Chapter 1 — Computing and service architecture

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

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Learning outcomes

You will (1) describe the services a retail business runs; (2) identify which components support each service; (3) record owners for governance.

1.1 Fenwick's services

Amina Yusuf is a student on the technical course at the fictional Dunmore Technical College. Her instructor, Ms. Clara Bell, uses one running case: the fictional Fenwick Building Supplies, with six branches, one hundred and eighty staff, an online shop and card terminals at every till. Amina lists Fenwick's services: in-branch sales, the online shop, deliveries, supplier ordering and payroll. Each service relies on computers, software, networks and people, and governance must know these links to protect what matters. Payroll, for example, has no customers watching it, yet a failure there would affect all one hundred and eighty staff at once.

1.2 Components

For each service Amina lists components. In-branch sales rely on till computers, card terminals, the point-of-sale software and the branch network. The online shop relies on a hosted web platform, a payment gateway and the stock database. Deliveries rely on tablets and a route planning service. She learns that drawing these links shows which single component could stop several services, such as the stock database, which both the shop and branches need. Ms. Bell asks her to mark the stock database on the diagram, since an outage there would stop both the online shop and every branch till.

1.3 Owners

Amina records an owner for each service and component. The sales director owns in-branch sales; the e-commerce manager owns the online shop; the IT technician team owns tills, networks and the stock database. Two components, the route planning service and the branch Wi-Fi, have no clear owner. She learns that unowned components are often where problems go unnoticed, so assigning owners is one of the first and simplest governance tasks. She adds the route planning service and branch Wi-Fi to the IT lead's agenda so owners can be agreed.

Worked example

Amina maps five Fenwick services to their components, identifies the stock database as shared and finds two unowned components.

Synthetic case. Dunmore, Fenwick and all details are synthetic.

Errors and limits

Maps omit informal tools. Owners may not accept responsibility.

Exercises

EX001 — Shared component. Which component supports both the shop and branches?
Show marking criteria
Rubric: 3 = the stock database;; 2 = stock database, hedged with another option;; 1 = vague;; 0 = none.
EX002 — Unowned items. Which two components had no owner?
Show marking criteria
Rubric: 3 = route planning service and branch Wi-Fi;; 2 = two;; 1 = vague;; 0 = none.
EX003 — Why owners. Why assign owners early?
Show marking criteria
Rubric: 3 = unowned components are where problems go unnoticed;; 2 = visibility;; 1 = vague;; 0 = none.
EX004 — Service list. Name three Fenwick services.
Show marking criteria
Rubric: 3 = in-branch sales, online shop, deliveries;; 2 = services;; 1 = vague;; 0 = none.