Overscan path watchdog

A quiet panel is not a calm one. In August 2003 an alarm list stayed empty because the alarm processor behind it had stalled, and nobody could tell that silence from a healthy one. A watchdog draws the path a screen depends on, one ring per stage, and a stage counts as working only when its counter moves: a beat that repeats its counter is running, not working. While any stage is unproven, the panel it guards is marked UNPROVEN QUIET, or PATH NOT PROVEN if it is showing alerts. A monitor that comes by the same feed as the panel refuses to vouch for it, and the page counts its own ticks so that a frozen page is seen afterwards. Every beat on this page is made by the page's own timer: a demonstration.

demo/watchdog.html, from this page

import 'overscan'
import 'overscan/overscan.css'

<ov-watchdog
  id="wd"
  label="ALARM PATH"
  guards="cw"
  stages="FIELD SCAN:2, FRONT END:1, ALARM PROC:2"
></ov-watchdog>

import { OvWatchdog } from 'overscan/react'

<OvWatchdog
  id="wd"
  label="ALARM PATH"
  guards="cw"
  stages="FIELD SCAN:2, FRONT END:1, ALARM PROC:2"
/>

import { OvWatchdog } from 'overscan/vue'

<OvWatchdog
  id="wd"
  label="ALARM PATH"
  guards="cw"
  stages="FIELD SCAN:2, FRONT END:1, ALARM PROC:2"
/>

import OvWatchdog from 'overscan/svelte/OvWatchdog.svelte'

<OvWatchdog
  id="wd"
  label="ALARM PATH"
  guards="cw"
  stages="FIELD SCAN:2, FRONT END:1, ALARM PROC:2"
/>

The 2003 case: the alarm processor stalls, the panel stays dark

Three stages feed the caution panel, each beating with a counter. STALL keeps the alarm processor beating with a counter that no longer moves: running, not working. Watch what the panel's silence is allowed to say.

variation: id="wd-ok" label="EXCEPTION FEED" guards="cw-ok" stages="KEEP-ALIVE:1"

import 'overscan'
import 'overscan/overscan.css'

<ov-watchdog
  id="wd-ok"
  label="EXCEPTION FEED"
  guards="cw-ok"
  stages="KEEP-ALIVE:1"
></ov-watchdog>

import { OvWatchdog } from 'overscan/react'

<OvWatchdog
  id="wd-ok"
  label="EXCEPTION FEED"
  guards="cw-ok"
  stages="KEEP-ALIVE:1"
/>

import { OvWatchdog } from 'overscan/vue'

<OvWatchdog
  id="wd-ok"
  label="EXCEPTION FEED"
  guards="cw-ok"
  stages="KEEP-ALIVE:1"
/>

import OvWatchdog from 'overscan/svelte/OvWatchdog.svelte'

<OvWatchdog
  id="wd-ok"
  label="EXCEPTION FEED"
  guards="cw-ok"
  stages="KEEP-ALIVE:1"
/>

Quiet, and proven

A report-by-exception feed says nothing when healthy. Only its keep-alive tells that silence from a dead one, so here the dark panel is allowed to be calm.

variation: id="wd-shared" label="RELAY PATH" source="relay" guards="dl" stages="RELAY:1"

import 'overscan'
import 'overscan/overscan.css'

<ov-watchdog
  id="wd-shared"
  label="RELAY PATH"
  source="relay"
  guards="dl"
  stages="RELAY:1"
></ov-watchdog>

import { OvWatchdog } from 'overscan/react'

<OvWatchdog
  id="wd-shared"
  label="RELAY PATH"
  source="relay"
  guards="dl"
  stages="RELAY:1"
/>

import { OvWatchdog } from 'overscan/vue'

<OvWatchdog
  id="wd-shared"
  label="RELAY PATH"
  source="relay"
  guards="dl"
  stages="RELAY:1"
/>

import OvWatchdog from 'overscan/svelte/OvWatchdog.svelte'

<OvWatchdog
  id="wd-shared"
  label="RELAY PATH"
  source="relay"
  guards="dl"
  stages="RELAY:1"
/>

A monitor on the feed it guards

The watchdog and the log both come by the relay feed. If the relay stalls, both go quiet together, so the watchdog refuses to vouch: NOT INDEPENDENT.

variation: id="wd-cold" label="SCAN PATH" guards="cw-cold" stages="SCAN:1, PROC:1"

import 'overscan'
import 'overscan/overscan.css'

<ov-watchdog
  id="wd-cold"
  label="SCAN PATH"
  guards="cw-cold"
  stages="SCAN:1, PROC:1"
></ov-watchdog>

import { OvWatchdog } from 'overscan/react'

<OvWatchdog
  id="wd-cold"
  label="SCAN PATH"
  guards="cw-cold"
  stages="SCAN:1, PROC:1"
/>

import { OvWatchdog } from 'overscan/vue'

<OvWatchdog
  id="wd-cold"
  label="SCAN PATH"
  guards="cw-cold"
  stages="SCAN:1, PROC:1"
/>

import OvWatchdog from 'overscan/svelte/OvWatchdog.svelte'

<OvWatchdog
  id="wd-cold"
  label="SCAN PATH"
  guards="cw-cold"
  stages="SCAN:1, PROC:1"
/>

The 2003 case: the alarm processor stalls, the panel stays dark

Quiet, and proven

A monitor on the feed it guards

Nothing has ever beaten

Every theme, on a healthy two-stage path

terminal

industrial

cyber

antiseptic

esper

neo

machina

holo

aegis

vector