Timesharing Operating Systems On a single processor system, o"Round robin"scheduling system switches between threads and processes fast enough that it appears that multiple programs are running o Only one is every truly executing at a time On multi-core or multi-processor systems, o Threads or processes can be allocated across the processors True parallel processing o“Round-robin”scheduling still occurs 6
Timesharing Operating Systems • On a single processor system, o “Round robin” scheduling system switches between threads and processes fast enough that it appears that multiple programs are running o Only one is every truly executing at a time • On multi-core or multi-processor systems, o Threads or processes can be allocated across the processors ▪ True parallel processing o “Round-robin” scheduling still occurs 6
Android Android starts a new Linux process for the application with a single thread of execution All components of the same application run in the same process and thread 。This thread is called the“main”thread or“U"thread Any updates to the Ul/display must be accomplished on the main thread
Android • Android starts a new Linux process for the application with a single thread of execution • All components of the same application run in the same process and thread • This thread is called the “main” thread or “UI” thread • Any updates to the UI/display must be accomplished on the main thread 7