-Design
-------
-
-```
- parallel +----------+ +----------+ +----------+
- stateless | sensor_1 | | sensor_2 | ... | sensor_n |
- collectors +----------+ +----------+ +----------+
- | | |
- data data data
- | | |
- V V V
- serial +-----------------------------------------+
- stateful | controller |
- observer +-----------------------------------------+
- |
- decisions
- |
- V
- serial +-----------------------------------------+
- stateless | actuator |
- executor +-----------------------------------------+
- |
- system commands
- |
- V
- ~~~~~~
- ~ OS ~
- ~~~~~~
-```
-
-Any errors encountered by any sensor are propagated as alerts by the
-controller, which are in turn actualized as desktop notifications by the
-actuator:
-![screenshot-self-error-propagation](screenshot-self-error-propagation.jpg)
+| Name | Status | Language | Tested-on | Description |
+|--------|----------|-----------|-------------------------|-------------|
+| __x1__ | Archived | Bash, AWK | Ubuntu 16.04 | Single, synchronous script, saving state in text files. |
+| __x2__ | Legacy | Bash, AWK | Debian 10, Ubuntu 18.04 | Sensors are child processes, IPC via parent pipe. |
+| __x3__ | Archived | OCaml | Debian 10 | Re-write and refinement of __x2__ |
+| __x4__ | Archived | Dash, AWK | Debian 10 | Sensors are opaque daemons, cache is a file tree |
+| __x5__ | Current | C | Ubuntu 18.04 | Sensors are opaque daemons, IPC via [pselect](https://en.wikipedia.org/wiki/Select_(Unix))ed FIFOs. |