1-1. Message passing is useful for exchanging smaller amounts of data, because no conflicts need be avoided. Message passing is also easier to implement than is shared memory for interprocess communication.
1-2.In shared memory model, memory is shared by cooperating processes, which can exchange information by reading and writing data but in message passing communication takes place by means of messages exchanged between the cooperating processes.
2-1. Providing the interface to communicate with the operating system kernal is called system call. Without system call, communication between operating system and hardware is not possible. Accessing the files and process communication is possible through system calls. Library functions provide system call functionalities.
3-1. Hardware configuration references the details and system resource settings allotted for a specific device. Many computer specialists improve hardware performance by adjusting configurations, which may also include settings for the motherboard and the BIOS, as well as the bus speeds.
With newer technology, most computers have plug-and-play (PnP) allowing the OS to detect and configure external and internal peripherals, as well as most adaptors. PnP has the ability to locate and configure hardware components without needing to reset jumpers and dual in-line package (DIP) switches.