From a78864252eee3f0c881797d11ba320765eb4d8f4 Mon Sep 17 00:00:00 2001 From: Thomas Schmitt Date: Mon, 16 Mar 2015 15:03:58 +0100 Subject: [PATCH] Mentioned official UEFI 2.4 specs in description of boot sectors. --- doc/boot_sectors.txt | 11 ++++++++--- 1 file changed, 8 insertions(+), 3 deletions(-) diff --git a/doc/boot_sectors.txt b/doc/boot_sectors.txt index c9c0d33..62e8253 100644 --- a/doc/boot_sectors.txt +++ b/doc/boot_sectors.txt @@ -54,6 +54,7 @@ Sources: El Torito, Bootable CD-ROM Format Specification, Version 1.0, 1995 which refers to ECMA-119, the standard for ISO 9660 filesystems. libisofs/eltorito.[ch] by Vreixo Formoso. + http://www.uefi.org/sites/default/files/resources/2_4_Errata_B.pdf ECMA-119 prescribes that the first 32 kB of an ISO 9660 image are System Area @@ -124,7 +125,7 @@ Defined by El Torito are: 0 = "80x86" which is used for standard PCs with Intel x86 or compatible CPU 1 = "PowerPC" (possibly for IBM machines with PowerPC CPU) 2 = "Mac" (possibly for Apple computers with MC68000 or PowerPC CPU) -Further in use by GRUB2 and ISOLINUX is: +UEFI 2.4 specifies in 12.3.2.1 "ISO-9660 and El Torito": 0xef = EFI, a competitor resp. successor to PC-BIOS, possibly in use with Intel ia64 Itanium and possibly with newer Apple machines. @@ -528,6 +529,7 @@ Sources: http://mjg59.fedorapeople.org/Fedora-LiveCD.iso http://en.wikipedia.org/wiki/GUID_Partition_Table http://en.wikipedia.org/wiki/GUID + http://www.uefi.org/sites/default/files/resources/2_4_Errata_B.pdf GPT is the partition map format of EFI, a successor of PC-BIOS. @@ -535,8 +537,11 @@ Block size is always 512. GPT consists of a header block at block address 1 and a partition table near the start of the medium. This is called the primary GPT. There is a backup copy of header and table near the end of the medium. -GPT is particularly designed to co-exist with MBR. If it is present, then the -booting firmware may or may not prefer it over the MBR partition table. +GPT is particularly designed to co-exist with MBR. Officially only with a +Protective MBR which covers the whole medium (except the MBR itself) by +a single partition of type 0xee. Inofficially often with filesystem partitions +marked in both, GPT and MBR. In the latter case the booting firmware may +or may not prefer GPT over the MBR partition table. GPT can co-exist with APM if APM block size is at least 1024. In this case, the primary partition table will begin after the last APM entry block.