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Developer tool: Use Cases for portability (Agile)

Posted: Mon Mar 07, 2016 11:20 am
by webfork

For developers who visit this site, you might wonder exactly what enabling portability is going to bring to your project. Do users really care about this feature? Here are a few Use Cases that try to help make clear who cares and why.


What is a Use Case? | What is Agile?

Use Case for portability
  • As someone who ...
    • Stores all their data on a cloud drive service (e.g. DropBox,, OneDrive, etc.)
    • Uses a USB drive to store all their data
    . . . I want to avoid re-entering my settings every time I move to a new computer. As such, saving settings to the local folder rather than AppData or the Registry is ideal. Additionally, since drive letters and specific folders can change, the program should generally avoid hard links (e.g. .\files rather than C:\User\USERNAME\Files\).

Additional Use Cases
  • As someone who ...
    • [Security] ... stores all their data inside an encrypted volume for security purposes (this could be a TrueCrypt, VeraCrypt, Windows VHD, etc), settings saved outside of that volume are a security/privacy issue. As such, I need settings to be saved to the local folder. I'd additionally like to avoid writing any program-related information outside of the application folder.
    • [Multi-machine] ... synchronizes two computers across a network, having the settings saved to the local folder makes this much easier. While there are ways to do this that include the AppData and Registry, it's much simpler to keep things in the application folder.
    • [Backup] ... expects my hard drive to fail at some point, I run frequent backups and don't wish to chase down all the little the settings files saved in AppData\Local, AppData\Roaming, ProgramData, Program Files, and a dozen other places.

      Note that, as with the "multi-machine" example above, there are ways to do this that include AppData and the Registry but they generally are more complex.
    • [Cross-platform] ... uses Windows programs on Mac/Linux/Android/etc. via a tool like WINE/Crossover, I avoid programs that save settings to Registry, as they're sometimes not well understood by WINE/Crossover and cause issues. As such, saving to the local folder is ideal.
    • [Software Quality Assurance] ... tests software, it's a lot easier to go through starting from a specific program state from backup. With standard software, I regularly have to uninstall, reboot, reinstall, and THEN test a program. If I make a mistake in the middle of the testing process, I'll have to do it all over again, which is a huge waste of time.

      Self-contained portable programs don't have this issue. You can even have multiple versions of the same program on one computer so you can see where an issue appeared, which enables faster determination of where a given code change created an issue.

      While installer testing is often still necessary, it's better to spend energy on something more likely to catch more bugs.
    • [Upgrade testing] ... needs to have software work reliably and effectively, I can easily test the upgrade process by copying my current program to another folder. I then perform an upgrade on the backup folder to see if it causes issues. I can then either re-run the upgrade on my original folder or just copy over the result. (Care of user vevy.)
    • [Single user account] ... wants to have multiple versions of the same program with unique settings, I can just create a copy and make changes. The only way to achieve this with installed applications is with multiple user accounts and lots of effort to log in and out to get to a modified environment. (Care of user vevy.)

      Some programs will even let you run multiple copies of the same program at the same time (usually referred to as "instances").
Use case for PortableApps
  • As someone who likes portable software (with features mentioned in above use cases) I also enjoy the ease of updating offered by the PortableApps format (PAF). That toolset allows me to set the extract folder to the destination and won't overwrite the contained files, since the PAF tool avoids overwriting the "settings" folder.
(Note that some users prefer not to use wrapper programs like portableApps. In this case, a clearly labeled separate settings file or folder can also function this way.)


Related: Hashing use cases

Re: Developer tool: Use Cases for portability (Agile)

Posted: Sat Jun 10, 2017 5:12 pm
by webfork
Update: came up with another use case that I've added to the above list (Testing)

Re: Developer tool: Use Cases for portability (Agile)

Posted: Mon Sep 07, 2020 10:26 am
by vevy
Something similar to your testing point is when I experiment with a potential upgrade. For example, when LibreOffice launched v7. I can "install" v7 to a separate folder to play with it. I can also make a copy of v6 folder and extract v7 on top to test if the upgrade would be smooth, etc.

Another use case is having separate sets of settings for an app beyond what it provides internally and without having to create another Windows user account. For example, you can have separate visual styles/themes for different uses of the same flexible app.

Re: Developer tool: Use Cases for portability (Agile)

Posted: Sun Sep 27, 2020 10:00 am
by webfork
vevy wrote:
Mon Sep 07, 2020 10:26 am
... experiment with a potential upgrade ... separate sets of settings for an app beyond what it provides internally
Both excellent additions, I'll add those with credit to the main list for easy reference.