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. 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, 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

  1. Difficulty estimation of programming tasks 02020-04-20 (2 minutes)
  2. Pure functional UI 02020-04-21 (4 minutes)
  3. Pure functional VM 02020-04-21 (1 minute)
  4. A reproducible vector-instruction VM? 02020-04-21 (updated 02020-06-17) (30 minutes)
  5. Ballpoint SPIF 02020-04-25 (7 minutes)
  6. Bitwise reproducibility 02020-04-25 (1 minute)

02020-05

  1. Reversible parsing 02020-05-11 (6 minutes)
  2. Bloomtags: a Bloom-filter tree for efficient and flexible database queries 02020-05-13 (21 minutes)
  3. Static hypertext on CCN 02020-05-16 (2 minutes)
  4. Feeds or streams on CCNs 02020-05-16 (15 minutes)
  5. Commit log transfer 02020-05-16 (1 minute)
  6. One pass sort 02020-05-16 (15 minutes)
  7. Optimized finger joints 02020-05-16 (4 minutes)
  8. Solar furnace CPC 02020-05-16 (12 minutes)
  9. Pandemic collapse 02020-05-17 (updated 02020-12-16) (22 minutes)
  10. Font rendering with all-pass filters 02020-05-18 (7 minutes)
  11. Single output build 02020-05-19 (4 minutes)
  12. Electronics kit 02020-05-23 (updated 02020-12-20) (14 minutes)

02020-06

  1. Sodium silicate 02020-06-04 (32 minutes)
  2. One big text file 02020-06-04 (updated 02020-06-06) (20 minutes)
  3. Monoid prefix sum 02020-06-05 (13 minutes)
  4. Writing a shopping list in TeX 02020-06-05 (4 minutes)
  5. A 6-bit “variac casero” 02020-06-06 (22 minutes)
  6. Tentative outline of a body of knowledge 02020-06-06 (updated 02020-10-28) (10 minutes)
  7. Ghettobotics soldering iron 02020-06-17 (4 minutes)
  8. An outline of the design process leading up to the Veskeno virtual machine 02020-06-17 (updated 02020-07-10) (88 minutes)
  9. Convincingness 02020-06-20 (1 minute)
  10. Lantern gears 02020-06-20 (updated 02020-06-28) (1 minute)
  11. Segments and blocks 02020-06-20 (updated 02020-12-16) (51 minutes)
  12. Slide rule addition 02020-06-22 (3 minutes)
  13. Hacker calendar 02020-06-28 (updated 02020-12-03) (15 minutes)
  14. Trying to drive a speaker with a buck converter 02020-06-29 (4 minutes)
  15. Using Numpy for non-numerical computation: what would a good example be? 02020-06-29 (updated 02020-06-30) (3 minutes)

02020-07

  1. Modelica notes 02020-07-06 (updated 02020-07-07) (9 minutes)
  2. Ultra machining 02020-07-06 (updated 02020-07-18) (5 minutes)
  3. Importing the WHO’s COVID-19 data into SQLite 02020-07-10 (2 minutes)
  4. Migrating app snapshots 02020-07-10 (updated 02020-07-11) (14 minutes)
  5. Virtual machine setup 02020-07-10 (updated 02020-07-14) (17 minutes)
  6. Long distance radio 02020-07-17 (19 minutes)
  7. A generic universal entity-component simulatorium 02020-07-18 (1 minute)
  8. Line-numbered ISAM buffers 02020-07-18 (updated 02020-07-23) (14 minutes)
  9. Retro teletext 02020-07-18 (updated 02020-07-23) (18 minutes)
  10. The orbital drive and stepped planetary drive 02020-07-28 (updated 02020-08-02) (10 minutes)

02020-08

  1. Fossil geothermal 02020-08-02 (updated 02020-11-13) (12 minutes)
  2. Pyrolysis 3-D printing 02020-08-02 (updated 02020-11-24) (20 minutes)
  3. Machine teeth 02020-08-02 (updated 02020-12-31) (8 minutes)
  4. 3-D printing iron by electrodeposition? 02020-08-15 (11 minutes)
  5. Peroxide and bleach 02020-08-15 (2 minutes)
  6. Cyclic fabrication systems 02020-08-17 (updated 02020-09-10) (56 minutes)
  7. Foil-marking glass 02020-08-18 (4 minutes)

02020-09

  1. Inductively-coupled plasma torches 02020-09-10 (5 minutes)
  2. Oxygen generator rocket 02020-09-10 (1 minute)
  3. Penalized bits 02020-09-10 (3 minutes)
  4. Phosphate precipitation 02020-09-10 (12 minutes)
  5. Notable quotes from Steinmetz’s 1892 hysteresis paper 02020-09-10 (2 minutes)
  6. The programmable world 02020-09-10 (0 minutes)
  7. Smart plumbing 02020-09-10 (updated 02020-09-12) (11 minutes)
  8. Inorganic burnout 02020-09-11 (updated 02020-09-12) (18 minutes)
  9. Micro material sorting 02020-09-12 (2 minutes)
  10. Sparse sinc 02020-09-17 (12 minutes)
  11. An index of the 1880 edition of Cooley’s Cyclopædia 02020-09-17 (updated 02020-10-23) (9 minutes)
  12. Spark gap logic 02020-09-20 (updated 02020-12-16) (25 minutes)
  13. Copper salts 02020-09-21 (updated 02020-09-23) (8 minutes)
  14. Hot fabrication 02020-09-21 (updated 02020-09-23) (16 minutes)
  15. Aluminum-air batteries 02020-09-23 (4 minutes)
  16. A digital Dagarti might save your life 02020-09-23 (3 minutes)
  17. Solar netting 02020-09-23 (9 minutes)
  18. Mild bases 02020-09-23 (updated 02020-10-01) (3 minutes)
  19. Magnesium fuel 02020-09-23 (updated 02020-10-09) (13 minutes)
  20. Ancient batteries 02020-09-23 (updated 02020-12-31) (4 minutes)
  21. Modern material processing 02020-09-24 (updated 02020-09-26) (8 minutes)
  22. Materials shopping list 02020-09-25 (updated 02020-12-20) (1 minute)
  23. Toolpath optimization 02020-09-27 (updated 02020-09-30) (19 minutes)
  24. Reducing sucrose 02020-09-30 (7 minutes)
  25. Wang tile chemicals 02020-09-30 (updated 02020-12-31) (2 minutes)

02020-10

  1. Scraping Sciencemadness 02020-10-01 (updated 02020-10-05) (4 minutes)
  2. Secure Scuttlebutt is a cool idea whose realization has fatal flaws 02020-10-02 (updated 02020-11-06) (17 minutes)
  3. Prate thoughts 02020-10-02 (updated 02020-12-30) (12 minutes)
  4. Lithium fuel 02020-10-04 (7 minutes)
  5. Globoflexia 02020-10-05 (updated 02020-10-10) (37 minutes)
  6. DNS Cache Rendezvous: a permissionless signaling channel for bootstrapping end-to-end connections 02020-10-07 (13 minutes)
  7. Nodebook: autotagging quantities for ad-hoc calculation and example-based end-user programming 02020-10-07 (7 minutes)
  8. Single-bridge Tor deanonymization? 02020-10-07 (4 minutes)
  9. LOGSL: Lisp object-graph serialization language 02020-10-07 (updated 02020-10-09) (8 minutes)
  10. Ancient machinists 02020-10-08 (26 minutes)
  11. Level shifter 02020-10-08 (updated 02020-10-10) (9 minutes)
  12. Merkle ropes 02020-10-09 (15 minutes)
  13. A seamless CMG-driven walker 02020-10-11 (updated 02020-10-12) (6 minutes)
  14. Rigid glider 02020-10-12 (1 minute)
  15. Skip list variants 02020-10-12 (4 minutes)
  16. VGA oscilloscope? 02020-10-13 (5 minutes)
  17. Wire machines 02020-10-13 (updated 02020-12-31) (12 minutes)
  18. Thermistors, resistance temperature detectors, and other thermal sensors 02020-10-14 (updated 02020-11-06) (12 minutes)
  19. Atkinson differential blower 02020-10-14 (updated 02020-12-31) (10 minutes)
  20. Inspiration 02020-10-15 (3 minutes)
  21. Oscillating flexion 02020-10-15 (updated 02020-10-16) (11 minutes)
  22. Reuleaux 02020-10-15 (updated 02020-10-18) (19 minutes)
  23. Intervals and gradients 02020-10-16 (4 minutes)
  24. Plaster foam 02020-10-16 (updated 02020-11-08) (8 minutes)
  25. Fluidic household pumping 02020-10-18 (updated 02020-10-19) (7 minutes)
  26. Muriate thermal mass 02020-10-18 (updated 02020-10-28) (11 minutes)
  27. Calcium strengthening 02020-10-21 (updated 02020-10-24) (23 minutes)
  28. Minimal cost computer 02020-10-23 (updated 02020-12-01) (12 minutes)
  29. Abbe-limited DRO 02020-10-24 (updated 02020-12-31) (11 minutes)
  30. LED computation? 02020-10-25 (5 minutes)
  31. Sequestered CO₂ would fill many oil fields 02020-10-25 (2 minutes)
  32. Residue number systems 02020-10-26 (2 minutes)
  33. COVID-19 risk and vitamin D 02020-10-27 (updated 02020-10-28) (12 minutes)
  34. Some of the cheapest memory ICs 02020-10-27 (updated 02020-10-30) (1 minute)
  35. Desiccant climate control 02020-10-27 (updated 02020-11-24) (31 minutes)
  36. Bluepill aspirations 02020-10-30 (updated 02020-11-01) (9 minutes)

02020-11

  1. Multimeter metrology 02020-11-01 (updated 02020-11-27) (23 minutes)
  2. Guide to finding datasheets and avoiding malicious datasheet SEO sites 02020-11-02 (updated 02020-12-22) (7 minutes)
  3. Audio vector image 02020-11-04 (2 minutes)
  4. Dead bugging 02020-11-04 (3 minutes)
  5. Ghettobotics nonshopping list 02020-11-04 (updated 02020-12-21) (22 minutes)
  6. Foaming infiltration 02020-11-06 (1 minute)
  7. Hard sticky balls 02020-11-06 (1 minute)
  8. OCR with linear optimization 02020-11-06 (1 minute)
  9. Pit firing 02020-11-06 (3 minutes)
  10. Machine-readable PNG circuit diagram watermarks 02020-11-06 (1 minute)
  11. Arduino support for STM32 02020-11-06 (10 minutes)
  12. Swashplate screwdriver 02020-11-06 (1 minute)
  13. Thermal expansion speaker 02020-11-06 (1 minute)
  14. Copper segelín 02020-11-06 (updated 02020-11-08) (19 minutes)
  15. Alien screws 02020-11-06 (updated 02020-11-11) (4 minutes)
  16. The Spungot sentential database for end-user logic programming 02020-11-06 (updated 02020-12-31) (27 minutes)
  17. Rosining chips 02020-11-08 (2 minutes)
  18. Cold plasma 02020-11-08 (updated 02020-11-24) (14 minutes)
  19. Cutting steel with steam 02020-11-11 (1 minute)
  20. Improvised humidity sensors with PET dielectric spectroscopy 02020-11-11 (3 minutes)
  21. Printf tracebacks 02020-11-11 (2 minutes)
  22. Random synchronous motor 02020-11-11 (2 minutes)
  23. Specular photogrammetry 02020-11-11 (3 minutes)
  24. A compact textual format for interchange of electronic circuit designs 02020-11-11 (updated 02020-11-26) (1 minute)
  25. Dictionary data structures for tiny memories 02020-11-12 (3 minutes)
  26. Adiabatic separation 02020-11-12 (updated 02020-11-14) (14 minutes)
  27. The rep-2 cuboid 02020-11-13 (5 minutes)
  28. Mica composites 02020-11-14 (3 minutes)
  29. Improvised display options for embedded hardware development 02020-11-16 (updated 02020-11-17) (16 minutes)
  30. Capacitor meter 02020-11-16 (updated 02020-12-03) (26 minutes)
  31. Rebraining 02020-11-16 (updated 02020-12-06) (12 minutes)
  32. Oscilloscope superresolution via compressed sensing? 02020-11-17 (1 minute)
  33. A solar panel from an LED garden light 02020-11-17 (updated 02020-12-01) (5 minutes)
  34. Representing E12 electronic component values musically 02020-11-17 (updated 02020-12-26) (16 minutes)
  35. Microcontroller inventory 02020-11-18 (updated 02020-11-28) (4 minutes)
  36. Keyboard object environment 02020-11-19 (13 minutes)
  37. Relay buzzer 02020-11-23 (2 minutes)
  38. Geomagnetic energy harvesting is barely feasible at near-kilometer scales 02020-11-24 (3 minutes)
  39. Lava time capsule 02020-11-24 (8 minutes)
  40. Lenticular air bearing 02020-11-24 (2 minutes)
  41. Machine readable microcontroller output 02020-11-26 (9 minutes)
  42. Muldiv 02020-11-26 (1 minute)
  43. AVR OSCCAL probably won’t give you an FM radio 02020-11-26 (2 minutes)
  44. A field-programmable RTL array: a more efficient alternative to FPGAs? 02020-11-26 (updated 02020-11-27) (11 minutes)
  45. Hardware queuing 02020-11-26 (updated 02020-12-16) (11 minutes)
  46. Foam electro-etching and related techniques 02020-11-26 (updated 02020-12-31) (10 minutes)
  47. Using C99 compound literals unjustifiably 02020-11-27 (6 minutes)
  48. A reverse-biased diode thermometer 02020-11-27 (9 minutes)
  49. My very first opamp 02020-11-27 (4 minutes)
  50. Taking screenshots 02020-11-27 (updated 02020-12-20) (14 minutes)
  51. Punk zine look 02020-11-28 (6 minutes)

02020-12

  1. Caching layout 02020-12-03 (8 minutes)
  2. Compressed imaging 02020-12-06 (3 minutes)
  3. A letter-by-letter Hamming code for manual ECC computation 02020-12-06 (updated 02020-12-16) (5 minutes)
  4. Majority logic with DRAM sense amps 02020-12-09 (30 minutes)
  5. Truth table search 02020-12-09 (11 minutes)
  6. Yablochkov arc cutter 02020-12-09 (1 minute)
  7. The Language of Choice, and other languages 02020-12-09 (updated 02020-12-31) (10 minutes)
  8. Scribal Basic: a 1960s language for the 02020s 02020-12-12 (updated 02020-12-15) (32 minutes)
  9. Hierarchical state space learning 02020-12-14 (8 minutes)
  10. Programming in the debugger 02020-12-15 (2 minutes)
  11. Transaction per call 02020-12-15 (updated 02020-12-23) (69 minutes)
  12. Materials YouTube 02020-12-16 (updated 02020-12-17) (1 minute)
  13. Electronics next project 02020-12-21 (updated 02020-12-22) (7 minutes)
  14. Electroforming networks 02020-12-22 (3 minutes)
  15. Time-scale material processing 02020-12-22 (3 minutes)
  16. Circle-portal GUI Ⅱ 02020-12-22 (updated 02020-12-23) (4 minutes)
  17. Methods for two-dimensional rotation with two or three real multiplies 02020-12-23 (updated 02020-12-26) (14 minutes)
  18. Light pen latency 02020-12-23 (updated 02020-12-28) (29 minutes)
  19. The sparsity of PEG memoization utility 02020-12-24 (updated 02020-12-28) (1 minute)
  20. Cheating étendue? 02020-12-26 (4 minutes)
  21. Stochastic fractional delay lines 02020-12-26 (9 minutes)
  22. Successive-approximation UI design 02020-12-28 (1 minute)
  23. Differential dividing plate 02020-12-31 (14 minutes)
  24. ECM engraving 02020-12-31 (5 minutes)
  25. Electro-etching graded-index optics in porous silicon 02020-12-31 (2 minutes)
  26. Electrodeposition welding 02020-12-31 (2 minutes)
  27. Jigsaw blades 02020-12-31 (5 minutes)
  28. Table text 02020-12-31 (4 minutes)

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