provides support for Coreboot tables.
• chain - This module offers chainloading capabilities.
• cmosdump - This command displays the raw CMOS data.
• cmp - The "cmp" command is provided by this module.
• configfile - This module provides the ability to read and manipulate configuration files.
• cpio_be - This module provides support for big-endian CPIO.
• cpio - This module provides support for CPIO.
• cpuid - This modules tests for various CPU features.
• crc64 - This module offers an error-detection tool known as Cyclic Redundancy Check (CRC).
• cryptodisk - This module is needed to mount a crypto disk.
• date - This module provides the "date" command.
• datetime - This module provides the "datetime" command.
• diskfilter - This module is needed to read RAID arrays.
• disk - This module is needed to read hard-drives.
• drivemap - This module contains functions related to BIOS drive mappings.
• echo - This module provides the "echo" command.
• efiemu - This module provides EFI emulation features.
• ehci - This module provides support for the Enhanced Host Controller Interface (EHCI) which is used by USBv2.
• elf - This module loads ELF files.
• eval - This module provides the "eval" command which is used to evaluate expressions.
• exfat - GRUB can gain support for FAT64 (also called exFAT) with this module.
• ext2 - This module provides support for EXT2 filesystems.
• fat - GRUB can gain support for the FAT filesystem with this module.
• file - This module provides the basic file I/O functions.
• font - This module provides many font-related functions.
• freedos - This module contains the code needed to boot FreeDOS.
• fshelp - This module contains functions related to filesystem-helpers.
• gcry_arcfour - This module provides support for the ARC4 cryptography tool.
• NOTE: "gcry_*" modules are GRUB Cryptography tools.
• gcry_blowfish - This module provides support for the Blowfish cryptography tool.
• gcry_camellia - This module provides support for the Camellia cryptography tool.
• gcry_cast5 - This module provides support for the CAST-128 (also called CAST5) cryptography tool.
• gcry_crc - This module provides support for the hash functions needed by Cyclic Redundancy Check utility.
• gcry_des - This module provides support for the Data Encryption Standard (DES) algorithm.
• gcry_dsa - This module provides support for the Digital Signature Algorithm (DSA) cryptography tool.
• gcry_idea - This module provides support for the International Data Encryption Algorithm (IDEA) cryptography tool.
• gcry_md4 - This module provides support for the MD4 checksum utility.
• gcry_md5 - This module provides support for the MD5 checksum utility.
• gcry_rfc2268 - This module provides support for the RFC2268 cryptography tool.
• gcry_rijndael - This module provides support for the Rijndael encryption algorithm cryptography tool (which is similar to DES).
• gcry_rsa - This module provides support for the RSA cryptography tool.
• gcry_seed - This module provides support for the SEED (block cypher) cryptography tool.
• gcry_serpent - This module provides support for the Serpent (a symmetric key block cipher) cryptography tool.
• gcry_sha1 - This module provides support for the SHA1 checksum utility.
• gcry_sha256 - This module provides support for the SHA256 checksum utility.
• gcry_sha512 - This module provides support for the SHA512 checksum utility.
• gcry_tiger - This module provides support for the Tiger (hash function) cryptography tool.
• gcry_twofish - This module provides support for the Twofish (a symmetric key block cipher) cryptography tool.
• gcry_whirlpool - This module provides support for the Whirlpool (hash function) cryptography tool.
• gdb - This module contains features related to the GNU Debugger (GDB).
• geli - This module provides a block device-layer disk encryption system for FreeBSD.
• gettext - This module provides language translation abilities.
• gfxmenu - This module provides the gfxmenu.
• gptsync - A GPT partition table can be synced with an MBR partition table using this module.
• gzio - This module offers Gzip I/O abilities.
• halt - This module provides the "halt" command.
• hashsum - This module provides the features needed to compute and check hash checksums.
• hdparm - GRUB can use this module to set and get ATA parameters.
• hello - This module is an "Hello World" example for making GRUB modules.
• help - This module provides the help utility.
• hexdump - This module offers hex dump capabilities.
• hfs - GRUB uses this module to gain support for the HFS filesystem.
• hfspluscomp - HFS+ compression is supported with this module.
• hfsplus - GRUB uses this module to gain support for the HFS+ filesystem.
• http - GRUB can boot systems that reside on a Network Filesystem (NFS). This means that GRUB may need some networking capabilities sometimes. The "http" module provides the Hyper Text Transfer Protocol.
• hwmatch - Blacklists and whitelists for hardware are used with this module.
• iorw - This module is used to read and write the input and output of devices..
• iso9660 - This module offers iso9660 support which is needed to read optical discs that use this filesystem.
• jfs - GRUB uses this module to gain support for the JFS filesystem.
• jpeg - GRUB can have background images (like a wallpaper). The "jpeg" module provides support for JPEG images, which GRUB can use as a background image.
• keylayouts - The keyboard layout can be changed using this module.
• keystatus - By using the keystatus module, GRUB can detect whether or not key modifiers are active (such as caps-lock, shift, ctrl, etc.).
• ldm - The LDM module offers support for the LDM partitioning layout (Microsoft's Logical Disk Manager).
• legacycfg - Backwards compatibility for various GRUB Legacy features are provided with this module.
• legacy_password_test - This module is used to test the legacy password system.
• linux16 - The "linux16" command is in this module. The command is used to load a 16-bit Linux system.
• linux - This module is just like the "linux16" module except that this is the standard "linux" command.
• loadenv - This module provides the "loadenv" command which is used to load variables from the environment block file.
• loopback - The "loopback" command comes from the "loopback" module. "loopback" provides the tools needed to create loopback devices.
• lsacpi - This module is used to list the detected ACPI devices.
• lsapm - This module lists Advanced Power Management (APM) devices. APM is the predessor to ACPI.
• lsmmap - This module displays the memory map (LiSt Memory Map).
• ls - This module provides GRUB with the "ls" command which is used to list devices or files.
• lspci - This module provides the "lspci" command which is used to list PCI devices.
• luks - Linux Unified Key Setup (LUKS) is a special disk-encryption format used by Linux systems. With this driver, GRUB can access LUKS partitions with this module.
• lvm - This module offers GRUB support for Linux's Logical Volume Manager (LVM).
• lzopio - This module provides support for reading and writing (I/O) files that are compressed with lzop. "lzop" is similar to Gzip and uses the LZO compression library.
• macbless - With this module, GRUB can "bless" a file or directory that resides on an HFS or HFS+ filesystem. To "bless" a file means to make it bootable and set various options related to startup.
• macho - Mach-O files cannot be loaded without using this module. A Mach-O file is a Mach Object file format that has replaced the "a.out" file format.
• mda_text - This driver provides text support for MDA (Monochrome Display Adapter) as opposed to VGA.
• mdraid09_be - RAID support with big-endian is given to GRUB via this module.
• mdraid09 - RAID support is given to GRUB via this module.
• mdraid1x - RAID1 support is offered with this module.
• memdisk - This module provides GRUB a way to boot old operating systems (like from floppy drives). http://www.syslinux.org/wiki/index.php/MEMDISK
• memrw - GRUB uses this module to read and write to physical memory.
• minicmd - The commands that are available in rescue mode come from this module.
• minix2_be - Support for MinixFS v2 with big-endian is provided by this module.
• minix2 - Support for MinixFS v2 without big-endian is provided by this module.
• minix3_be - Support for MinixFS v3 with big-endian is provided by this module.
• minix3 - Support for MinixFS v3 without big-endian is provided by this module.
• minix_be - Support for MinixFS v1 with big-endian is provided by this module.
• minix - General support for Minix filesystems is offered by this module.
• mmap - This module provides the needed code for memory mapping.
• morse - GRUB can provide information via Morse Code when this module is loaded.
• mpi - GRUB can support the Message Passing Interface (MPI) which is commonly seen on clusters.
• msdospart - Support for MS-DOS partitions (commonly called "MBR partitions") is provided by this module.
• multiboot2 - This module provides various functions needed to support multi-booting systems (just like the "multiboot" system). However, this module provides additional and newer features.
• multiboot - This module provides various functions needed to support multi-booting systems.
• named-colors - This module is a library that contains various color names with the RGB values for that color.
• nativedisk - This module makes GRUB use native disk drivers such as pata, ahci, usbms, ohci, uhci, and ehci.
• net - Many network drivers and functions are contained in this module. GRUB is able to boot from remote hard-drives via the network.
• newc - NewC is a special CPIO format. This module provides a way for GRUB to access such CPIO files.
• nilfs2 - This module provides support for NILFS2 (New Implementation of Log filesystem v2).
• normal - This module provides "Normal Mode" which is the opposite of "Rescue Mode".
• ntfscomp - GRUB is able to support the compression commonly used in NTFS with this module.
• ntfs - GRUB uses this module to gain support for the NTFS filesystem.
• ntldr - This module is based on the "chainloader" module and is used to boot a Windows partition. This module does not read the Volume Boot Record. This is helpful in cases when the Volume Boot Record is corrupted.
• odc - This module provides support for a special CPIO format known as "Octet-oriented cpio format".
• ohci - Open Host Controller Interface (OHCI) is a hardware standard commonly used by FireWire devices.
• part_acorn - This module provides support for Acorn partitions and partitioning tables.
• part_amiga - This module provides support for Amiga partitions and partitioning tables.
• part_apple - This module provides support for Apple partitions and partitioning tables.
• part_bsd - This module provides support for BSD partitions and partitioning tables.
• part_dfly - This module provides support for DFLY partitions and partitioning tables.
• part_dvh - This module provides support for DVH partitions and partitioning tables.
• part_gpt - This module provides support for GPT (GUID Partition Table) partitions and partitioning tables.
• part_msdos - This module provides support for MS-DOS (MBR) partitions and partitioning tables.
• part_plan - This module provides support for Plan9 partitions and partitioning tables.
• part_sun - This module provides support for Sun partitions and partitioning tables.
• part_sunpc - This module provides support for SunPC partitions and partitioning tables.
• parttool - This module provides the "parttool" command.
• password - This module provides the "password" command.
• pata - Support for the Parallel ATA (PATA) disk interface is provided by this module.
• pbkdf2 - This module provides the PBKDF2 (Password-Based Key Derivation Function 2) cryptography tool.
• pcidump - This module provides information on the detected PCI devices.
• pci - This module provides support for Peripheral Component Interconnect (PCI) computer buses.
• plan9 - This module is needed by GRUB to load Plan9 kernels.
• play - This module provides the "play" command which is used to play sound via the BIOS speaker.
• png - PNG files can be used as the background image when this module is loaded.
• probe - This module is used to probe for device information.
• procfs - This module provides support for ProcFS.
• progress - This module provides a progress bar.
• pxechain - This module supports PXE chainloading.
• pxe - GRUB uses this module to gain support for Preboot eXecution Environment (PXE). This is used to boot an operating system independently of local storage units.
• raid5rec - This module provides RAID5 support.
• raid6rec - This module provides RAID6 support.
• read - This module provides the "read" command.
• reboot - This module provides the "reboot" command.
• regexp - Regular Expressions (REGEX wildcards) are supported via this module.
• reiserfs - This module provides support for the Reiser Filesystem.
• romfs - This module provides RomFS support.
• scsi - This module provides support for the SCSI (Small Computer System Interface) hardware protocols and standards.
• sendkey - This module provides the "sendkey" command which is used to send emulated key-presses to GRUB.
• serial - This module provides support for serial devices.
• setjmp - This module is a library that provides support for non-local jumps. This is needed to manage errors and interrupts.
• setpci - This module is used to configure PCI devices.
• sfs - Support for the Smart Filesystem (SFS) is offered by this module. SFS is a journaling filesystem used by Amiga systems.
• sleep - The "sleep" command is provided by this module. The "sleep" command is just like the one in BASH; execution will wait/pause for the specified time.
• sleep_test - This module is used to test for proper "sleep" support.
• spkmodem - This module is a generic speaker driver for GRUB. Enabling this feature can slow down the booting process.
• spkmodem-recv - This module decodes spkmodem signals.
• squash4 - GRUB can access Squash Filesystem with this module. SquashFS is a read-only filesystem that is compressed.
• syslinuxcfg - GRUB can support SysLinux configuration files with this module.
• tar - Support for Tar files is offered with this module.
• terminal - This module provides support for terminals.
• terminfo - GRUB can read terminfo entries via this module.
• testload - GRUB can load a file multiple ways to test for errors.
• test - This module provides the "test" command which is used to evaluate an expression.
• testspeed - GRUB's fle reading speed can be measured with this module.
• tftp - Trivial File Transfer Protocol (TFTP) provides GRUB a way to get files needed for booting from another system. This also provides a way to support diskless booting.
• tga - This module offers support for the Tandy Graphics Adapter (TGA) which is a technology similar to VGA.
• time - This module provides the "time" command which prints the current time.
• trig - This module provides trigonometric functions to GRUB.
• tr - The "tr" command is provided by this module. This is the same "tr" command as seen in BASH and other shells.
• truecrypt - Truecrypted MBR partitions require that this module be loaded so that GRUB can boot such partitions. TrueCrypt is an on-the-fly-encryption (OTFE) utility for files or partitions.
• true - This module provides the boolean commands "true" and "false".
• udf - The "udf" module provides support for the Universal Disk Format (UDF).
• ufs1_be - Support for the Unix Filesystem v1 with big-endian is provided with this module.
• ufs1 - Support for the Unix Filesystem v1 is provided with this module.
• ufs2 - Support for the Unix Filesystem v2 is provided with this module.
• uhci - This module provides support for the Universal Host Controller Interface (UHCI).
• usb_keyboard - USB keyboards are supported with this module.
• usb - USB devices in general are supported with the "usb" module.
• usbms - USB mice are supported by this module that offers features needed for USB data streams.
• usbtest - USB support is tested with this module.
• vbe - VESA BIOS Extensions (VBE) is a specific VESA standard that this module supports.
• verify - File signatures can be verified using the "verify" module.
• vga - This module provides VGA support.
• vga_text - This module provides the text-only (VGA) mode.
• video_bochs - This module provides the Bochs video driver.
• video_cirrus - This module provides the Cirrus video driver.
• video_colors - Many functions related to color come from this module.
• video_fb - This module is for the video framebuffer.
• videoinfo - Various information concerning the graphics can be displayed using the tools that are part of the "videoinfo" module.
• video - This provides code needed for various video modes.
• videotest - The video settings can be tested using this module.
• xfs - GRUB uses this module to gain support for the XFS filesystem.
• xnu - This module provides support for XNU kernels (like OS X).
• xnu_uuid - This module converts the 64-bit UUIDs to the 128-bit UUIDs used by Xnu kernels.
• xnu_uuid_test - This module is used to ensure that two 128-bit UUIDs match.
• xzio - This module provides read and write support for xz-compressed files.
• zfscrypt - Encryption tools for the ZFS filesystem are in this module.
• zfsinfo - This module displays various information about a ZFS filesystem/partition.
• zfs - GRUB uses this module to gain support for the ZFS filesystem.

Many other modules exist, but these are some of the most common ones.

Further Reading

• Linux Bootloaders - https://dcjtech.info/topic/linux-bootloaders/
• GRUB and a Little Dash of BURG - https://dcjtech.info/topic/grub-and-a-little-dash-of-burg/
• Grub Commands - https://dcjtech.info/topic/grub-commands/