The Fire HD 8 comes preloaded with the Amazon Appstore, which defaults to the Amazon Underground version of the store. The Amazon Appstore is a curated version of Google Play, which means a smaller selection.
A: A single-user multitasking operating system is an operating system that allows a single user to simultaneously run multiple applications on a computer. This type of operating system is found in personal desktop and laptop computers. The most popular single-user multitasking operating systems include Microsoft Windows and Macintosh. Continue Reading
Time-sharing systems are multi-user systems. Most batch processing systems for mainframe computers may also be considered multi-user, to avoid leaving the CPU idle while it waits for I/O operations to complete. However, the term  multitasking  is more common in this context.