Chapter 2

Question 1

What is the purpose of Os systems?

Answer 1

make programming easier

Question 2

describe UI

Answer 2

• command line interface (CLI) uses text commands and methods for entering
• batch interface uses commands to commands are entered into files which are executed
• graphical user interface uses a window system with a pointing device to direct i/o, choose from menus, make selections, and a keyboard to enter text

Question 3

describe execution

Answer 3

load program to memory, run program, and execution

Question 4

describe i/o operations

Answer 4

for efficiency and protection, users usually cannot control i/o devices directly

Question 5

describe file-system manipulation

Answer 5

read/write/create/delete files

Question 6

describe communications

Answer 6

implemented via shared memory; 2+ processes read and write to a shared section of memory, or message passing, in which packets of info in predefined formats are moved between processes by the OS

Question 7

describe error detection

Answer 7

errors may occur in CPU, memory hardware, i/o devices, and user program

Question 8

describe resource allocation

Answer 8

resources need to be allocated for multiple jobs/users running concurrently

Question 9

describe accounting

Answer 9

for statistics or billing

Question 10

describe protection and security

Answer 10

concurrent processes could cause interference so protection and security is useful and necessary

Question 11

2 fundamental approaches for users to interface with OS

Answer 11

1. command-line interface allows users to directly enter command to be performed
2. uses a GUI

Question 12

define shells

Answer 12

interpreters with systems of multiple command interpreters to choose from

Question 13

main function of command interpreter

Answer 13

get and execute next user-specified command

Question 14

2 general ways of implementation of command interpreters

Answer 14

1. command interpreter contains code to execute the command

2. uses command to identify a file to be loaded into memory and executed

Question 15

define graphical user interface

Answer 15

interpreter that uses a mouse-based window and menu system: desktop
gestures on the touch screen on the ipad

Question 16

a benefit of command line interfaces

Answer 16

it makes repetitive tasks easier

Question 17

describe system calls

Answer 17

they provide an interface to the services made available by an OS

Question 18

define system-call interface

Answer 18

interprets function calls in the API and invokes the necessary system calls within the OS

Question 19

3 general methods to pass parameters to OS

Answer 19

1. pass parameters in registers
2. store parameters in block/table/memory and then pass its address
3. parameters placed/pushed onto stack and popped off the stack by OS

Question 20

6 major categories of system calls

Answer 20

1. process control
2. file manipulation
3. device manipulation
4. information maintenance
5. communications
6. protection

Question 21

define debugger

Answer 21

system program designed to aid the programmer in finding and correcting errors to determine problem

Question 22

steps of process control

Answer 22

1. OS transfers control to invoking command interpreter
2. command interpreter reads next command
3. different systems continue differently
   - ensure integrity of shared data, there is a system call allowing a process to lock shared data

Question 23

describe interactive system

Answer 23

assumed user will issue an appropriate command to respond to any error

Question 24

describe batch system

Answer 24

command interpreter terminates entire job and moves on to next job

Question 25

an example of single-tasking system

Answer 25

MS-DOS

Question 26

an example of multi-tasking system

Answer 26

FreeBSD

Question 27

MS-DOS definition and steps

Answer 27

has a command interpreter that is invoked when computer has started, doesn't create a new process, loads program into memory, sets instructions pointer to first instructions, runs, error causes trap or program executes system call to terminate (error is saved), reloads rest of command interpreter from disk

Question 28

define FreeBSD

Answer 28

accepts commands and executes programs that the user requests, multi-tasking of loading and running

Question 29

define single step

Answer 29

trap is executed by CPU after every instruction; microprocessors provide this CPU mode

Question 30

2 common models of interprocess communication

Answer 30

1. the messaging model | 2. shared-memory model

Question 31

define messaging model

Answer 31

communication process exchange messages with on another to transfer information

Question 32

define host name

Answer 32

name of computer in a network, usually has a network identifier; IP address

Question 33

define process name

Answer 33

name of process which is translated into an identifier

Question 34

define daemons

Answer 34

system programs, special-purpose, server

Question 35

define shared-memory model

Answer 35

use system calls to create and gain access to regions of memory owned by other processes

Question 36

define protection

Answer 36

provides a mechanism for controlling access to the resources provided by a computer system

Question 37

list computer hierarchy from least to greatest

Answer 37

hardware --> OS --> system programs --> application programs

Question 38

define system programs

Answer 38

system utilities; provide a convenient environment for program development and execution

Question 39

define file management

Answer 39

programs create/copy/delete/receive and manipulate files and directories

Question 40

define status information

Answer 40

use a registry which stores/receive configuration information

Question 41

define file modification

Answer 41

there are special commands to search and modify files

Question 42

define programming-language support

Answer 42

compilers, assemblers, debuggers, and interpreters

Question 43

define program loading/execution

Answer 43

must be loaded into memory to be executed

Question 44

define communications

Answer 44

creating virtual connections among processes, users, and computer systems

Question 45

define background services

Answer 45

services, subsystems, or daemons

Question 46

define mechanisms

Answer 46

determine HOW to do something

Question 47

define policies

Answer 47

determine what will be done

Question 48

why are policies important

Answer 48

for all resource allocation

Question 49

what does the kernel do through system calls

Answer 49

- provides the file system - cpu scheduling - memory management - other OS functions

Question 50

what is the bottom layer of OS

Answer 50

hardware

Question 51

what is the highest layer of OS

Answer 51

user interface

Question 52

what are problems with layered approach of OS

Answer 52

less efficient, hard to define the various layers

Question 53

define MACH

Answer 53

operating system that modularized the kernel using the microkernel approach

Question 54

name a benefit of the microkernel approach

Answer 54

easier to port from one hardware design to another

Question 55

define loadable kernel modules

Answer 55

kernel to provide core services while other services are implemented dynamically, as the kernel is running, more flexible than a layered approach, more efficient

Question 56

7 types of loadable kernel modules

Answer 56

1. scheduling classes 2. file systems 3. loadable system calls 4. executable formats 5. stream modules 6. miscellaneous 7. device and bus drivers

Question 57

define kernel extensions

Answer 57

I/O kit for development of device drivers and dynamically loadable modules

Question 58

define iOS

Answer 58

closed-sourced, structured on MAC OS X but does not directly run MAC OS X applications, used for mobile devices, such as touch screens

Question 59

define android

Answer 59

open-source, layered

Question 60

define core dump

Answer 60

capture of the memory of the process

Question 61

define crash

Answer 61

failure in kernel

Question 62

define crash dump

Answer 62

where memory of log file is saved to

Question 63

define trace listings

Answer 63

provide traces of all 'significant' events where errors are tracked

Question 64

define Dtrace

Answer 64

facility that dynamically adds probes to a running, both in user process and in the kernel

Question 65

define profiling

Answer 65

periodically sampling the instruction pointer to determine which code is being executed shows statistical trends but not individual activities

Question 66

define system generation (SYSGEN)

Answer 66

process for specific computer

Question 67

define booting system

Answer 67

starting computer by loading the kernel

Question 68

define bootstrap program or bootstrap loader

Answer 68

locates the kernel, loads to main memory, starts its execution

Question 69

define GRUB

Answer 69

open-source bootstrap program for LINUX systems

Question 70

define boot disk or system disk

Answer 70

disk with partition