ELF Hello World Tutorial
.strtab Updated 2025-07-16Holds strings for the symbol table.
This section has
sh_type == SHT_STRTAB.It is pointed to by outputs:
sh_link == 5 of the .symtab section.readelf -x .strtab hello_world.oHex dump of section '.strtab':
0x00000000 0068656c 6c6f5f77 6f726c64 2e61736d .hello_world.asm
0x00000010 0068656c 6c6f5f77 6f726c64 0068656c .hello_world.hel
0x00000020 6c6f5f77 6f726c64 5f6c656e 005f7374 lo_world_len._st
0x00000030 61727400 art.This implies that it is an ELF level limitation that global variables cannot contain NUL characters.
ELF Hello World Tutorial
STT_NOTYPE Updated 2025-07-16Then come the most important symbols:
Num: Value Size Type Bind Vis Ndx Name
4: 0000000000000000 0 NOTYPE LOCAL DEFAULT 1 hello_world
5: 000000000000000d 0 NOTYPE LOCAL DEFAULT ABS hello_world_len
6: 0000000000000000 0 NOTYPE GLOBAL DEFAULT 2 _start ELF Hello World Tutorial
.text section Updated 2025-07-16Now that we've done one section manually, let's graduate and use the
readelf -S of the other sections: [Nr] Name Type Address Offset
Size EntSize Flags Link Info Align
[ 2] .text PROGBITS 0000000000000000 00000210
0000000000000027 0000000000000000 AX 0 0 16.text is executable but not writable: if we try to write to it Linux segfaults. Let's see if we really have some code there:objdump -d hello_world.ohello_world.o: file format elf64-x86-64
Disassembly of section .text:
0000000000000000 <_start>:
0: b8 01 00 00 00 mov $0x1,%eax
5: bf 01 00 00 00 mov $0x1,%edi
a: 48 be 00 00 00 00 00 movabs $0x0,%rsi
11: 00 00 00
14: ba 0d 00 00 00 mov $0xd,%edx
19: 0f 05 syscall
1b: b8 3c 00 00 00 mov $0x3c,%eax
20: bf 00 00 00 00 mov $0x0,%edi
25: 0f 05 syscallIf we grep
b8 01 00 00 on the hd, we see that this only occurs at 00000210, which is what the section says. And the Size is 27, which matches as well. So we must be talking about the right section.The most interesting part is line to pass the address of the string to the system call. Currently, the This modification is possible because of the data of the
a which does:movabs $0x0,%rsi0x0 is just a placeholder. After linking happens, it will be modified to contain:4000ba: 48 be d8 00 60 00 00 movabs $0x6000d8,%rsi.rela.text section. Elliptic geometry Updated 2025-07-16
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Emission theory (vision) Updated 2025-07-16
It is so mind blowing that people believed in this theory. How can you think that, when you turn on a lamp and then you see? Obviously, the lamp must be emitting something!!!
Then comes along this epic 2002 paper: pubmed.ncbi.nlm.nih.gov/12094435/ "Fundamentally misunderstanding visual perception. Adults' belief in visual emissions". TODO review methods...
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Aprender em Comunidade by Prof. José Pacheco
. Source. In Portuguese. Title translation: "Learn in community". Essential nutrient Updated 2025-07-16
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Étienne-Louis Malus Updated 2025-07-16
Europe Updated 2025-07-16
For the most part, a great pseudo-country to live in with lots of cultural diversity, art and safety.
However, Europe is in economic decline after all its Jewish and German geniuses fled in/after World War II and due to having more than one natural language is bad for the world.
Ciro Santilli moved to Europe in 2010.
EverybodyWiki Updated 2025-07-16
Appears to be a Wikipedia clone but with much lower/no notability requirements guidelines, which overcomes one of Wikipedia's main issues: deletionism.
They do have the interesting idea of importing deleted Wikipedia pages as a source of content, which leads to some epic "most viewed pages" such as en.everybodywiki.com/List_of_erotic_and_sex_workers_with_unnatural_death which currently reads:
Stop Being Pervs, Go Watch Lichfaop/Faoplich Instead and you can also visit MR Info 24 for more details.
We can for example see Ciro Santilli's deleted entry PsiQuantum at: en.everybodywiki.com/PsiQuantum, Wikipedia deletion page: en.wikipedia.org/wiki/Wikipedia:Articles_for_deletion/PsiQuantum. Their attribution is atrocious however, e.g. it does not seem possible to find any mention of "Ciro Santilli" on the edit history, which just points to the delete article which is not visible anymore. They could really get into trouble for this one day.
Their main use case, as suggested by the website itself, if for people/brands to create pages about themselves.
There are unlisted articles, also show them or only show them.