Test 1

An OS kernal can use internal threads.

Condition variables are like general semaphores

Wait() in UNIX is a condition variable wait operation.

Each interrupt handler has its own process control block

Threads are more expensive for an OS to create than processes

To provide multiuser protection, hardware must have at least two execution modes.

An OS should never create more processes than the available number of processors

An OS provides a single, global waiting list for all the threads that are in the waiting state.

When a user attempts to execute a privileged instruction in user mode the CPU should stop.

On modern processors, all instructions are atomic. E.g., an x86 string move instruction is atomic

A loadable device driver means that the kernel does not have to be recompiled to use the device.

Fork() in UNIX creates a new thread, which then executes the function that is passed as an argument.

The interrupt vector table should be held in user memory so that users can assign exception handlers.

In a typical modern OS, each schedulable unit of execution needs to have a different protection domain.

When using fine-grain locking, all the locks should be stored together in a single array in kernel memory.

Virtual machine.

Disk details such as sector size are hidden.

Higher-level objects are provided, such as files.

Resource allocation among users and applications.

Files written by one application can be read by another

Facilitates a common "look and feel" across applications.

Controls boundaries to allow applications to communicate

Prevent users from accessing each other's files without permission

Valid to execute a store instruction in this mode.

Mode need to reset the reset the hardware timer(yes it's like this on the test)

An exception occurs if the execution of a privileged instruction is attempted in this mode

In this mode, the effective address generated by load instruction is checked so that access is allowed only to a designated region of memory

Has an associated control block.

Has an associated data segment

Has an associated PC(program counter)

Has an individual set of process registers