Diffstat (limited to 'doc')
6 files changed, 68 insertions, 57 deletions
diff --git a/doc/comboot.txt b/doc/comboot.txt
index f39d7243..4b4b8803 100644
@@ -426,8 +426,12 @@ AX=000Ah [2.00] Get Derivative-Specific Information
Output: AL 31h (SYSLINUX), 34h (EXTLINUX)
DL drive number
CL sector size as a power of 2 (9 = 512 bytes) [3.35]
+ CH mode [3.73]
+ 1 = CBIOS mode
+ 2 = EBIOS mode
ES:BX pointer to partition table entry (if DL >= 80h)
FS:SI pointer to initial ES:DI value [3.53]
+ GS:DI pointer to partition offset (QWORD) [4.00]
Note: This function was broken in EXTLINUX 3.00-3.02.
@@ -448,6 +452,7 @@ AX=000Ah [2.00] Get Derivative-Specific Information
ECX Local IP number (network byte order) [3.85]
ES:BX pointer to PXENV+ or !PXE structure
FS:SI pointer to original stack with invocation record
+ GS:DI pointer to network information [4.00]
Note: DX notes the API version detected by PXELINUX,
which may be more conservative than the actual version
@@ -481,6 +486,13 @@ AX=000Ah [2.00] Get Derivative-Specific Information
[fs:si+44] PXE return IP <- t.o.s. when PXELINUX invoked
[fs:si+46] PXE return CS
+ GS:DI points to a structure of the following form:
+ [gs:di+0] 4 - IPv4
+ [gs:di+4] My IP
+ [gs:di+8] Boot server IP
+ [gs:di+12] Gateway IP
+ [gs:di+16] Netmask
Input: AX 000Ah
@@ -493,6 +505,7 @@ AX=000Ah [2.00] Get Derivative-Specific Information
2 = Hybrid (hard disk), EBIOS mode
ES:BX pointer to El Torito spec packet
FS:SI pointer to initial ES:DI value [3.53]
+ GS:DI pointer to partition offset (QWORD) [4.00]
Note: Some very broken El Torito implementations do
not provide the spec packet information. If so, ES:BX
@@ -500,10 +513,6 @@ AX=000Ah [2.00] Get Derivative-Specific Information
AX=4B01h to obtain the spec packet directly from the
BIOS if necessary.
- This call gives information specific to a particular Syslinux
- derivative. The value returned in AL is the same as is
- returned in DL by INT 22h AX=0001h.
AX=000Bh [2.00] Get Serial Console Configuration
@@ -824,8 +833,8 @@ AX=0018h [3.30] Query custom font
AX=0019h [3.50] Read disk [SYSLINUX, ISOLINUX, EXTLINUX]
Input: AX 0019h
- EDX Sector number
- ESI Reserved - MUST BE ZERO
+ EDX Sector number (LSW)
+ ESI Sector number (MSW) [4.00]
EDI Reserved - MUST BE ZERO
CX Sector count
ES:BX Buffer address
diff --git a/doc/extlinux.txt b/doc/extlinux.txt
index 53f9f483..6974a517 100644
@@ -97,9 +97,9 @@ preferred way to boot is:
- Install the MBR on *each disk*, and mark the RAID-1 partition
-- Run "extlinux -i /boot" to install extlinux. This will install it on
- all the drives in the RAID-1 set, which means you can boot any
- combination of drives in any order.
+- Run "extlinux --raid --install /boot" to install extlinux. This
+ will install it on all the drives in the RAID-1 set, which means
+ you can boot any combination of drives in any order.
diff --git a/doc/gpt.txt b/doc/gpt.txt
index 14c1ee8e..09099320 100644
@@ -1,13 +1,10 @@
GPT boot protocol
-There is no official MBR-to-partition handover protocol defined for
-booting from disks partitioned using GPT partition tables with
-BIOS-style firmware. This is because the GPT partition format comes
-from the EFI spec, which thinks the universe is all going to be EFI.
+There are two ways to boot a GPT-formatted disk on a BIOS system.
+Hybrid booting, and the new GPT-only booting protocol originally
+proposed by the author, and later adopted by the T13 committee in
+slightly modified form.
-There are thus two alternatives: hybrid booting, and defining a new
*** Hybrid booting ***
@@ -29,31 +26,16 @@ GPT disk with BIOS firmware.
*** New protocol ***
-This defines an alternative (experimental) booting protocol for GPT
-partitions with BIOS firmware. It maintains backwards compatibility
-to the extent possible. It is implemented by the file mbr/gptmbr.bin.
+This defines the T13-approved protocol for GPT partitions with BIOS
+firmware. It maintains backwards compatibility to the extent
+possible. It is implemented by the file mbr/gptmbr.bin.
- -> The PMBR
+The (P)MBR format is the normal PMBR specified in the UEFI
+documentation, with the first 440 bytes used for the boot code. The
+partition to be booted is marked by setting bit 2 in the GPT Partition
+Entry Attributes field (offset 48); this bit is reserved by the UEFI
+Forum for "Legacy BIOS Bootable".
-The PMBR (the first 512-byte sector of the disk) is divided up as
- Offset Size Contents
- 0 424 PMBR boot code
- 424 16 GUID of the boot partition
- 440 4 MBR-compatible disk ID
- 444 2 Magic number: 1D 9A
- 446 16 PMBR protective entry
- 462 48 PMBR null entries
- 510 2 Boot signature: 55 AA
-To change the bootable partition, verify that the magic number is
-present (to avoid corrupting software not compatible with this
-specification) and enter the GUID of the boot partition at offset
-424. It might be wise to verify that the data already there is a
-valid partition GUID already, or at least warn the user if that is not
-> The handover protocol
@@ -66,11 +48,12 @@ form:
0 1 0x80 (this is a bootable partition)
1 3 CHS of partition (using INT 13h geometry)
- 4 1 0xEE (partition type: EFI data partition)
+ 4 1 0xED (partition type: synthetic)
5 3 CHS of partition end
8 4 Partition start LBA
12 4 Partition end LBA
- 16 varies GPT partition entry
+ 16 4 Length of the GPT entry
+ 20 varies GPT partition entry
The CHS information is optional; gptmbr.bin currently does *NOT*
calculate them, and just leaves them as zero.
@@ -80,9 +63,7 @@ partition entry), except that the information is provided
synthetically. The MBR-compatible fields are directly usable if they
are < 2 TB, otherwise these fields should contain 0xFFFFFFFF and the
OS will need to understand the GPT partition entry which follows the
-MBR one. The "!GPT" magic number in EAX and the 0xEE partition type
+MBR one. The "!GPT" magic number in EAX and the 0xED partition type
also informs the OS that the GPT partition information is present.
-Currently, this is compatible with Syslinux as long as the Syslinux
-partition is < 2 TB; this probably will be improved in a future
+Syslinux 4.00 and later fully implements this protocol.
diff --git a/doc/memdisk.txt b/doc/memdisk.txt
index c7244abc..fecf2dcb 100644
@@ -139,6 +139,7 @@ h) Some systems without a floppy drive have been known to have
doesn't work, you can use the option:
nopass Hide all real drives of the same type (floppy or hard disk)
+ nopassany Hide all real drives (floppy and hard disk)
Some interesting things to note:
@@ -190,13 +191,14 @@ The MEMDISK info structure currently contains:
[ES:DI+2] byte MEMDISK minor version
[ES:DI+3] byte MEMDISK major version
[ES:DI+4] dword Pointer to MEMDISK data in high memory
- [ES:DI+8] dword Size of MEMDISK data in 512-byte sectors
+ [ES:DI+8] dword Size of MEMDISK data in sectors
[ES:DI+12] 16:16 Far pointer to command line
[ES:DI+16] 16:16 Old INT 13h pointer
[ES:DI+20] 16:16 Old INT 15h pointer
[ES:DI+24] word Amount of DOS memory before MEMDISK loaded
[ES:DI+26] byte Boot loader ID
- [ES:DI+27] byte Currently unused
+ [ES:DI+27] byte Sector size as a power of 2
+ (If zero, assume 512-byte sectors)
[ES:DI+28] word If nonzero, offset (vs ES) to installed DPT
This pointer+16 contains the original INT 1Eh
diff --git a/doc/menu.txt b/doc/menu.txt
index c912c1df..e2dd1e1c 100644
@@ -309,7 +309,12 @@ MENU NOSAVE
On the other hand, it handles changes in the configuration
- The MENU SAVE information can be cleared with
+ NOTE: In software RAID-1 setups MENU SAVE only stores the
+ default label on the actual boot disk. This may lead to
+ inconsistent reads from the array, or unexpectedly change the
+ default label after array resynchronization or disk failure.
+ The MENU SAVE information can be fully cleared with
"extlinux --reset-adv <bootdir>".
A MENU SAVE or MENU NOSAVE at the top of a (sub)menu affects
@@ -492,16 +497,23 @@ MENU VSHIFT 0
screen (25 for text mode, 28 for VESA graphics mode.)
-F1 textfile background
+F1 textfile [background]
-F12 textfile background
+F12 textfile [background]
Displays full-screen help (also available at the command line.)
The same control code sequences as in the command line
interface are supported, although some are ignored.
- Additionally, a second argument allows a different background
- image (see MENU BACKGROUND for supported formats) to be displayed.
+ Additionally, a optional second argument allows a different
+ background image (see MENU BACKGROUND for supported formats)
+ to be displayed.
+MENU HELP textfile [background]
+ Creates a menu entry which, when selected, displays
+ full-screen help in the same way as the F-key help.
The menu system honours the TIMEOUT command; if TIMEOUT is specified
diff --git a/doc/syslinux.txt b/doc/syslinux.txt
index 76cae245..51d1332c 100644
@@ -163,11 +163,10 @@ IPAPPEND flag_val [PXELINUX only]
... based on the input from the DHCP/BOOTP or PXE boot server.
- THE USE OF THIS OPTION IS NOT RECOMMENDED. If you have to use
- it, it is probably an indication that your network configuration
- is broken. Using just "ip=dhcp" on the kernel command line
- is a preferrable option, or, better yet, run dhcpcd/dhclient,
- from an initrd if necessary.
+ NOTE: The use of this option is no substitute for running a
+ DHCP client in the booted system. Without regular renewals,
+ the lease acquired by the PXE BIOS will expire, making the
+ IP address available for reuse by the DHCP server.
2: indicates that an option of the following format
should be generated and added to the kernel command line:
@@ -180,6 +179,14 @@ IPAPPEND flag_val [PXELINUX only]
This allows an initrd program to determine from which
interface the system booted.
+ 4: indicates that an option of the following format
+ should be generated and added to the kernel command line:
+ SYSUUID=<system uuid>
+ ... in lower case hexadecimal in the format normally used for
+ UUIDs (same as for the configuration file; see pxelinux.txt.)