x86 Paging Tutorial Play with physical addresses in Linux Updated 2025-07-11 +Created 1970-01-01
Convert virtual addresses to physical from user space with
/proc/<pid>/pagemap
and from kernel space with virt_to_phys
:Dump all page tables from userspace with
/proc/<pid>/maps
and /proc/<pid>/pagemap
:Read and write physical addresses from userspace with
/dev/mem
:The term "visible life" refers to multicellular from before people knew there was life in the proterozoic.
How ASML Won Lithography by Asianometry (2021)
Source. First there were dominant Elmer and Geophysics Corporation of America dominating the market.
Then a Japanese government project managed to make Nikon and Canon Inc. catch up, and in 1989, when Ciro Santilli was born, they had 70% of the market.
youtu.be/SB8qIO6Ti_M?t=240 In 1995, ASML had reached 25% market share. Then it managed the folloging faster than the others:
- TwinScan, reached 50% market share in 2002
- Immersion litography
- EUV. There was a big split between EUV vs particle beams, and ASML bet on EUV and EUV won.
- youtu.be/SB8qIO6Ti_M?t=459 they have an insane number of software engineers working on software for the machine, which is insanely complex. They are big on UML.
- youtu.be/SB8qIO6Ti_M?t=634 they use ZEISS optics, don't develop their own. More precisely, the majority owned subsidiary Carl Zeiss SMT.
- youtu.be/SB8qIO6Ti_M?t=703 IMEC collaborations worked well. Notably the ASML/Philips/ZEISS trinity
- www.youtube.com/watch?v=XLNsYecX_2Q ASML: Chip making goes vacuum with EUV (2009) Self promotional video, some good shots of their buildings.
Cool data embedded in the Bitcoin blockchain Len Sassaman tribute Updated 2025-07-11 +Created 1970-01-01
Tribute to computer security researcher Len Sassaman, who killed himself on 2011-07-03, starting with an ASCII art portrait followed by text.
Because it comes so early in the blockchain, and because it is the first ASCII art on the blochain as far as we can see, and because is so well done, this is by far the most visible ASCII art of the Bitcoin blockchain.
Present at tx 930a2114cdaa86e1fac46d15c74e81c09eee1d4150ff9d48e76cb0697d8e1d72. It does not show well on Bitcoin Inscription Indexer however with rationale described at: github.com/cirosantilli/bitcoin-inscription-indexer/tree/3f53e152ec9bb0d070dbcb8f9249d92f89effa70#smart-newline-joining
But it can be seen at on bitcoinStrings.com at: bitcoinstrings.com/blk00003.txt.
Transaction: www.blockchain.com/btc/tx/930a2114cdaa86e1fac46d15c74e81c09eee1d4150ff9d48e76cb0697d8e1d72 from 2011-07-30, a few weeks after the suicide.
Discussion: bitcoin.stackexchange.com/questions/3370/in-which-block-was-len-sassaman-memorialised/101276#101276
Created by famous computer security researcher Dan Kaminsky and Travis Goodspeed, presumably this other security researcher, evidence:
- signature on the tribute
- the art is highlighted at Video 1. "Black OPS of TCP/IP by Dan Kaminsky (2011)", which happened very few days after the art was uploaded to the blockchain, thus making it exceedingly unlikely that someone else could have done it
"Bernanke" is a reference to Ben Bernanke, who was one of the economists in power in the US Government during the financial crisis of 2007-2008, and much criticized by some, as shown for example in the documentary Inside Job (2010). As hinted in the Genesis block message, the United States Government bailed out many big banks that were going to go bankrupt with taxpayer money, even though it was precisly those banks that had started the crisis through their reckless investment, thus violating principles of the free market and business accountability. This was one of the motivations for the creation Bitcoin, which could reduce government power over economic policy.
It is worth mentioning that there do exist some slightly earlier "artistic" inscriptions in the form Punycode inscription in the Namecoin blockchain, but as far as we've seen, the are all trivial compared to
BitLen
in terms of artistic value/size.---BEGIN TRIBUTE---
#./BitLen
:::::::::::::::::::
:::::::.::.::.:.:::
:.: :.' ' ' ' ' : :
:.:'' ,,xiW,"4x, ''
: ,dWWWXXXXi,4WX,
' dWWWXXX7" `X,
lWWWXX7 __ _ X
:WWWXX7 ,xXX7' "^^X
lWWWX7, _.+,, _.+.,
:WWW7,. `^"-" ,^-'
WW",X: X,
"7^^Xl. _(_x7'
l ( :X: __ _
`. " XX ,xxWWWWX7
)X- "" 4X" .___.
,W X :Xi _,,_
WW X 4XiyXWWXd
"" ,, 4XWWWWXX
, R7X, "^447^
R, "4RXk, _, ,
TWk "4RXXi, X',x
lTWk, "4RRR7' 4 XH
:lWWWk, ^" `4
::TTXWWi,_ Xll :..
=-=-=-=-=-=-=-=-=-=
LEN "rabbi" SASSAMA
1980-2011
Len was our friend.
A brilliant mind,
a kind soul, and
a devious schemer;
husband to Meredith
brother to Calvin,
son to Jim and
Dana Hartshorn,
coauthor and
cofounder and
Shmoo and so much
more. We dedicate
this silly hack to
Len, who would have
found it absolutely
hilarious.
--Dan Kaminsky,
Travis Goodspeed
P.S. My apologies,
BitCoin people. He
also would have
LOL'd at BitCoin's
new dependency upon
ASCII BERNANKE
:'::.:::::.:::.::.:
: :.: ' ' ' ' : :':
:.: _.__ '.:
: _,^" "^x, :
' x7' `4,
XX7 4XX
XX XX
Xl ,xxx, ,xxx,XX
( ' _,+o, | ,o+,"
4 "-^' X "^-'" 7
l, ( )) ,X
:Xx,_ ,xXXXxx,_,XX
4XXiX'-___-`XXXX'
4XXi,_ _iXX7'
, `4XXXXXXXXX^ _,
Xx, ""^^^XX7,xX
W,"4WWx,_ _,XxWWX7'
Xwi, "4WW7""4WW7',W
TXXWw, ^7 Xk 47 ,WH
:TXXXWw,_ "), ,wWT:
::TTXXWWW lXl WWT:
----END TRIBUTE----
Code 1.
Len Sassaman tribute
. Official portrait of Ben Bernanke (2008)
Source. Reference image from Wikipedia for the ASCII art.Black OPS of TCP/IP by Dan Kaminsky (2011)
Source. Presented at the BlackHat 2011 conference. Dan unveils the Len memorial at the given timestamp around 8:41. The presentation was done on 2011-08-03 or 04, so very few days after the upload to the blockchain.From the JSON transaction we understand the encoding format:So it is really encoded one line at a time in the
"out":[
{
"spent":false,
"tx_index":0,
"type":0,
"addr":"1CqKQ2EqUscMkeYRFMmgepNGtfKynXzKW7",
"value":1000000,
"n":0,
"script":"76a91481ccb4ee682bc1da3bda70176b7ccc616a6ba9da88ac"
},
{
"spent":false,
"tx_index":0,
"type":0,
"addr":"157sXa7duStAvq3dPLWe7J449sgh47eHzw",
"value":1000000,
"n":1,
"script":"76a9142d2d2d424547494e20545249425554452d2d2d2088ac"
},
...
{
"spent":false,
"tx_index":0,
"type":0,
"addr":"157sXYpjvAyEJ6TdVFaVzmoETAQnHB6FGU",
"value":1000000,
"n":77,
"script":"76a9142d2d2d2d454e4420545249425554452d2d2d2d2088ac"
}
script
of the transaction outputs.By the rich founder of Mt. Gox and Ripple, Jed McCaleb.
Obelisk is the Artificial General Intelligence laboratory at Astera. We are focused on the following problems: How does an agent continuously adapt to a changing environment and incorporate new information? In a complicated stochastic environment with sparse rewards, how does an agent associate rewards with the correct set of actions that led to those rewards? How does higher level planning arise?
Includes its own copy of sqlite3, you don't use the system one, which is good to ensure compatibility. The version is shown at: github.com/mapbox/node-sqlite3/blob/918052b538b0effe6c4a44c74a16b2749c08a0d2/deps/common-sqlite.gypi#L3 SQLite source is tracked compressed in-tree: github.com/mapbox/node-sqlite3/blob/918052b538b0effe6c4a44c74a16b2749c08a0d2/deps/sqlite-autoconf-3360000.tar.gz horrendous. This explains why it takes forever to clone that repository. People who don't believe in git submodules, there's even an official Git mirror at: github.com/sqlite/sqlite
It appears to spawn its own threads via its C extension (since JavaScript is single threaded and and SQLite is not server-based), which allows for parallel queries using multiple threads: github.com/mapbox/node-sqlite3/blob/v5.0.2/src/threading.h
Hello world example: nodejs/node-sqlite3/index.js.
As of 2021, this had slumped back a bit, as maintainers got tired. Unmerged pull requests started piling more, and
better-sqlite3
Node.js package started pulling ahead a little.- github.com/mapbox/node-sqlite3/issues/1381
FATAL ERROR: Error::ThrowAsJavaScriptException napi_throw
with Node.jsworker_threads
vsbetter-sqlite3
Node.js package github.com/JoshuaWise/better-sqlite3/issues/237
Year 3 of the physics course of the University of Oxford Updated 2025-07-11 +Created 1970-01-01
async
is all present in JavaScript for two reasons:- you make network requests all the time
- JavaScript is single threaded, so if you are waiting for a network request, the UI freezes, see remarks on the deprecation of synchronous HTTP request at: developer.mozilla.org/en-US/docs/Web/API/XMLHttpRequest/Synchronous_and_Asynchronous_Requests
However, it is also Hell: how to convert
async
to sync in JavaScript. A Three-Dimensional Model of the Myoglobin Molecule Obtained by X-Ray Analysis (1958) Updated 2025-07-11 +Created 1970-01-01
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