10-10 update
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Ideas.md.gpg
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@ -21,7 +21,10 @@ _Ideas.md and Classes.md are encrypted, so these links will not work_
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* [[tech/databases|Databases & SQL]] - Databases and SQL
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* [[tech/os|Operating Systems Design]] - Basic building blocks of an OS
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* [[tech/embedded|Embedded Programming]] - Embedded Systems like arduinos and (kinda) pi's
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* [[electronics|Digital and Analog]] - Digital and analog electronics
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* [[tech/electronics|Digital and Analog]] - Digital and analog electronics
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* [[tech/unix|Unix]] - Gentoo and other unix systems
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* [[tech/3D_printing|3D Printing]] - Print objects from plastic
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* [[tech/android|Android]]
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* [[tech/misc|Misc]] - Miscellaneous tools
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== [[lang/index|Languages]] ==
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@ -44,6 +47,7 @@ _Ideas.md and Classes.md are encrypted, so these links will not work_
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* [[sci/chemistry|Chemistry]]
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* [[sci/physics|Physics]]
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* [[sci/biology|Biology]]
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* [[sci/chemicals/index|Chemicals]]
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== [[botany/index|Botany]] ==
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@ -51,6 +55,8 @@ _Ideas.md and Classes.md are encrypted, so these links will not work_
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* [[botany/hydroponics|Hydroponics]]
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* [[botany/aquaponics|Aquaponics]]
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== Cooking ==
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== Local to GentooBox ==
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=== School ===
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@ -98,4 +98,20 @@ ${FOO//from/to} #replace all instances of from with to
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${#FOO} #length of foo
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}}}
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== Common tasks ==
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Rename push all .png files through convert
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{{{
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for file in *.png; do
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convert $$file "$${file%.png}.eps"
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done
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}}}
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[[index]]
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10
lang/C.wiki
10
lang/C.wiki
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@ -6,6 +6,16 @@ Systems language. One of the fastest langs around
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* [[bithacks]] - Wacky was to break memory
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== stdlib ==
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standard library functions
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* man atoi
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- string to int
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* man strtol
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- string to long
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* man fgets
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- get string from file
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== Also See ==
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@ -0,0 +1,13 @@
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= Python =
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Wonderful little scripting language
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== Libraries ==
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== Built ins ==
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=== Map ===
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takes a function (can be a lambda) and an iterator to perform the function upon
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[[index]]
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@ -14,7 +14,10 @@
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* [[Rust|Rust]]
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* [[Go|Go]]
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* [[sql|SQL]]
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* [[x86|x86]]
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== Also see ==
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* [[../tech/index]]
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[[../index]]
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@ -1,7 +1,8 @@
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= Acids =
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Any substance that releases H^+ ion in aqueous [[solution]], aka H is first in
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chemical formula
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chemical formula.
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Hydrogen released by acids are called hydronium ions
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* HCL
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* HCL + H,,2,,O => H,,3,,O^+ + Cl^-
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@ -9,8 +10,24 @@ chemical formula
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== Common Acids ==
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* HF,,(g),, - hydrogen fluoride
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* HF,,(aq),, - hydofluoric acid
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* HF,,(aq),, - hydrofluoric acid
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* HCl,,(g),, - hydrogen chloride
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* HCl,,(aq),, - hydrocloric acid
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* HCl,,(aq),, - hydrochloric acid
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* citric acid
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* ascorbic acid
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* lactic acid
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== Common characteristics ==
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* Taste sour
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* turn litmus paper red
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* react with metal to release hydrogen
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== Also see ==
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* [[bases]]
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* [[salts]]
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* [[pH]]
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* [[bronsted-lowry]]
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[[index]]
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@ -1,7 +1,25 @@
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= Bases =
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Any substance that releases OH^- ion in aqueous solution, *bonds with a metal*
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The OH is referred to as hydroxide ion
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* NaOH + H,,2,,O => Na^+ OH^-
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== Common bases ==
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* NaOH (lye)
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* Ammonia (NH,,3,,)
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== Common Characteristics ==
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* Taste bitter
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* turn litmus paper blue and feel slippery
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== Also see ==
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* [[acids]]
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* [[salts]]
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* [[pH]]
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* [[bronsted-lowry]]
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[[index]]
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@ -0,0 +1,25 @@
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= Bronsted-Lowry =
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A definitions of acids and bases that describes an acid as a compound that is
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capable of donating a proton (H+) to form the hydronium ion (H,,3O^+) in aq
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solution. Weak acids are partially ionized
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== How to identify ==
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* Strong Acid
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- All solute it ionized
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- One of the ions is hydronium
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* Weak Acid
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- Some of solute is ionized
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- One of the ions is hydronium
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* Non acid
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- Any amount is ionized
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- No hydronium is formed
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== Also see ==
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* [[acids]]
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* [[salts]]
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* [[pH]]
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[[index]]
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@ -0,0 +1,13 @@
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= NCL3 =
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Nitrogen tri-chloride, one of the most finicky explosives, aka touch powder.
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NOTE reacts with plastic, be sure to use teflon paper
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== How to make ==
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Requires an oxidizing source of chlorine, and source of nitorgen like Urea
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Can be made using [[TCCA]] and [[amonia]]
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[[index]]
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@ -0,0 +1,14 @@
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= Chemicals =
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A list of chemicals that are interseting
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== General ==
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* [[peroxide]]
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== Dangerous ==
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* [[NCl3]]
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[[../index]]
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@ -0,0 +1,6 @@
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= Peroxide =
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A peroxide is any chemical in which two oxygen atoms are linked together by a
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single covalent bond.
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[[index]]
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@ -10,5 +10,4 @@ Took chemistry I Fall 2021. These are those notes
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* [[reactions|Reactions]]
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[[index]]
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@ -0,0 +1,29 @@
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= Electrolytes =
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* Electrolytes
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- Any substance that conducts electricity when disolved into water
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* Non-electrolytes
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- Any substance that does not conduct when dissolved in water
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If ions are not formed, the compound is not an electrolyte.
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* [[salts]]
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- MetalAnion = Metal^+ + Anion^-
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* [[acids]]
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- HAnion = H + Anion^-
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* [[bases]]
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- MOH = Metal + OH^-
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== Strong and weak electrolytes ==
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* Most salts of alkali and alkali earth metals are strong electrolytes
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* Most acids are weak electrolytes
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* Hydroxides (OH) of alkali metals are strong [[bases]]
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* Molecular substances (non metals bounded with non-metals) are
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non-electrolytes
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== Also see ==
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[[solution]]
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[[index]]
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@ -6,6 +6,8 @@ Notes on how all of it works, from school or from simulating it
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* [[chemistry|Chemistry]]
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* [[physics|Physics]]
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* [[biology|Biology]]
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* [[chemicals/index|Chemicals]]
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[[../index]]
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@ -0,0 +1,24 @@
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= Ionic Equations =
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Chemical equations that show each substance as it exists in a [[solution]]
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* Unionized equation
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- Compounds in the equation are written in molecular or normal form
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* Total ionic equation
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- Compounds written in ionic form or true form in solution
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* Net ionic equation
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- Only the species that are involed in the reaction are shown
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* Spectator ions
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- Ions not directly involved in the reaction, yet are still present
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== Rules for writing euqations ==
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1) Ionic compounds (acids bases and salts) that are shown as (aq) are written
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in ionic form
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2) Covalent compunds are free eleemnts are never written in ionic form
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3) Net ionic equations only show substances undergoing change
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4) Equations must be balanced
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== Also see ==
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[[solution]]
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@ -31,5 +31,26 @@ Naming compounds of ions
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* Name = cation + anion
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- MgO = magnesium oxide
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- Fe,,2,,(CO,,3,,),,3,, = iron(III)carbonate ferric carbonate
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== Naming acids ==
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See [[acids]]
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* Named based on anion attached to the hydrogen
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* When binary acid (one ion with hydrogen)
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- Prefix -hydro
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- first syllable of anion
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- suffic -ic
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* Complex acids have Oxygen in them
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* Acid with polyatomic ion (OH), (NO,,3,,)
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- replace -ate with -ic
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* Polyatomic with one extra oxygen (compared to typical polyatomic ion)
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- prefix per-
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- suffic -ic
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* Polyatomic ions with one fewer oxygen (compared to typical)
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- suffix -ous
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* Polyatmoic ions with two fewer oxygen
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- prefix hypo-
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- suffix -ous
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[[index]]
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= pH =
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Measure how basic or acidic solution is, based on number of H,,3,,O on
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logarithmic scale.
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Values range from 0 to 14
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pH = -log(H,,3,,O)
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The interaction between 2+ substances
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== [[solution|Solutions]] ==
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A substance suspended in another (usually water)
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see [[solution|Solutions]]
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== [[electrolytes|Electrolytes]] ==
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see [[electrolytes|Electrolytes]]
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== Ionic Equations ==
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see [[ionic_equations|Ionic Equations]]
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[[index]]
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@ -6,4 +6,10 @@ To neutralize is to react and acid and base
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* HCl,,(aq),, + NaOH => NaCl + H,,2,,O
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== Also see ==
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* [[bases]]
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* [[salts]]
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* [[pH]]
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[[index]]
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@ -9,6 +9,15 @@ A substance suspended in a liquid
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When suspended, molecule is surrounded by solvent
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* Saturated
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- A solution containing the max amount of dissolved solute at a given temp
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* Unsaturated
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- A solution containing less than the max amount of dissolved solute at a
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given temp
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* Supersaturated
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- Solution containing more than the max amount of dissolved solute at given
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temp. In a non equilibrium situation.
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== Measuring ==
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Molarity is moles_solute/liters_solution
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@ -17,4 +26,86 @@ This is a ratio
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Dilution reduces this ratio
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== Dissolution Process ==
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When a solute dissolved into a solvent
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Can be interaction of any two states of matter (except plasma)
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* Solute-Solute
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- interactions are broken
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- Endothermic
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* Solvent-Solvent
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- interactions are broken
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- Endothermic
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* Solvent-Solute
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- interactions are formed
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- exothermic
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The oposite charge of the water molecule pulls molecules of other molecules off
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of structure and into the solution. Works with ionic compounds ie NaCl
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== Solubility ==
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A quantitative term that describes the max amount of a substance that will
|
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dissolve in a given amount of solvent. Usually in g/100mL
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* sucrose
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- 204g/100mL
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* AgCl
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- 9 x 10^-5 g/100mL
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* Micsible
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- Liquids that are mutuall soluble in all proportions
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* Immiscible
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- Liquids that are mutually insoluble
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Nature of solute and solvent, ie _likes disolve likes_
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Temperature increases in solids/liquids means incresed solubility, due to
|
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increase in solute-solvent interactions
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For gasses the opposite is true. For gasses, as pressure increases, so does
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solubility. *Henry's Law*
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=== Guidlines for water ===
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* Compounds with Group I ions (NH,,4,, , NO,,3,,) are *always soluble in water*
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* Compounds containing
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- Cl, Br, I
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- Unless in soln with Ag, Cu, Hg^2 and Pb^2
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- SO,,4,,^2
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- Unless in soln with Ba Ca Hg^2 Pb^2 and Sr^2
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^ Above are always soluble in water
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Insoluble
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* OH^-
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- Except with Alkali metals and ammonium
|
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* S^2-
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- Except with Barium, strontium, magnesium, sodium, potasium, and ammonium
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* Carbonates, oxalates, chromates, and phostates
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- Except with Alkali metals and ammonium
|
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== Hydrates ==
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Compounds that have water molecules imbedded into their structure. Amount of
|
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water is inidicated with latin prefixes.
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Named via prefix + hydrate
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== Concentration ==
|
||||
|
||||
* Concentration
|
||||
- A quantitative expression of the amount of solute dissolved into a solvent
|
||||
* Concentrated solution
|
||||
- A solution of high concentration
|
||||
* Dilute solution
|
||||
- Solution of low concentration
|
||||
|
||||
== [[electrolytes|Electrolytes]] ==
|
||||
|
||||
see [[electrolytes|Electrolytes]]
|
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|
||||
[[index]]
|
||||
|
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@ -0,0 +1,6 @@
|
|||
= 3D Printing =
|
||||
|
||||
3D printers can make stuff from raw spools of plastic
|
||||
|
||||
|
||||
[[index]]
|
||||
|
|
@ -0,0 +1,7 @@
|
|||
= K-map =
|
||||
|
||||
K-maps are ways of simplifying boolean expressions.
|
||||
|
||||
They are usually created from the sum of min values, graphed out into a grid
|
||||
|
||||
[[index]]
|
||||
|
|
@ -39,5 +39,12 @@ Different ways to store and operate on data, with differing efficiency
|
|||
* [[greedy_algorithm|Greedy Algorithms]]
|
||||
* [[brute_force|Brute Force]]
|
||||
* [[randomized_algorithm|Randomized Algorithms]]
|
||||
* [[genetic|Genetic Algorithms]]
|
||||
* [[swarm|Swarm Inteligence]]
|
||||
* [[neural|Neural Networks]]
|
||||
|
||||
== Common operations ==
|
||||
|
||||
* [[gcd]] - Find the GCD of two numbers
|
||||
|
||||
[[index]]
|
||||
|
|
|
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|
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@ -0,0 +1,23 @@
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|||
= Android =
|
||||
|
||||
A mobile operating system for phones and tablets
|
||||
|
||||
== Tools ==
|
||||
|
||||
* adb
|
||||
|
||||
== Tasks ==
|
||||
|
||||
=== Data recovery ===
|
||||
|
||||
How to get the data off of an android phone
|
||||
|
||||
1) Have adb installed on the host system
|
||||
2) Have MTF installed on the host system
|
||||
3) Enable USB Debugging on the device
|
||||
4) adb devices
|
||||
- Keep changing the USB mode till the device shows up in the list that is
|
||||
shown
|
||||
5) adb shell
|
||||
- This drops you into a bash-like shell on the device
|
||||
6)
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||||
|
|
@ -11,12 +11,14 @@ see [[arduino_techniques|Programming Techniques]]
|
|||
* 2Kbytes SRAM
|
||||
* 32Kbytes flash
|
||||
* 1Kbytes EEPROM
|
||||
* Three on board LED's
|
||||
* 20 IO pins
|
||||
* Three on board LED's * 20 IO pins
|
||||
* 6 PWM and 6 ADC
|
||||
|
||||
== Notes ==
|
||||
|
||||
* WHEN UPLOADING BE SURE TO SET BOARD TO ATMEGA328OLD
|
||||
- this is the atmega328old for BOARD_SUB in the makefile
|
||||
|
||||
=== Memory ===
|
||||
|
||||
* AVR instructions are 16 or 32bits wide, therefore the flash is 16K x 16
|
||||
|
|
@ -36,6 +38,11 @@ see [[arduino_techniques|Programming Techniques]]
|
|||
|
||||
=== Pins ===
|
||||
|
||||
Pins are controller by the atmega's ports. Each port has different port
|
||||
registers. Each bit of the 8 bit register controls a single pin. Port D
|
||||
controls pins 0 through 7, C controls the analog pins, and B controls 8 through
|
||||
13
|
||||
|
||||
* PortC
|
||||
- Port C data regiser
|
||||
- 0x28
|
||||
|
|
@ -65,4 +72,9 @@ Same pattern:
|
|||
* PortD
|
||||
- 0x2B - 0x29
|
||||
|
||||
=== Interrupts ===
|
||||
|
||||
Interrupts are the same as OS typical interrupts, controlled by the Interrupt
|
||||
lookup table. On this device the ILT is instead a control register.
|
||||
|
||||
[[embedded]]
|
||||
|
|
|
|||
|
|
@ -0,0 +1,24 @@
|
|||
= Binary tree =
|
||||
|
||||
A branching data structure that is pointer heaven. Traversal is very fun
|
||||
|
||||
== Good For ==
|
||||
|
||||
* Finding data in log(n) time
|
||||
* Organizing tiered data
|
||||
|
||||
== Bad For ==
|
||||
|
||||
* Cache Hits
|
||||
|
||||
== Common operations ==
|
||||
|
||||
=== Level Order Traversal ===
|
||||
|
||||
To traverse a tree level by level it requires a queue to keep track of what is
|
||||
next to traverse. To do this we first push the all child nodes onto the queue.
|
||||
We then visit each element in the node and push on its children into the queue.
|
||||
We do this for every element till we have no elements in the queue. When this
|
||||
happens, we have traversed the entire tree level by level.
|
||||
|
||||
[[algorithms]]
|
||||
|
|
@ -0,0 +1,46 @@
|
|||
= Cross Toolchain =
|
||||
|
||||
Setting up the tool chain involves getting a compiler for a different
|
||||
architechure compiled on your machine. With gentoo its pretty straight forward,
|
||||
and thats what this are instructions for. This example uses avr, but can be
|
||||
subsititued for arm if needbe
|
||||
|
||||
== Cross-compiler toolchain ==
|
||||
|
||||
Here is how to get the cross compiler toolchain setup, at least on gentoo
|
||||
|
||||
1) emerge sys-devel/crossdev
|
||||
- Gentoo package for crossdev tools
|
||||
2) mkdir -p /var/db/repos/portage-crossdev/{profiles,metadata} && echo 'crossdev'
|
||||
> /var/db/repos/portage-crossdev/profiles/repo_name && echo 'masters =
|
||||
gentoo' > /var/db/repos/portage-crossdev/metadata/layout.conf && chown -R
|
||||
portage:portage /var/db/repos/portage-crossdev
|
||||
- All of this sets up a local portage repo, for compiling tools for other
|
||||
systems
|
||||
3) have portage and crossdev use this new repo \
|
||||
{{{
|
||||
#/etc/portage/repos.conf/crossdev.conf
|
||||
[crossdev]
|
||||
location = /var/db/repos/portage-crossdev
|
||||
priority = 10
|
||||
masters = gentoo
|
||||
auto-sync = no
|
||||
}}}
|
||||
- This tells portage about crossdev and that packages can be in it, but not
|
||||
to try and update them with out our permission
|
||||
4) Add the following to a new file
|
||||
{{{
|
||||
#/etc/portage/profile/package.use.force/avr-STRING_HERE
|
||||
cross-avr/gcc -pie -pic
|
||||
}}}
|
||||
5) crossdev -s4 --stable --portage --verbose --target avr
|
||||
- s4 means to build everything from binutils to a full compiler
|
||||
- stable means to use latest stable versions
|
||||
- portage tells what flas to pass to emerge
|
||||
- target specifies our target, the avr arch.
|
||||
- *For arm specificy arm, this also includes other things like pis*
|
||||
6) If any errors are thrown, follow them and try again. Common errors include
|
||||
- make package.mask a directory
|
||||
|
||||
|
||||
[[index]]
|
||||
|
|
@ -7,13 +7,13 @@
|
|||
* [[libcurl|Libcurl]] - Curl the tool, but the API
|
||||
* [[periodictable|Periodic Table]] - Python periodic table
|
||||
|
||||
|
||||
== Tools ==
|
||||
|
||||
* [[gcc|GCC]] - Gnu compiler
|
||||
* [[cgdb]] - Vim like front end for the GNU Debugger
|
||||
* [[make|Make]] - Automate compiling
|
||||
* [[vim]] - Text editor
|
||||
* [[qemu]] - Virtual machine
|
||||
|
||||
|
||||
|
||||
|
|
|
|||
|
|
@ -3,13 +3,19 @@
|
|||
Both digital and analog components
|
||||
|
||||
|
||||
= Combinational =
|
||||
== Combinational ==
|
||||
|
||||
* [[multiplexer|Multiplexer]]
|
||||
|
||||
|
||||
= Sequential =
|
||||
== Sequential ==
|
||||
|
||||
* [[buffer|Buffer]]
|
||||
|
||||
== Theoretical ==
|
||||
|
||||
* [[K-map]]
|
||||
|
||||
|
||||
|
||||
[[index]]
|
||||
|
|
|
|||
|
|
@ -8,17 +8,26 @@ user, sometimes so that they don't even know there is a computer
|
|||
* https://www.microchip.com/en-us/product/ATmega328
|
||||
* [[RISC]] Processor type
|
||||
|
||||
== Raspberry pi ==
|
||||
|
||||
* https://datasheets.raspberrypi.org/rpi4/raspberry-pi-4-datasheet.pdf
|
||||
- Pi 4 Model B
|
||||
* https://datasheets.raspberrypi.org/pico/pico-datasheet.pdf
|
||||
- Pi Pico
|
||||
* [[ARM]] Processor type
|
||||
|
||||
=== Line of products ===
|
||||
|
||||
* [[arduino_nano|Arduino Nano]]
|
||||
* [[arduino_uno|Arduino Uno]]
|
||||
|
||||
* [[raspberry_pi|Raspberry Pi]]
|
||||
* [[rapsberry_pi_pico|Raspberry Pi Pico]]
|
||||
|
||||
=== Programming ===
|
||||
|
||||
* [[../lang/C|C]]
|
||||
* [[../lang/C++|C++]]
|
||||
* [[arduino_techniques|Techniques]]
|
||||
|
||||
* [[cross_toolchain|Arduino Cross-Toolchain setup]]
|
||||
|
||||
[[index]]
|
||||
|
|
|
|||
|
|
@ -0,0 +1,22 @@
|
|||
= FFmpeg =
|
||||
|
||||
Command line tool for working with video
|
||||
This is just a collection of common tasks
|
||||
|
||||
== Rencode as another video ==
|
||||
|
||||
{{{
|
||||
ffmpeg -i in.mkv out.mp4
|
||||
}}}
|
||||
|
||||
== Export clip from video ==
|
||||
|
||||
This will grab a clip starting at 30s that lasts for 10s
|
||||
|
||||
All timestamps must be of format HH:MM:SS.xxx
|
||||
|
||||
{{{
|
||||
ffmpeg -i in.mp4 -ss 00:00:30.0 -c copy -t 00:00:10.0 out.mp4
|
||||
}}}
|
||||
|
||||
[[index]]
|
||||
|
|
@ -0,0 +1,16 @@
|
|||
= GCD =
|
||||
|
||||
Greatest common divisor is the multiple that two numbers have in common
|
||||
|
||||
== Extended Euclidean's Algorihtm ==
|
||||
|
||||
Way to find the greatest common divisor of two numbers
|
||||
|
||||
* Theorm
|
||||
- If m,n are relatively prime then n has an inverse mod m
|
||||
* n^-1 = b mod m
|
||||
- Where a,b are any integer solutions to
|
||||
* a * m = b * n = 1 mod m
|
||||
- and b would be a modular inverse of n
|
||||
|
||||
[[index]]
|
||||
|
|
@ -0,0 +1,61 @@
|
|||
= Gentoo Cheat Sheet =
|
||||
|
||||
Some common operations you need to do to administer a gentoo machine
|
||||
|
||||
== Sync methods ==
|
||||
|
||||
{{{
|
||||
#sync main gentoo repo
|
||||
emerge --sync
|
||||
#sync overlays managed with layman
|
||||
layman -S
|
||||
}}}
|
||||
|
||||
== Managing packages ==
|
||||
|
||||
{{{
|
||||
#install and allow to be managed by portage
|
||||
emerge www-client/firefox
|
||||
#install without adding to world file
|
||||
emerge --oneshot www-client/firefox
|
||||
|
||||
#remove a package
|
||||
emerge --deselect www-client/firefox
|
||||
#actually clean up no longer installed packages
|
||||
emerge --depclean
|
||||
|
||||
#update entire system
|
||||
emerge --ask --verbose --update --changed-use --deep @world
|
||||
|
||||
#apply --autounmask changes
|
||||
dispatch-conf
|
||||
}}}
|
||||
|
||||
== Troubleshooting ==
|
||||
|
||||
{{{
|
||||
#check for missing libraries and rebuild them
|
||||
revdep-rebuild -v
|
||||
|
||||
#check which packages depend on the given package
|
||||
#ie what does firefox depend on?
|
||||
equery d www-client/firefox
|
||||
}}}
|
||||
|
||||
== Use flags ==
|
||||
|
||||
Use flags are kept in /etc/portage/package.use/
|
||||
|
||||
== Overlays ==
|
||||
|
||||
{{{
|
||||
#list all existing overlays
|
||||
layman -L
|
||||
#list installed overlays
|
||||
layman -l
|
||||
|
||||
#add an overlay
|
||||
layman -a OVERLAY
|
||||
}}}
|
||||
|
||||
[[index]]
|
||||
|
|
@ -6,7 +6,7 @@ flavors.
|
|||
|
||||
== Good For ==
|
||||
|
||||
* Crazy fast [[look]] ups
|
||||
* Crazy fast look ups
|
||||
|
||||
== Bad for ==
|
||||
|
||||
|
|
|
|||
|
|
@ -0,0 +1,16 @@
|
|||
= Imagemagick =
|
||||
|
||||
Tools for conveting images on the command line
|
||||
This is just a list of random stuff you can do using it
|
||||
|
||||
== Make a gif ==
|
||||
|
||||
{{{
|
||||
#make a gif out of images
|
||||
convert IMG.png IMG2.png ... -delay DELAY -loop 0 out.gif
|
||||
|
||||
#make a gif that quickly changes images
|
||||
convert IMG.png IMT2.png ... -loop 1 out.gif
|
||||
}}}
|
||||
|
||||
[[index]]
|
||||
|
|
@ -10,6 +10,13 @@ Everything dealing with my awful addiction to computers
|
|||
* [[os|Operating Systems Design]] - Basic building blocks of an OS
|
||||
* [[embedded|Embedded Programming]] - Embedded Systems like arduinos and (kinda) pi's
|
||||
* [[electronics|Digital and Analog]] - Digital and analog electronics
|
||||
* [[unix|Unix]] - Gentoo and other unix systems
|
||||
* [[3D_printing|3D Printing]] - Print objects from plastic
|
||||
* [[android|Android]]
|
||||
* [[misc|Misc]] - Miscellaneous tools
|
||||
|
||||
== Also see ==
|
||||
|
||||
* [[../lang/index]]
|
||||
|
||||
[[../index]]
|
||||
|
|
|
|||
|
|
@ -0,0 +1,85 @@
|
|||
= Linux kernel =
|
||||
|
||||
The part actually called Linux. Some stuff on compiling for it and things it
|
||||
provides
|
||||
|
||||
== Proc ==
|
||||
|
||||
/proc is a virtual filesystem provided by the kernel that has info on processes
|
||||
running and some basic system info. Here are some useful things from it.
|
||||
|
||||
* meminfo
|
||||
- info about ram usage
|
||||
* acpi/*
|
||||
- info about things that control power (such as laptop lid, power button, etc)
|
||||
* sys/kernel/*
|
||||
- info about the status of the kernel
|
||||
* crypto
|
||||
- encryption algorithms built into the kernel
|
||||
* uptime
|
||||
- system uptime
|
||||
* fs/*
|
||||
- all supported filesystems
|
||||
|
||||
== Dev ==
|
||||
|
||||
The device virtual file system, located at /dev. Each device is a file and can
|
||||
be talked to here. Here is some useful info from it
|
||||
|
||||
* random
|
||||
- random data
|
||||
* urandom
|
||||
- less predictable random data
|
||||
* zero
|
||||
- outputs nothing
|
||||
* tty*
|
||||
- All of the different virual terminals
|
||||
* cpu/*
|
||||
- All cpu cores
|
||||
* snd/*
|
||||
- All sound devices
|
||||
* usb/*
|
||||
- USB devices
|
||||
* disk/*
|
||||
- All available disks, can be viewed by uuid, partlabel, and more
|
||||
* mapper/*
|
||||
- Where LVM partitions are mounted, including encrypted partitions and drives
|
||||
|
||||
== Updating the kernel ==
|
||||
|
||||
First be sure to mount the boot parition to /boot
|
||||
|
||||
Next copy your .config from the source directory of your previous kernel to
|
||||
somewhere safe
|
||||
|
||||
For gentoo, you'll need to switch your /usr/src/linux symlink using eselect now
|
||||
|
||||
Now begins the commands
|
||||
|
||||
1) make mrproper
|
||||
- make clean with no additional atrtifacts
|
||||
2) cp /path/to/kernel/config .config
|
||||
- Install old config file
|
||||
3) make olddefconfig
|
||||
- copy over old config options to new kernel config
|
||||
4) make modules_prepare
|
||||
- Prepare kernel modules on system
|
||||
5) make -jX
|
||||
- make the kernel! replace X with number of desired threads
|
||||
6) make modules_install && make install
|
||||
- install the new kernel and modules
|
||||
7) (Gentoo) emerge @module-rebuild
|
||||
- Recompile kernel modules to work with the new kenel
|
||||
8) (Encrypted root only) genkernel --luks --lvm --kernel-config=/path/to/kernel/config initramfs
|
||||
- If not on gentoo use distros initramfs build tool. splash adds a splash
|
||||
screen and is not required
|
||||
9) (Optional) Clean up all kernels
|
||||
- Go ahead and remove all references in /boot to an older kernel. DO NOT
|
||||
delete the current kernel, you may need it in case installing this kernel
|
||||
fails!
|
||||
10) grub-mkconfig -o /boot/grub/grub.cfg
|
||||
- Let grub update its config to know that the new kernel exists
|
||||
11) reboot
|
||||
- reboot and hope it worked!
|
||||
|
||||
[[index]]
|
||||
|
|
@ -0,0 +1,26 @@
|
|||
= ls =
|
||||
|
||||
List files in directory
|
||||
|
||||
== Usage and flags ==
|
||||
|
||||
ls [FLAGS] [FILE]
|
||||
|
||||
* [FILE]
|
||||
- folder/file to list contents of. defaults to current dir.
|
||||
* -a aka --all
|
||||
- include hidden files in listing
|
||||
* --color
|
||||
- color the output
|
||||
* -l aka --long
|
||||
- show more info about files, like ownership, time last modified, etc
|
||||
* -d aka --directory
|
||||
- list only directories
|
||||
* -h aka --human-readable
|
||||
- list sizes of files in human readable format
|
||||
* -s aka -size
|
||||
- Print sizes of each file
|
||||
|
||||
For full usage use man ls
|
||||
|
||||
[[index]]
|
||||
|
|
@ -2,4 +2,14 @@
|
|||
|
||||
Misc. Stuff relating to computers and tech in general
|
||||
|
||||
== Tools ==
|
||||
|
||||
* [[imagemagick]]
|
||||
* [[ffmpeg]]
|
||||
|
||||
== Stuff to do ==
|
||||
|
||||
* [[wireless_usb]]
|
||||
|
||||
|
||||
[[index]]
|
||||
|
|
|
|||
|
|
@ -0,0 +1,25 @@
|
|||
= Openrc =
|
||||
|
||||
The init system I use
|
||||
|
||||
== Configuration ==
|
||||
|
||||
* /etc/rc.conf
|
||||
- global openrc config file
|
||||
* /etc/conf.d
|
||||
- Individual config file for each script
|
||||
|
||||
== Usage ==
|
||||
|
||||
{{{
|
||||
#remove from a runlevel
|
||||
rc-update delete <service> default
|
||||
|
||||
#show all init-script and their current runlevel
|
||||
rc-update show -v
|
||||
|
||||
#show status of all services
|
||||
rc-status --servicelist
|
||||
}}}
|
||||
|
||||
[[index]]
|
||||
20
tech/os.wiki
20
tech/os.wiki
|
|
@ -3,8 +3,28 @@
|
|||
The primary 'program' running on a machine that allows a user to run several
|
||||
programs at once, manages drivers and hardware abstraction, etc
|
||||
|
||||
also see [[kernel]]
|
||||
|
||||
== CPUs ==
|
||||
|
||||
* [[RISC]]
|
||||
* [[x86]]
|
||||
* [[ARM]]
|
||||
|
||||
== Assembly ==
|
||||
|
||||
* [[../lang/x86]]
|
||||
|
||||
== Concepts ==
|
||||
|
||||
* [[scheduler]]
|
||||
* [[microkernel]]
|
||||
* [[monolithic_kernel]]
|
||||
* [[system_calls]]
|
||||
|
||||
== Tools ==
|
||||
|
||||
* [[qemu]]
|
||||
* [[cross_toolchain|Cross compiler toolchain]]
|
||||
|
||||
[[index]]
|
||||
|
|
|
|||
|
|
@ -0,0 +1,16 @@
|
|||
= pwd =
|
||||
|
||||
Print the working directory
|
||||
|
||||
== Usage and Flags ==
|
||||
|
||||
pwd [-L|-P]
|
||||
|
||||
* -L
|
||||
- print pwd that usually appears in command line status, aka LOGICAL path
|
||||
* -P
|
||||
- ignore symlinks, aka PHYSICAL path
|
||||
|
||||
also see man pwd
|
||||
|
||||
[[index]]
|
||||
|
|
@ -0,0 +1,49 @@
|
|||
= QEMU =
|
||||
|
||||
QEMU is a lightweight cli virtual machine program
|
||||
|
||||
== Making a virtual disk ==
|
||||
|
||||
To run a vm you need a virtual hard drive. To make one,
|
||||
|
||||
{{{
|
||||
qemu-img create -f file_format <image_name> image_size
|
||||
}}}
|
||||
|
||||
File format can be raw, qcow2, etc
|
||||
|
||||
size is notated with G for gigabytes, ie 5G is 5 gigabytes
|
||||
|
||||
== Making a virtual machine ==
|
||||
|
||||
We need a virtual disk and an iso file to run. To do this
|
||||
|
||||
{{{
|
||||
qemu-system-x86_64 -cdrom iso_image -cpu host -enable-kvm -m RAM_size -smp
|
||||
number_of_core -drive file=disk_image.iso,format=qcow2
|
||||
}}}
|
||||
|
||||
-cdrom is for iso_image
|
||||
|
||||
-cpu host is to emulate the host processor
|
||||
|
||||
-enable-kvm uses the kernel virtual machine
|
||||
|
||||
-m is for memory, ie 2048
|
||||
|
||||
-smp is for the number of cores, ie 4
|
||||
|
||||
To run off of an already installed hard drive without an iso, run
|
||||
|
||||
{{{
|
||||
qemu-system-x86_64 -cpu host -enable-kvm -m 2048 -smp 2 -drive
|
||||
file=/path/to/vdisk.qcow2,format=qcow2
|
||||
}}}
|
||||
|
||||
== Emulating different systems ==
|
||||
|
||||
If we want to emulate i386, replace 'qemu-system-x86_64' with
|
||||
'qemu-system-i386'. This works with most other architectures, assuming you have
|
||||
them installed.
|
||||
|
||||
[[index]]
|
||||
|
|
@ -0,0 +1,9 @@
|
|||
= Raspberry Pi Pico =
|
||||
|
||||
Raspberry pi's micrcontroler, based on the RP2040
|
||||
|
||||
* https://datasheets.raspberrypi.org/pico/pico-datasheet.pdf
|
||||
|
||||
|
||||
|
||||
[[index]]
|
||||
|
|
@ -0,0 +1,18 @@
|
|||
= Raspberry Pi =
|
||||
|
||||
Mainline tiny linux computers. Cheap as hell too
|
||||
|
||||
== Features ==
|
||||
|
||||
* [[ARM]] processors
|
||||
* Can boot several OS's including linux
|
||||
* Usually 802.11 and bluetooth
|
||||
* 40 gpio pins
|
||||
|
||||
== Projects ==
|
||||
|
||||
* [[octopi]]
|
||||
* [[NAS]]
|
||||
* [[wireless_usb|Wireless USB]]
|
||||
|
||||
[[index]]
|
||||
|
|
@ -2,9 +2,18 @@
|
|||
|
||||
Tools useful for security, either offensive or defensive
|
||||
|
||||
== Cryptology ==
|
||||
|
||||
Hiding information
|
||||
|
||||
=== Ciphers ===
|
||||
|
||||
* [[substitution|Substitution]]
|
||||
|
||||
== Reconnaissance ==
|
||||
|
||||
* [[nmap|nmap]] - port scanner
|
||||
* [[masscan]]
|
||||
|
||||
|
||||
|
||||
|
|
|
|||
|
|
@ -0,0 +1,43 @@
|
|||
= Substitution =
|
||||
|
||||
A Cipher where characters are replaced based on a mapping
|
||||
|
||||
== Monoalphabetic Subsititutions ==
|
||||
|
||||
Cipher where each occurrence of a plaintext symbol is replaced by a
|
||||
corresponding ciphertext symbol
|
||||
|
||||
=== Afline ===
|
||||
|
||||
An affine cipher E(x) = (ax + b) MOD 26 is a monoalphabetic sub cipher, where a
|
||||
and b are given constants
|
||||
|
||||
=== Columnar Transposition ===
|
||||
|
||||
Use letters to create columns, then fill all remaining columns with remaining
|
||||
letters in alphabetic order
|
||||
|
||||
|
||||
|
||||
|
||||
== Cryptoanalysis ==
|
||||
|
||||
=== Monoalphabetic Substitution ===
|
||||
|
||||
We make some assumptions
|
||||
|
||||
* Its english and has same stats as standard english
|
||||
* word divisions are not preserved
|
||||
* use frequency analysis to guess high frequency letters
|
||||
- E E N O R I A S are 70% of letters in english
|
||||
* identify
|
||||
- vowels
|
||||
- diagraphs (common combos of letters ie TH)
|
||||
* Use cribs
|
||||
* guess and rely on luck
|
||||
|
||||
== Also see ==
|
||||
|
||||
* [[gcd]]
|
||||
|
||||
[[index]]
|
||||
|
|
@ -0,0 +1,18 @@
|
|||
= Tar =
|
||||
|
||||
Make tar balls and compress them
|
||||
|
||||
== Compress a folder ==
|
||||
|
||||
{{{
|
||||
tar -czvf outfile.tar.gz /dir/to/compress
|
||||
}}}
|
||||
|
||||
== Open a tar ball ==
|
||||
|
||||
{{{
|
||||
tar -xzvf /path/to/tar/ball.tar.gz
|
||||
}}}
|
||||
|
||||
|
||||
[[index]]
|
||||
|
|
@ -0,0 +1,32 @@
|
|||
= Unix =
|
||||
|
||||
The bell labs proposal for the best OS design ever
|
||||
|
||||
== Standard Utilities ==
|
||||
|
||||
* [[../lang/Bash]]
|
||||
* [[ls]]
|
||||
* [[cd]]
|
||||
* [[pwd]]
|
||||
* [[grep]]
|
||||
* [[awk]]
|
||||
* [[sed]]
|
||||
* [[sort]]
|
||||
* [[uniq]]
|
||||
* [[shuf]]
|
||||
* [[tar]]
|
||||
|
||||
== Gentoo ==
|
||||
|
||||
* [[gentoo_cheat_sheet|Gentoo Cheat Sheet]]
|
||||
* [[openrc|Openrc]]
|
||||
* [[kernel|Kernel updates and configuration]]
|
||||
- [[kernel#Updating the kernel]] - Steps to update the kernel
|
||||
* [[cross_toolchain|Cross toolchain]] - Setting up a cross compiling toolchain
|
||||
|
||||
|
||||
== Cool stuff ==
|
||||
|
||||
* [[wireless_usb]]
|
||||
|
||||
[[index]]
|
||||
|
|
@ -0,0 +1,36 @@
|
|||
= Vim =
|
||||
|
||||
This text editor, most likely unless you're on the website
|
||||
|
||||
== To use ==
|
||||
|
||||
run
|
||||
|
||||
{{{
|
||||
:h vim
|
||||
}}}
|
||||
|
||||
== Useful things ==
|
||||
|
||||
=== Dos to Unix line endings ===
|
||||
|
||||
To save the current file with different line endings, run
|
||||
|
||||
{{{
|
||||
:w ++ff=unix
|
||||
:w ++ff=mac
|
||||
:w ++ff=dos
|
||||
}}}
|
||||
|
||||
Replace w with e to replace the line endings in the editor
|
||||
|
||||
=== Search and replace ===
|
||||
|
||||
This will replace all instances of FOO with BAR:w
|
||||
|
||||
{{{
|
||||
:s/FOO/BAR/g
|
||||
}}}
|
||||
|
||||
|
||||
[[index]]
|
||||
|
|
@ -0,0 +1,40 @@
|
|||
= Wireless USB =
|
||||
|
||||
Provided a usb device over a network for another device
|
||||
Best done with a [[raspberry_pi|Raspberry pi]]
|
||||
|
||||
== Steps ==
|
||||
|
||||
First you'll want a working pi with an internet connection. Be sure its
|
||||
updated
|
||||
|
||||
1) sudo apt-get install usbip
|
||||
- This is the actual kernel module that will be doing the heavy lifting
|
||||
2) sudo modprobe usbip_host
|
||||
- load the module into the kernel
|
||||
3) now edit your modules file to add usbip on boot
|
||||
{{{
|
||||
#file: /etc/modules
|
||||
usbip_host
|
||||
}}}
|
||||
4) Find the device you want to share (lsusb). Keep this in mind
|
||||
5) usbip list -p -l
|
||||
- This will list all the usb devices in a way usbip can understand. Find the
|
||||
matching busid from above for your device
|
||||
6) usbip bind --busid=<BUSID>
|
||||
- Will bind the usb device to usbip
|
||||
7) sudo usbipd
|
||||
- Starts the usbip daemon. Will display what it is listening on
|
||||
8) On the client machine, install usbip as well.
|
||||
9) sudo modprobe vhci-hcd
|
||||
- Load the module for networked usb
|
||||
- Be sure that you have USB/IP support enabled compiled into your kernel
|
||||
10) (Optional) /etc/modules
|
||||
- Same as the pi
|
||||
11) sudo usbip attach -r <PI_IP> -b <BUSID>
|
||||
- Binds the usb device
|
||||
|
||||
And thats it! It should work now. This doesn't have to be with a raspberry pi
|
||||
it can be with any device
|
||||
|
||||
[[index]]
|
||||
Loading…
Reference in New Issue