Ciro Santilli @cirosantilli 40

Ciro Santilli 40 Updated 2025-07-16

sudo apt install hipcc
git clone https://github.com/ROCm/HIP-Examples
cd HIP-Examples/HIP-Examples-Applications/HelloWorld
make

TODO fails with:

/bin/hipcc -g   -c -o HelloWorld.o HelloWorld.cpp
clang: error: cannot find ROCm device library for gfx1103; provide its path via '--rocm-path' or '--rocm-device-lib-path', or pass '-nogpulib' to build without ROCm device library
make: *** [<builtin>: HelloWorld.o] Error 1

Generic Ubuntu install bibliograpy:

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Amazon EC2 HOWTO by

Ciro Santilli 40 Updated 2025-07-16

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Amazon Machine Image by

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qiskit/initialize.py by

Ciro Santilli 40 Updated 2025-07-16

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In this example we will initialize a quantum circuit with a single CNOT gate and see the output values.

By default, Qiskit initializes every qubit to 0 as shown in the qiskit/hello.py. But we can also initialize to arbitrary values as would be done when computing the output for various different inputs.

Output:

     ┌──────────────────────┐
q_0: ┤0                     ├──■──
     │  Initialize(1,0,0,0) │┌─┴─┐
q_1: ┤1                     ├┤ X ├
     └──────────────────────┘└───┘
c: 2/═════════════════════════════

init: [1, 0, 0, 0]
probs: [1. 0. 0. 0.]

init: [0, 1, 0, 0]
probs: [0. 0. 0. 1.]

init: [0, 0, 1, 0]
probs: [0. 0. 1. 0.]

init: [0, 0, 0, 1]
probs: [0. 1. 0. 0.]

     ┌──────────────────────────────────┐
q_0: ┤0                                 ├──■──
     │  Initialize(0.70711,0,0,0.70711) │┌─┴─┐
q_1: ┤1                                 ├┤ X ├
     └──────────────────────────────────┘└───┘
c: 2/═════════════════════════════════════════

init: [0.7071067811865475, 0, 0, 0.7071067811865475]
probs: [0.5 0.5 0.  0. ]

which we should all be able to understand intuitively given our understanding of the CNOT gate and quantum state vectors.

quantumcomputing.stackexchange.com/questions/13202/qiskit-initializing-n-qubits-with-binary-values-0s-and-1s describes how to initialize circuits qubits only with binary 0 or 1 to avoid dealing with the exponential number of elements of the quantum state vector.

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RDFlib by

Ciro Santilli 40 Updated 2025-07-16

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Hello world: stackoverflow.com/questions/16829351/is-there-a-hello-world-example-for-sparql-with-rdflib

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Ubuntu 23.10 by

Ciro Santilli 40 Updated 2025-07-16

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Brazilian creamy cornmeal cake by

Ciro Santilli 40 Updated 2025-07-16

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www.tudogostoso.com.br/receita/3468-bolo-de-fuba-cremoso.html

December 2023:
- replacements:
  - used 3 soy milk + 1 milk cup instead of 4 milk
  - salted butter rather than margarine
  - 1 cup of sugar rather than 3, because OMG 3 cups of sugar for 4 cups of milk is insane, Brazil!
Turned out very good.

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Science fiction author by

Ciro Santilli 40 Updated 2025-07-16

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Knol by

Ciro Santilli 40 Updated 2025-07-16

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Very similar to OurBigBook.com!

People who worked on it:

Udi Manber: project lead
www.wired.com/2008/07/google-knol/ mentions various engineers. The original page had photos, including the full team photo, but these died, but are visible on the archive: web.archive.org/web/20151220002650/http://www.wired.com/2008/07/google-knol/.
Ben McMahan: "Developed, launched, and maintained Knol", mentioned at:
- x.com/benjmcmahan
- www.benjaminmcmahan.com/ has email ben.j.mcmahan@gmail.com
Michael McNally (2007-2009), "project's technical lead": mentioned at: www.wired.com/2008/07/google-knol/,
github.com/xiangtiandai Xiangtian Dai xiangtian.dai@google.com
Mohsin Ahmed: can't find any online profiles

Video 1.

How to use Google Knol by Hack Learning (2011)

Source. One of the last users of the website for sure! The owner of that YouTube channel is a Mark Barnes:

Video 2.

Jimmy Wales on Google's Knol (2008)

Source.

Replying to a listener phone-in question WNYC radio, mediated by Brian Lehrer.
It was about to launch it seems, and it was not clear at the time that anyone could write content, as opposed to only selected people.

Jimmy then corrects that misinformation. He then clearly states that since there can be multiple versions of each article, including opinion pieces, like OurBigBook.com, Knol would be very different to Wikipedia, more like blogging than encyclopedia.

Video 3.

Google Knol: the future of academic journals? by Doug Belshaw (2010)

Source.

Bibliography:

Wikipedia & Knol: Why Knol Already Failed by gwern.net (2009). So there was some kind of monetary payment on the site. Interesting and sad.

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Organise the world's information by

Ciro Santilli 40 Updated 2025-07-16

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E.g. about.google/ in 2022.

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SourceForge by

Ciro Santilli 40 Updated 2025-07-16

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RIP: www.quora.com/Is-SourceForge-still-relevant-to-open-source-projects/answer/Ciro-Santilli

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Sallie (FutureAI) by

Ciro Santilli 40 Updated 2025-07-16

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Not having a manipulator claw is a major issue with this one.

But they also have a co-simulation focus, which is a bit of a win.

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Financial crisis of 2007-2008 by

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High-frequency trading by

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Video 1.

High Frequency Trading by WEED e.V. (2014)

Source.

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There are no known eukaryotes which never had mitochondria by

Ciro Santilli 40 Updated 2025-07-16

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As of 2020, there are no known eukaryotes which have never had mitochondria.

Known eukaryotes without mitochondria, which are very rare, have lost mitochondria they previously had.

Having mitochondria appears to be a requisite for being an eukaryote. This is one of the central thesis of Power, Sex, Suicide by Nick Lane (2006).

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ELF Hello World Tutorial / Generate the example by

Ciro Santilli 40 Updated 2025-07-16

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Let's break down a minimal runnable Linux x86-64 example:

hello_world.asm

section .data
    hello_world db "Hello world!", 10
    hello_world_len  equ $ - hello_world
section .text
    global _start
    _start:
        mov rax, 1
        mov rdi, 1
        mov rsi, hello_world
        mov rdx, hello_world_len
        syscall
        mov rax, 60
        mov rdi, 0
        syscall

Compiled with:

nasm -w+all -f elf64 -o 'hello_world.o' 'hello_world.asm'
ld -o 'hello_world.out' 'hello_world.o'

TODO: use a minimal linker script with -T to be more precise and minimal.

Versions:

NASM 2.10.09
Binutils version 2.24 (contains ld)
Ubuntu 14.04

We don't use a C program as that would complicate the analysis, that will be level 2 :-)

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ELF Hello World Tutorial / ELF header by

Ciro Santilli 40 Updated 2025-07-16

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Running:

readelf -h hello_world.o

outputs:

Magic:   7f 45 4c 46 02 01 01 00 00 00 00 00 00 00 00 00
Class:                             ELF64
Data:                              2's complement, little endian
Version:                           1 (current)
OS/ABI:                            UNIX - System V
ABI Version:                       0
Type:                              REL (Relocatable file)
Machine:                           Advanced Micro Devices X86-64
Version:                           0x1
Entry point address:               0x0
Start of program headers:          0 (bytes into file)
Start of section headers:          64 (bytes into file)
Flags:                             0x0
Size of this header:               64 (bytes)
Size of program headers:           0 (bytes)
Number of program headers:         0
Size of section headers:           64 (bytes)
Number of section headers:         7
Section header string table index: 3

Running:

readelf -h hello_world.out

outputs:

Magic:   7f 45 4c 46 02 01 01 00 00 00 00 00 00 00 00 00
Class:                             ELF64
Data:                              2's complement, little endian
Version:                           1 (current)
OS/ABI:                            UNIX - System V
ABI Version:                       0
Type:                              EXEC (Executable file)
Machine:                           Advanced Micro Devices X86-64
Version:                           0x1
Entry point address:               0x4000b0
Start of program headers:          64 (bytes into file)
Start of section headers:          272 (bytes into file)
Flags:                             0x0
Size of this header:               64 (bytes)
Size of program headers:           56 (bytes)
Number of program headers:         2
Size of section headers:           64 (bytes)
Number of section headers:         6
Section header string table index: 3

Bytes in the object file:

00000000  7f 45 4c 46 02 01 01 00  00 00 00 00 00 00 00 00  |.ELF............|
00000010  01 00 3e 00 01 00 00 00  00 00 00 00 00 00 00 00  |..>.............|
00000020  00 00 00 00 00 00 00 00  40 00 00 00 00 00 00 00  |........@.......|
00000030  00 00 00 00 40 00 00 00  00 00 40 00 07 00 03 00  |....@.....@.....|

Executable:

00000000  7f 45 4c 46 02 01 01 00  00 00 00 00 00 00 00 00  |.ELF............|
00000010  02 00 3e 00 01 00 00 00  b0 00 40 00 00 00 00 00  |..>.......@.....|
00000020  40 00 00 00 00 00 00 00  10 01 00 00 00 00 00 00  |@...............|
00000030  00 00 00 00 40 00 38 00  02 00 40 00 06 00 03 00  |....@.8...@.....|

Structure represented:

# define EI_NIDENT 16

typedef struct {
    unsigned char   e_ident[EI_NIDENT];
    Elf64_Half      e_type;
    Elf64_Half      e_machine;
    Elf64_Word      e_version;
    Elf64_Addr      e_entry;
    Elf64_Off       e_phoff;
    Elf64_Off       e_shoff;
    Elf64_Word      e_flags;
    Elf64_Half      e_ehsize;
    Elf64_Half      e_phentsize;
    Elf64_Half      e_phnum;
    Elf64_Half      e_shentsize;
    Elf64_Half      e_shnum;
    Elf64_Half      e_shstrndx;
} Elf64_Ehdr;

Manual breakdown:

0 0: EI_MAG = 7f 45 4c 46 = 0x7f 'E', 'L', 'F': ELF magic number
0 4: EI_CLASS = 02 = ELFCLASS64: 64 bit elf
0 5: EI_DATA = 01 = ELFDATA2LSB: little endian data
0 6: EI_VERSION = 01: format version
0 7: EI_OSABI (only in 2003 Update) = 00 = ELFOSABI_NONE: no extensions.
0 8: EI_PAD = 8x 00: reserved bytes. Must be set to 0.
1 0: e_type = 01 00 = 1 (big endian) = ET_REl: relocatable format
On the executable it is 02 00 for ET_EXEC.
Another important possibility for the executable is ET_DYN for PIE executables and shared libraries.
ET_DYN tells the Linux kernel that the code is position independent, and can loaded at a random memory location with ASLR.
This is explained further at:
- stackoverflow.com/questions/2463150/what-is-the-fpie-option-for-position-independent-executables-in-gcc-and-ld/51308031#51308031
- stackoverflow.com/questions/34519521/why-does-gcc-create-a-shared-object-instead-of-an-executable-binary-according-to/55704865#55704865
1 2: e_machine = 3e 00 = 62 = EM_X86_64: AMD64 architecture
1 4: e_version = 01 00 00 00: must be 1
1 8: e_entry = 8x 00: execution address entry point, or 0 if not applicable like for the object file since there is no entry point.
On the executable, it is b0 00 40 00 00 00 00 00. The kernel puts the RIP directly on that value when executing. It can be configured by the linker script or -e. But it will segfault if you set it too low: stackoverflow.com/questions/2187484/why-is-the-elf-execution-entry-point-virtual-address-of-the-form-0x80xxxxx-and-n
2 0: e_phoff = 8x 00: program header table offset, 0 if not present.
40 00 00 00 on the executable, i.e. it starts immediately after the ELF header.
2 8: e_shoff = 40 7x 00 = 0x40: section header table file offset, 0 if not present.
3 0: e_flags = 00 00 00 00 Arch specific. i386 docs say:
The Intel386 architecture defines no flags; so this member contains zero.
3 4: e_ehsize = 40 00: size of this elf header. TODO why this field needed? Isn't the size fixed?
3 6: e_phentsize = 00 00: size of each program header, 0 if not present.
38 00 on executable: it is 56 bytes long
3 8: e_phnum = 00 00: number of program header entries, 0 if not present.
02 00 on executable: there are 2 entries.
3 A: e_shentsize and e_shnum = 40 00 07 00: section header size and number of entries
3 E: e_shstrndx (Section Header STRing iNDeX) = 03 00: index of the .shstrtab section.