Lec3 - Part2

Android services are pre-installed by the system

Android uses less battery than iOS

Android supports more flexible multitasking using services

iOS didn’t support memory allocation

A process that was suspended and never resumed

A child process that is still running without its parent

A terminated process that hasn't been collected by its parent

A process without access to memory

The child is forced to terminate immediately

The child becomes an orphan and may be adopted by the init/system process

The child remains blocked forever

The OS restarts the parent automatically

A graphical interface for background apps

A special type of process that controls CPU scheduling

A component that performs background tasks without a UI

A class used to stop processes on exit

They are reused by the system immediately

They remain in the process table as a zombie

They are discarded silently

The kernel blocks the parent until it collects the child

Termination of parent causes suspension of child

Termination of parent causes all children to be terminated

Child kills parent and takes over PID

Processes terminate one after another in round robin

Zombie: running; Orphan: terminated

Zombie: no parent; Orphan: parent doesn’t wait

Zombie: terminated but not collected; Orphan: alive but parentless

Both mean the same

kill()

fork()

wait()

exec()

Foreground process

Service process

Visible process

Empty process

Because it’s automatically reparented to a kernel thread that invokes wait()

Because the kernel suspends orphan processes until memory is freed

Because zombies only occur if the child finishes before being adopted by init

Because init (PID 1) adopts the orphan and immediately calls wait() upon its termination