June 23, 2010

T13/2132-D Revision 3

7.3.6 Section Entry

Section entries shall follow Section Headers. The Section Entry identifies a single boot image. This entry shall be the same as the Initial/Default entry with one exception: the reserved bytes at the send of the entry contain selection criteria. The Section Header ID string identifies the section type, and the section type determines how the selection criteria bytes are interpreted. An example would be a section titled "Languages", the 19 bytes could then be language identifiers. If the system language were set to a language, such as French or Japanese, the system may then boot using an image designed for that language. Table 19 describes a Section Entry.

If the 19 bytes provided for selection criteria are insufficient, Section Entry Extensions may be used. There are a possible 30 bytes of information available per extension, see 7.2.6 for more information on Section Entry Extensions.

 

 

 

Table 19 — Section Entry

 

 

 

 

Offset

Type

 

Description

00h

Byte

88h - Header ID indicates a bootable image is present. 00h indicates that a non-bootable

 

 

image is present

 

 

 

01h

Byte

Boot media type. The boot image shall fall into one of three categories: Floppy, Hard Drive,

 

 

or None.

 

 

 

ID

Description

 

 

0

No Emulation

 

 

1

1.2MB diskette

 

 

2

1.44MB diskette

 

 

3

2.88MB diskette

 

 

4

Hard Drive

 

 

05h-FFh

Reserved

 

 

 

02-03h

Word

Load Segment. This shall be the segment address where the first emulated sector of data

 

 

is loaded into system memory. If this field cleared to zero, the default value of 07C0h shall

 

 

be used. For flat memory model architectures (such as Motorola), this is the memory

 

 

address divided by 10h.

 

 

 

04h

Byte

System type. This shall be a copy of byte 5 (system type) from the partition table found in

 

 

the boot image.

05h

Byte

Reserved

 

 

 

 

06h-07h

Word

Sector Count. This shall be the number of emulated sectors the system shall transfer from

 

 

the CD to the Load Segment address in system memory during the boot process. This field

 

 

will normally be set to 01h for 80x86 systems that are booting a floppy or hard drive image.

 

 

For No Emulation Booting, this field could potentially ask for 32MB of data to be loaded from

 

 

the CD or DVD before jumping to the boot address.

 

 

 

08h-0Bh

DWord

Load Block. This shall be the absolute start sector on the CD or DVD of the image to be

 

 

used in the emulation.

0Ch

Byte

Selection Criteria. The selection criteria determines the format for the selection criteria.

 

 

The following formats are currently assigned:

 

 

Type

Description

 

 

00h

No selection criteria

 

 

01h

Language and version information (IBM format)

 

 

02h-FFh

Reserved

 

 

 

0Dh-1Fh

Byte

Selection Criteria

 

 

 

 

Working Draft Enhanced Disk Drive - 4 (EDD-4)

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Western Digital manual June 23 T13/2132-D Revision Section Entry, Type Description