Usability & UX

Software that is too complicated to use, is often unused. Thus, usability and user experience of Qubes OS is an utmost priority for us, as we want as many people as possible to benefit from the unique security properties of Qubes OS!

We ask anyone developing for Qubes OS to please read through this guide to better understand the user experience we strive to achieve. Also, please review our style guide for other design related information.


Easy To Use

An ideal user experience is friendly and welcomes a new user to explore the interface and in this process easily discover how to use the software. Additionally, security focused software has the responsibility of providing safety to a user and their data.

Interfaces Should Not
  • Require numerous settings to be entered before a user can begin doing things
  • Make it possible to break provided features or actions in unrecoverable ways
  • Perform actions which compromise security and data
  • Overwhelm with too much information and cognitive load

Perhaps the most common cause of mistakes is complexity. Thus, if there is a configuration setting that will significantly affect the user experience, choose a safe and smart default then tuck this setting in an Advanced Settings panel.

Interfaces Should
  • Make it easy to discover features and available actions
  • Provide some understanding of what discovered features do
  • Offer the ability to easily undo mistakes
  • Choose intelligent defaults for settings

A crucial thing in making software easy to use, is being mindful of cognitive load which dictates that “humans are generally able to hold only seven +/- two units of information in short-term memory.” This short-term memory limit is perhaps the most important factor in helping a user feel comfortable instead of overwhelmed.


Easy to Understand

There will always be the need to communicate things to users. In these cases, an interface should aim to make this information easy to understand. The following are simple guides to help achieve this- none these are absolute maxims!

Avoid Acronyms

Acronyms are short and make good names for command line tools. Acronyms do not make graphical user interfaces more intuitive for non-technical users. Until one learns an acronyms meaning, it is otherwise meaningless. Avoid acronyms whenever possible!

  • DVM - Disposable Virtual Machine
  • GUID - Global Unique Identifier
  • PID - Process Identification
  • NetVM - Networking Virtual Machine
Use Simple Words

Use the minimum amount of words needed to be descriptive, but also informative. Go with common words that are as widely understood as possible. Sometimes, inventing a word such as Qube to describe a virutal machine in the context of Qubes OS, is a good idea.

  • Use Disposable Qube instead of DVM
  • Use interface instead of GUI
  • Use application instead of PID
  • Use Networking or Networking Qube instead of NetVM given context

However, acronyms like USB are widely used and understood due to being in common use for over a decade. It is good to use these acronyms, as the full words Universal Serial Bus is more likely to confuse users.


Avoid Technical Words

Technical words are usually more accurate, but they often only make sense to technical users and are confusing and unhelpful to non-technical users. Examples of technical words that might show up in Qubes OS are:

  • root.img
  • savefile
  • qrexec-daemon

These are all terms that have at some point showed up in notification messages presented users. Each term is very accurate, but requires understanding virtualization

Use Common Concepts

Large amounts of the global population have been using computers for one or two decades and have formed some mental models of how things work. Leveraging these mental models are a huge gain.

  • Use disk space instead of root.img while not quite accurate, it makes contextual sense
  • Usesaving instead of savefile as the former is the action trying to be completed
  • Use Qubes instead of qrexec-daemon as it is the larger context what is happening

These words are more abstract and user relevant- they help a user understand what is happening based on already known concepts (disk space) or start to form a mental model of something new (Qubes).


Avoid Inconsistencies

It is easy to start abbreviating (or making acronyms) of long terms like Disposable Virtual Machine depending on where the term shows up in an interface.

  • DVM
  • DispVM
  • DisposableVM

This variation in terms can cause new users to question or second guess what the three different variations mean, which can lead to inaction or mistakes.

Make Things Consistent

Always strive to keep things consistent in the interfaces as well as documentation and other materials.

  • Use Disposable Qube at all times as it meets other criteria as well.

By using the same term throughout an interface, a user can create a mental model and relationship with that term allowing them to feel empowered.


Avoid Duplicate Words

It is easy when trying to be descriptive and accurate to add words like Domain before items in a list or menu such as:

Menu
- Domain: work
- Domain: banking
- Domain: personal

The repeated use of the word Domain requires a user to read it for each item in the list, which takes extra time for the eye to parse out the relevant word like work, banking, or personal. This also affects horizontal space on fixed width lines.

Create Groups & Categories

It is more efficient to group things under headings like Domains as this allows the eye to easily scan the uniqueness of the items.

Domains
- Work
- Banking
- Personal

Easy To Complete

Lastly, expected (and unexpected) situations will happen which require user actions or input. Make resolving of these actions as easy as possible to complete the action or find.

Don't Leave Users Stranded

Consider the following notifications which are shown to a user:

  • The disk space of your Qube "Work" is full
  • There was an error saving Qube "Personal"
Offer Actionable Solutions

An error message or limit such as that can be greatly improved upon by adding buttons or links to helpful information.

  • Add a button Increase Disk Space
  • Add a link to documentation Troubleshoot saving data

Adhering to these principles, make undesirable situations more manageable for users instead of feeling stranded.


Avoid Repetitive Tasks

There are many cases where a user wants to perform an action on more than one file or folder. However in order to do the action, the user must repeat certain steps such as:

  1. Click on Open File from a menu or button
  2. Navigate through file system
    • Click Folder One
    • Click Folder Two
    • Click Folder Three
    • Click Folder Four
  3. Select proper file
  4. Complete task on file

That subtle act of clicking through a file system can prove to be significant if a user needs to open more than a couples files in the same directory.

Minimize Repetitive Steps
  1. Click on Open File from a menu or button
  2. Remember last open file system
  3. Select proper file
  4. Complete task

Clearly, cutting out navigating through the file system can save a user quite a bit of time. Alternatively, adding a button or menu item Open Multiple Files could be even better, as using hot keys to select multiple files is often a thing only power users know how to do!


GNOME, KDE, and Xfce

The the desktop GUIs which QubesOS versions 1 - 3.1 offer are KDE, as well as Xfce. We are currently migrating towards using GNOME. We know some people prefer KDE, however, we believe the overalluser experience of GNOME is more focused on simplicity and ease of use for average non-technical users. Xfce will always be supported, and technical users will always be able to still use KDE or other desktop environments.

This means you should use GTK rather than Qt for new GUIs.

All three desktop environments have their own human interface guidelines and we suggest you familiarize yourself with the platform you developing for.


Further Learning & Inspiration

Learning to make well designing intuitive interfaces and software is specialized skillset that can take years to cultivate, but if you are interested in furthering your understanding of usability and experience, we suggest the following resources.