T Level Digital: Environments and Infrastructure

Infrastructure questions reward knowing exactly where one thing ends and the next begins. Two firms both use the cloud: one rents virtual machines and installs its own operating system, the other opens a design tool in a browser and manages nothing but its own files — and naming which model each is using is the first step towards the question that closes this set, which is who has to patch the operating system when something goes wrong. The answer surprises people, and the shared responsibility model is where the most expensive assumptions in this subject live. In between: what running six servers on one machine actually buys, what an availability figure of 99.9 per cent commits a supplier to and how many hours of downtime it still permits, why a firm with excellent bandwidth can have poor video calls, what a second site in another building protects against and what it does not, and why a nightly copy kept on the same server is not a backup no matter how many copies you keep. Every scenario is invented, and every wrong option is a belief someone actually holds rather than an obviously silly answer. Zestly is an independent study tool. It is not affiliated with any exam board and it is not an exam centre.

• Tell infrastructure, platform and software as a service apart by what the client still has to manage
• State what virtualisation gains and what it does not, including licensing and hardware failure
• Read an availability figure in a service level agreement as a permitted amount of downtime
• Identify a star topology and say why a cable fault is contained
• Separate bandwidth from latency and say which one a real-time service depends on
• Say what a second site provides and which risks it leaves untouched
• Explain why copies kept on the same server are not a backup, however many there are
• Apply the shared responsibility model to decide who patches what

Formby Dental copies its records every night to a second folder on the same server, keeping the last thirty nightly copies. What risk does this not cover? — Anything that takes the whole server out. A backup is defined by being somewhere the original's disaster cannot reach.