Tech in the 603, The Granite State Hacker

Data Persistence in Windows Universal (8.1) apps (Boston Code Camp 23)

Thanks to everyone who joined me for my Boston Code Camp 23 presentation.  Shuffling data around is a core responsibility of any serious computing platform.  Windows Universal really goes above and beyond the mundane call of duty with consistency and utility. It’s part of what makes the Windows client platform a true “cloud car”, especially with its Backup, Roaming Settings / Folders, and Roaming Password Vault capabilities as native functionality… all from the Windows.Storage namespace.

Here are

For the individual who asked what encryption level the Windows Password Vault functionality uses, I looked it up, and it’s 128bit AES encryption.  Stern stuff there.

Another question came up about app backups.  As I said in the presentation, the content of the Local storage is backed up automatically to the cloud by the OS.  (Isn’t that fantastic?!)

Likewise, as mentioned, the Temporary storage is excluded from backups.

One detail I missed however… the LocalCache storage area.  LocalCache is like Local except that it is not backed up.  LocalCache differs from Temporary storage in that the OS will not wipe it as it occasionally does the Temporary storage.  Next time I do this presentation, I’ll make sure to update it to discuss LocalCache.

Here’s a comparison of the storage options available to developers in the 8.1/universal platform. Note that each user on a device gets their own app-specific sandbox *and* OneDrive space for each installed app.

Type Availability Limits Settings hashtable Backed Up By OS Sync’d to all App / User / Devices by OS Encryption Wiped By OS if space is low Uri prefix Suggested use
Install Package Universal Static/ReadOnly Media from Install No No No Sandboxed No ms-appx:// Version specific static app media
Local Universal Available free storage Yes Yes No Sandboxed No ms-appdata:///local/ General
Local Cache Windows Phone Only Available free storage Yes No No Sandboxed No   Persistent cache
Temporary Universal Available free storage Yes No No Sandboxed Yes ms-appdata:///temp Semi-persistent cache
SD/Removable Universal Available free storage No No No None No   Removable/general
Roaming Universal 100k Yes (by virtue of roaming) Yes Cloud Partitioned No ms-appdata:///roaming Roaming settings
Password Vault Universal 100k (included in Roaming) Password-friendly structure (by virtue of roaming) Yes Cloud Partioned + 128bit AES No   Roaming credentials /OAuth tokens

I asked my stunt audience (the kids) later what my presentation had been about.  I was glad to know at least one of them had gotten it right. 

They were inspired, though, and that’s the important part. 

I hope you found inspiration in technology from both the day and maybe in some small part from my presentation.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google+ photo

You are commenting using your Google+ account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s