June 23, 2010 |
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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.
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| Table 19 — Section Entry |
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Offset | Type |
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00h | Byte | 88h - Header ID indicates a bootable image is present. 00h indicates that a | |
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| image is present | |
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01h | Byte | Boot media type. The boot image shall fall into one of three categories: Floppy, Hard Drive, | |
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| or None. |
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| ID | Description |
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| 0 | No Emulation |
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| 1 | 1.2MB diskette |
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| 2 | 1.44MB diskette |
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| 3 | 2.88MB diskette |
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| 4 | Hard Drive |
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| Reserved | |
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Word | Load Segment. This shall be the segment address where the first emulated sector of data | ||
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| is loaded into system memory. If this field cleared to zero, the default value of 07C0h shall | |
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| be used. For flat memory model architectures (such as Motorola), this is the memory | |
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| address divided by 10h. | |
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04h | Byte | System type. This shall be a copy of byte 5 (system type) from the partition table found in | |
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| the boot image. | |
05h | Byte | Reserved |
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Word | Sector Count. This shall be the number of emulated sectors the system shall transfer from | ||
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| the CD to the Load Segment address in system memory during the boot process. This field | |
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| will normally be set to 01h for 80x86 systems that are booting a floppy or hard drive image. | |
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| For No Emulation Booting, this field could potentially ask for 32MB of data to be loaded from | |
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| the CD or DVD before jumping to the boot address. | |
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DWord | Load Block. This shall be the absolute start sector on the CD or DVD of the image to be | ||
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| used in the emulation. | |
0Ch | Byte | Selection Criteria. The selection criteria determines the format for the selection criteria. | |
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| The following formats are currently assigned: | |
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| Type | Description |
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| 00h | No selection criteria |
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| 01h | Language and version information (IBM format) |
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| Reserved | |
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Byte | Selection Criteria | ||
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Working Draft Enhanced Disk Drive - 4 | 27 |