Now, let's talk about software and mobile operating systems. We're going to mostly use examples from iOS and Android. But other mobile operating systems work in a similar way. If your mobile device is using a specialized OS, you'll find information on how that software works and the devices documentation. Software for mobile OS's is distributed as mobile applications or apps. Apps have to come from a source that the mobile device has been configured to trust. On most OS's, you can't just download an app from a random website and install it. Instead, mobile operating systems use app stores. App stores are a central managed marketplace for app developers to publish and sell mobile apps. The App Store app acts like a Package Manager, and the App Store Service acts like a package repository. People use App Stores to access free and paid applications from a central source through a single interface. Apps published through an App Store have usually been through a security review and have been approved by the store owner. Apps published through an App Store are signed by the developer of the app. Though OS is configured to only trust code that's been signed by publishers that it recognizes. We'll talk more about co-signing in a future module. For now, just think of it like signing a letter. The developer is saying I wrote this. There's one way that code signing is different than signing a letter though. If anyone changes the code, the signature becomes invalid. This lets the operating system know if the code's been tampered with. Centralized App Stores work great for apps that are available to the public. But what if your organization needs to run some type of custom App? You'll need to use enterprise app management, which allows an organization to distribute custom mobile apps. These apps were developed by or for the organization, and aren't available to the general public. Enterprise apps are assigned with an enterprise certificate that has to be trusted by the devices that are installing the applications. As an IT Support Specialist, you might help manage enterprise app installation through the mobile device management or MDM service, which we'll learn about in a future video. There's one other way to install an app into a mobile OS, and that's called side-loading. Side-loading is where you install mobile apps directly without using an App Store. Side-loading packages is riskier than installing through an App Store, and you would generally only do this if you're an app developer. Mobile apps are standalone software packages. So they contain all their dependencies. When you install an app, it will already have everything it needs to run baked in. Mobile apps are assigned a specific storage location for their data. As you use a mobile app, anything that's changed or created with that app will end up in that apps assigned storage location or cache. So resetting a mobile app to how it was when it was first installed is a simple as deleting or clearing the cache. In your IT support role, you might help people troubleshoot mobile apps. Clearing the cache will remove all changes to the settings and sign out of any accounts that the app was signed into. It might not be the first thing you should try when trying to wrinkle in unruly app. But it is a great technique for when things are really broken. Check out the supplemental reading for a guy on how to do this. Mobile devices will usually be configured to check for app updates on a regular schedule. In IT support, you might need to make sure an app is updated. You'll find details on how to check for app updates in the supplemental reading.
