Review for the Midterm

All chapter #s are for the 9^th edition.

Chapter 1

What is an O.S?
The kernel
A traffic cop
A resource allocator
The kernel + utilities and stuff

Chapter 2

• System Calls

  • It’s a request to the OS to do something

  • It’s

    • Load registers

    • TRAP

    • Answer in a return register

• I/O Overlap

  • Why

  • How to achieve

Chapter 3

• What is a process

  • Different from thread

  • Different from executable

• Process queues

  • Running

  • Ready

  • New

  • Exit

  • Wait

• Ways to make a new process

  • Fork

  • Spawn/system

Chapter 4

• Threads -- definition of

• Threads share code, heap(global variables and new/delete stuff) but not stack(local variables)

• How to program threads using the pthread library

  • pthread_creat()

  • pthread_join

  • locking

    • Even readers need to lock if there is anyone writing.

Chapter 5 (Skip)

Chapter 6

• CPU Burst -- definition

• Preemptive scheduling

• Aging

• Criteria

  • CPU Utilization

  • Throughput

  • Wait time

  • Starvation

  • Fairness

• Algortihms

  • FCFS

  • Shortest Job Next

  • Round Robin

  • Priority

  • Multi-level feedback queues (yes, really)

  • Real Time

    • Priority Inversion -- the definition and the solution

    • Which process goes next

      • Most important????

      • Soonest deadline???

    • Soft vs Hard real time

Chapter 7

• Deadlock

  • Definition

  • Avoid by ordering resources

  • Avoid by using two phases

  • Avoid by drawing the wait-for graph

  • Avoid by timeouts

Chapter 8 and 9

• Definition of swapping

• Segments

  • Hardware needed

  • External fragmentation

  • Choosing a spot

    • First fit

    • Best fit

    • Worst fit

• Paging

  • Hardware needed

  • What do do on an MMU interrupt (see chart 9.2.2, page 405)

  • Page Tables

    • Protection

    • Computing the size

    • Multi-level page tables

  • Page table base registers

  • Translation lookaside buffer

  • Internal fragmentation

  • Sharing pages

    • Code

    • Heap (if you’re two threads of the same process)

    • copy-on-write

  • Replacement algorithms

    • Optimal (Belady's Min)

    • LRU

    • FIFO

    • Additional bits

Chapter 10

• Disk scheduling algorithms

  • FCFS

  • Elevator

  • Cyclic elevator

  • Shortest seek next

• RAID (especially levels 0, 1, 5)

  • What to do for error

  • What to do when a new disk is inserted

  • Speed

    • Small reads

    • small writes

    • large reads

    • large writes

  • Capacity

  • Sledge hammer factor

File systems (Chapter 11 a little bit)

Mounting is when you put a file system on top of a directory
Consistency Semantics (11.5.3)
Session (open/close) consistency
Unix (single image) consistency
Immutable consistency
Ad hoc consistency (not in the book)

Other Stuff

• VFAT

  • VFAT organization

  • File names and long file names

Device Drivers

• Interrupts

  • Maskable

  • Types

    • Caused by I/O

    • Caused by processor exception

    • Caused by software

• Polling

• DMA

  • Who can

  • Who should

  • Interaction with paging subsystem

Microkernels (very minimal)

• Advantages

  • Flexible

  • Subsystem crashes don't kill everything

• Disadvantages

  • Performance????