Force a thermal condition and instrument it so the evidence survives a reboot

short · 60 min · Objective 5.1

Task

Set up continuous logging, force a load, and produce a record that would still identify the cause if the machine had shut down mid-test -- because an intermittent fault's evidence must be written down before it happens.

Steps

  1. Set up temperature and clock logging to a FILE that is written continuously, not held in memory, and record the tool and interval in lab/interm/instrument.md.
  2. Record ten minutes of idle behaviour into lab/interm/idle.csv with header t,temp_c,clock_mhz.
  3. Force a sustained load for twenty minutes, logging into lab/interm/load.csv with the same header.
  4. Restrict airflow safely -- close the case, or raise the ambient temperature slightly -- and repeat, logging into lab/interm/restricted.csv, and stop early if the processor reaches its limit.
  5. Write lab/interm/pattern.md stating the peak in each condition, the time to reach it, and whether the clock fell -- and state which of the three files would have identified the cause if the machine had shut down without warning.

Verify

grep -c . lab/interm/instrument.md
awk -F, 'NR>1 {n++} END {print n" idle reading(s)"}' lab/interm/idle.csv
awk -F, 'NR>1 {n++} END {print n" load reading(s)"}' lab/interm/load.csv
awk -F, 'NR>1 {n++} END {print n" restricted reading(s)"}' lab/interm/restricted.csv
awk -F, 'NR>1 {if($2>m)m=$2} END {print "peak under load "m" C"}' lab/interm/load.csv
grep -c . lab/interm/pattern.md

An instrument note, twenty or more readings in each of three conditions, a computed peak, and the pattern note. A log held only on screen would have been lost in a shutdown, which is why the instrument note has to say the file was written continuously.

Notes

Do not remove a heatsink to force the condition. That damages hardware and produces a fault shape -- immediate shutdown -- that is not the gradual pattern this lab is teaching.

This is an independent study companion for CompTIA A+ Core 1 220-1201 and is not produced by or endorsed by CompTIA.