(OS) 1. Desktop Computers - Architecture & OS Review

The CPU fetches the next instruction from memory according to the value of the _______

• program counter
• status register
• instruction register
• program status word

An operating system …

• acts as an intermediary between the users of a computer and the hardware
• acts as a control program for the various I/O devices and user programs
• acts as a resource allocator to arbitrate resource allocation to programs
• all of the mentioned

User programs use _______ to access the functions of the operating system

• system calls
• hardware interrupts
• library functions
• assembly instructions

What events can generate an access to the operating system?

• A hardware generated interrupt from an I/O device
• A software generated interrupt caused by an error
• A software generated interrupt caused by a request from a user program
• All of the mentioned

The hardware allows _______ instructions to be executed only in kernel mode

• load/store
• privileged
• sensitive
• assembly

What support does the hardware offer to access the operating system?

• It differentiates among various modes of operation
• It loads the code of the corresponding interrupt handler and executes it when interrupts happen
• It transitions automatically from user to kernel mode when interrupts and traps happen
• All of the mentioned

Which operation is performed by an interrupt handler?

• Saving the current state of the system
• Loading the code of the interrupt service routine and executing it
• Once done handling, bringing back the system to the original state it was before the interrupt occurred
• All of the mentioned

Cache memory speeds up memory access because …

• it exploits temporal locality
• it exploits spatial locality
• it exploits temporal and spatial locality
• it contains the same data stored in the main memory

An address generated by a process during its execution is a _______

• physical address

• absolute address

• logical address

• none of the mentioned

Run time mapping from logical to physical addresses is done by the _______

• memory management unit
• CPU
• memory DIMMs
• none of the mentioned