Giới thiệu về hệ điều hành

H iu hnh Operating System

1

2

Thong tin can biet

Tai lieu tham khao

[1] Remzi H. Arpaci-Dusseau and Andrea C. Arpaci-Dusseau, Operating Systems: Three Easy Pieces, 0.8v, 2014.

[2] Silberschatz et al, Operating System Principles, 9th Ed., 2012.

[3] A. Tanenbaum, Modern Operating Systems, Prentice Hall, 4nd Ed., 2014.

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Noi dung

Tong quan

Khai niem ve qua trnh

ong bo va giai quyet tranh chap

Deadlock va phng cach giai quyet

nh thi bieu cho qua trnh

Quan ly bo nh

Thay the trang

Quan ly nhap xuat

He thong file Three pieces Concurrency

Virtualization

Persistence

4

Chng 1: Tong Quan

Gii thieu

Cau truc luan ly cua he thong may tnh

nh ngha he ieu hanh

Cac chc nang chnh cua he ieu hanh

Qua trnh phat trien

May tnh ln (mainframe system)

May e ban (desktop system)

a x ly (multiprocessor system)

Phan bo (distributed system)

Thi gian thc (real-time system)

Cam tay (handheld system)

What is an operating system?

5

6

nh ngha

He ieu hanh la g?

Phan mem trung gian gia

phan cng may tnh va ngi

s dung, co chc nang ieu

khien phan cng va cung cap

cac dch vu c ban cho cac ng

dung

Muc tieu

Giup ngi dung de dang s

dung he thong

Quan ly va cap phat tai nguyen

he thong mot cach hieu qua

[yeu to kinh te]

Phan cng

He ieu Hanh

Cac ng dung

Ngi dung

7 1.1 Fig 1.1

Cac thanh phan cua he thong may tnh

CPU, b nh, cc thit b nhp

xut cung cp ti nguyn tnh ton

cho h thng

kim sot v phn phi cc ti nguyn

cho cc ng dng khc nhau cho

nhng ngi dng khc nhau

x l vn bn, bng tnh, cc tin ch

gii tr ,

8

Cac chc nang chnh cua OS

Phan chia thi gian x ly tren CPU (nh thi)

Phoi hp va ong bo hoat ong gia cac qua trnh

Quan ly tai nguyen he thong hieu qua

Kiem soat qua trnh truy cap, bao ve he thong

Duy tr s nhat quan cua he thong, kiem soat loi va phuc

hoi he thong khi co loi xay ra

Cung cap giao dien lam viec thuan tien cho ngi dung

9

Lch s phat trien

May tnh ln (mainframe)

X ly bo (batch, 1960)

a chng (multiprogrammed, 1970)

a nhiem (time-sharing, multitasking; 1970)

10

Lch s phat trien

(Mainframe) Batch system,

1960

I/O: card uc lo, bang t (tape),

line printer

Can co ngi van hanh

(operator)

Giam setup time bang cach

ghep nhom (batching) cong

viec (job)

Vd: ghep cac cong viec

cung s dung trnh bien

dch Fortran

T ong nap lan lt cac cong

viec t card reader

11

Lch s phat trien (tt)

(Mainframe) Batch system n

gian

Uniprogramming

Khi mot job thc thi xong,

quyen ieu khien tr ve he

ieu hanh (resident monitor)

Resident monitor oc job

ke tiep t card reader vao

bo nh

Thc thi job cho en khi

xong

resident

monitor

user job

Layout bo nh

13

Mainframe computer

in 1967

14 1.2.2

(Mainframe) Multiprogrammed system

Nhieu job c gi ong thi trong bo nh

CPU thc thi luan phien gia cac job trong

bo nh

Tan dung c thi gian ranh, tang hieu

suat s dung CPU

Yeu cau oi vi he ieu hanh

nh thi job

nh thi CPU

Quan ly bo nh (memory management)

Cap phat tai nguyen (a, may in,)

Bao ve

Lch s phat trien he ieu hanh (tt)

15


16 1.2.3


(Mainframe) Time-sharing

system

Multiprogrammed system

khong cung cap kha nang

tng tac hieu qua vi user

CPU thc thi luan phien gia

cac cong viec

Moi cong viec c chia

mot phan nho thi gian

CPU (time slice, quantum

time)

Cung cap tng tac gia

user va he thong vi thi

gian ap ng (response

time) nho (1 s)

Computer terminal, 1982

17


Yeu cau oi vi OS trong he thong time-sharing

Quan ly bo nh

Virtual memory

Quan ly cac qua trnh

nh thi CPU

ong bo cac qua trnh (synchronization)

Giao tiep gia cac qua trnh (process communication)

Van e deadlock

Quan ly he thong file, he thong lu tr (memory system)

Cap phat hp ly cac tai nguyen

Bao ve

18


May e ban (desktop system,

personal computer)

Nhieu thiet b I/O: ban phm,

chuot, man hnh, may in,

Phuc vu ngi dung n le

Muc tieu chnh cua OS

Thuan tien cho user va kha

nang tng tac cao

Khong can toi u hieu suat

s dung CPU va thiet b

ngoai vi

Nhieu he ieu hanh khac nhau

MS Windows, Mac OS, Unix, Linux,

1981: IBM 5150

19 1.4


He thong song song (parallel, multiprocessor, hay

tightly-coupled system)

Nhieu CPU

Chia se computer bus, clock

u iem

System throughput: cang nhieu processor th cang nhanh

xong cong viec ( d oan thi tiet)

Multiprocessor system t ton kem hn multiple single-

processor system: v co the dung chung tai nguyen (a,)

o tin cay: khi mot processor hong th cong viec cua no

c chia se gia cac processor con lai

20 1.4


Phan loai he thong song song

a x ly oi xng (symmetric multiprocessor SMP)

Moi processor van hanh mot identical copy cua he ieu

hanh

Cac copy giao tiep vi nhau khi can

a x ly bat oi xng (asymmetric multiprocessor)

Moi processor thc thi mot cong viec khac nhau

Master processor nh thi va phan cong viec cho cac

slave processor

21 1.5


He thong phan bo (distributed system, loosely-coupled

system)

Mi processor co bo nh rieng, cac processor giao tiep qua

cac kenh noi nh mang, bus toc o cao, leased line

Ngi dung ch thay mot he thong n nhat

u iem

Chia se tai nguyen (resource sharing)

Chia se sc manh tnh toan (computational sharing)

o tin cay cao (high reliability)

o san sang cao (high availability): cac dch vu cua he

thong c cung cap lien tuc cho du mot thanh phan

hardware tr nen hong

23 1.5.1, 1.5.2


He thong phan bo (tt)

Cac mo hnh he thong phan bo

Client-server

Server: cung cap dch vu

Client: co the s dung dch vu cua server

24


He thong phan bo

Cac mo hnh he thong phan bo (tt)

Peer-to-peer (P2P,1990s)

Cac peer (may tnh trong he thong) eu ngang hang nhau

Khong da tren c s d lieu tap trung

Cac peer la t tr

Vd: mang gnutella, mot mang trong Internet e chia se file

25 1.7


He thong thi gian thc (real-time system)

ieu khien trong xe hi, day chuyen cong nghiep,

Rang buoc ve thi gian: ap ng cua he thong phai thoa thi

han (deadline) e x ly bien co (event)

Phan loai

Hard real-time

ieu khien may no, airbag trong xe hi, robotics,

Do han che (hoac khong co) bo nh th cap, tat ca d lieu

nam trong bo nh chnh (RAM hoac ROM)

Yeu cau ve thi gian ap ng/x ly rat nghiem ngat

Soft real-time

Multimedia, virtual reality

Yeu cau mem deo hn ve thi gian ap ng

26


Thiet b cam tay (handheld system)

http://www.phonearena.com/phones/compare/Apple-iPhone-

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Iphone 6 Samsung Galaxy Note 4

Device

type Smart phone Smart phone

OS iOS (8.x) Android (4.4)

Dimensi

ons

5.44 x 2.64 x 0.27

inches (138.1 x 67 x 6.9

mm)

6.04 x 3.09 x 0.33 inches

(153.5 x 78.6 x 8.5 mm)

Weight 4.55 oz (129 g)

6.21 oz (176 g)

Body

material Aluminium

History of Windows

History of Windows

https://www.youtube.com/watch?v=aqkkByP8RDM

History of Android

https://www.youtube.com/watch?v=DNAQtgH1ErI

History of Linux

http://www.youtube.com/watch?v=0kteK4-RSJ8

27

Cau truc he thong may

tnh

28

29

Kien truc c ban cua he thong PC

CPU

Disk controller USB controller Graphics adapter

MEMORY

Disks

Mouse

Keyboard

Printer

Monitor

em d lieu (local buffer)

C che van hanh cua he thong

31

Chu trnh hoat ong cua CPU

Start Fetch Next

Instruction

Execute

Instruction

HALT

Check for interrupt;

Process interrupt Interrupts

enabled

Interrupts

disabled

32

Ngat quang

Phan loai: ngat quang do

Program: tran so hoc, chia cho 0, truy cap bo nh bat hp phap

Timer: cho phep CPU thc thi mot tac vu nao o theo nh ky

I/O: ket thuc tac vu I/O, xay ra loi trong I/O

Hardware failure: H hong nguon, loi memory parity,

Trap (software interrupt): yeu cau dch vu he thong (goi system call),

Lc o thi gian khi process co yeu cau cac tac vu I/O

33

Qua trnh x ly ngat quang

X ly trap tng t x ly HW interrupt

i

i+1

0

M

User

Program

Interrupt

handler thc thi

0

21 00ffe23f

N

Interrupt

vector table

int. 0x21

0

00ffe23f interrupt

0x21 routine

ret

ffffffff

1

2

3

Cau truc he thong I/O

35

ieu khien thiet b I/O

Tren device controller co

Thanh ghi lenh (command / control register) e nhan yeu

cau I/O t OS

Thanh ghi trang thai (status register) e bao OS tnh

trang san sang / ang ban / loi cua thiet b

Thanh ghi d lieu (data register) OS oc d lieu t thiet b hay ghi d lieu ra thiet b qua thanh ghi nay

36

Cac ky thuat thc hien I/O (1/2)

Ky thuat I/O dung polling

I/O code ch thiet b san sang bang cach lien tuc (nh bang

cach dung vong lap) kiem tra tnh trang cua thiet b

Khi thiet b san sang, I/O code gi lenh, va oc/ghi d lieu thong

qua cac thanh ghi cua thiet b

37

Cac ky thuat thc hien I/O (2/2)

Ky thuat I/O dung ngat quang (interrupt-driven I/O)

I/O code gi lenh, va oc/ghi d lieu thong qua cac thanh ghi

cua thiet b

Khi thiet b hoan tat lenh I/O th se gay ngat en CPU

38

Truyen d lieu gia bo nh va thiet b

Programmed I/O

OS dung CPU cycle e di chuyen d lieu gia bo nh va thiet b

Nhan xet: programmed I/O khong hu hieu (can nhieu CPU

cycle) khi thc hien di chuyen khoi lng ln d lieu

Ky thuat Direct Memory Access (DMA)

DMA can co phan cng ho tr ac biet, o la DMA controller

Ky thuat DMA thc hien truyen d lieu trc tiep gia thiet b I/O

va bo nh ma khong can s can thiep cua CPU

39 2.2.1 Fig 2.3

Ky thuat thc hien I/O mc ng dung

Blocking Nonblocking, asynchronous

-- Thng bo I/O hon tt bng signal hay callback

Blocking / nonblocking I/O

- - - : bo qua oan ma

kernel kernel

40 2.2.1 Fig 2.4

Quan ly cac truy cap thiet b I/O

Cac hang i (wait queue) I/O

Hang i cac yeu cau I/O, vd

Cau truc & phan cap

he thong lu tr

42 2.3

He thong lu tr

Lu tr (memory, storage) la mot trong nhng dang thc

I/O quan trong

Bo nh chnh (main memory, primary memory)

Trc tiep th CPU ch co the truy cap c cac thanh ghi

(register) va bo nh ROM, RAM

Bo nh phu (secondary storage): He thong lu tr thong tin ben

vng (nonvolatile storage)

a t (magnetic disk): a mem, a cng, bang t

a quang (optical disk): CD-ROM, DVD-ROM

Flash ROM: USB disk

43

Metaphor (an du) cho phan cap he thong lu tr

oc sach th vien

Ke sach phong oc

Phong / ham lu tr sach

Ban oc memory

a cng

bang t

Dung

lng

tang

44 2.4 Fig 2.6

Phan cap he thong lu tr

Toc o nhanh

Gia thanh moi byte re

Dung lng ln

vd: file-system data

45 2.4 Fig 2.7

Ky thuat caching

Caching: nap trc d lieu vao thiet b lu tr co toc o

truy cap cao hn

Tai sao dung cache?

Cai thien toc o truy cap d lieu

A: d lieu

46 2.4 Fig 2.7

Ky thuat caching

V sao caching works?

Nguyen ly cuc bo (locality principle)

Van e:

D lieu ln, con kch thc cache nho phai quan ly cache:

thay noi dung nao cua cache khi no ay?

Mot d lieu co the c lu tr nhieu ni can bao am tnh

nhat quan d lieu: cache coherency problem

Bao ve tai nguyen chia se

48 2.5.1

Dual mode (1/3)

Muc tieu: bao ve he ieu hanh va chng trnh ng dung

Giai phap

Ky thuat dual mode: CPU thc thi di mot trong hai che

o (mode)

User mode ch thc thi c cac lenh nonprivileged

Application chay trong user mode

Kernel mode (con goi la supervisor mode, system mode, monitor

mode) thc thi c tat ca cac lenh (privileged va nonprivileged) cua CPU

Kernel chay trong kernel mode

49

Dual mode (2/3)

Hnh cua Dror G. Feitelson

50

Dual mode (3/3)

Phan cng co them mode bit e kiem soat mode hien hanh:

mode bit = kernel (= 0) -- kernel mode

mode bit = user (= 1) -- user mode

Khi CPU b ngat (do thiet b ngoai vi, trap,), CPU se chuyen sang kernel mode va thc thi interrupt service routine tng ng.

Dong thc thi va thay oi che o CPU khi goi system call

kernel user

mode bit = user

mode bit = kernel

51 2.5.2 Fig 2.8

Bao ve I/O

Ngan user s dung I/O khong hp le

Giai phap: lenh I/O eu la privileged

instruction

User mode program khong thc thi c lenh I/O ( trap), phai thong qua li goi system call

System call

La phng thc duy nhat e process yeu cau cac dch vu cua he ieu hanh

System call se gay ra ngat mem (trap), quyen ieu khien c chuyen en

trnh phuc vu ngat tng ng, ong

thi thiet lap mode = kernel

He ieu hanh kiem tra tnh hp le, ung an cua cac oi so, thc hien

yeu cau roi tra quyen ieu khien ve

lenh ke tiep ngay sau li goi system

call, mode = user

52 2.5.3 Figs 2.9 + 2.10

Bao ve bo nh (1/2)

V du: bao ve vung nh cap

phat cho cac process, ho tr

bi phan cng

Base register

Limit register

53 2.5.3 Figs 2.9 + 2.10

Bao ve bo nh (2/2)

Truy cap bo nh ngoai vung xac nh bi thanh ghi base va thanh

ghi limit se sinh ra trap

Lenh nap gia tr cho cac thanh ghi base va thanh ghi limit eu la

privileged instruction

memory

54 2.5.4

Bao ve CPU

Bao ve CPU

Bao am OS duy tr c quyen ieu khien CPU

Lam g trng hp CPU thc thi trong vong lap vo han?

C che thc hien la dung timer e kch khi cac ngat

quang nh ky

Bo em timer se giam dan sau moi xung clock

Khi bo em timer bang 0 th ngat timer c kch hoat he ieu

hanh se nam lai quyen ieu khien

Lenh nap gia tr bo em timer la privileged instruction

55 2.5.4

Timer

Co the s dung timer e thc hien time-sharing

Thiet lap timer gay ngat nh ky N ms (N: time slice, quantum

time) va nh thi CPU sau moi lan ngat

Co the dung timer e tnh thi gian troi qua (elapse time)

56 3.1.1

Cac thanh phan cua he ieu hanh (1/7)

Quan ly qua trnh

Qua trnh vs chng trnh

Mot qua trnh can cac tai nguyen cua he thong nh CPU, bo

nh, file, thiet b I/O, e hoan thanh cong viec

Cac nhiem vu

Tao va huy qua trnh

Tam ngng / tiep tuc thc thi (suspend / resume) qua trnh

Cung cap cac c che

ong bo hoat ong cac qua trnh

giao tiep gia cac qua trnh

x ly deadlock

57 3.1.2


Quan ly bo nh chnh

Can thiet v nhieu qua trnh chay ong thi trong he thong phai

chia se bo nh

Tuy thuoc kien truc may tnh

e co hieu suat cao, he ieu hanh can dung giai thuat quan ly

bo nh thch hp

Cac nhiem vu

Theo doi, quan ly cac vung nh trong va a cap phat

Quyet nh se nap chng trnh nao khi co vung nh trong

Cap phat va thu hoi cac vung nh

58 3.1.3


Can thiet cho viec lu tr d lieu ben vng (persistent):

Tien ch file va quan ly file

He thong file (file system)

File

Th muc

Cac dch vu ma thanh phan cung cap

Tao va xoa file/th muc

Cac tac vu x ly file/th muc (rename, copy, move, new,)

Anh xa file/th muc vao thiet b lu tr th cap tng ng

Sao lu va phuc hoi d lieu

59 3.1.4


Quan ly he thong I/O

Che dau cac ac trng rieng biet cua tng

thiet b I/O oi vi user

Co chc nang

Buffering, caching, spooling

Buffer: vung nh e lu d lieu khi

chung c truyen gia hai thiet b

hay gia thiet b va ng dung

Cung cap giao dien chung en cac trnh

ieu khien thiet b (device-driver

interface)

Trnh ieu khien thiet b cho moi chung

loai thiet b phan cng khac nhau

60 3.1.5


Quan ly he thong lu tr th cap

Bo nh chnh: kch thc nho, la moi trng cha tin khong ben

vng can he thong lu tr th cap e lu tr ben vng cac d

lieu, chng trnh

Phng tien lu tr thong dung la a t, a quang

Nhiem vu

Quan ly vung trong

Cap phat khong gian lu tr (storage allocation)

nh thi a (disk scheduling)

61 3.1.7


He thong bao ve (protection system) can thiet khi he

thong cho phep nhieu user hay nhieu qua trnh

Kiem soat qua trnh ngi dung ang nhap/xuat (login, logout)

va s dung he thong

Kiem soat viec truy cap cac tai nguyen trong he thong

Bao am ch nhng ngi dung/qua trnh u quyen han mi

c phep s dung cac tai nguyen tng ng

Cac nhiem vu

Cung cap c che kiem soat ang nhap/xuat

Phan nh c s truy cap tai nguyen hp le va bat hp le

(authorized / unauthorized)

Phng tien thi hanh cac chnh sach (enforcement of policies)

Chnh sach: can bao ve d lieu cua ai oi vi ai

62 3.1.8


Trnh thong dch lenh (command line interpreter)

La giao dien chu yeu gia ngi dung va OS

V du: shell, mouse-based window-and-menu

Khi user login

He thong khi tao command line interpreter (shell) cho user,

va no ch nhan lenh t ngi dung, thc thi lenh va tra ket

qua ve

Lien he chat che vi cac thanh phan khac cua he ieu hanh e

thc thi cac yeu cau cua ngi dung

63 3.1.8


Trnh thong dch lenh (tt)

Cac nhom lenh trnh thong dch lenh e

Tao, huy, xem thong tin qua trnh, he thong

ieu khien truy cap I/O

Quan ly, truy cap he thong lu tr th cap

Quan ly, s dung bo nh

Truy cap he thong file

64 3.2

Cac dch vu he ieu hanh cung cap (1/2)

Mot so dch vu chu yeu ma ngi dung hay chng trnh

can

Thc thi chng trnh

Thc hien cac tac vu I/O do yeu cau cua chng trnh

Cac tac vu len file

oc/ghi hay tao/xoa file

Giao tiep, trao oi thong tin gia cac qua trnh

Shared memory

Message passing

Phat hien loi

Tren thiet b I/O: d lieu h, het giay,

Chng trnh ng dung: chia cho 0, truy cap en a ch bo

nh khong c phep

65 3.2

Cac dch vu he ieu hanh cung cap (2/2)

Cac dch vu khac

Cap phat tai nguyen

Tai nguyen: tape drives,

OS co cac routine tng ng

Ke toan (accounting)

V du e tnh ph

66 3.3

Giao dien gia qua trnh va he ieu

hanh

System call

Phng phap hien thc giao dien gia qua trnh va he ieu hanh

Vd: open, read, write file

Thong thng dang th vien nh phan (binary library)

Trong cac ngon ng lap trnh cap cao, mot so th vien lap trnh

c xay dng da tren cac th vien he thong (v du Windows

API, th vien GNU C/C++ nh glibc, glibc++,)

Ba cach truyen tham so trong system call

Truyen tham so qua thanh ghi

Truyen tham so thong qua mot vung nh, a ch cua vung

nh c gi en he ieu hanh qua thanh ghi

Truyen tham so qua stack

V d v system call

67

68 3.4

Cac chng trnh he thong

Chng trnh he thong (phan biet vi application program)

gom

Quan ly file: nh create, delete, rename, list

Thong tin trang thai he thong: nh time, dung lng bo nh trong

Soan thao van ban: nh vi/vim tren Unix/Linux

Ho tr ngon ng lap trnh: nh compiler, assembler, interpreter

Nap, thc thi, giup tm loi chng trnh: nh loader, debugger

Giao tiep: nh email, talk, web browser

Ngi dung cuoi chu yeu lam viec thong qua cac system

program (khong s dung trc tiep cac system call).

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