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v0.31:Computing
| This article is about an older version of DF. |
Computing in dwarf fortress is the practice of setting up complex constructions to perform logical operations and calculations, ideally to control some functionality of your fortress. Even if it isn't a young concept anymore, there is still lots of room for improvement and development. One reason is that there are many ways to solve one problem. Innovation and invention is encouraged.
Binary information
Binary information can have one of two possible states: true or false, respectively 1 or 0. In dwarf fortress they can be represented by different entities:
- on/off state or signal of a trigger (pressure plate, lever)
- power or connection state of a machine component
- open or closed state of a door or similar buildings
- low/high or flowing/standing fluid
- present creatures and borgs
Electronic devices and computers base on this elementary form of information, and if you want to go into computing, you’ll have to familiarize yourself with it. propositional calculus
Input/Output
Input can be any device which can be linked to another device with mechanisms, such as levers or pressure plates. Pressure plates can measure water, magma, or creature weight, and can be set to react to your own dwarves if measuring creature weight. If measuring water or magma you specify the minimum and maximum levels at which it should output 'on', and at all other levels it will output an 'off' signal. Regardless of the actual amount of water, magma, or creature weight on your pressure plate, the plate can only output an 'on' or 'off' signal (1 or 0) to whatever devices it is linked to. So everything you build will have a binary base.
Input elements
- manual: lever -> binary on/off signal
- triggered: pressure plate -> binary on/off signal
According to input, output can be anything that is able to react to an on/off signal. This can be doors, bridges, floodgates allowing or stopping flow, gears controlling pumps and much more. In some special configurations - when mechanical logic is involved - output may not be a on/off signal but power, thus running or not running a machine component.
Currently to convert from power to an on/off signal, the only way is to use a screw pump connected to that power source with an unlimited amount of water and drainage at the output, and a pressure plate to measure whether water is being pumped out by the pump.
Output elements
- signal: pressure plate -> binary on/off signal -> linkable Object(s)
- power: gear assembly -> binary power on/power off -> machine
Binary logic
Basic binary logic takes one or two input bits and creates an output based on them. The devices that perform these operations are commonly called logic gates.
- NOT - takes one input and returns the opposite of the input
| input A | NOT |
|---|---|
| 0 | 1 |
| 1 | 0 |
- AND - takes two inputs and returns true if both inputs are true
- OR - takes two inputs and returns true if at least one input is true
- XOR - takes two inputs and returns true if exactly one input is true
- NAND - takes two inputs and returns true if either input is false
- NOR - takes two inputs and returns true if both inputs are false
- NXOR - takes two inputs and returns true if both inputs are identical
| input A | input B | AND | OR | XOR | NAND | NOR | NXOR |
|---|---|---|---|---|---|---|---|
| 0 | 0 | 0 | 0 | 0 | 1 | 1 | 1 |
| 0 | 1 | 0 | 1 | 1 | 1 | 0 | 0 |
| 1 | 0 | 0 | 1 | 1 | 1 | 0 | 0 |
| 1 | 1 | 1 | 1 | 0 | 0 | 0 | 1 |
The most human-understandable logic system requires NOT, AND and OR gates, but having a design for either a NAND or a NOR gate is enough to build any of the other gates. Some gates are easier to create or need fewer components than others depending on what discipline your logic relies on. Designing each individual gate that you will need (or using designs that had each individual gate designed) rather than building a gate out of multiple NAND gates or the like will generally result in your dorfputer reacting faster and using less resources (power, water, kittens, construction materials, what-have-you).
Complex gates
- Latch - storing and reading a single binary value
- Repeater - sending a repeating signal
- Counter/Adder - binary calculation
Disciplines
Historically, prior to DF2010 there have been 3 main disciplines of dwarfputing, depending on what would drive the dwarfputer. Each of them had its assets and drawbacks. So far, DF2010 at 0.31.01 appears to be essentially the same as far as power transmission goes, barring some differences with pump vertical power transmission (they don't without the floor between being channeled, apparently). Science! will determine what, if anything, differs as far as water flow, falling, and animal pathfinding.
The three disciplines are:
Fluid logic
Infinite flow fluid logic is controlling the flow of fluid over different pressure plates. Fluid logic can be easily constructed and every known logic gate in dwarf fortress has already been built with it. On the other hand this discipline depends on a somehow unlimited source of the used fluid to deal with its evaporation and destruction.
Mechanical logic
Mechanical logic uses systems of axles and gear assemblies to build logical gates. Mechanical logic reacts very fast and can be easily constructed (if not as easily understood and designed as fluid logic gates), except for the need for a fluid-pump-based power->signal converter in every gate. Since every gear can itself be linked to a trigger (or multiple triggers), and automatically connect to adjacent gears for transferring power, mechanical logic gates are very flexible and don't require anywhere near the number of different devices that tend to be used in fluid logic gates (except, again, for the requirement for a fluid-pump-based power->signal converter in every gate). On the other hand this discipline uses a LOT of mechanical power, and due to the lack of a power->signal converter, also referred to as a "rotation sensor" (a device to convert from power to on/off link signals), you need to build one using fluid logic components (pump, pressure plate, unlimited fluid, unlimited drain) if you want to connect multiple mechanical logic gates together or connect a mechanical logic gate to any output other than a pump. So, in truth, current mechanical logic is more correctly termed mechanical-fluid hybrid logic, as you need an essentially unlimited source of water along with an unlimited drain to power the pump-based signal converters. (That said, an aquifer would work perfectly)
Animal logic
Animal logic places animals in an enclosed room, with a door blocking the path to where they desire to go, and a pressure plate below a hatch, with obstacles which are controlled by triggers. The animal thinks it can walk through the door, and if it has a path to the door will walk up to it and stand on the hatch. When the hatch is opened by a trigger, it falls onto the pressure plate. As long as the hatch is open, or other obstacles block its path to the door it remains on the pressure plate and the output is 'on'. Once it sees a path to the door it will leave the pressure plate. Generally this is made possibly by the fact that animals try to go to their parent while they're children, or to the meeting area. There are also be designs which use captured hostiles.
There was a fourth, theoretical, discipline, Borg Logic, but there was never any reported success inventing any functioning and useful borg logic systems.
Examples of things you could do with logic gates
Repeater: Repeatedly toggling hatches open and closed, or spikes up and down. Latch: Making resettable one-use pressure plates which are reset by a lever. NOT gate: Reversing the effect of a switch or creature-sensing pressure plate, generally linked to a latch device. You can, of course, mod the latch device to send the opposite signal instead of using a NOT gate. AND gate: Requiring more than one condition to be true for something to occur. For instance, you could have a group of AND gates, with a system on/off switch, and and other triggers, with each trigger linked to a different AND gate with the system on/off switch linked to the the second input on all the AND gates, so that when the system on/off switch is OFF the output will be OFF on all the AND gates. OR gate: You could link two 1-7 water sensors to an OR gate, and link that to a NOT gate, and link that to some floodgates or doors which act as emergency bulkheads, closing when water is detected in the area. Or, link the OR gate to bridges which raise instead (but you may crush things, and bridges are slower than doors). XOR gate: You could use pressure plates hooked to latches at different points in your fort to detect enemy intrusion, and set them up to seal off the area with both an interior and exterior bulkhead when the intrusion occurs, but hook your latches up with an XOR gate and hook the output to the interior bulkhead to unseal that one if your pressure plates have detected that the enemy has gotten past it. NOR gate: A NOR gate returns TRUE (ON) only if both inputs are FALSE. Instead of using the OR gate example with a NOT gate, you could use a NOR gate linked to two 1-7 water sensors, whose output goes to doors or floodgates. When the pressure plates are both waterless, the floodgates will be open. When one detects water, the floodgates close. (If you used 0-0 pressure plates with an OR, you would get an OFF signal if both plates detected water, or an ON signal otherwise (which is the same as 1-7 NAND 1-7)) NAND gate: A NAND gate returns TRUE (ON) whenever both inputs are not both TRUE (e.g. ON NAND ON is OFF, but every other combination is ON). Instead of the OR NOT or NOR example, you could link two 0-0 water sensors to a NAND gate, and link the NAND gate's output to raising bridges. 0-0 NAND 0-0 is the same as 1-7 OR 1-7. If there is no water on both pressure plates, the NAND gate will output an OFF signal. If, however, either has water, it will output an ON signal.
And here's a more complicated example, omitting the details of what gates to use: An automated swimming training room, where you pull a lever to close exit doors and open hatches to drop water into it, then pressure plates detect when there's enough water and close the hatches, and after a certain amount of time (using a very slow repeater, for instance), drains and exit doors open and the system resets until you pull the lever again. Or, the lever could be taken out entirely and the system could be made fully automatic (with dwarves set to train in the room, for instance) using the repeater.