x86 memory access segmentation fault

Question

I am learning x86 assembly out of curiosity. I\'m currently using a Linux based OS with the NASM assembler. I am having a difficult time understanding why

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Answer 1

You don't have unrestricted RAM. Furthermore, you don't have unrestricted access to the part of your address space which is backed by RAM. Code pages are mapped read-only. And as a ring-3 program, you can't change that yourself.