lecture 1

Question 1

What are the two main roles of an operating system?

Answer 1

OS is a resource allocator
* Manages all resources
* Decides between conflicting requests for efficient and fair
resource use
* OS is a control program
* Controls execution of programs to prevent errors and improper
use of the computer

Question 2

What is an operating system?

Answer 2

A program that acts as an
intermediary between a user of
a computer and the computer
hardware

Question 3

What are the three goals of an operating system?

Answer 3

• Execute user programs and make
  solving user problems easier
• Make the computer system
  convenient to use
• Use the computer hardware in an
  efficient manner

Question 4

Old way of interacting with I/O devices

Answer 4

• A user program requests a
  system call to use an i/o
  device
• The system calls the driver
• The driver starts the I/O
  device and continuously polls
  to see if it is done
• When the device tells the
  driver it is done, the driver
  puts the data where required
  and finishes

Question 5

The new way of processing interrupts:

Answer 5

• A user program requests a
  system call to use an I/O device
• The system calls the driver
• The driver starts the I/O device
  and returns
• The CPU can look for another job
  to do
• When the device is done, it sends
  an INTERRUPT to signal it
  finished
• The CPU processes the data
  received

Question 6

What are the 4 services that the OS provides?

Answer 6

• I/O communication
• Storage management
• File management
• Process management

Question 7

What are the main tasks of memory mangement?

Answer 7

Memory management
* Keeping track of which parts of memory are currently being
used and which process is using them
* Allocating and deallocating memory space as needed
* Deciding which processes (or parts of processes) and data to
move into and out of memory

Question 8

What are the main tasks of mass storage management

Answer 8

Mass storage management
* Mounting and unmounting
* Free-space management
* Storage allocation
* Disk scheduling
* Partitioning
* Protection

Question 9

What are the main tasks of file management?

Answer 9

• Creating and deleting files
• Creating and deleting directories to organize files
• Supporting primitives for manipulating files and directories
• Mapping files onto mass storage
• Backing up files on stable (nonvolatile) storage media

Question 10

What are the main tasks of process management?

Answer 10

• Creating and deleting both user and system processes
• Scheduling processes and threads on the CPUs
• Suspending and resuming processes
• Providing mechanisms for process synchronization
• Providing mechanisms for process communication

Question 11

What is the bootstrap program?

Answer 11

• Init computer
• Load operating system and start it