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18 lines
674 B
Markdown
18 lines
674 B
Markdown
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This is very exciting, we're going to create our own boot sector!
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When the computer boots, the BIOS doesn't know how to load the OS, so it
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delegates that task to the boot sector. Thus, the boot sector must be
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placed in a known, standard location. That location is the first sector
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of the disk (cylinder 0, head 0, sector 0) and it takes 512 bytes.
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To make sure that the "disk is bootable", the BIOS checks that bytes
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511 and 512 of the alleged boot sector are bytes `0xAA55`.
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This is the simplest boot sector ever:
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```asm
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e9 fd ff 00 00 00 00 00 00 00 00 00 00 00 00 00
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00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
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00 00 00 00 00 00 00 00 00 00 00 00 00 00 55 aa
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```
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