> For the complete documentation index, see [llms.txt](https://prof-rossetti.gitbook.io/intro-to-python/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://prof-rossetti.gitbook.io/intro-to-python/notes/hardware/servers.md).

# Servers

## Prerequisites

* [Software Distribution Models](/intro-to-python/notes/software.md#distribution-models)
* [Computer Networks](/intro-to-python/notes/info-systems/networks.md)

Today's software services are powered by scores of keyboard-less, mouse-less, monitor-less computers called **servers**, which generally run all day or at scheduled intervals.

Most servers are operated "in the cloud" by providers like [Amazon Web Services](https://aws.amazon.com/) and [Heroku](https://www.heroku.com/). These "remote servers" provide business advantages at least in terms of:

* Cost
* Scalability
* Efficiency
* Security
* Usability
* Reliability

Different kinds of servers perform different functions. Common server types include:

* Application Servers
* Database Servers
* Email Servers
* Web Servers

### Application Servers

When an application's source code is uploaded to a remote server, the server is capable of running that software in a similar way as it would be run on a developer's local machine.

#### Deployment Environments

The same application can exist on many different computers, in different "environments".

| Name        | Description                                                                                                                                                                                                                                            | Common Developer Tasks                                                        | Primary Audience                                                 | Level of Risk |
| ----------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ | ----------------------------------------------------------------------------- | ---------------------------------------------------------------- | ------------- |
| Development | A computer, often a personal computer, on which you produce, develop, and test an application's source code.                                                                                                                                           | Running a local web server, editing code in a text-editor, and running tests. | One or more individual members of the software development team. | Low           |
| Staging     | A computer, often a remote server, onto which you deploy an application's source code to emulate as best as possible the production environment to get a sense for how code changes will affect the application running on the production environment. | Performing usability tests, monitoring server scalability and performance.    | One or more collective members of the software development team. | Medium        |
| Production  | A computer, often a remote server, onto which you deploy your application's source code for "live" usage.                                                                                                                                              | Monitoring server logs.                                                       | Users, customers, and the public at large.                       | Very High     |