Derctuo Derctuo-020201231, by Kragen Javier Sitaker, 02020
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Derctuo ⁘⁛⁛⁘ Kragen Javier Sitaker Buenos Aires December, 02020 Public domain work ⁘⁛⁛⁘ Derctuo is a book of notes on various topics, mostly science and engineering with some math, from the first year of the COVID-19 pandemic, 02020 CE. Its primary published form is a gzipped tarball of 9MB of HTML files and sources, although there’s also an inferior PDF version of about 1000 pages for reading on hand computers or printing. It uses a page size slightly smaller than standard for improved readability on hand computers. My original plan was to write a reproducible computation system so that the book would be entirely reproducible from a minimal computational core, allowing all of its calculations to be not only verified but also easily extended, reused, and studied. I didn’t get very far on that plan. Instead it’s mostly just about a quarter million words of dead text, with some static inline images, plus a bundled library of source material, which is not included in the PDF version. It contains some novel discoveries, but some of it is just my notes from exploring the enormous feast of knowledge now available on the internet to anyone who takes the time to taste of it, and some other parts are explorations that didn’t pan out — left here only as a cautionary tale to the next explorer. There are lots of notes in here that aren’t “finished” in the usual sense; they end in the middle of a sentence, or say “XXX”, or have a note in them that the foregoing is wrong in such-and-such a way. But I am publishing the final version of Derctuo today. I might make future versions of some of these notes, but not of Derctuo itself. Derctuo is the sequel to Dercuano, a larger collection of my notes which I published in 02019. Like Dercuano, Derctuo is lacking in scholarship: many of the notes reflect fields I understand poorly, and so often they fall victim to known pitfalls, and fail to describe how they relate to existing knowledge. It is best thought of as working notes published despite their incomplete state. Often in Derctuo, as in Dercuano, I refer to something being “published”. By this I generally mean “made public”. There’s a current fad in academia (over the last, say, half century) to use “published” to mean “brought up to the standards of scholarly publication and approved as such by means of scholarly peer review”. This is usually not what I mean. Public-domain dedication As far as I’m concerned, everyone is free to redistribute Derctuo, in whole or in part, modified or unmodified, with or without credit; I waive all rights associated with it to the maximum extent possible under applicable law. Where applicable, I abandon its copyright to the public domain. I wrote and published Derctuo in Argentina in 02020 (more conventionally called 2020, or 2020 AD). The exception to the above public-domain dedication is the ET Book font family used, licensed under the X11 license (p. 13). This doesn’t impede you from redistributing or modifying Derctuo but does prohibit you from removing the font’s copyright notice and license (unless you also remove the font). The PDF embeds part of FreeFont and of the DejaVu fonts, whose copyright notices are also included (p. 14), but DejaVu and FreeFont are not used in the HTML tarball. Gitlab At this writing, there’s a replica of this repo on Gitlab. Notes 02020-04 • Difficulty estimation of programming tasks (p. 16) 02020-04-20 (2 minutes) • Pure functional UI (p. 17) 02020-04-21 (4 minutes) • Pure functional VM (p. 19) 02020-04-21 (1 minute) • A reproducible vector-instruction VM? (p. 20) 02020-04-21 (updated 02020-06-17) (30 minutes) • Ballpoint SPIF (p. 36) 02020-04-25 (7 minutes) • Bitwise reproducibility (p. 39) 02020-04-25 (1 minute) 02020-05 • Reversible parsing (p. 40) 02020-05-11 (6 minutes) • Bloomtags: a Bloom-filter tree for efficient and flexible database queries (p. 44) 02020-05-13 (21 minutes) • Static hypertext on CCN (p. 51) 02020-05-16 (2 minutes) • Feeds or streams on CCNs (p. 52) 02020-05-16 (15 minutes) • Commit log transfer (p. 57) 02020-05-16 (1 minute) • One pass sort (p. 58) 02020-05-16 (15 minutes) • Optimized finger joints (p. 63) 02020-05-16 (4 minutes) • Solar furnace CPC (p. 65) 02020-05-16 (12 minutes) • Pandemic collapse (p. 69) 02020-05-17 (updated 02020-12-16) (22 minutes) • Font rendering with all-pass filters (p. 76) 02020-05-18 (7 minutes) • Single output build (p. 79) 02020-05-19 (4 minutes) • Electronics kit (p. 81) 02020-05-23 (updated 02020-12-20) (14 minutes) 02020-06 • Sodium silicate (p. 86) 02020-06-04 (32 minutes) • One big text file (p. 97) 02020-06-04 (updated 02020-06-06) (20 minutes) • Monoid prefix sum (p. 105) 02020-06-05 (13 minutes) • Writing a shopping list in TeX (p. 110) 02020-06-05 (4 minutes) • A 6-bit “variac casero” (p. 112) 02020-06-06 (22 minutes) • Tentative outline of a body of knowledge (p. 120) 02020-06-06 (updated 02020-10-28) (10 minutes) • Ghettobotics soldering iron (p. 124) 02020-06-17 (4 minutes) • An outline of the design process leading up to the Veskeno virtual machine (p. 126) 02020-06-17 (updated 02020-07-10) (88 minutes) • Convincingness (p. 164) 02020-06-20 (1 minute) • Lantern gears (p. 165) 02020-06-20 (updated 02020-06-28) (1 minute) • Segments and blocks (p. 166) 02020-06-20 (updated 02020-12-16) (51 minutes) • Slide rule addition (p. 183) 02020-06-22 (3 minutes) • Hacker calendar (p. 185) 02020-06-28 (updated 02020-12-03) (15 minutes) • Trying to drive a speaker with a buck converter (p. 191) 02020-06-29 (4 minutes) • Using Numpy for non-numerical computation: what would a good example be? (p. 193) 02020-06-29 (updated 02020-06-30) (3 minutes) 02020-07 • Modelica notes (p. 196) 02020-07-06 (updated 02020-07-07) (9 minutes) • Ultra machining (p. 200) 02020-07-06 (updated 02020-07-18) (5 minutes) • Importing the WHO’s COVID-19 data into SQLite (p. 202) 02020-07-10 (2 minutes) • Migrating app snapshots (p. 204) 02020-07-10 (updated 02020-07-11) (14 minutes) • Virtual machine setup (p. 209) 02020-07-10 (updated 02020-07-14) (17 minutes) • Long distance radio (p. 216) 02020-07-17 (19 minutes) • A generic universal entity-component simulatorium (p. 223) 02020-07-18 (1 minute) • Line-numbered ISAM buffers (p. 224) 02020-07-18 (updated 02020-07-23) (14 minutes) • Retro teletext (p. 229) 02020-07-18 (updated 02020-07-23) (18 minutes) • The orbital drive and stepped planetary drive (p. 235) 02020-07-28 (updated 02020-08-02) (10 minutes) 02020-08 • Fossil geothermal (p. 238) 02020-08-02 (updated 02020-11-13) (12 minutes) • Pyrolysis 3-D printing (p. 242) 02020-08-02 (updated 02020-11-24) (20 minutes) • Machine teeth (p. 251) 02020-08-02 (updated 02020-12-31) (8 minutes) • 3-D printing iron by electrodeposition? (p. 255) 02020-08-15 (11 minutes) • Peroxide and bleach (p. 259) 02020-08-15 (2 minutes) • Cyclic fabrication systems (p. 260) 02020-08-17 (updated 02020-09-10) (56 minutes) • Foil-marking glass (p. 277) 02020-08-18 (4 minutes) 02020-09 • Inductively-coupled plasma torches (p. 279) 02020-09-10 (5 minutes) • Oxygen generator rocket (p. 281) 02020-09-10 (1 minute) • Penalized bits (p. 282) 02020-09-10 (3 minutes) • Phosphate precipitation (p. 284) 02020-09-10 (12 minutes) • Notable quotes from Steinmetz’s 1892 hysteresis paper (p. 288) 02020-09-10 (2 minutes) • The programmable world (p. 289) 02020-09-10 (0 minutes) • Smart plumbing (p. 290) 02020-09-10 (updated 02020-09-12) (11 minutes) • Inorganic burnout (p. 294) 02020-09-11 (updated 02020-09-12) (18 minutes) • Micro material sorting (p. 300) 02020-09-12 (2 minutes) • Sparse sinc (p. 301) 02020-09-17 (12 minutes) • An index of the 1880 edition of Cooley’s Cyclopædia (p. 305) 02020-09-17 (updated 02020-10-23) (9 minutes) • Spark gap logic (p. 309) 02020-09-20 (updated 02020-12-16) (25 minutes) • Copper salts (p. 317) 02020-09-21 (updated 02020-09-23) (8 minutes) • Hot fabrication (p. 320) 02020-09-21 (updated 02020-09-23) (16 minutes) • Aluminum-air batteries (p. 326) 02020-09-23 (4 minutes) • A digital Dagarti might save your life (p. 328) 02020-09-23 (3 minutes) • Solar netting (p. 330) 02020-09-23 (9 minutes) • Mild bases (p. 333) 02020-09-23 (updated 02020-10-01) (3 minutes) • Magnesium fuel (p. 335) 02020-09-23 (updated 02020-10-09) (13 minutes) • Ancient batteries (p. 340) 02020-09-23 (updated 02020-12-31) (4 minutes) • Modern material processing (p. 342) 02020-09-24 (updated 02020-09-26) (8 minutes) • Materials shopping list (p. 345) 02020-09-25 (updated 02020-12-20) (1 minute) • Toolpath optimization (p. 347) 02020-09-27 (updated 02020-09-30) (19 minutes) • Reducing sucrose (p. 354) 02020-09-30 (7 minutes) • Wang tile chemicals (p. 357) 02020-09-30 (updated 02020-12-31) (2 minutes) 02020-10 • Scraping Sciencemadness (p. 358) 02020-10-01 (updated 02020-10-05) (4 minutes) • Prate thoughts (p. 361) 02020-10-02 (updated 02020-12-30) (12 minutes) • Secure Scuttlebutt is a cool idea whose realization has fatal flaws (p. 365) 02020-10-02 (updated 02020-12-31) (17 minutes) • Lithium fuel (p. 371) 02020-10-04 (7 minutes) • Globoflexia (p.