Chapter 4: Operating Systems

What are the components of the Kernel?

-File manager -Memory manager -Device Drives Scheduler and Dispatcher

What are the five components of the OS?

-Kernel ~File Manager ~Memory Manager ~Device drivers ~Scheduler and Dispatcher -User Interface ~text based ~gui ~Windows manager

What does the OS do?

-Supports the computer's basic functions -Oversee operation of computer -Schedule programs for execution -Coordinate the execution of programs -Store and retrieve files

What are the components of the User Interface

-Windows manager

What information is contained when the process is added in the process table?

-location (memory area) assigned -priority of the process -whether the process is ready or waiting

What are examples of device drivers?

-printers -monitor -disk drive

How does the CPU react to an interrupt?

Completes its current machine cycle, saves its current position in the current process, and begins executing a program, interrupt handler (describes how the dispatcher should respond to the interrupt signal.)

What is a Dispatcher?

Controls the allocation of time slice to the processes in the process table *end of the time slice is signaled by an interrupt

How/Why processes are scheduled?

Each time an action is executed or requested, the scheduler creates a new entry for that process in the process table.

What are interrupts?

Each time the dispatcher awards a time slice to a process, it initiates a timer circuit that will indicate the end of the slice by generating a signal

Operating System (OS)

System software that provides an interface between the user or application program and the computer hardware.

What is the difference between the user interface and the kernel?

The kernel is the internal part of an OS and contains software components that perform basic functions required by the computer installation. Whereas the user interface handles communication with their users.

What is a kernel?

The main program of the operating system that manages the other programs in the operating system.

process table

To keep track of all the processes.. the scheduler maintains a block of information in the main memory

What is the user interface?

a system that allows a computer and a user to interact and perform useful functions

what is a Scheduler?

adds new processes in the process and removes completed processes from the pool

Dispatcher

controls the allocation of time to these activities

What is virtual memory?

extended storage space created by the memory manager

How are virtual addresses are translated?

the os sets up "page tables" that replace upper bits of a memory address with a different physical location

What are device drivers?

the software that runs on the CPU/communicate with the controllers. Also, carry out operations on the devices attached to the machine.

What happens during a context switch?

when the kernel transfers control of the CPU from an executing process to another that is ready to run...first saves the context of that process then start executing a new one