Chapter02-Operating System Structures

Chng 2Cu trc H iu Hnh

ThS: H L Hoi Trung

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n tp chng 1

Nu cu trc h thng my tnh?

HH c nhng chc nng chnh no?

Theo gc h thng x l, HH c

phn thnh my loi? K tn?

Nhng yu cu ca h iu hnh i vi

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Mc tiu

Bit c cc thnh phn ca h iu hnh

Hiu c cc dch v m h iu hnh

cung cp

Phn bit system call & library

Hiu c cu trc ca mt h thng my

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Ni Dung

Cac thanh phan cua he ieu hanh

Cac dch vu he ieu hanh cung cap

Li goi he thong (System call)

Cac chng trnh he thong (system programs)

Cau truc he thong

May ao (virtual machine)

Cc thnh phn ca H iu Hnh

Qun l qu trnh

Qun l b nh chnh

Qun l file

Qun l h thng I/O

Qun l h thng lu tr th cp

H thng bo v

H thng thng dch lnh

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2.1. Cac thanh phan cua he ieu hanh

- Qua trnh (hay tien trnh process) la g?

- Qua trnh khac chng trnh iem g?

- 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 cua thanh phan

Tao va huy qua trnh

Tam dng/thc thi tiep (suspend/resume) qua trnh

Cung cap cac c che

ong bo hoat ong cac qua trnh (synchronization)

giao tiep gia cac qua trnh (interprocess communication)

khong che tc nghn (deadlock)

2.1.1. Quan ly qua trnh (process management)

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Bo nh chnh la trung tam cua cac thao tac, x ly

e nang cao hieu suat s dung CPU, he ieu hanh can quan ly bo nh thch hp

Cac nhiem vu cua thanh phan

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 khi can thiet

2.1.2. Quan ly bo nh chnh

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He thong file (file system)

File

Th muc

Cac dch vu ma thanh phan cung cap

Tao va xoa file/th muc.

Cac thao tac x ly file/th muc (mkdir, 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

2.1.3. Quan ly file (file management)

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Che dau s khac biet cua cac thiet b I/O trc

ngi dung

Co chc nang

C che: buffering, caching, spooling

Cung cap giao dien chung en cac trnh ieu khien

thiet b (device-driver interface)

Bo ieu khien cac thiet b (device driver) phan cng.

2.1.4. Quan ly he thong I/O (I/O system management)

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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 cua he ieu hanh trong quan ly a

Quan ly khong gian trong tren a(free space management)

Cap phat khong gian lu tr (storage allocation)

nh thi hoat ong cho a (disk scheduling)

S dung thng xuyen => anh hng ln en toc o cua ca

he thong => can hieu qua

2.1.5. Quan ly he thong lu tr th cap (secondary

storage management)

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Trong he thong cho phep nhieu user hay nhieu process dien ra ong thi:

Kiem soat qua trnh ngi dung ang nhap/xuat va s dung he thong

Kiem soat viec truy cap cac tai nguyen trong he thong

Bao am nhng user/process ch c phep s dung cac tai nguyen

danh cho no

Cac nhiem vu cua he thong bao ve

Cung cap c che kiem soat ang nhap/xuat (login, log out)

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

(authorized/unauthorized)

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

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

2.1.6. He thong bao ve

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La giao dien chu yeu gia ngi dung va OS

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

Khi user login

command line interpreter (shell) chay, va ch nhan lenh t ngi

dung, thc thi lenh va tra ket qua ve.

Cac lenh ->bo ieu khien lenh ->he ieu hanh

Cac lenh co quan he vi cac viec:

Tao, huy, va quan ly qua trnh, he thong

Kiem soat I/O

Quan ly bo lu tr th cap

Quan ly bo nh chnh

Truy cap he thong file va c che bao mat

2.1.7. He thong thong dch lenh

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2.2. Cac dch vu he ieu hanh cung cap

Thc thi chng trnh

Thc hien cac thao tac I/O theo yeu cau cua chng trnh

Cac thao tac tren he thong file

oc/ghi hay tao/xoa file

Trao oi thong tin gia cac qua trnh qua hai cach:

Chia xe bo nh (Shared memory)

Chuyen thong iep (Message passing)

Phat hien loi

Trong CPU, bo nh, tren thiet b I/O (d lieu h, het giay,)

Do chng trnh: chia cho 0, truy cap en a ch bo nh khong cho phep.

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2.2. Cac dch vu he ieu hanh cung cap

Ngoai ra con cac dch vu giup tang hieu suat cua he thong:

Cap phat tai nguyen (resource allocation)

Tai nguyen: CPU, bo nh chnh, tape drives,OS co cac routine tng ng

Ke toan (accounting)

Nham lu vet user e tnh ph hoac n gian e thong ke.

Bao ve (protection)

Hai qua trnh khac nhau khong c anh hng nhau

Kiem soat c cac truy xuat tai nguyen cua he thong

An ninh (security)

Ch cac user c phep s dung he thong mi truy cap c tai

nguyen cua he thong (vd: thong qua username va password)

Mode

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2.3. Li goi he thong (System call)

Dung e giao tiep gia qua trnh va he ieu hanh

Cung cap giao tip gia qua trnh va he ieu hanh

Vd: open, read, write file

Thong thng dang th vien nh phan (binary libraries) hay giong nh cac lenh hp ng.

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 phng phap truyen tham so khi s dung system call

Qua thanh ghi

Qua mot vung nh, a ch cua vung nh c gi en he ieu hanh qua thanh ghi

Qua stack

Truyn tham s qua bng

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V d v system call

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Cc loi system call

Qu trnh

Qun l File

Qun l cc thit b I/O

Cung cp c ch giao tip

Thng tin

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System call & library

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System call & library

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2.4. Cac chng trnh he thong

Chng trnh he thong (system program, phan biet vi application

program) gom

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

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

Soan thao file: nh file editor

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 chu yeu lam viec thong qua cac system program (khong

lam viec trc tiep vi cac system call)System call & library???

V d system call

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Cu trc h thng

Cu trc n gin - MS-DOS

Cu trc phc tp hn UNIX

Cu trc phn tng

Cu trc vi nhn

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2.5. Cau truc he thong

Cau truc n gian (monolithic) MS-DOS: khi thiet ke, do gii

han ve dung lng bo nh nen

khong phan chia thanh cac

module (modularization) va cha

phan chia ro chc nang gia cac

phan cua he thong.

Cau truc phan tang cua MS-DOS

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Cau truc n gian (monolithic)UNIX: gom hai phan co the tach ri nhau

Nhan (cung cap file system, CPU scheduling, memory management, va mot so chc nang khac) va system program

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Cau truc phan tang: HH c chi thanh nhieu lp (layer). Lp di cung: hardware

Lp tren cung la giao tiep vi user

Lp tren ch phu thuoc lp di

Mot lp ch co the goi cac ham cua lp di va cac ham cua no c goi bi lp tren

Moi lp tng ng mot oi tng tru tng: cau truc d lieu + thao tac

Phan lp co li ch g? G roi (debugger, kiem tra he thong, thay oi chc nang)

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Cau truc phan tang: Lan au tien c ap dung cho HH THE (Technische Hogeschool

Eindhoven)

Lp 5 user programm

Lp 4 Tao buffer cho thiet b I/O

Lp 3 Device driver thao tac man hnh

Lp 2 Quan ly bo nh

Lp 1 Lap lch CPU

Lp 0 Phan cng

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Vi nhan: phan chia module theo microkernel (CMU Mach OS, 1980) Chuyen mot so chc nang cua OS t kernel space sang user space

Thu gon kernel => microkernel, microkernel ch bao gom cac chc nang toi thieu nh quan ly qua trnh, bo nh va c che giao tiep gia cac qua

trnh

Giao tiep gia cac module qua c che truyen thong iep

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Vi nhan:- Li ch: de m rong HH

- Mot so HH hien ai s dung vi nhan:

+ Tru64 UNIX (Digital UNIX trc ay): nhan Mach

+ Apple MacOS Server : nhan Mach

+ QNX vi nhan cung cap: truyen thong iep, nh thi CPU, giao tiep mang cap thap va ngat phan cng

+ Windows NT: chay cac ng dung khac nhau win32, OS/2, POSIX

(Portable OS for uniX)

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2.6. May ao

Hien thc y niem VM Lam the nao e thc thi mot chng trnh

MS-DOS tren mot he thong Sun vi he

ieu hanh Solaris ?

1. Tao mot may ao Intel ben tren he ieu

hanh Solaris va he thong Sun

2. Cac lenh Intel (x86) c may ao

Intel chuyen thanh lenh tng ng cua

he thong Sun.

Sun hardware

Solaris kernel

VM interpretation

Intel x86 VM

Intel x86 Application

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2.6. May ao

T OS layer en may ao (virtual machine)

Non-virtual machine

system modelVirtual machine system model

processes

kernel

hardware

processes

processes

processes

kernel kernel kernel

VM1 VM2 VM3

Virtual-machine

implementation

hardware

programming

interface

Documents

Chapter02-Operating System Structures