Real Mode ———
- less than 1MB of RAM
- no virtual memory
- no hardware memory protection
Starts in 16-bit Real Mode, for compatibility reasons
Zero the data segment registers first thing, since their content is unknown.
The BIOS transfers the first 512 bytes of data from the device into 0x7c00. The last two bytes need to be 0x55 and then 0xAA to be considered a valid bootsector.
- IA-64 refers to Itanium, not the Intel 64-bit x86 architecture.
- x86 is little endian