JCVI-syn3B Updated 2025-07-16
www.biorxiv.org/content/10.1101/2022.09.19.508583v1.fullIt is also interesting to see how they are interested in co-culture with HeLa cells, presumably to enable infectious bacterial disease studies.
CVI-syn3B strains differ from JCVI-syn3.0 by the presence of 19 additional non-essential genes that result in a more easily manipulated cell. JCVI-syn3B additionally includes a dual loxP landing pad that enables easy Cre recombinase mediated insertion of genes
At biology.indiana.edu/news-events/news/2023/lennon-minimal-cells.html (2023) they let it re-evove to it it would regain some fitness, and it did.
Jean-Luc Ponty Updated 2025-07-16
Jena SPARQL hello world Updated 2025-07-16
They have a tutorial at: jena.apache.org/tutorials/sparql.html
Once you've done the Apache Jena CLI tools setup we can query all users with Full Name (FN) "John Smith" directly fom the rdf/vcard.ttl Turtle RDF file with the rdf/vcard.rq SPARQL query:and that outputs:
sparql --data=rdf/vcard.ttl --query=rdf/vcard.rq---------------------------------
| x |
=================================
| <http://somewhere/JohnSmith/> |
--------------------------------- Jerry Sanders Updated 2025-07-16
AMD Founder Jerry Sanders Interview (2002)
Source. Source: exhibits.stanford.edu/silicongenesis/catalog/hr396zc0393. Fun to watch.- youtu.be/HqWWoaA8pIs?t=779 Newton Minow mandated UHF on all television sets in 1961, and the oscillator needed for the tuner was one of the first major non-military products from Fairchild, the 28918 (?).
- youtu.be/HqWWoaA8pIs?t=1053 Fairchild had won the first round of a Minuteman contract, but lost the second one due to poor management
Jimmy Wales Updated 2025-07-16
Joan Feynman Updated 2025-07-16
My brother, Richard: How he came to be so smart interview with Joan Feynman by Web of Stories (2019)
Source. Ah, shame to see Joan so old. Some good stories. The tiles game thing was not mentioned in Genius: Richard Feynman and Modern Physics by James Gleick (1994) I think. John Bardeen Updated 2025-07-16
The Story of John Bardeen at the University of Illinois (2010)
Source. - youtu.be/OyV8qSwGUHU?t=976 of when Bardeen demoed the transistor in class is particularly memorable
- youtu.be/OyV8qSwGUHU?t=1105 some of his golf colleagues didn't know he had won a Nobel Prize!
Join two images side-by-side Updated 2025-07-16
Join two SVG side-by-side from the command line Updated 2025-07-16
ELF Hello World Tutorial Section header table Updated 2025-07-16
Array of
Elf64_Shdr structs.Each entry contains metadata about a given section.
e_shoff of the ELF header gives the starting position, 0x40 here.So the table takes bytes from 0x40 to
0x40 + 7 + 0x40 - 1 = 0x1FF.Some section names are reserved for certain section types: www.sco.com/developers/gabi/2003-12-17/ch4.sheader.html#special_sections e.g.
.text requires a SHT_PROGBITS type and SHF_ALLOC + SHF_EXECINSTRRunning:outputs:
readelf -S hello_world.oThere are 7 section headers, starting at offset 0x40:
Section Headers:
[Nr] Name Type Address Offset
Size EntSize Flags Link Info Align
[ 0] NULL 0000000000000000 00000000
0000000000000000 0000000000000000 0 0 0
[ 1] .data PROGBITS 0000000000000000 00000200
000000000000000d 0000000000000000 WA 0 0 4
[ 2] .text PROGBITS 0000000000000000 00000210
0000000000000027 0000000000000000 AX 0 0 16
[ 3] .shstrtab STRTAB 0000000000000000 00000240
0000000000000032 0000000000000000 0 0 1
[ 4] .symtab SYMTAB 0000000000000000 00000280
00000000000000a8 0000000000000018 5 6 4
[ 5] .strtab STRTAB 0000000000000000 00000330
0000000000000034 0000000000000000 0 0 1
[ 6] .rela.text RELA 0000000000000000 00000370
0000000000000018 0000000000000018 4 2 4
Key to Flags:
W (write), A (alloc), X (execute), M (merge), S (strings), l (large)
I (info), L (link order), G (group), T (TLS), E (exclude), x (unknown)
O (extra OS processing required) o (OS specific), p (processor specific)The
struct represented by each entry is:typedef struct {
Elf64_Word sh_name;
Elf64_Word sh_type;
Elf64_Xword sh_flags;
Elf64_Addr sh_addr;
Elf64_Off sh_offset;
Elf64_Xword sh_size;
Elf64_Word sh_link;
Elf64_Word sh_info;
Elf64_Xword sh_addralign;
Elf64_Xword sh_entsize;
} Elf64_Shdr; ELF Hello World Tutorial Section vs segment Updated 2025-07-16
- section: exists before linking, in object files.Major information sections contain for the linker: is this section:
- segment: exists after linking, in the executable file.Contains information about how each segment should be loaded into memory by the OS, notably location and permissions.
ELF Hello World Tutorial Specified file formats Updated 2025-07-16
The ELF standard specifies multiple file formats:
- Object files (
.o).Intermediate step to generating executables and other formats:Source code | | Compilation | v Object file | | Linking | v ExecutableObject files exist to make compilation faster: withmake, we only have to recompile the modified source files based on timestamps.
- Executable files (no standard Linux extension).This is what the Linux kernel can actually run.
- Archive files (
.a).Libraries meant to be embedded into executables during the Linking step.
- Shared object files (
.so).Libraries meant to be loaded when the executable starts running.
- Core dumps.Such files may be generated by the Linux kernel when the program does naughty things, e.g. segfault.They exist to help debugging the program.
In this tutorial, we consider only object and executable files.
ELF Hello World Tutorial Standards Updated 2025-07-16
ELF is specified by the LSB:
The LSB basically links to other standards with minor extensions, in particular:
- Generic (both by SCO):
- System V ABI 4.1 (1997) www.sco.com/developers/devspecs/gabi41.pdf, no 64 bit, although a magic number is reserved for it. Same for core files. This is the first document you should look at when searching for information.
- System V ABI Update DRAFT 17 (2003) www.sco.com/developers/gabi/2003-12-17/contents.html, adds 64 bit. Only updates chapters 4 and 5 of the previous document: the others remain valid and are still referenced.
- Architecture specific (by the processor vendor):
A handy summary can be found at:
man elf ELF Hello World Tutorial
STT_FILE Updated 2025-07-16- 10 8:
st_name=01000000= character 1 in the.strtab, which until the following\0makeshello_world.asmThis piece of information file may be used by the linker to decide on which segment sections go: e.g. inldlinker script we write:segment_name : { file(section) }segment_name : { *(section) } - 10 13:
st_shndx= Symbol Table Section header Index =f1ff=SHN_ABS. Required forSTT_FILE. - 20 0:
st_value= 8x00: required for value forSTT_FILE - 20 8:
st_size= 8x00: no allocated size
Now from the
readelf, we interpret the others quickly. ELF Hello World Tutorial
.symtab Updated 2025-07-16Section type:
sh_type == SHT_SYMTAB.A good high level tool to disassemble that section is:which gives:
nm hello_world.o0000000000000000 T _start
0000000000000000 d hello_world
000000000000000d a hello_world_lenThis is however a high level view that omits some types of symbols and in which the symbol types . A more detailed disassembly can be obtained with:which gives:
readelf -s hello_world.oSymbol table '.symtab' contains 7 entries:
Num: Value Size Type Bind Vis Ndx Name
0: 0000000000000000 0 NOTYPE LOCAL DEFAULT UND
1: 0000000000000000 0 FILE LOCAL DEFAULT ABS hello_world.asm
2: 0000000000000000 0 SECTION LOCAL DEFAULT 1
3: 0000000000000000 0 SECTION LOCAL DEFAULT 2
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 _startThe binary format of the table is documented at www.sco.com/developers/gabi/2003-12-17/ch4.symtab.html
The data is:which gives:
readelf -x .symtab hello_world.oHex dump of section '.symtab':
0x00000000 00000000 00000000 00000000 00000000 ................
0x00000010 00000000 00000000 01000000 0400f1ff ................
0x00000020 00000000 00000000 00000000 00000000 ................
0x00000030 00000000 03000100 00000000 00000000 ................
0x00000040 00000000 00000000 00000000 03000200 ................
0x00000050 00000000 00000000 00000000 00000000 ................
0x00000060 11000000 00000100 00000000 00000000 ................
0x00000070 00000000 00000000 1d000000 0000f1ff ................
0x00000080 0d000000 00000000 00000000 00000000 ................
0x00000090 2d000000 10000200 00000000 00000000 -...............
0x000000a0 00000000 00000000 ........The entries are of type:
typedef struct {
Elf64_Word st_name;
unsigned char st_info;
unsigned char st_other;
Elf64_Half st_shndx;
Elf64_Addr st_value;
Elf64_Xword st_size;
} Elf64_Sym; Eli Benderski Updated 2025-07-16
Homepage: eli.thegreenplace.net/
Also has many great contributions on Stack Overflow: stackoverflow.com/users/8206/eli-bendersky
As of 2016, Eli worked at Google (reference). TODO before that, I had found his earlier info previously but lost it.
Eli focuses mostly on compiler toolchains.
He also has some mathematics stuff, so cute: eli.thegreenplace.net/2015/change-of-basis-in-linear-algebra/
Eligius pool Updated 2025-07-16
Created by Luke Dashjr.
The pool is named after Saint Eligius, patron of miners[ref]
Eligius also means to "choose" or "chosen" in Latin: en.wiktionary.org/wiki/Eligius, same root as "to elect" in modern English presumably.
Saint Eligius by Petrus Christus
. Source. Eligius pool is named after Saint Eligius, patron of goldsmiths and miners[ref]
Elis Regina Updated 2025-07-16
Mostly interpreter of songs written by others. But she's just too amazing, many of her interpretations are better than the original.
God, even Ciro Santilli is slightly shocked by her death, which happened before he was born, can you imagine it at the time? She was MPB's golden girl...
Atrás da Porta performed by Elis Regina
. Source. Composed by Francis Hime and Chico Buarque.Águas de março performed by Elis Regina
. Source. From the 1972 eponymous album. Composed by Antônio Carlos Jobim. Elliptic-curve Diffie-Hellman Updated 2025-07-16
The algorithm is completely analogous to Diffie-Hellman key exchange in that you efficiently raise a number to a power times and send the result over while keeping as private key.
The only difference is that a different group is used: instead of using the cyclic group, we use the elliptic curve group of an elliptic curve over a finite field.
Elliptic curves by Computerphile (2018)
Source. youtu.be/NF1pwjL9-DE?t=143 shows the continuous group well, but then fails to explain the discrete part.Variant of Diffie-Hellman key exchange based on elliptic curve cryptography.
Josephson effect Updated 2025-07-16
Discrete quantum effect observed in superconductors with a small insulating layer, a device known as a Josephson junction.
To understand the behaviour effect, it is important to look at the Josephson equations consider the following Josephson effect regimes separately:
Bibliography:
- www.youtube.com/watch?v=cnZ6exn2CkE "Superconductivity: Professor Brian Josephson". Several random excerpts from Cambridge people talking about the Josephson effect
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