Chapter 3 — Operating systems and identities
Lesson map
Lesson 03 published. Map, example, EX009.
flowchart TD
N0["Learning outcomes"]
N1["3.1 Individual logins"]
N2["3.2 Screen locks"]
N3["Lab — Unlocked terminal minutes before and after bad"]
N4["3.3 Seasonal staff"]
N5["Synthesis"]
N0 --> N1 --> N2 --> N3 --> N4 --> N5
N5 --> EX["Worked example"]
EX --> Q["Exercise EX009"]
Logical drawing
flowchart LR
N0["Learning outcomes"]
N1["3.1 Individual logins"]
N2["3.2 Screen locks"]
N3["Lab — Unlocked terminal minutes before and after bad"]
N4["3.3 Seasonal staff"]
N5["Synthesis"]
N0 --> N1 --> N2 --> N3 --> N4 --> N5 --> Q["EX009"]
[Learning outcomes]
|
v
[3.1 Individual logins]
|
v
[3.2 Screen locks]
|
v
[Lab — Unlocked terminal minutes before and after bad]
|
v
[3.3 Seasonal staff]
|
v
[Synthesis]
|
v
[Worked example] --> [Exercise EX009]
Learning outcomes
You will (1) replace a shared terminal password with usable individual logins; (2) configure screen locks for warehouse work; (3) manage accounts for seasonal staff.
3.1 Individual logins
Priya proposes replacing the wall password with badge logins on warehouse terminals. Each worker taps a badge to log in and taps again to log out, taking about two seconds. Individual logins let IT see who made each change, which helps investigate errors and misuse. She tests the badge readers on one terminal for a week. Workers find the tap quicker than typing the shared password. Making the secure option faster than the insecure one is the key to adoption. Supervisors support the trial.
3.2 Screen locks
Shared terminals stayed logged in for whole shifts. With badge logins, Priya configures the terminals to lock after two minutes of inactivity, since unlocking now takes a tap. Office laptops lock after five minutes and unlock with a fingerprint or PIN. She counts how often terminals were left unlocked before and after over a test week. The short lock time is accepted because the unlocking cost is small, which shows how usability and security can reinforce each other. The supervisors agree to the settings.
Lab — Unlocked terminal minutes before and after badges
# Unlocked terminal minutes per test week before and after badge logins (synthetic, 4 terminals).
before = [480, 500, 460, 480]; after = [20, 25, 18, 22]
print("before:", sum(before), "after:", sum(after))
Run with python3 lab_unlocked.py. Verified output:
before: 1920 after: 85
3.3 Seasonal staff
Kestrel hires fifty seasonal workers each winter. Previously they shared accounts. Priya sets up a process: HR sends a list before each season, IT creates accounts with an end date, badges are issued at induction and accounts expire automatically at the end date. She writes a checklist for HR and IT. Seasonal staff receive a two-minute induction on reporting and badges. Automatic expiry removes the risk of old accounts remaining active, which no one would otherwise remember to remove. HR agrees to the checklist.
Worked example
Priya replaces a shared password with badge logins, shortens screen locks and sets up expiring accounts for seasonal workers.
Synthetic case. Data are synthetic.
Errors and limits
Badges can be lost or shared. End dates may need extension.
Exercises
- EX009 — Badge time. How long does a badge login take? Rubric: 3 = about two seconds;; 2 = 2 seconds;; 1 = vague;; 0 = none.
- EX010 — Lab unlocked minutes. How did unlocked minutes change in the lab? Rubric: 3 = from 1,920 to 85 per week;; 2 = fall;; 1 = vague;; 0 = none.
- EX011 — Lock acceptance. Why is a two-minute lock accepted? Rubric: 3 = unlocking only needs a tap;; 2 = low cost;; 1 = vague;; 0 = none.
- EX012 — Seasonal expiry. How do seasonal accounts end? Rubric: 3 = they expire automatically at an end date;; 2 = expiry;; 1 = manual removal;; 0 = none.
Synthesis
Usable identities make the secure option the quickest one.
Continue studying — chapter 03 of 18
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