NLHDH Chuong 4

8/3/2019 NLHDH Chuong 4

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Chng 4.

H THNG TP TIN


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Phan Trung Kin 2

Cc yu cu ca ngi dng Persistence

Speed Size

Sharing/protection

Ease of use


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Phan Trung Kin 3

S h tr t phn cng v h iu hnh

Phncng

Persistence: cc thitblutrbnvng (non-volatile memory) Speed: cung cpkhnng truy xutngu nhin, nng cao tca (5400 7200 10K 15K rpm)

Size: dung lngln, 20M 700M 40G 200G 1T byte

Hiu hnh

Persistence: lutrdtha, back-upphcv cho recovery Vd: RAID (Redundant Array of Independent Disks)

Ease of use:

Gn tn cho mtchui cc khidliu file

Htrqun l cc filethmc

User khng cn quan tm n cc chi tit hardware (giao tipvi disk controllertheo IDE, SCSI,).

Sharing/Protection: cho php thitlp cc quyn truy cpfile/thmc


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Phan Trung Kin 4

nh ngha file File l mtchui cc dliuct tn, cc tc v c ththc

thi ln mt file l Read

Write


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Phan Trung Kin 5

Cc loi file Cc loi file

regularfile ASCII

binary

directory

special files (trong UNIX): characterspecial file, blockspecial file,


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Phan Trung Kin 6

Cc kiu file Cch phnbitkiu file

extension magic number


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Cc kiu file thng dng



nh dng file (1) ngdng c thlu v dindchdliu trong file theo nhdng ring

MS Word

PDF ELF



nh dng file (2)

Executable file Archive

V d trong UNIX



Cu trc file Cu trc file: m hnh file ngi dng lp trnh

Khng c cu trc: mtchui byte (Unix, DOS, Windows), Hnh a

Cu trc record Fixed length, Hnh b Variable length: h tr tm nhanh chng mt record vi key cho trc (IBM

mainframe), Hnh c



Cc cch truy cp file Dng cc tc v thng thng trn file,

truy cptunt(sequential access) truy xutdliu theo tht,tng byte hoc record truy cpbtk (random access)

truy xutdliu, byte hoc record, tiv trbtk truy cp dng kha

truy xutmt record da vo key ca n

Memory-mappedfile Gis c cc system call map v umap Gi map chiu file vo khng gian achoca qu trnh Dng cc tc v truy xutbnh truy xut file

Gi umap khi xong



Cc thuc tnh ca file



Cc tc v trn file Create

Tomt file mi

Write Thchin tc v ghi dliu vo file tiv tr con tr ghi

Read

Thchin tc vcdliut file tiv tr con trc

Reposition

Thitlp con trc/ghinv tr do qu trnh chnh Delete

Xa file

Truncate Gilittc cc thuc tnh ca file, ngoitr kch thc file cthitlpv 0

Open Qu trnhphimfile trc khi sdng

Close

Qu trnhphing file sau khi sdng



Th mc Th mc (directory, folder) l mt tin ch ca h iu hnh

ngi dng tchc cc file ca mnh Ngi dng c th xc nh file thucvhay nm trongmt directory; cch

ni khc, directory cha file



Cc tc v trn th mc Vdt UNIX

Create Tomt directory mi

Delete

Xa mt directory trng

Opendir

Qu trnhphimdirectory trc khi c n

Closedir

Qu trnhphing directory sau khi c n

Readdir

c entry tica directory

Link

Unlink



Cc loi cu trc ca th mc

Single-level directory Multi-level directory

Tree-structureddirectory

Acyclic-graph directory

General graph directory



Cc loi cu trc ca th mc (1) Single-level directory

Ch c mt directory cho mi file trong h thng (CDC 6600, IBM MVS,PalmOS)



Cc loi cu trc ca th mc (2) Citincu trc single-level directory

Mtsmc tiu Thun tin cho user khi t tn file, cc user khc nhau c tht tn file

trng nhau

File c th c nhiuhnmt tn

H trphn nhm (grouping): tchc cc files cng cim vo chungmt nhm (vd nhm file m ngun ngn ng C, nhm file Word,)



Cc loi cu trc ca th mc (3) Nu directory, ngoi file ra, cn c thcha directory khc

Two-level directory



Cc loi cu trc ca th mc (4) Tree-structureddirectory

Mt cy th mc trong UNIX



Cc loi cu trc ca th mc (5) Acyclic-graph directory


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Phan Trung Kin 22

Cc loi cu trc ca th mc (6) General-graph directory

Vn: cycle c thxuthin dng giithutkim tra chu trnh mi khi to file?


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Phan Trung Kin 23

ng dn Dng ngdn (path name) nmt file ctv trca file

trong cy hay rng directory Vd

UNIX, LINUX /usr/ast/mailbox

DOS, Windows \usr\ast\mailbox

ngdntuyti Thmchinthi (current directory, working directory)

ngdntngi


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File system mounting (1) Phign (mount) file system c th truy xut file ca n

Thmcgn vo mt file system cgi l mount point

thchinlnhgn

# mount /device/thedisk /mountpoint hiu hnhphithc thi ccbc

OS kim tra xem file system c hpl hay khng

Gn file system vo v tr mountpoint

Nu mount point c cha file?

Cc file cha trong thmcmount pointsb che cho n khi unmount file system.


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File system mounting (2)

file system trongpartition /dev/hda3

Cc file b che khi file system trong partition /dev/hda3 c mount vilnh mount /dev/hda3 /users

mount point


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Phan Trung Kin 26

File system mounting (3)

Sau khi mount, c th truy cp cc file trong partition /dev/hda3


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Phan Trung Kin 27

Chia s file Nhu cu chia s file trong hthng multi-user

Vic chia sphithchindicchbov,kim sot nghim ngt Hthngn: hard linkv soft link, thitlpquynhn chia s,

Trn hthngmng, file c thc chia s qua mng my tnh Truy cp filebng FTP

Network File System (NFS) l phng php chia s file rtphbin dng cch

RPC (m hnh client-server) File system t xa phi c gn (mount) trc khi s dng. V d:

mount ditlab.hcmut.edu.vn:/oscourse /home/mydir

Khi file system c mount, mi truy xutn file hay thmc trn nhbnh thng, user khng phnbit l local hay remote.


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Hard link v soft link

Trong UNIX

Hard link: ln /dict/count /spell/count

Soft link: ln -s /spell/words/list /dict/all


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V d mount remote file system

/

home

paper mydir

/

oscourse

IO VM

IO VM

/home/mydir/VM

/oscourse/VM

ditlab.hcmut.edu.vn

Local Client Remote Server


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Phan Trung Kin 30

Bo v (protection) Hiu hnh phih trch nhn ca file khnngkim sot qu trnh truy

cp file Cc tc v c ththchin trn file? Nhng ai cquynthchin thao tc trn file?

Cc quyn truy xut file Read

Write Execute

Append

Delete

Cch tipcn thng thng Mi file c mtAccess-control list(ACL), gm cc cp

Windows NT/2K/XP, Linux

user c th l mt nhm


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Phan Trung Kin 31

Access Control List

Owner ca process

B: R

File F1:- Mi qu trnh ca user A c quyn c/ghi- Mi qu trnh ca user B c quyn c


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Phan Trung Kin 32

Cc Access Control Bit Cc ch truy cp: read, write, execute

Ba nhm user: owner, group, other (public) User name v user identifier (user ID) Group name v group identifier (group ID)

Vd trong UNIX: mi nhm user c 1 field, mi field c 3 bit Field: read | write | execute Tr: 0/1 0/1 0/1

r w xowner access 7 1 1 1

group access 6 1 1 0

public access 1 0 0 1


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Phan Trung Kin 33

S b tr (layout) h thng file (1)

i-nodesPartition control block FCBs


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Phan Trung Kin 34

S b tr (layout) h thng file (2)

Partition control block:

lu s lng block trong partition, kch thc block, s lng free blockhinthi v cc con trchn chng,

luslng free FCB hinthi v cc con trchn chng,

Vd, UNIX File System: superblock

File control block (FCB): mi file cqun l thng qua FCBca n lu cc thng tin v file , kc cc con trchn cc data block ca n

Vd, UNIX File System: i-node


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Phan Trung Kin 35

VFSVirtual File System

diskpartition

diskpartition

ext2 file system FAT file system NFS file system

ng dng

VFS

: gi hm/th tcopen, read, write, opendir,


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Phan Trung Kin 36

Hin thc file Cp pht khng gian lutr cho file/directory, mc tiu:

sdng khng gian ahuhiu truy cp file nhanh

Ccphng php cp phtphbin

Cp pht lin tc (contiguous allocation) Cp pht theo danh sch lin kt(linked list allocation)

Cp pht dng chmc (indexed allocation)


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Phan Trung Kin 37

Cp pht lin tc

Seek time? Di chuynuc? C th truy xutngu nhin mt block ca file:

block nr = start + block offset Phn mnhngoi Vn khi to file mi v khi cn thm block

cho file ngdng: ISO-9660 (CDROM)


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Phan Trung Kin 38

Cp pht theo danh sch lin kt(1)

-1

-1

pointer

data

layout ca block


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Phan Trung Kin 39

Cp pht theo danh sch lin kt (2)

uim D dng thm block cho file khi cn

Qun l khng gian trngbng danhsch Khng c phn mnhngoi

Nhcim Ch truy xut hiu qu i vi

sequential-access file

Tn khng gian lutr cc con tr tin cy: pointer trong block c thbhng

Phn mnh ni khi n v cp pht lcluster (mthngs cc block)


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Phan Trung Kin 40

Bin th ca cp pht theo danh sch lin kt: FAT

FAT (File Allocation Table) Mi block actngtrngbi

mt entry trong FAT

Block vi block nr i c tngtrngbi entry vichs (index) i

Entry cha block nr k tiptrong file, nu file gm nhiublock

FAT

number of disk blocks - 1

C h d h (1)


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Phan Trung Kin 41

Cp pht dng ch mc (1)

Bngindex (index block) chaach cc block ca file

th t cc a ch trn trong bngcng l tht cc block trong file

C h d h (2)


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Phan Trung Kin 42

Cp pht dng ch mc (2)

uim Random v sequential access

Khng c phn mnhngoi

Khuytim Tn khng gian lutrbng index khi file c kch thcch vi block

Vn: kch thc index block bao nhiu l ph hp?

Giiquyt: multilevel index

i d


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Phan Trung Kin 43

i-node

UNIX v7 i-node: 13 pointers

Linux ext2 i-node: 15 pointers

i-node

Hi th th


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Phan Trung Kin 44

Hin thc th mc

MS-DOS UNIX, Linux

Thmcc dng chabng nh x t tn file (chui k t ASCII) n

thng tin cnthitnhv cc block dliuca file Tchcthmc

Danh sch tuyn tnh (array hay linear list),bngbm,

first block nr

FAT


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Phan Trung Kin 45

FAT Vd

H th fil FAT


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Phan Trung Kin 46

H thng file FAT FAT dng chbng FAT v cng dng chhthng file

Layout camt partition chahthng file FAT

Boot sector FAT Root directory Data blocks

Hi th t fil di


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Phan Trung Kin 47

Hin thc tn file di Giiquytvn tn file di (Win98, 2000, XP, *NIX,...)

(a) In-line

(b) Heap

i d (1)


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Phan Trung Kin 48

i-node (1)

V d

i d (2)


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Phan Trung Kin 49

i-nodes (2) Layout camt partition chahthng file UNIX

i d hi fil (1)


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Phan Trung Kin 50

i-node: chia s file (1)

i d hi fil (2)


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Phan Trung Kin 51

i-node: chia s file (2)


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Qun l khng gian trng


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Phan Trung Kin 53

Qun l khng gian trng

Ccphng php

Bit vector(bit map) Linked list

Grouping

Counting

Phng php bit vector (bit map)


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Phan Trung Kin 54

Phng php bit vector(bit map)

n gin v hiu qu khi cn tmkhi trngu tin hocchuikhi

trng lin tc Thao tc trn bit

Cn khng gian lutr. Vd

Kch

thcblock = 212 bytes

Kch thca = 230 bytes

n = 230/212 = 218 bit (32KB)V d:

bit vector 00111100

block 0, 1 trngblock 2, 3, 4, 5 c cp

block 6, 7 trng

0 1 2 n - 1

bit[ i ] =

0 block i cn trng

1 block i c cp

Phng php dng linked list


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Phan Trung Kin 55

Phng php dng linked list

Phng php Lin kt cc khitrngvi nhau

Ch cn gi con tr n khi nhtrng u tin trn a hoc cachetrongbnhchnh tngtc

t lng ph khng gian a

Dbitkhong khng gian trng lin tc?

Khng hiuqu: trong trnghpxunhtphiduyttonba tm khng gian trng lin tc

Grouping v counting (1)


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Phan Trung Kin 56


Phng php grouping

achcankhitrngclu trong khinhu tin. Khinhthnchaachcankhinhtrngktip.

Phng php counting

Tchcbngchmc, trong miphntcabngchaach trnacakhitrngu tin trong nhm khitrng lin tc km theo mtsm (chobitskhitrng trong nhm).

C thcp pht hoc thu hingthinhiukhinhlin tc



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Counting2 4

8 617 225 3

GroupingBlock 2 3, 4, 5Block 5 8, 9, 10Block 10 11, 12, 13Block 13 17, 28, 25Block 25 26, 27

V d

Open file structures


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Phan Trung Kin 58

Open file structures Thuc tnh ton cc (global attributes)

Disk location, size

Times

Buffers

Open count

Lock(s)

Thuc tnh ring ca process File pointer Access permissions

Systemopen file table

P1

P2

P3

UNIX: open file structure


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UNIX: open file structure

User space

Kernel space

datablocks

i-nodes

open filetable

swappable

r/wfile

descriptor

file structuretable

in-corei-nodes

resident

Sao lu v phc hi d liu


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Sao lu v phc hi d liu Kim tra snht qun dliu (consistency checker)so snh dliu trong cu

trc thmcvi cc khidliu trn a v sacha cc li khng nht qundliugia hai bn.

Dng chng trnh hthngsao lu (backup) dliuta sang cc thitblutrph khc nhamm,a quang,bngt,... vphchidliubmttbn sao lu.

C s phn chia loi hnh sao lu


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Cs phn chia loi hnh sao lu

Thuc tnh Archivel thuc tnh cn dng xc nh c cn sao

lu tp tin hay th mc hay khng. Vi Archive c chn ta s sao lu tp tin/th mc ny. Khi tp

tin va c to, mc nh thuc tnh Archive c thitlp.Archive b reset (thng sau khi sao lu), nu sau tp tin cchnh sa th Archive li c thitlp.

Phan Trung Kin 61

Cc kiu sao lu d liu


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Phan Trung Kin 62

Day 3

Day 2

Cc kiu sao lu d liu Normal Incremental

Data

Day 1

Data

CopiedDay 1

Day 2

Day 3

Differential

Data

CopiedDay 1

Day 2

Day 3

Cc kiu sao lu d liu


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Cc kiu sao lu d liu

Normal (Full):

Ttc cc tp tin cchnuc sao lu,btchp xc lpcathuc tnh Archive.

Khi tp tin c sao lu,Archive c reset.

Nu sau c ngichnhsa tp tin, Archive sc thit

lpli chobit n cnc sao lu. Copy:

Ttc cc tp tin cchnuc sao lubtchp xc lpcathuc tnh Archive.

Khc vi loi hnh sao lu Full, sau khi sao lu thuc tnhArchive trn tp tin khng h thay itrng thi.

Phan Trung Kin 63

Cc kiu sao lu d liu


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Cc kiu sao lu d liu

Differential:

cthitk sao lu cc tp tin thay iktt sao lu Fullcui cng.

Thuc tnh Archive chobittp tin ny csai v chtp tin no c thuc tnh ny mic sao lu.

Tuy nhin sau sau khi sao lu thuc tnh Archive s khngthay itrng thi.

Phan Trung Kin 64

Cc kiu sao lu d liu


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Cc kiu sao lu d liu

Incremental:

cthitk sao lunhngtp tin thay iktt saolu Full hoc Incremental cui cng.

Shindinca Archive chobittp tin ny c thay iv chtp tin no c thuc tnh ny mic sao lu.

Sau khi sao luthuc tnh Archive sb reset. Nu sau c ngichnhsa tp tin, Archive sc thit

lp,ch ra rngtp tin cn sao lu.

Phan Trung Kin 65

Cc kiu sao lu d liu


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Cc kiu sao lu d liu Daily:

Sao lutp tin da vo ngy chnhsacui cng trn chnh tp tin. Nutp tin chiuchnh cng ngy vi ngy sao lunhk th tp tinsc sao lu.

Khng lm thay ithuc tnh Archive catp tin.

Phan Trung Kin 66

Journaling file system


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Phan Trung Kin 67

Journaling file system Journaling file system

Ghi nhn cc lncpnht trn file system thnh cc giao tc (transaction) Mi transaction uphic ghi nhn trong log file

Mt transaction c xem l hon tt (commit) c ghi nhnytrong log file (lc ny, file system c thchaccpnht)

Khi file system ccpnhtviymi tc v trong transaction th

transaction sc xa i trong log file. Nu file systembhnghiu hnh da vo cc transaction trong log

file sacha

Tham kho thm Linux-ext3, JFS, NTFS

MS-DOS File System (1)


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MS DOS File System (1)

MS-DOS directory entry

MS-DOS File System (2)


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Phan Trung Kin 69

Maximum partition for different block sizes The empty boxes represent forbidden combinations

MS DOS File System (2)

Windows 98 File System (1)


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Phan Trung Kin 70


Extended MOS-DOS directory entry used in Windows 98

Bytes



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An entry for (part of) a long file name in Windows 98

Bytes

Checksum

The Windows 98 File System (3)


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The Windows 98 File System (3)

An example of how a long name is stored in Windows 98

QUN L FILE TRONG WINDOWS


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73

QUN L FILE TRONG WINDOWS

Mcch:

Minh ho nguyn lbng tham siukhin,Tnh ktha v thch nghi,

Cchbov,

T CHC THNG TIN TRN A T


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74

T CHC THNG TIN TRN A T

Track

1

1

1

22

2

3

3

3

Sector

ut

CC KHI NIM C BN


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75

CC KHI NIM C BN Sector:

nhst 1, S Sector/trackConstant, Hsan xen (Interleave)nguyn t cng nhau vis sector/track, Kch thc 1 sector:

128B

256B 512B 1KB

CC KHI NIM C BN


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76

Cylinder: 0,1,2, . . . u t (Header): 0, 1, 2, . . . Cluster:

Nhm sectors lin tip lgic, n v phn phi cho ngi dng, nh s: 2, 3, 4, . . . Kch thc: 1, 2, 4, 8, 16, 32, 64 (S),

a ch vt l:(H, S, Cyl), a ch tuyt i: 0, 1, 2, . . .

CC KHI NIM C BN

0 1 2 3 4 . . . . . . . . .

CU TRC THNG TIN TRN A T


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77

CU TRC THNG TIN TRN A T

MB BS FAT1 FAT2 ROOT FILES

Vng h thng(System Area)

FAT16

MB BS FAT1

Vng h thng(System Area)

FAT32

FAT2 ROOT

FILES

0E

0E24 24

1616

1C

1C11

2C

BOOT SECTOR


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78

BOOT SECTOR

c th

Ch k(Signature)

Nh nhau vi mia cho mi loi

OS

Chng trnhmi

(Boot StrapLoader)

Tham s

55AA

BOOT SECTOR


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79

BOOT SECTORStt Offs L (Byte) Ngha

1 0 3 Lnh JMP (EB xx 90)2 3 8 Tn h thng Format a

3 B 2 Kch thc Sector

4 D 1 Sec/Cluster

5 E 2 a ch tuyt i FAT1 trong a l gc

6 10H

1 S lng bng FAT

7 11 2 FAT16: S phn t ROOTFAT32: 00 00

8 13 2 sect/Disk (


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80

9 15 1 Kiu a t (F8 HD, F0 1.44MB)

10 16 2 FAT16:

Sec/FATFAT32: 00 00

11 18 2 Sec/ Track

12 1A 2 S u t13 1C 4 a ch tuyt BS trong a vt l14 20 4 Sec / Disk (32MB) hoc 0

15 24 4

Sec / FAT16 28 2 Flags

17 2A 2 Version

18 2C 4 a ch ROOT (Cluster)

BOOT SECTOR


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81

19 30 2 Inf

20 32 2 a ch lu BS21 34 1210 D tr (00...00)22 40 1 a ch a ( 80 C:)23 41 1 0024 42 1 29 BIOS m rng25 43 4 Serial Number

26 47 1110 Volume Name

27 52 8 FAT32

Boot Sector FAT 16


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82

Boot Sector FAT 16

15 24 1 a ch a ( 80 C:)16 25 1 00

17 26 1 29 BIOS m rng

18 27 4 Serial Number19 2B 1110 Volume Name

20 36 8 FAT16

V d


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83

V d

EB 58 90 4D 53 57 49 4E 34 2E 31 00 02 08 2D 00

02 00 00 00 00 F8 00 00 3F 00 40 00 3F 00 00 00

41 0C 34 00 03 0D 00 00 00 00 00 00 02 00 00 00

01 00 06 00 00 00 00 00 00 00 00 00 00 00 00 00

80 00 29 D1 09 47 32 20 20 20 20 20 20 20 20 20

20 20 46 41 54 33 32 20 20 20 FA 33 C9 8E 41 BC

TH MC


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84

TH MC

ng vai tr mclc tra cu, tm kim, Mi h thng uphi c vi nhng tn khc nhau

(Catalog, Directory, Folder,. . .),

Bao gm: Thmcgc (ROOT) + Thmc con, Cc hthngca Microsoft v OS IBMcu trc cy, UNIX - cu trc phn cp, Thmc = {Phnt},miphnt: 3210 B Phnt file,

Thmc con v ROOT: File c cu trc.

Cu trc phn t th mc tn ngn


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85


Stt Offs L ngha1 0 8 Tn (Name)

2 8 3 Phn m rng (Extention)

3 B 1 Thuc tnh (Attribute)4 C 2 Thi im to file5 E 2 Ngy to file

6 10H 2 Ngy truy nhp gn nht7 12 1 00 (Cho NT)

8 13 1 S 0.1 ca thi im to file



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86

p g

9 14 2 2 bytes cao ca cluster xutpht

10 16 2 Thi im cp nht cui cng

11 18 2 Ngy cp nht cui cng

12 1A 2 2 bytes thp ca cluster xutpht

13 1C 4 Kch thc file (Byte)



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87

p g Byte s 0: Vai tr cbit.

00 Cha s dng,phn t cha sdng u tin - du hiu kt thc thmc,

E5() b xo,

05Tnbtubng k t, 2E 20 (. )Phntth I cathmc

con,

2E 2E (..)Phntth II cathmccon

xx

xx

xx

xx

00


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88

...

.

..

Thuc tnh0 0

32

16

8

4

2

1


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89

5 bitsGi

6 bitsPht

5 bits2 Giy

Timex x x x x x x x x x x x x x x x

7 bits

Nm - 1980

4 bitsThng

5 bitsNgy

Datex x x x x x x x x x x x x x x x

1998 181999 192000 202001 21

D tr thi gian:

1980 + 27-1 = 2107

System

0Xx

0Xx

2Ax

6Dx

8Vx

4Sx

2Hx

1Rx

Read Only

Hidden

Vol. Name

DirectoryArchive

Reserved

Tn di


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90

Khng qu 255 k t, Unicode, H thng phn bit theo 66

k tu tin,

Lutr theo cch a vo, Nhndng: avch hoa.

Phn t tn di n

Phn t tn di n-1

Phn t tn di1

.

.

.

Phn t8.3

Lu tr tn di

Cu trc phn t tn di


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91

p

Stt Offs L ngha

1 0 1 S th t i (64+i)

2 1 1010 5 k t C1 C53 B 1 Thuc tnh (00001111B)

4 C 1 00 du hiu phn t tn di

5 D 1 Kphn t 8.3

6 E 1210

C6 C

11

7 1A 2 00 00

8 1C 4 C12 C13

File Allocation Table (FAT)


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92

( )

Chcnng:

Qun lbnhphnphi cho tng file, Qun lbnht do trn a,

Qun lbnhkm chtlng.

FAT = {phnt}

Phnt: nhs:0, 1, 2, . . .

Tphnts 2:phnt Cluster

FAT


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93

Phn t

12 bits 16 bits 32 bits

FAT 16 FAT 32

Phn t 0: Fxx FFF8 FFFFFFF8

Phn t 1: FFF xx11FF8 0xx11FFFFF8

Bit Shutdown

Bit Diskerror Bit Shutdown

Bit Diskerror

FAT


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94

FAT Bit Shutdown = 1Ra khihthngng cch

Bit Diskerror = 1khng c li truy nhpalntruy nhpcui cng. Tphnt 2 tri:

Gi tr 0Cluster t do,

FF7 (FFF7, 0FFFFFF7)Bad cluster, Cc gi tr khc phnphi, Ccphnttngngnhng Clusters camt file - to thnh mt

danh sch mc ni, EOC (End of Cluster Chain)FFF (FFFF, FFFFFFFF).

Clusterxut pht

FAT


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95

FF0

FFF

FF0

5

FFF

4

9

3

7

8

0

1

2

3

4

5

6

7

8

9

6 9 8 7 3 5 4

DISK

C

C

C

I

I

I

RAM

MASTER BOOT


96/127

96

55AA

Chng trnhnhn bit cu

trc(Master Boot

Record - MBR)c th

Ch k(Signature)

Bng phnvng

Nh nhau vi mia cho mi loi

OS

FDISK /MBR

MASTER BOOT


97/127

97

Nguyn tc khai thc HD:Chia HD thnh cc phn,miphn c kch thc

cnh,

Miphnsdngnhmta tc lp: a l

gic ( Logical Volume). OS cho php to cc a kch thcng trong

mia l gic.

MASTER BOOT

Cu trc bng phn vng


98/127

98

g p g Bng phn vngbtutach 1BEH,

Bng phn vng = {4phnt}, Miphntsdnga l gic,

Tn ti c ch cho php to nhiu hn 4 a l gc trnmtavt l.

a ch vt lu a ch vt lcui a ch tuyti u Tng sSectors

4 Bytes 4 Bytes 4 Bytes 4 Bytes

Cu trc phn t bng phn vng


99/127

99

a ch vt lu

a ch vt lcui

a ch tuyt iu

Tng s Sectors

4 Bytes 4 Bytes 4 Bytes 4 Bytes

SYS H S Cyl

x x x x x x x x x x x x x x x x

6 bits Sector

2 8

10 bits Cylinder

Type H S Cyl

x x x x x x x x x x x x x x x x

6 bits Sector

2 810 bits Cylinder

00 Cm truy nhp, 0B FAT32 ( 2047 GB)01 DOS12, 0C 0B, ch LBA,04 DOS16, 0E 06, ch LBA,06 BIGDOS, 0F 05, ch LBA,05 M rng (Extended)

Bng phn vng


100/127

100

g p g80 01 01 000B 3F FF 4D3F 00 00 0041 0C 34 00

00 00 00 0000 00 00 0000 00 00 0000 00 00 0000 00 00 0000 00 00 0000 00 00 0000 00 00 0000 00 00 0000 00 00 0000 00 00 0000 00 00 0055AA

80010100 010511BF 11000000 6F4C0000

000001C0 5105511F 804C0000 40260000

00004120 510551DF C0720000 804C0000

000041E0 5105D132 40BF0000 12870000

55AA

Truy nhp Boot Sector


101/127

101

Dng cc hm API, Chng trnh c v a ra mn hnh ni dung BS caamm A:

(Hexa v ASCII):Program R_BS_A;

Uses Crt, Dos;

Const s16: string[16]=0123456789ABCDEF;

Var B: array[0..511] of char;reg: registers;

i,j,k: integer;

c: char;

BEGIN

clrscr;

fillchar(b,sizeof(b),0);

writeln(Cho dia vao o A: va bam phim bat ky.);c:=readkey;


102/127

102

I := 0;

Repeat

with reg do

begin

dl := 0; { 0 -> A:, 128 -> C:}

dh := 0; {ut}cl := 1; {Sector}

ch := 0; {Cylinder}

al := 1; {So Sectors can doc}

ah := 2; {2 -> Read; 3 -> Write;. . .}

es := seg(b);

bx := ofs(b)

end;

intr($13,reg);

i (i)


103/127

103

inc(i)

Until i = 2;

for i := 0 to 511 do

begin

j := b[i] shr 4 + 1;

k := b[i] and $0F + 1;

write(s16[j]:2, s16[k]);

if (i+1) mod 16 = 0 then

begin write(:5);

for j := i-15 to i doif (b[j]


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104

writeln;

if i = 255 then c:= readkeyend

end;

RepeatUntil keypressed

END.

Cac HH Windows


105/127

105

MS DOS 2.X

MS DOS 3.3

MS DOS

4.01 6.X

WINDOWS 95

WINDOWS 98

WINDOWS NT

WINDOWS

2000

WINDOWS XP

Qun lfiles

Cng c tchc TTsong song

Qun l ahn 32MB

a nhim 1user

Cng ckt niInternet

Qun lmng vhtql file

mi

a nhimnhiu

users

- Tng cng giao din,- Phc v kt ni Per to Per,- MultiOs


106/127

Phan Trung Kin 106

UNIX V7 File System (1)


107/127

Phan Trung Kin 107

A UNIX V7 directory entry

i-nodenumber



108/127

Phan Trung Kin 108

A UNIX i-node

i-node



109/127

Phan Trung Kin 109

The steps in looking up /usr/ast/mbox

QUAN LY A CNG


110/127

Cau truc a cng Noi dung a cng Truy xuat a & nh thi truy xuat a Quan ly a Hien thc he thong lu tr on nh Cac ky thuat tang hieu suat a cng

-110-

CAU TRUC A CNG


111/127

-111-

NOI DUNG LOGIC A CNG


112/127

-112-

FAT32

NTFS

EXT2

UFS

Partitions

Master boot record

(cyl 0, head 0, sector 0)

Volume boot sector

NOI DUNG A CNG


113/127

-113-

Master Boot Record Master Partition Table:

Cha thong tin ve tng partition: partition ID, Activity flags,start CHS, end CHS Link ti Extended Partition Table (cha thong tin ve o aluan ly th 1 tren a)

Master Boot Code: Cha ma nap OS cac partition active

Partition Vung khong gian lien tuc tren ia Cha 1 he thong file hoac n o a luan ly (logical volume)

Moi o a luan ly co 1 Volume Boot Sector (VBS) Disk Parameter Block: thong tin ve a luan ly Volume Boot Code: ma e khi ong OS tren o luan ly nay

TRNH T KHI ONG HE THONG


114/127

-114-

Power-On Self Test (POST) Kiem tra phan cng Chay cac ham BIOS m rong trong cac ROM cac mach ngoai

vi BIOS goi interrupt 13h, nap MBR va khi ong Master

Boot Code (MBC)

MBC nap VBS cua partition chnh tch cc au tien trena khi ong Volume Boot Code khi ong OS Cac BIOS & OS mi co the cho boot t CDROM, a

mem, a ZIP hoac qua mang (Remote Boot)

TRUY XUAT A CNG


115/127

-115-

3 yeu to anh hng thi gian truy xuat a Seek time: thi gian di chuyen au oc ti track Latency: thi gian e quay a sao cho sector can oc nam di

au oc Transfer time: thi gian oc/ ghi d lieu len sector

Thc te: Seek time >> latency time > transfer time

Toi u seek time nh thi truy xuat a Toi u latency time:

Lam a nho, quay nhanh hn, lu tr d lieu lien quan gan nhau Chon kch thc sector, ni lu tr cac file thng dung hp ly

CAC GIAI THUAT NH THI A


116/127

-116-

Bai toan: Co n yeu cau oc a cac track khac nhau x1,x2, , xN vao cac thi iem tng ng t1, t2, , tN phuc vu cac yeu cau o vao thi iem nao?

Tieu chuan anh gia Cong bang Hieu suat cao

Thi gian ap ng trung bnh thap D oan c thi gian phuc vu

Mot so giai thuat tieu bieu: FCFS

SSTF SCAN, N-step-SCAN, C-SCAN CLOOK

NH THI TRUY XUAT A FCFS


117/127

-117-

Nhan xet ?

GIAI THUAT SSTF (Shortes Seek Time First)


118/127

-118-

Phuc vu yeu cau oc gan v tr au oc hien tai nhat.

GIAI THUAT SCAN


119/127

-119-

Phuc vu theo hng phuc vu t trong ra ngoai Khi au oc ra ti track ngoai cung, phuc vu theo hngngc lai t ngoai vao trong

Nhan xet?

V DU VE GIAI THUAT SCAN


120/127

-120-

GIAI THUAT N-step-SCAN


121/127

-121-

Nhom cac yeu cau truy xuat lai Phuc vu nguyen 1 nhom yeu cau theo 1 chieu dichuyen cua au oc

GIAI THUAT C-SCAN


122/127

-122-

Nh giai thuat N-step-SCAN nhng theo ch phucvu theo 1 hng duy nhat

Nhan xet?

V DU VE GIAI THUAT C-SCAN


123/127

-123-

Nh giai thuat N-step-SCAN nhng ch phuc vu theo 1hng duy nhat

Nhan xet?

GIAI THUAT C-LOOKNh C SCAN h h di h i k


124/127

-124-

Nh C-SCAN, nhng ch di chuyen au oc ti trackngoai cung c phuc vu roi quay lai track trong cung

can phuc vu

QUAN LY A Low level formatting: chia a ra cac sector e disk


125/127

-125-

Low-level formatting: chia a ra cac sector e diskcontroller co the oc, ghi c

Lu cau truc d lieu cua OS len a Partitioning: phan vung a High-level formatting: tao he thong file tren partition

Tao boot block

X ly loi: ky thuat sector sparing Quan ly vung swap Tao vung swap khi nao? S dung dung swap-map

Lap at a qua cong I/O qua mang (Network Attached Storage)

HE THONG LU TR ON NH(Stable Storage System)


126/127

-126-

am bao thong tin lu tr luon ton tai du bat ky loi naoxay ra trong qua trnh oc/ghi.

Cac van e xay khi oc/ghi a thng: Ghi thanh cong: block ch cha thong tin mi That bai mot phan: block ch cha thong tin sai

That bai hoan toan: block ch cha thong tin nh cu Hien thc: dung 2 block vat ly cho 1logical block

Ghi thong tin vao block (vat ly) th 1 roi th 2. Viec ghi thanh cong block th 2 ghi xong Kiem tra s giong nhau cua 2 block phat hien loi va x ly e

am bao tnh nhat quan thong tin

CAC KY THUAT TANG HIEU SUAT A CNG


127/127

Lu d lieu truy xuat thng xuyen trong bo nh virtual disk, disk caching

Ky thuat bufferring Read ahead, write-behind

Defragment a giam seek time Phan vung a phan manh b gii han Nen d lieu at cac ng dung/ file/ directory structure gia a Dung he nhieu a cng (RAID system) Hien thc giai thuat nh thi a bang phan cng

Documents

NLHDH Chuong 4