windows3-4  Exercise 1: Count the Content Processes
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Verification: Level 1 (run on the author's machine, read-only, no administrator rights).

Prediction (work this out before running the script):

  Before running: guess how many of Firefox's processes are tab (content) processes, and whether the
  summed working set will be larger or smaller than the summed private working set.
  (Mozilla's default is 8 shared web content processes, plus one per isolated site.)

Command (firefox_roles.ps1 saved in the current folder; for Edge or Chrome change 'firefox' to 'msedge' or
'chrome' everywhere, but note their command lines name process types differently, so the role rule will
need changing):

  .\firefox_roles.ps1

Output (real, from the author's machine on 2026-10-24; your numbers will differ):

  tab       20 procs   private WS  1,186 MB   working set  2,006 MB   commit  2,222 MB
  parent     1 procs   private WS    231 MB   working set    360 MB   commit    396 MB
  gpu        1 procs   private WS     81 MB   working set    155 MB   commit    804 MB
  utility    3 procs   private WS      7 MB   working set     58 MB   commit     32 MB
  rdd        1 procs   private WS      2 MB   working set     13 MB   commit     39 MB
  socket     1 procs   private WS      1 MB   working set      7 MB   commit      9 MB
  TOTAL     27 procs   private WS  1,507 MB   working set  2,599 MB   commit  3,503 MB

WHY THIS WORKS AS AN ANSWER
---------------------------
  Answers from this output: 20 tab (content) processes. The largest role by private working set is tab
  (1,186 MB, against 231 MB for the parent). The summed working set (2,599 MB) is larger than the summed
  private working set (1,507 MB) because the working set of each process includes pages it shares with other
  processes, and adding the processes together counts each shared page once per process; private working set
  counts only what a process holds that nothing else shares (chapter 1). Commit (3,503 MB) is larger again because it includes
  memory reserved but not in RAM, as the GPU process shows (81 MB private, 804 MB commit).
  Common mistakes: reporting the 'working set' total as "what Firefox uses"; reading the process count as the
  memory cost (the non-tab roles other than the parent are under 100 MB together); and expecting your own
  numbers to match, since they depend on which sites you have open and on the Firefox version (this run was
  Firefox Nightly 161.0a1).