This document discusses input/output (I/O) concepts in operating systems. It covers I/O devices and controllers, principles of I/O software including device independence and uniform naming. Memory-mapped I/O, direct memory access, and interrupts are described. Page replacement algorithms like not recently used and first-in first-out are introduced. The document also examines disk hardware components, formatting, and scheduling algorithms. Error handling and stable storage concepts for disks are summarized. References for further reading on operating system concepts are provided.

1. Sistem Operasi
IKH311
Masukan Luaran (Input/Output)

2. Prinsip I/O
2

3. Device Controllers

I/O devices have components:
●
mechanical component
●
electronic component

The electronic component is the device
controller
●
may be able to handle multiple devices

Controller's tasks
●
convert serial bit stream to block of bytes
●
perform error correction as necessary
●
make available to main memory

4. Principles of I/O Software
Goals of I/O Software (1)
 Device independence
● programs can access
any I/O device
● without specifying
device in advance
– (floppy, hard drive, or
CD-ROM)
 Uniform naming
● name of a file or
device a string or an
integer
● not depending on

5. Memory-Mapped I/O

6. Memory-Mapped I/O

7. Direct Memory Access (DMA)

8. Interrupt

9. Not Recently Used Page Replacement
Algorithm
 Each page has
Reference bit,
Modified bit
 bits are set when
page is
referenced,
modified
 Pages are classified
 not referenced,
not modified
 not referenced,
modified

10. Device-Independent I/O Software
(1)
Uniform interfacing for device drivers
Buffering
Error reporting
Allocating and releasing dedicate devices
Providing a deice-independent block size
Functions of the device-independent I/O software
10

11. FIFO Page Replacement
Algorithm

Maintain a linked list of all pages

in order they came into memory

Page at beginning of list replaced

Disadvantage

page in memory the longest may be often used

12. Device-Independent I/O Software
(3)
(a) Unbuffered input
(b) Buffering in user space
(c) Buffering in the kernel followed by copying to user space
(d) Double buffering in the kernel 12

13. Device-Independent I/O Software
(4)
Networking may involve many copies
13

14. Disks
Disk Hardware (1)
Disk parameters for the original IBM PC floppy disk 14
and a Western Digital WD 18300 hard disk

15. Disk Hardware (2)

Physical geometry of a disk with two zones

A possible virtual geometry for this disk 15

16. Disk Hardware (3)

Raid levels 0 through 2

Backup and parity drives are shaded 16

17. Disk Hardware
(4)

Raid levels 3 through 5

Backup and parity drives are shaded 17

18. Disk Hardware (5)
Recording structure of a CD or CD-ROM 18

19. Disk Hardware (6)
Logical data layout on a CD-ROM
19

20. Disk Hardware (7)

Cross section of a CD-R disk and laser
●
not to scale

Silver CD-ROM has similar structure
●
without dye layer
●
with pitted aluminum layer instead of gold 20

21. Disk Hardware (8)
A double sided, dual layer DVD disk
21

22. Disk Formatting (1)
A disk sector
22

23. Disk Formatting (2)
An illustration of cylinder skew 23

24. Disk Formatting (3)

No interleaving

Single interleaving

Double interleaving
24

25. Disk Arm Scheduling Algorithms (1)
• Time required to read or write a disk
block determined by 3 factors
1. Seek time
2. Rotational delay
3. Actual transfer time
• Seek time dominates
• Error checking is done by controllers
25

26. Disk Arm Scheduling Algorithms (2)
Initial Pending
position requests
Shortest Seek First (SSF) disk scheduling algorithm
26

27. Disk Arm Scheduling Algorithms (3)
The elevator algorithm for scheduling disk requests
27

28. Error Handling

A disk track with a bad sector

Substituting a spare for the bad sector

Shifting all the sectors to bypass the bad one
28

29. Stable Storage
Analysis of the influence of crashes on stable writes
29

30. Pustaka

Avi Silberschatz, "Operating System Concepts"

http://codex.cs.yale.edu/avi/os-
book/OS8/os8j/index.html

Andrew Tanenbaum, "Modern Operating
Systems"

http://www.cs.vu.nl/~ast/books/mos2/

Harvey Deitel, "Operating Systems"

http://cs.nyu.edu/~yap/classes/os/resources/origin_of
_PV.html

tjerdastangkas.blogspot.com/search/label/ikh311