Fingercomp

There was no IRC library for OpenComputers, so I've made one. Here's a demo bot that uses it:
local com = require("component") local event = require("event") local thread = require("thread") local gpu = com.gpu local irc = require("irc") local events = irc.events local env = setmetatable({ irc = irc, events = events, }, {__index = _G}) local client = irc.builder() :connection { host = "irc.esper.net:6667", throttling = { maxDelay = 2, maxThroughput = 5, }, } :auth { nickname = "oc-finger-irc", username = "fingercomp", realname = "OpenComputers IRC client library", } :bot { channels = {"#oc-finger-irc"}, tracking = { users = true, modes = true, account = true, userInfo = true, }, } :execution { threaded = true, reconnect = true, catchErrors = true, } :subscribe(events.irc.command, events.priority.high, function(self, client, evt) gpu.setForeground(0x00ff00) print("→ " .. evt.rawLine) gpu.setForeground(0xffffff) end) :subscribe(events.irc.write, events.priority.normal, function(self, client, evt) gpu.setForeground(0x00dbff) print("← " .. evt.line:gsub("[\r\n]*$", "")) gpu.setForeground(0xffffff) end) :subscribe(events.irc.message, irc.events.priority.normal, function(self, client, evt) if evt.source.nickname == "fingercomp" then if evt.message == "::quit" then evt:reply("Quitting.") evt.client:stop(("%s told me to quit."):format(evt.source.nickname)) elseif evt.message == "::spam" then evt:reply("1") evt:reply("2") evt:reply("3") evt:reply("4") evt:reply("5") elseif evt.message == "::longmsg" then local msg = {} for i = 1, 256 do if i == 128 then table.insert(msg, tostring(i) .. " ") else table.insert(msg, tostring(i)) end end evt:reply(table.concat(msg)) elseif evt.message == "::error" then (nil).test() elseif evt.message:sub(1, #"::exec ") == "::exec " then local code = evt.message:sub(#"::exec " + 1) local chunk, reason = load("return " .. code, "=irc", "t", env) if not chunk then chunk, reason = load(code, "=irc", "t", env) end if not chunk then evt:reply(("\x0304Error:\x0f %s"):format(reason)) else local result = table.pack(xpcall(chunk, debug.traceback)) local success = table.remove(result, 1) result.n = result.n - 1 for i = 1, result.n, 1 do if type(result) ~= "string" and type(result) ~= "number" and type(result) ~= "boolean" and type(result) ~= "nil" then result[i] = tostring(result[i]) else result[i] = ("%q"):format(result[i]):gsub("\\\n", "\n") end end if not success then evt:reply(("\x0304Error:\x0f %s"):format(result[1]:match("^[^\n]*"))) io.stderr:write(("%s\r\n"):format(result[1])) elseif result.n > 0 then evt:reply(table.concat(result, " ", i, result.n)) else evt:reply("\x0309Success") end end end end end) :subscribe(events.irc.ctcpRequest, irc.events.priority.normal, function(self, client, evt) if evt.ctcpCommand == "TIME" then evt:reply(os.date("%F %T")) end end) :subscribe(events.client.error, irc.events.priority.top, function(self, client, evt) print("Caught: " .. evt.traceback) evt:cancel() end) :build() local t = thread.create(function() repeat local evt = event.pull("interrupted") until evt end) env.client = client client:run() thread.waitForAny({t, client.thread}) client:stop("Quitting.") os.exit() I don't want to brag about it too much, but I think the code is pretty.
Features
Threaded execution. A nice API. IRCv3.2 capability negotiation. Throttling to prevent the bot from triggering anti-flood mechanisms. Tracks channel members, modes, nick changes, account names, etc. Automatically reconnects if it's disconnected from the IRC server. Splits long messages over multiple lines. The event bus can use coroutines as message handlers. Links
The GitLab repository: https://gitlab.com/cc-ru/irc-oc Documentation: https://gitlab.com/cc-ru/irc-oc/-/wikis/home Demo programs: https://gitlab.com/cc-ru/irc-oc/snippets

Sorry for my English, im just Russian.
 
http://codepen.io/Krutoy242/full/xGOgJG/
 
This converter allows you to open .vox files from awesome MagicaVoxel program and convert them to format for print3d program.
 

 
 
Usage
Download and open MagicaVoxel. Make model of your dreams. Save it.

  Open file in my converter written on JavaScript, and it will instantly generate chunks from model and show result, ready to copy-past in OC file for printing. Converter have options:
Split to states will split your model in two by X coordinate (to right), if it will be more then 16 voxels length, and will make second state from this model. Use this to make two-stated prints, like buttons of trapdoors. Label, tooltip, redstone, button mode and light level just add this fields to model. You can determine textures and tint colors in table for each color, used in MagicaVoxel. Program slightly optimized, but sometime human brain can make model with 2-3 less chunks.
Result in minecraft:

 
Please, write here if you want some additional features or if you found bugs.

This is a working clone of Super Mario Bros. (with some missing features ). It was made thanks to the VRAM buffers feature (only available in experimental builds), the game runs quite smoothly and uses the Computronics Sound Card to play music on the same computer. It loads sprites from .bmp files, levels from Tiled (a free level editor) .json file and music is in some custom format that can be converted from MIDI files. This makes the game quite easily moddable.
Source code
 

uncpio is a rather simple binary CPIO extractor (File begins with 0x71C7 or 0xC771, made with cpio -oHbin). To acquire uncpio, run
pastebin get YbrVjRwa /bin/uncpio.lua To use, make the directory you'll be extracting your CPIO archive to, cd into it, then run
uncpio path/to/your/file.cpio And it will extract to the current directory. Currently only works in OpenOS, as far as I know.

I had this problem quite a long time ago, and I think I fixed it by also updating the settings client-side to match those on the server.

There was no IRC library for OpenComputers, so I've made one. Here's a demo bot that uses it:
local com = require("component") local event = require("event") local thread = require("thread") local gpu = com.gpu local irc = require("irc") local events = irc.events local env = setmetatable({ irc = irc, events = events, }, {__index = _G}) local client = irc.builder() :connection { host = "irc.esper.net:6667", throttling = { maxDelay = 2, maxThroughput = 5, }, } :auth { nickname = "oc-finger-irc", username = "fingercomp", realname = "OpenComputers IRC client library", } :bot { channels = {"#oc-finger-irc"}, tracking = { users = true, modes = true, account = true, userInfo = true, }, } :execution { threaded = true, reconnect = true, catchErrors = true, } :subscribe(events.irc.command, events.priority.high, function(self, client, evt) gpu.setForeground(0x00ff00) print("→ " .. evt.rawLine) gpu.setForeground(0xffffff) end) :subscribe(events.irc.write, events.priority.normal, function(self, client, evt) gpu.setForeground(0x00dbff) print("← " .. evt.line:gsub("[\r\n]*$", "")) gpu.setForeground(0xffffff) end) :subscribe(events.irc.message, irc.events.priority.normal, function(self, client, evt) if evt.source.nickname == "fingercomp" then if evt.message == "::quit" then evt:reply("Quitting.") evt.client:stop(("%s told me to quit."):format(evt.source.nickname)) elseif evt.message == "::spam" then evt:reply("1") evt:reply("2") evt:reply("3") evt:reply("4") evt:reply("5") elseif evt.message == "::longmsg" then local msg = {} for i = 1, 256 do if i == 128 then table.insert(msg, tostring(i) .. " ") else table.insert(msg, tostring(i)) end end evt:reply(table.concat(msg)) elseif evt.message == "::error" then (nil).test() elseif evt.message:sub(1, #"::exec ") == "::exec " then local code = evt.message:sub(#"::exec " + 1) local chunk, reason = load("return " .. code, "=irc", "t", env) if not chunk then chunk, reason = load(code, "=irc", "t", env) end if not chunk then evt:reply(("\x0304Error:\x0f %s"):format(reason)) else local result = table.pack(xpcall(chunk, debug.traceback)) local success = table.remove(result, 1) result.n = result.n - 1 for i = 1, result.n, 1 do if type(result) ~= "string" and type(result) ~= "number" and type(result) ~= "boolean" and type(result) ~= "nil" then result[i] = tostring(result[i]) else result[i] = ("%q"):format(result[i]):gsub("\\\n", "\n") end end if not success then evt:reply(("\x0304Error:\x0f %s"):format(result[1]:match("^[^\n]*"))) io.stderr:write(("%s\r\n"):format(result[1])) elseif result.n > 0 then evt:reply(table.concat(result, " ", i, result.n)) else evt:reply("\x0309Success") end end end end end) :subscribe(events.irc.ctcpRequest, irc.events.priority.normal, function(self, client, evt) if evt.ctcpCommand == "TIME" then evt:reply(os.date("%F %T")) end end) :subscribe(events.client.error, irc.events.priority.top, function(self, client, evt) print("Caught: " .. evt.traceback) evt:cancel() end) :build() local t = thread.create(function() repeat local evt = event.pull("interrupted") until evt end) env.client = client client:run() thread.waitForAny({t, client.thread}) client:stop("Quitting.") os.exit() I don't want to brag about it too much, but I think the code is pretty.
Features
Threaded execution. A nice API. IRCv3.2 capability negotiation. Throttling to prevent the bot from triggering anti-flood mechanisms. Tracks channel members, modes, nick changes, account names, etc. Automatically reconnects if it's disconnected from the IRC server. Splits long messages over multiple lines. The event bus can use coroutines as message handlers. Links
The GitLab repository: https://gitlab.com/cc-ru/irc-oc Documentation: https://gitlab.com/cc-ru/irc-oc/-/wikis/home Demo programs: https://gitlab.com/cc-ru/irc-oc/snippets

What is STEM?
Did you ever want to have a linked card, but without this pair-to-pair limitations?
Well, you have internet card. And that is already half of the solution. The other half is to use Stem.

Stem is a message transmitter for your OpenComputers devices with internet cards.
Using a small OpenOS library you can use Stem to send and receive messages. Unlike the standard `modem` component, Stem-messaging uses not addresses, but `channels`. You can send messages to any channels, and you can subscribe to any number of channels to listen for messages from them.
Installation
The best way is to use HPM:
hpm install stem If you do not have HPM, install it like this:
pastebin run vf6upeAN If you do not want to use HPM repository, you can just use wget:
wget https://gitlab.com/UnicornFreedom/stem/raw/master/stem.lua Example of a program using STEM
local event = require('event') -- use STEM client library local stem = require('stem') -- open a connection to a STEM server -- the `stem.fomalhaut.me` is a default one local server = stem.connect('stem.fomalhaut.me') -- subscribe for messages from the channel with ID 'my-channel-id' server:subscribe('my-channel-id') -- then listen for events in a loop... while true do local name, channel_id, message = event.pull('stem_message') if name ~= nil then print(channel_id, message) end end -- ...or register an event listener event.listen('stem_message', function(_, _, channel_id, message) print(channel_id, message) end) -- you can also send message to the channel -- (you do not need to be subscribed to this channel, to send a message) server:send('my-channel-id', 'hello there') -- unsubscribe from channel server:unsubscribe('my-channel-id') -- completely close the connection to the STEM server server:disconnect()  
That is all.
But there is more.
Web client
If you open the link to Stem server in your browser: https://stem.fomalhaut.me/
You will see some statistics and the web client. Enter your channel ID into the form, and you can send messages to your robot in real time, right from your phone, without even starting Minecraft.

The web client is limited with UTF-8 encoding, though.
(Using OpenOS you can send literally anything, as long as the message fits in 64kb of data.)
Security Questions
The channels by default do not have any special security measures applied. They do not have any authentication mechanisms, the do not have any encryption.
Anyone who knows the ID of a channel can send a message to it and can listen for responses. But.
The length of ID is 256 bytes. And that can be any bytes - from 0 to 255. That means, that you have 256^256 possible combinations for your ID. And that is a giant number. If you need to secure your channel - just use something long and incomprehensible as your ID.
As an additional measure you can use end-to-end encryption, or anything else - this is up to you.
Default STEM server uses HTTPS, and does not store any information - message in, message out.
Self-hosted STEM solution
For those of you who are strong in spirit and computer knowledge - there is a self-hosted option. You can build Stem server from sources and run it on your machine.
This is also pretty easy. Additional instructions can be found on GitLab.
Useful links
GitLab repository: https://gitlab.com/UnicornFreedom/stem
Protocol description: https://gitlab.com/UnicornFreedom/stem/wikis/protocol
Default server: https://stem.fomalhaut.me/
HPM package: https://hel.fomalhaut.me/#packages/stem
 
If I forgot something - feel free to ask here, or in IRC (my nickname is Totoro there). Also the project contains at least one "Easter egg" feature, that can offer some interesting options if you know HTML/CSS/JS.
The Stem protocol is open - you can modify it, you can create your own clients in any programming language, etc.

Program and library for building GPS network.
https://github.com/DOOBW/OC-GPS
Download:
wget https://raw.githubusercontent.com/DOOBW/OC-GPS/master/usr/bin/gps.lua /bin/gps.lua
wget https://raw.githubusercontent.com/DOOBW/OC-GPS/master/usr/lib/gps.lua /lib/gps.lua
The functionality is the same as in the ComputerCraft.
Additional command "flash" allows to upload firmware to EEPROM.
When the coordinates are precisely determined, when flashing the position of the microcontroller can be omitted - at the first start it will determine its position from neighboring satellites and save on EEPROM.
GPS network startup example.
 

This is a suggestion on how and why to rework OC's sysyield timeouts. The required fixes basically give ability to implement preemptive multitasking for free.
1. Current implementation of sysyield timeouts is insufficient
Currently, it is not a real protection against executor thread hogging. It is only a safeguard, and a very efficient one.
Consider the following code:
local function dos() while true do end end while true do pcall(coroutine.resume, coroutine.create(dos)) computer.pullSignal(0) end Flash it onto a EEPROM, and throw that into a bare T1 case with just a CPU, a smallest RAM stick, and some power to keep it going.
Turn on that computer, and you have a hogged a single executor thread until someone shuts it down. Boot some more computers off the same EEPROM, and you can easily hog all executor threads on a server.
On default config, running just 4 of such hogs makes other computers practically unusable, every sysyield causes a 5 second delay.
Tweaking the timeout won't really help, since then programs will have to pull(0) much more often, and in the presence of such hogs every yield will cause a delay.
Just killing the whole machine when it starts hogging executors won't help in some cases, specifically if computer is turned on by WoL, redstone signal or another computer.
Even though it's highly unlikely, such hogging can happen accidentally. Specifically, if a system is built so that it restarts on unknown errors, sysyield timeout will not stop an accidental infinite loop in it.
2. How it is currently implemented
I don't think I have a complete understanding yet, but that's how I see it:
The coroutine library is wrapped:
coroutine.yield() adds an extra nil as the first value, to differentiate normal yields from sysyields coroutine.resume() repeatedly does following: Call sethook() on the coroutine to terminate it on a sysyield timeout Call the real coroutine.resume() If the first returned value is nil (i.e. normal yield), return the rest Otherwise (i.e. sysyield), yield all values and continue the loop Therefore, when sysyield happens (i.e. on computer.pullSignal), the whole stack of running coroutines is unwound, and the outermost one yields the computer. On the next tick, or whenever a signal comes, the computer is resumed, and the same stack of coroutines is rebuilt, and the innermost one continues its execution.
The hook that is attached to each coroutine checks if computer has been running for too long, and throws an error if so, which terminates the currently running coroutine. It also extends the deadline by half a second exactly once, so that the parent coroutine has a chance to recover. So long as it does a sysyield in those half a second, or yields/returns and lets its parents do that, the deadline is reset and the computer can continue operating. If it does not, the remaining parent coroutines do not get a chance to recover, and the computer is halted with an error. And until the innermost coroutine times out, nothing can stop it unless it yields control.
For example, if you type while true do end in the LUA repl, it will start that code in a coroutine and print an error message when it times out. If that same loop is explicitly started inside a coroutine, the error is caught and another infinite loop is started, the REPL will not get a chance to do anything, and the whole computer will crash.
3. The suggested implementation
The basic problem is, the hook set by Lua code with debug.sethook() cannot yield a coroutine. It can only throw an error, terminating the coroutine, therefore the timeout has to be long enough to let the program do whatever it needs to without doing sysyields all the time. This is problematic, since all the computers share the same few executor threads, and the timeout also has to be short enough to allow other computers to run normally.
However, the debug hooks actually can yield, under certain very restrictive conditions: https://www.lua.org/manual/5.3/manual.html#lua_Hook The catch is, it can only happen from the native code (C for normal Lua, probably Java for LuaJ), and no values can be returned. I've written a simple test library in C to allow setting yieldable Lua hooks from Lua code: https://github.com/evg-zhabotinsky/yieldhook I tried to implement it myself at first, but then realized that I'm reimplementing debug.sethook... So I just copied it, cut out the unneeded bits and added a loader. If possible, it's probably cleaner to modify the original Lua library (ldblib.c for C version, not sure about LuaJ).
The final interface of the modified debug.sethook() is that if hook mask contains an 'y', event is either 'line' or 'count' and the hook function returns truth, the paused coroutine is yielded with no values, i.e. coroutine.resume() returns just true. The normal return from coroutine with no arguments can be differentiated from a hook yield by checking if coroutine is now dead, and the normal yields can be wrapped to prepend an extra true value.
tl;dr: see the test program in my repo, it demonstrates a simple preemptive multitasking implementation. Its wrapper for coroutine.resume returns:
true plus the values on normal yield or return false plus the error message on error nothing on a hook yield (that's what different from the standard behavior) It should be pretty easy to modify the OC's existing wrapper and hook functions to sysyield instead of throwing an error on timeout. That timeout can then be made much shorter, since coroutines are no longer terminated. Preferably, it should be adjusted dynamically by machine.lua, so that cycles are distributed fairly (incl. according to CPU and memory tiers) with no leftovers and each computer runs exactly once every tick. Preferably, something like computer.getSliceTime() and computer.getRemainingTime() should return how much time the computer has been assigned during the tick and how much of it is left. The units of those functions can be declared "abstract cycle amounts" for the sake of "realism", in which case the slice time will be CPU frequency (quite unstable, just like the tooltip suggests xD) and the remaining time will be cycle count until the next bus synchronization or whatever.
Having done that, there basically will be preemptive multitasking between all the computers, and none of them will have to wait long for their turn to run. For compatibility, the current "die if hung for 5s" behavior can be implemented in OpenOS, and allowed to be disabled for the sake of "power users".
To allow for user-controlled preemptive multitasking on a single computer, I propose adding computer.setTimeout(time, coroutine), with time being the same units as computer.remainingTime() and coroutine being the timeout handler coroutine. The debug hook will work all the same, except it will yield prematurely if the soft deadline happens to be earlier. The wrapped coroutine.resume() will see that a timeout has happened, but hard timeout hasn't expired yet, and instead of yielding any further will disable soft timeout and resume the specified coroutine. The coroutine.status() has to be wrapped too to mark the "yielded by hook" coroutine as "normal", as if it called resume() on the handler coroutine. While the handler coroutine is running, soft timeouts are ignored. When it yields, the paused coroutine is resumed and soft timeout is enablet, if it was set again by the handler. However, if there is a pending soft timeout, the handler coroutine is immediately resumed again.
The setTimeout behavior suggested above matches closely how a timer interrupt would be handled in a real CPU, exactly what machine.lua should contain. The rest of multitasking implementation and protection is on the OS.
Apart of implementing a scheduler, synchronization mechanisms have to be implemented. Count hook can trigger in the middle of any non-trivial expression, so normal assignments cannot be used for unconditionally reliable synchronization. However, a coroutine cannot be resumed unless it's suspended, and everything on a computer runs in a single Lua state, so any coroutine body is a natural critical region, which can easily be leveraged to implement any kind of synchronization.
4. Who is going to implement all that?
Given some time, I can implement the Lua side of things. The native side, though... I'm afraid to break something there, and even though I've done the same modifications for the official Lua implementation, I don't know yet how to do the same for JNLua and LuaJ and in the context of OpenComputers specifically. Plus, I'm not keen on rebuilding OpenComputers from source. If someone confirms that there's nothing to learn or break and that it should just work, I'll probably do that too.
Once the core functionality is implemented, I'm thinking more like implementing a more Unix-like OS, aiming for POSIX compatibility, and the ability to implement proper preemptive multitasking is a must for that. The ultimate goal is to be able to compile and run most normal C programs without modifications. I'm already working on a primitive C to Lua compiler, because I gave up porting a simplistic MP3 decoder to Lua by hand. (I want to have online radio in my bunker!)
Aaanyway, comments and suggestions are welcome. I was more interested in the technical part, so I haven't really though much about API function names or how exactly to divide time among computers of different tiers, so there's that. (Also, is there a way to figure out tiers of arbitrary component from inside the computer?) I didn't think at all about how OpenOS would provide preemptive multitasking to its programs, too, and I have absolutely no idea if it would crash and burn when anything starts running "in parallel".

I just finished the first version of bundle - a rc application which virtually merges multiple filesystems into a bigger one. You can use it whenever a RAID full of tier 3 HDD isn't enough for your needs. On the picture above, for example, you can see 10 RAIDs with 30 tier 3 HDDs which yield a virtual HDD that can store over 200MB of data. You can also use filesystems of different size and create files bigger than any of the used filesystems since bundle is capable of storing a file on multiple HDDs.
If you encounter any bug, please report it on my github repository. Also check out the wiki page.
How to use it
First of all you can download it from pastebin (id: TmeSNidd) or my github repository and install the file in the directory for rc script (/etc/rc.d/bundle.lua). Before using it you should configure the constants at the top of the script in accordance with their descriptions. Otherwise Bundle might work incorrectly. Then you need to add some filesystems by executing
rc bundle add [address] in the shell. Please replace [address] by the address of the desired filesystem. Doing so wipes the added filesystem. However, Bundle never incorporates filesystems automatically. Next you should allow bundle to run in background by executing
rc bundle enable Just reboot the computer and it should be listed by
df
Note that the label of the first added filesystem and the filesystem provided by Bundle are always equal since that's the way how bundle stores it. You can also view the added filesystems by executing
rc bundle list You can also remove added filesystems by
rc bundle remove [forcefully] Currently, this just removes the last added filesystem, however. If the removal causes the lose of data this fails except you set [forcefully].
Usage notes
Don't install the OS on a Bundle filesystem since Bundle requires some functions of OpenOS. Bundle uses a virtual copy of the file structure. On the one hand this makes "hardware" operations faster, on the other hand it might lead to errors when running out of memory. Bundle works with Lua 5.2 as well as Lua 5.3. Known bugs
Seek operations that set the current position to a value that is bigger than the size of the file cause the file the become bigger than its actual physical size. This is also the case on filesystem components of Open Computers but with bundle it might cause internal errors. That is it for now, have fun using Bundle.

Of course there is. Assembling a drone with a leash upgrade produces a drone that can transport cows, horses, sheeps, and pigs. Like this:

Or... like this:

Besides, drones are entities. They move in straight lines; they don't get stuck in the fence and can actually enter a house through a door. They move pretty fast — about 6 blocks a second (robots are at least 2 times slower). Drone's movement is asynchronous, so the machine can execute some other code in the middle of the flight. Drones can fly above the block height limit. The screenshot above was made while enjoying the flight at a height of 260 blocks, for example. Oh, they can fly below the bedrock, too.
Also, drones look cool.
Jobs at which drones clearly outperform robots include player transportation (thanks to the leash upgrade) and item transportation (due to their mobility). And, if used with robots, drones can be useful for crop farming, autocrafting, and construction, for example.

Of course there is. Assembling a drone with a leash upgrade produces a drone that can transport cows, horses, sheeps, and pigs. Like this:

Or... like this:

Besides, drones are entities. They move in straight lines; they don't get stuck in the fence and can actually enter a house through a door. They move pretty fast — about 6 blocks a second (robots are at least 2 times slower). Drone's movement is asynchronous, so the machine can execute some other code in the middle of the flight. Drones can fly above the block height limit. The screenshot above was made while enjoying the flight at a height of 260 blocks, for example. Oh, they can fly below the bedrock, too.
Also, drones look cool.
Jobs at which drones clearly outperform robots include player transportation (thanks to the leash upgrade) and item transportation (due to their mobility). And, if used with robots, drones can be useful for crop farming, autocrafting, and construction, for example.

Of course there is. Assembling a drone with a leash upgrade produces a drone that can transport cows, horses, sheeps, and pigs. Like this:

Or... like this:

Besides, drones are entities. They move in straight lines; they don't get stuck in the fence and can actually enter a house through a door. They move pretty fast — about 6 blocks a second (robots are at least 2 times slower). Drone's movement is asynchronous, so the machine can execute some other code in the middle of the flight. Drones can fly above the block height limit. The screenshot above was made while enjoying the flight at a height of 260 blocks, for example. Oh, they can fly below the bedrock, too.
Also, drones look cool.
Jobs at which drones clearly outperform robots include player transportation (thanks to the leash upgrade) and item transportation (due to their mobility). And, if used with robots, drones can be useful for crop farming, autocrafting, and construction, for example.

The sound card is added by Computronics, a wonderful addon for OpenComputers. There are a few who actually know what it does. Even less people are able to use it. No one dares to understand how it works, or so I hope.
Anyway, it appeared a few years (?) ago, and is still mostly undocumented. There is a page in the in-game manual, which fails to explain how great the card is. Of course it does! It has a heap of different methods, which you can use to cast many crazy magics to make the sound card sound, and it's impossible to teach someone to do magic by reading a single page.
OK, I'm serious now. Last year I managed to understand how to use it, and even wrote a few posts about that. In Russian. Half a year later, I translated them to English. And now I thought of posting a topic here so that you could read them, too.
Here's the link.
The first two parts are all about basic things, like getting simple sounds, ADSR, and modulation. The third part features a little bit more complex things, like complex numbers and Fourier transforms. I tried to keep it simple, so I could get something wrong. If so, please leave a comment there pointing out the mistake. Grammar fixes are also highly appeciated.

https://minecraft.curseforge.com/projects/openpython
https://github.com/EcmaXp/OpenPython
OpenPython makes micropython available on OpenComputers.
micropython is Python for embedded devices and is different from CPython.
Currently, micropython is partially compatible with Python version 3.4 as of October 2018.
Features include:
- Fully persistable.
- Runs in a sandboxed environment and does not require a separate native DLL.
- Supports virtual file system.
- It can call other components and supports Lua architecture's UserData.
Limitations include:
- The firmware is 256 KB and the memory limit has the same limit as the Lua architecture, but the stack is allocated in a separate memory.
- Most modules are difficult to use because the battery is partially included.
- The operating system is not yet fully implemented, so the Python interpreter now runs.
- Ctrl + C is not supported, so if you accidentally run infinite repeated code, the only way to stop it is to turn the computer off and then on.
To use the Python architecture, you need the following items:
- EEPROM (OpenPython): I'm sorry, but you have to bring items from the Creative tab.
- Floppy Disk (OpenPython OS): This item can be obtained by creating a floppy disk and Scrench, or you can check it on the Creative tab.
- OpenPython CPU: You can choose OpenPython architecture by holding Shift + Right Click on the Lua architecture CPU.
It is still unstable, but we plan to make further improvements in the future.
I need help from people who are familiar with OpenComputers and Python.
Thank you for playing.

https://github.com/asiekierka/opencomputers-hires-video-prototype/
Apologies for scarce documentation, it's a bit of a project dump. It has a GUI, however. Feel free to fork and clean it up with the terms of the license in mind.

sence i saw igor Timofeev's mineos i was thinking if it was posible to get those static windows to move and infact there is:
 
welcome to the first showcase of the (really un-creative named) tacti OS:
 
as you can see it figtures moveable, sizeable, and interactive windows infact all programs running in the OS will be windowed!
useing my easy-to-use windowLib and windowed-program-api i'll happyly resive any feedback (download link avalable in the below posts)
(also its gonna happen anyway so come with those grammer currections poeple, i can take it)
 
i hope you guys will like my project
-thanks

Yeah, there is a way to make it faster. In fact, way faster. One of the things that makes it slow is... gpu.setBackground. It's quite expensive in terms of perfomance (tier 3 GPUs consume 1/128 of the call budget when this method is called). Fortunately, your program only involves 4 colors, so it can be easily optimized.
Actually, there are two ways to do it. A somewhat naive way would be to process all cells of one color first, then process all cells of another color, etc. That would solve the issue with gpu.setBackground, but there's another thing to worry about. The gpu.set method isn't free. In fact, that program does 160 × 50 = 8000 sets, assuming it's running on the max tier 3 resolution. And that is a lot.
Fortunately, OC supports Unicode. In particular, there's a character in Unicode called a full block — █. On OC, I prefer to think of it as of an inverse of " " (a space). If the foreground and background colors are swapped, the space would look like the full block, and vice versa. And it can help us reduce amount of GPU calls significantly. Try replacing the loops with the following:
-- i = 0 gpu.setBackground(0xff0000) gpu.set(1, 1, " ") -- i = 1 gpu.setBackground(0x00ff00) gpu.set(1, 2, " ") -- i = 2, 3 gpu.setForeground(0xffff00) gpu.setBackground(0x0000ff) local fullBlock = "\u{2588}" local oddRow = (" " .. fullBlock):rep(math.floor(mx / 2)) local evenRow = (fullBlock .. " "):rep(math.floor(mx / 2)) for y = 1, my do local x = 1 if y % 2 == 1 then if y == 1 then -- Shift the x by 2 to the right to avoid rewriting -- the first two characters. -- OC truncates everything that goes out of the screen bounds, -- so there's no need to worry about that. x = x + 2 end gpu.set(x, y, oddRow) else gpu.set(x, y, evenRow) end end I can't launch Minecraft to run the program and measure the render time, but I can calculate the amount of call budget consumed by the GPU. Assuming the program runs on a tier 3 GPU and screen, there are 4 gpu.setForeground/gpu.setBackground calls, and 52 gpu.set calls. We get (4 × 1 / 128) + (52 × 1 / 256) = 15 / 64 ≈ 0.23. This is enough even if you have a tier 1 processor (whose call budget is 0.5), and the program should be able to run at 20 FPS, though it doesn't really change each frame.
Oh, I meant to say "T3" (tier 3), sorry. A tier 2 GPU can only perform 128 sets and 64 fills.
https://github.com/MightyPirates/OpenComputers/blob/master-MC1.7.10/src/main/scala/li/cil/oc/server/component/GraphicsCard.scala#L55-L60
Also, there's a comment a few lines above in that file, which reminds me of yet another reason OC makes indirect calls take 1 tick to run — synchronization. OpenComputers, very much unlike ComputerCraft, saves the state of running computers so that they can be resumed when the chunk is reloaded. Methods that interact with the world in some way (like moving items around) must perform synchronization with the Minecraft world to avoid, well, messing things up. The comment says it's especially important on world saves. Despite that, the GPU methods were made direct, although a "nasty trick" was needed to do this. Well, safe concurrency is hard to achieve.

Please calm down.
There are some component methods that block the computer for a tick when called, yes. Such methods usually interact with the world. For example, a transposer allows to transfer items between invetories by calling the transferItem method, which takes a tick to execute (so you get up to 20 stacks/second).
On the other hand, there are a lot of direct methods, which can be called several times per tick. For example, the GPU's methods are direct. And the processor (as well as RAM) determines how many direct calls are allowed per tick. I think T2 T3 setup allows you to call gpu.get one thousand times every tick. Or 256 gpu.sets. Or 128 gpu.fills.
I also believe you don't realize how bad ComputerCraft is for servers. A really simple and stupidly-written program can eat up all the memory the server has. That's why OC limits the memory available for an in-game computer. And running CPU-intensive tasks on a CC's computer makes the whole server run slow, whereas OC requires scripts to pause to allow other in-game computer to run. OpenComputers imposes the limits not because the mod developers want users to suffer (although I do sometimes think of that when I try to do some stupidly complex things with it), but to make it server-friendly.
What's important is that OC allows you to configure these limits for your needs. Have you opened its configuration file? It is more than a 1.5k lines long, and has more than 300 settings you can change, each with a comment that explains the effect of the setting. There's callBudgets to increase the direct call number limit. Or decrease it. There's also the ramSizes setting for memory, and hddSizes for the HDD sizes.
But even with all of these limits, OC can run a lot of programs, including graphical shells, 3D games, reactor control systems. It allows you to send HTTP requests to the real websites, and open raw TCP sockets to interact with network services. It can display 320x200 images. It can even play videos — inside the game, and on the default OC settings!

Please calm down.
There are some component methods that block the computer for a tick when called, yes. Such methods usually interact with the world. For example, a transposer allows to transfer items between invetories by calling the transferItem method, which takes a tick to execute (so you get up to 20 stacks/second).
On the other hand, there are a lot of direct methods, which can be called several times per tick. For example, the GPU's methods are direct. And the processor (as well as RAM) determines how many direct calls are allowed per tick. I think T2 T3 setup allows you to call gpu.get one thousand times every tick. Or 256 gpu.sets. Or 128 gpu.fills.
I also believe you don't realize how bad ComputerCraft is for servers. A really simple and stupidly-written program can eat up all the memory the server has. That's why OC limits the memory available for an in-game computer. And running CPU-intensive tasks on a CC's computer makes the whole server run slow, whereas OC requires scripts to pause to allow other in-game computer to run. OpenComputers imposes the limits not because the mod developers want users to suffer (although I do sometimes think of that when I try to do some stupidly complex things with it), but to make it server-friendly.
What's important is that OC allows you to configure these limits for your needs. Have you opened its configuration file? It is more than a 1.5k lines long, and has more than 300 settings you can change, each with a comment that explains the effect of the setting. There's callBudgets to increase the direct call number limit. Or decrease it. There's also the ramSizes setting for memory, and hddSizes for the HDD sizes.
But even with all of these limits, OC can run a lot of programs, including graphical shells, 3D games, reactor control systems. It allows you to send HTTP requests to the real websites, and open raw TCP sockets to interact with network services. It can display 320x200 images. It can even play videos — inside the game, and on the default OC settings!

Please calm down.
There are some component methods that block the computer for a tick when called, yes. Such methods usually interact with the world. For example, a transposer allows to transfer items between invetories by calling the transferItem method, which takes a tick to execute (so you get up to 20 stacks/second).
On the other hand, there are a lot of direct methods, which can be called several times per tick. For example, the GPU's methods are direct. And the processor (as well as RAM) determines how many direct calls are allowed per tick. I think T2 T3 setup allows you to call gpu.get one thousand times every tick. Or 256 gpu.sets. Or 128 gpu.fills.
I also believe you don't realize how bad ComputerCraft is for servers. A really simple and stupidly-written program can eat up all the memory the server has. That's why OC limits the memory available for an in-game computer. And running CPU-intensive tasks on a CC's computer makes the whole server run slow, whereas OC requires scripts to pause to allow other in-game computer to run. OpenComputers imposes the limits not because the mod developers want users to suffer (although I do sometimes think of that when I try to do some stupidly complex things with it), but to make it server-friendly.
What's important is that OC allows you to configure these limits for your needs. Have you opened its configuration file? It is more than a 1.5k lines long, and has more than 300 settings you can change, each with a comment that explains the effect of the setting. There's callBudgets to increase the direct call number limit. Or decrease it. There's also the ramSizes setting for memory, and hddSizes for the HDD sizes.
But even with all of these limits, OC can run a lot of programs, including graphical shells, 3D games, reactor control systems. It allows you to send HTTP requests to the real websites, and open raw TCP sockets to interact with network services. It can display 320x200 images. It can even play videos — inside the game, and on the default OC settings!

No spoiler in the title. Just watch the video.
EDIT: Apparently someone's ComputerCraft fork is more findable on Google than the original OpenComputers repository, so here's the official source code: https://github.com/asiekierka/lunatic86
 
 

The sound card is added by Computronics, a wonderful addon for OpenComputers. There are a few who actually know what it does. Even less people are able to use it. No one dares to understand how it works, or so I hope.
Anyway, it appeared a few years (?) ago, and is still mostly undocumented. There is a page in the in-game manual, which fails to explain how great the card is. Of course it does! It has a heap of different methods, which you can use to cast many crazy magics to make the sound card sound, and it's impossible to teach someone to do magic by reading a single page.
OK, I'm serious now. Last year I managed to understand how to use it, and even wrote a few posts about that. In Russian. Half a year later, I translated them to English. And now I thought of posting a topic here so that you could read them, too.
Here's the link.
The first two parts are all about basic things, like getting simple sounds, ADSR, and modulation. The third part features a little bit more complex things, like complex numbers and Fourier transforms. I tried to keep it simple, so I could get something wrong. If so, please leave a comment there pointing out the mistake. Grammar fixes are also highly appeciated.

The sound card is added by Computronics, a wonderful addon for OpenComputers. There are a few who actually know what it does. Even less people are able to use it. No one dares to understand how it works, or so I hope.
Anyway, it appeared a few years (?) ago, and is still mostly undocumented. There is a page in the in-game manual, which fails to explain how great the card is. Of course it does! It has a heap of different methods, which you can use to cast many crazy magics to make the sound card sound, and it's impossible to teach someone to do magic by reading a single page.
OK, I'm serious now. Last year I managed to understand how to use it, and even wrote a few posts about that. In Russian. Half a year later, I translated them to English. And now I thought of posting a topic here so that you could read them, too.
Here's the link.
The first two parts are all about basic things, like getting simple sounds, ADSR, and modulation. The third part features a little bit more complex things, like complex numbers and Fourier transforms. I tried to keep it simple, so I could get something wrong. If so, please leave a comment there pointing out the mistake. Grammar fixes are also highly appeciated.

The bug is really simple. To find it, follow through the code line-by-line, analyzing what happens at each line. (This is something I do quite often when debugging an obscure problem.)
First, skip the first few dozens of lines until we get to the L65 (short for line 65), where the loop is defined. We then encounter the if block at L68, of which the first branch is actually run (page == "page1" as it was set to this value on L63), resulting in the pageOne call.
The next line to examine is L79, where the program stops until it pulls the touch event. Here, I check that the event parameters weren't mixed up. All right, let's go on and press the button.
The first condition, on L82, is satisfied (page == "page1", set on L63), so we get the page variable updated to the new value, "page2". But there's more code to run before we loop back! The second condition, on L89. The coodinate mess after the first and evaluates to true. What about page? Well, we've just set it to "page2", so... it, too, yields true. Therefore, the whole condition is satisfied. And the variable is set back to "page1". We loop back, and redraw the first page.
This is how we've just spotted the bug. In case you wonder why Event 2 isn't written to the screen: well, it is written. At position (4, 45). You've just mistaken x for y (and vice versa): 4 is the column, 45 is the row. This is clearly beyond the viewport 58×18, so you see nothing actually printed.
OK. How should you fix it? It's simple: use elseifs.
if (x >= w / 2 - 5 and x <= w / 2 - 5 + 11 and y >= h / 2 - 1 and y <= h / 2 + 1) then if page == "page1" then mon.set(4, 10, "Event 1") table.insert(a, "X") page = "page2" elseif page == "page2" then mon.set(45, 10, "Event 2") page = "page1" end end