One machine, ten jobs
A small firm has one big computer. It runs the web site, the mail and the files. A fault in the web site takes down the mail as well.
There are three ways to split the work. Each one changes how safe the jobs are from each other.
Key words
| Word | What it means |
|---|---|
| Server | A computer that serves data or services to other devices. |
| Client-server | A setup where client devices ask a server for data or services. |
| Physical server | A real machine that runs apps directly on its hardware. |
| Virtualisation | Running many separate computers on one real machine. |
| Virtual server | A pretend computer inside a real one, with its own OS. |
| Container | A sealed package of one app and what it needs, kept apart from other packages. |
| Operating system | The main software that runs a device. Short form: OS. |
| Portability | Being easy to move and run somewhere else. |
| Isolation | Keeping one part completely apart from the rest. |
The cells students fill in are left blank in this preview.
By the end of this lesson
Note
I can describe physical servers, virtual servers and containers, and say how each one helps security.
Starter: what you already know
Have a go
Starter: what you already know
3 questionsYour answers are marked here and are not kept. A college account keeps every student’s marks.
Physical servers
A physical server runs apps directly on real hardware. The apps have full access to that hardware. This gives the best speed.
But one machine can only do so much. A problem in one app can slow or stop the others. And each real machine costs money, space and power.
Virtual servers
Virtualisation lets one real machine run many virtual servers at once. Each one has its own OS and software. They sit in isolated spaces.
If one virtual server is attacked, the others are still apart from it. You also need fewer real machines.
Containers
A container holds one app and only the packages it needs. It is kept apart from other containers and from the OS underneath. This adds security and portability.
Fewer packages means fewer weaknesses. A container shares the host's OS, so it starts fast and is small.
Check: three kinds
Have a go
Check: three kinds
4 questionsYour answers are marked here and are not kept. A college account keeps every student’s marks.