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Bachelor's · Chapter 11 · English

Chapter 11 — Operating systems

Open, free learning for anyone who wants to protect people and technology. No account is required to read this text or its worked answers.

Chapter 11 — Operating systems

Lesson map

Lesson 11 published. Map, example, EX031.

flowchart TD
  N0["Learning outcomes"]
  N1["11.1 Accounts on shared devices"]
  N2["11.2 Permissions and shares"]
  N3["11.3 Logs"]
  N4["11.4 Disposal"]
  N5["Synthesis"]
  N0 --> N1 --> N2 --> N3 --> N4 --> N5
  N5 --> EX["Worked example"]
  EX --> Q["Exercise EX031"]

Logical drawing

flowchart LR
  N0["Learning outcomes"]
  N1["11.1 Accounts on shared devices"]
  N2["11.2 Permissions and shares"]
  N3["11.3 Logs"]
  N4["11.4 Disposal"]
  N5["Synthesis"]
  N0 --> N1 --> N2 --> N3 --> N4 --> N5 --> Q["EX031"]

[Learning outcomes]
    |
    v
[11.1 Accounts on shared devices]
    |
    v
[11.2 Permissions and shares]
    |
    v
[11.3 Logs]
    |
    v
[11.4 Disposal]
    |
    v
[Synthesis]
    |
    v
[Worked example] --> [Exercise EX031]

Learning outcomes

You will (1) configure accounts and permissions for school devices; (2) manage logs and temporary files; (3) plan secure disposal of devices.

11.1 Accounts on shared devices

Elena studies how operating systems manage accounts. On shared classroom computers, pupils log in with individual accounts so that work and browsing are separated. She finds that one school uses a single shared account for all pupils, which means files and browser histories are visible to everyone. She recommends individual accounts with automatic clean-up of temporary files at logout. She explains to the school's technician that operating system settings are the first line of privacy on shared devices, before any application is opened.

11.2 Permissions and shares

Teachers save documents to network shares. Elena checks permissions and finds a folder of safeguarding notes readable by all staff. She works with the technician to restrict it to safeguarding leads. She also turns on auditing for the folder so that access can be reviewed. The episode shows that sensitive information often sits in ordinary file shares rather than in protected systems, and that permissions drift over years as staff change roles without anyone reviewing who can still open which folders. Reviews fix this.

11.3 Logs

Operating systems log logins and file access. Elena explains that logs help investigate incidents but also contain personal data about staff and pupils. She recommends keeping logs long enough for investigations, such as six months, restricting access to IT security staff and telling staff in the acceptable use policy that activity is logged. Transparency, she notes, is required by GDPR Articles 13 and 14 for staff as well as for pupils, and staff are entitled to know what is recorded about them. Staff can request them.

11.4 Disposal

Old laptops and tablets are sold or recycled. Elena finds that devices are wiped by deleting user accounts, which may leave data recoverable. She recommends using built-in secure erase functions or full-disk encryption with key destruction, and keeping a disposal record for each device. She learns that disposal is part of the data life cycle and that many breaches in the sector have involved devices sold without proper wiping, which is an avoidable and embarrassing way to lose children's data. Certificates prove wiping.

Worked example

Elena replaces a shared pupil account with individual accounts, restricts and audits a safeguarding folder, sets log retention with transparency to staff and introduces secure erase and disposal records.

Synthetic case. Devices and folders are synthetic; GDPR Articles 13 and 14 are real.

Errors and limits

Secure erase methods differ by device; verify that the method works on each model.

Exercises

Synthesis

Chapter 11 secures systems. Chapter 12 uses probability and statistics.

Continue studying — chapter 11 of 40

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