plan9-review-1plan 921128013725-phpapp02

8/9/2019 plan9-review-1plan 921128013725-phpapp02

1/57

Plan 9: Not (Only) A Better UNIX

Jim Huang( )

e!elo"er# 0xlab http://0xlab.org/

$ay % '0%' JuluOe!


2/57

Rights to copy

Attribution ShareAlike 3.0

You are free

to *o"y# +i,tribute# +i,"lay# an+ "er-orm te /or to mae +eri!ati!e /or, to mae *ommer*ial u,e o- te /or

Under the following onditions

Attribution. 1ou mu,t gi!e te original autor *re+it.

Share Alike. I- you alter# tran,-orm# or buil+ u"on ti, /or# you may +i,tribute te

re,ulting /or only un+er a li*en,e i+enti*al to ti, one.

2or any reu,e or +i,tribution# you mu,t mae *lear to oter, te li*en,e term, o- ti,/or.

Any o- te,e *on+ition, *an be /ai!e+ i- you get "ermi,,ion -rom te *o"yrigt ol+er.

Your fair use and other rights are in no wa! affeted b! the above.

3i*en,e text4tt"4*reati!e*ommon,.orgli*en,e,by5,a6.0legal*o+e

7o"yrigt '0%' 0"lab

tt"40xlab.org

*onta*[email protected]

7orre*tion,# ,ugge,tion,# *ontribution, an+

tran,lation, are /el*ome8

3ate,t u"+ate4 $ay % '0%'
http://creativecommons.org/licenses/by-sa/3.0/legalcodehttp://creativecommons.org/licenses/by-sa/3.0/legalcode


3/57

Beyond this presentation

http://sync.in/16W2nkk2vZ Design our own world-dominating !.

i,*u,, 9lan :# an O tat many "eo"le tougt,oul+ a!e +ominate+ te /orl+.

$eeting o- O"en our*e U,er, in ;ainan (&%:)http://mosut.org/

7O7U9 '0%'" Oe! rou"

" 7all -or 9arti*i"ation8

N7=U 3e*ture (e" '0%')" 3earn ,y,tem "rogramming -or A$ 7ortex5$

" ;O# tool*ain# ,y,tem mo+eling


4/57

History always inspires us

is not a new word." #louds$

7lou+, i, a*tually ' ,e"arate o"erating ,y,tem,

" 7lou+, ?%# ba,e+ on ?AX ernel (%:)

" 7lou+, ?'# ba,e+ on a ernel (%::)

9ur"o,e4 u""ort +i,tribute+ re,ear* at eorgiaIn,titute o- ;e*nology


5/57

Clouds Ba,e+ on te obCe*ttrea+ "ara+igm

At O le!el tere i, only one ty"e o- obCe*t D clouds

a ernel im"lement, "er,i,tent !irtual memory" ;rea+, tra!el troug obCe*t,

" Entry "oint,


6/57

*BSD

Linux

!"#

from clkao


7/57

In memory of the heros

Dennis %. &itchie 'dmr( 1)*1-2+11," 0 lan )

" &elated talk: lan ) %ay 13 2+12

Jo*en 3ie+te (%:&65'00%)

" 3F mi*roernel" elate+ tal4 3F $i*roernel# 2eb G# '0%'


8/57


9/57

Agenda #$% Design Concepts#&% 'ssential (lan )

#% Renaissance


10/57

Design Concepts


11/57

+nix ,rigins #-.$)/)%

Bell 3ab, a, a long i,tory in early o"erating ,y,tem,# -orexam"le BE51 -or IB$ G0:x ma*ine, $ulti*,

=en ;om",on /ante+ to /rite a *om"uter o"erating ,y,temby te %:0,4" Ex"lore ,tru*ture, -or buil+ing O

" Buil+ ,ometing -or our o/n grou" to u,e

2un+amental i+ea4 a goo+ /ay to re"re,ent +ata (+i, -ile,)

2ir,t ,te", -or Unix4" -in+ *on*rete re"re,entation -or +ata on +i,

" +e-ine a**e,, meto+, to +ata

Earlie,t Unix ,im"ly trie+ to buil+ ,ome ,u"er,tru*ture to te,t;om",on, i+ea,


12/57

'arly Ideas a0out +nix #$)/).$)1&%

%uch was inherited especially 4rom %ultics pro5ect

2ile, *ontain Cu,t a ,euen*e o- byte,4" inter"retation i, u" to a""li*ation,

" o"timiMation o- a**e,, i, u" to o"erating ,y,tem

" "re-eren*e i, -or -ile, /it rea+able text# not binary

2ile, are name+ in a ierar*i*al# tree5lie name,"a*e# e.g.

/usr/dmr/japan/japanslides.ppt


13/57

2ile System access operations

asic operations are very simple:" handle = open(filename, read-or-write-mode)

" handle = create (filename, protection-mode)

" read(handle, buffer, nbtes)

"write(handle, buffer, nbtes)

" close(handle)

" see!(handle, place)


14/57

Hierarchical 3ames

/

-- source

-- shell

sh".c

sh#.c

#

-- usr

-- !en

#

-- dmr

-- japan

japanslides.ppt

# #

-- bin

$h

#

-- ...

3 f h h


15/57

3ames for other things

ni7 introduced a consistent a8straction: names 4or/ devices as part o4 the same hierarchy 4or e7ample" /de%/tt#& (name of terminal 23)

" $de%/dis!/dis!0& (name of a whole disk)

" /de%/mem (name for main memory)

;e,e really exi,t in te -ile ,y,tem an+ te ,ame"rote*tion an+ o/ner,i" "ro"ertie, are a""lie+ a,/it or+inary -ile,

;o te extent "o,,ible# tey loo lie te ,ame byte

,tream, a, "lain +i, -ile, ome (lie terminal, an+ net/or,) a!e ,ome

,"e*ial o"eration, tat a""ly4 KIO *ontrol,L


16/57


17/57

3 (l ) #$))5 &55%


18/57

3ext step4 (lan ) #$))5.&55%

Designed in mid 9+Bs 8y many o4 the creators o4 0'&o8 ike Cen


19/57

lan ) 4rom ell >a8s 8ased on lan ) 4rom uter !pace.

or,t mo!ie e!er ma+e

(by E+ oo+)

(l ) f B ll l 0


20/57

(lan ) from Bell la0s

Designed in mid 9+Bs 8y many o4 the creators o4 0'&o8 ike Cen


21/57

ersonal Workstation !ystems

#entralied


22/57

(lan ) Design (rinciples

E!eryting i, a -ileL" tan+ar+ naming system-or all re,our*e,4 "atname,

Kemote a**e,,L i, te *ommon *a,e" tan+ar+ resource access protocol!K:9L (K:9'000L)

" U,e+ to a**e,, any -ile5lie ting# remote or lo*al

9er,onal name,"a*e," Naming conventionsee" it ,ane

A "ra*ti*al i,,ue4 O"en our*e" Unix ,our*e not a!ailable at KBell 3ab,L# it, birt"la*e8

(lan ) !ssumptions


23/57

(lan ) !ssumptions

eliable ma*ine5room file servers are+5memory multi"ro*e,,or !le %&PU' servers

" 3o*ate+ near -ile ,er!er, -or -a,t a**e,,

emote5a**e,, /or,tation ter(inals

" A**e,, your viewo- te en!ironment

" onSt ontainyour en!ironment

" i, i, o"tional

A ;y"i*ally u,e+ -or -a,ter booting# -ile *a*e" Koot +ire*toryL i, lo*ate+ on your "rimary -ile

,er!er

'"erything is a 2ile really


24/57

'"erything is a 2ile really

n many early operating systems di44erent types o48lock devices had di44erent ;Bs.

One maCor inno!ation in UNIX /a, te ,ingle -ile IOA9I -or multi"le +e!i*e,.

9lan : treat, !irtually all +e!i*e, an+ ,er!i*e, a, -ile5ba,e+ ,er!i*e,4" telnet

" -t"

" n-,

3ota0le architecture


25/57

3ota0le architecture

;ll system inter4aces through 4ile system. 'pre->inu7,

or,tation 5 in+e"en+ent /oring en!ironment" aggregate+ re,our*e,# remote an+ lo*al.

/proc

" All "ro*e,,e, are !i,ible a, -ile, net

" All net/or tra--i* rea+/ritten troug -ile ,y,tem

7an im"ort 9OIX a"",# emulate Bereley ,o*etinter-a*e troug A9E (ANI9OIX En!ironment)

'xample4 ,pen a socket


26/57

'xample4 ,pen a socket

% cat /net/tcp/clone/ctl

44

% cd /net/tcp/''

% echo connect "#.#."'.0*+ ctl

% echo ping data

% cat datapong

3amespace


27/57

27

;ny 4ile resource can 8e ?mounted@ in a customia8ledirectory hierarchy or namespace:

e!eral +ire*torie, *an be mounte+ at te ,ame "ointD re"la*e, te nee+ -or a T9A;Hbind /home/shilad/bin /bin

bind /i386/bin /bin

7o"ying a lo*al -ile footo a remote -lo""y4import lab.pc /a: /n/dos

cp foo /n/dos/

9i"ing te out"ut o- foo on host" to baron host2cpu -h host1 foo | cpu -h hos2 bar

3amespace

Communication (rotocol


28/57

28

ile-8ased ; supports 1F standard / 4ile operations

Ke!i*e +ri!er,L (e.g. a telnet ,er!er) nee+ onlyim"lement te %G o"eration,.

A mounting ,er!i*e tran,"arently tran,mit, lo*al -ile*omman+, to remote ,y,tem, u,ing te :9 "roto*ol.

Communication (rotocol

Synchroni7ation


29/57

Synchroni7ation

rendezvous system call:

;rea+ % ;rea+ '

rendevous("foo",value1) rendezvous("foo",value2)

8oth calls 8lockuntil they receive

the ?4oo@ tagvalue2 value1

Security


30/57

Security

o superuser

An autenti*ation ,er!er maintain, a +ataba,e o-autenti*ation ey, -or all u,er,

Bot *lient an+ ,er!er ex*ange en*ry"tion

*allenge, an+ re,"on,e, ,o ea* ,i+e i, *on!in*e+o- te oter, i+entity.

All :9 net/or *ommuni*ation, are ,e*ure

(lan ) 2ailure


31/57

(lan ) 2ailure

n 1))9 >ucent pulled developers o44 o4 lan ) to4ocus on related Inferno!.

Neiter 9lan : nor In-erno /ere *ommer*ially,u**e,,-ul.

$o,t ex"ert, agree tat 9lan : /a, te*ni*ally,u"erior to UNIX but

$o,t ex"ert, agree tat 9lan : /a, not ,u"eriorenoughto *on!ert u,er, o- UNIX


32/57


33/57

'ssential (lan )

Definitions


34/57

Definitions )*

" ;e 9lan : /in+o/ ,y,tem# /i* "ro!i+e, textual IO an+ bitma" gra"i* ,er!i*e,

to bot lo*al an+ remote *lient "rogram, by o--ering a multi"lexe+ -ile ,er!i*e toto,e *lient,. It ,er!e, tra+itional UNIX -ile, lie +e!tty a, /ell a, more unu,ualone, tat "ro!i+e a**e,, to te mou,e an+ te ra/ ,*reen. Bitma" gra"i*,o"eration, are "ro!i+e+ by ,er!ing a -ile *alle++e!bitblt tat inter"ret, *lientme,,age, to "er-orm ra,ter o"eration,.

+

" A *omman+ inter"reter -or 9lan : tat "ro!i+e, ,imilar -a*ilitie, to UNIX, Bourne,ell# /it ,ome ,mall a++ition, an+ le,, i+io,yn*rati* ,yntax.

9P Protool" ;e 9lan : -ile ,y,tem "roto*ol. It i, ,tru*ture+ a, a ,et o- tran,a*tion, tat ,en+ a

reue,t -rom a *lient to a (lo*al or remote) ,er!er an+ return te re,ult.

,- Protool" I3 i, a *u,tom im"lemente+ net/or "roto*ol to tran,"ort te remote "ro*e+ure *all

me,,age, :9.

2ile ser"ice architecture


35/57

#lient computer !erver computer

;pplicationprogram

;pplicationprogram

#lient module

lat 4ile service

Directory service

Lookup

AddNameUnName

GetNames

Read

Write

Create

Delete

GetAttributes

SetAttributes

2ile ser"ice architecture

32S architecture


36/57

#lient computer !erver computer

04ile

system

!

client

!

server

04ile

system

;pplicationprogram

;pplicationprogram

Girtual 4ile systemGirtual 4ile system

ther

4ilesystem

0 kernel

system calls

!protocol

'remote operations,

0

perations

on local 4iles

perations

on

remote 4iles

*

;pplicationprogram

!#lient

Cernel;pplication

program

!

#lient

#lient computer

32S architecture

32S ser"er operations #simplified%


37/57

read(fh, offset, count) -> attr, datawrite(fh, offset, count, data) -> attr

create(dirfh, name, attr) -> newfh, attr

remove(dirfh, name) status

getattr(fh) -> attr

setattr(fh, attr) -> attr

lookup(dirfh, name) -> fh, attrrename(dirfh, name, todirfh, toname)

link(newdirfh, newname, dirfh, name)

readdir(dirfh, cookie, count) -> entries

symlink(newdirfh, newname, string) -> status

readlink(fh) -> string

mkdir(dirfh, name, attr) -> newfh, attr

rmdir(dirfh, name) -> status

statfs(fh) -> fsstats

fh = file handle:

ilesystem identi4ier i-node number i-node generation

Model flat file serviceRead(FileId, i, n) -> Data

Write(FileId, i, Data)

Create() -> FileId

Delete(FileId)

GetAttributes(FileId) -> Attr

SetAttributes(FileId, Attr)

Model directory service

Lookup(Dir, Name) -> FileId

AddName(Dir, Name, File)

UnName(Dir, Name)

GetNames(Dir, Pattern)

->NameSeq

p # p %

32S ser"er operations #simplified%


38/57

read(fh, offset, count) -> attr, datawrite(fh, offset, count, data) -> attr

create(dirfh, name, attr) -> newfh, attr

remove(dirfh, name) status

getattr(fh) -> attr

setattr(fh, attr) -> attr

lookup(dirfh, name) -> fh, attrrename(dirfh, name, todirfh, toname)

link(newdirfh, newname, dirfh, name)

readdir(dirfh, cookie, count) -> entries

symlink(newdirfh, newname, string) -> status

readlink(fh) -> string

mkdir(dirfh, name, attr) -> newfh, attrrmdir(dirfh, name) -> status

statfs(fh) -> fsstats

fh = file handle:

Filesystem identifier i-node number i-node generation

Model flat file service

Read(FileId, i, n) -> Data

Write(FileId, i, Data)

Create() -> FileId

Delete(FileId)

GetAttributes(FileId) -> AttrSetAttributes(FileId, Attr)

Model directory service

Lookup(Dir, Name) -> FileId

AddName(Dir, Name, File)UnName(Dir, Name)

GetNames(Dir, Pattern)

->NameSeq

p # p %

32S access control and authentication


39/57

!tateless server

" the userHs identity and access rights must 8e checked 8ythe server on each reIuest.

" In te lo*al -ile ,y,tem tey are *e*e+ only on open()

E!ery *lient reue,t i, a**om"anie+ by te u,erI an+

grou"I" in,erte+ by te 97 ,y,tem

er!er i, ex"o,e+ to im"o,ter atta*, unle,, te u,erIan+ grou"I are "rote*te+ by en*ry"tion

" =erbero, a, been integrate+ /it N2 to "ro!i+e a,tronger an+ more *om"reen,i!e ,e*urity ,olution

Local and remote file systems


40/57

yaccessi0le on an 32S client

5im 5ane 5oeann

usersstudents

usrvmuni7

#lient !erver 2

. . . n4s

&emote

mountsta44

8ig 8o85on

people

!erver 1

e7port

'root,

&emote

mount

. . .

7

'root, 'root,

Note: The file system mounted at/usr/studentsin the client is actually the sub-tree located at/export/peoplein Server 1;

the file system mounted at/usr/staffin the client is actually the sub-tree located at/nfs/usersin Server 2.

*

(lan )4 Resource +nified to 2iles


41/57

;ll resources in lan ) look like 4ile systems.

2ile Oriente+ a**e,," Hierar*i*al name tree

" A**e,,ible by name

" A**e,, *ontent, by rea+ an+ /rite *all,

(lan ) Communications


42/57

rovides diagnostic in4ormation on the current status o4 the connectionstatus

rovides in4ormation on the other side o4 the connectionremote

rovides in4ormation on the callerHs side o4 the connectionlocal

sed to accept incoming connection setup reIuestslisten

sed to read and write datadata

sed to write protocol-speci4ic control commandsctlDescriptionFile

2ile, a,,o*iate+ /it a ,ingle ;79 *onne*tion in 9lan :.

2ile ser"er 8 3aming4 union directory


43/57

)( (rotocol


44/57

!tandard rotocol 4or accessing

resources Bell lab, im"lemente+ I3 9roto*ol -or

net/or tran,"ort o- :9 me,,age,

Security


45/57

2a*totum i, te *entral *om"onent o- te ,e*urity ar*ite*ture.

2a*totum ,e*urely ol+, a *o"y o- te u,er, ey, an+negotiate, autenti*ation "roto*ol,# on beal- o- te u,er# /it,e*ure ,er!i*e, aroun+ te net/or" Ea* box i, a (ty"i*ally) ,e"arate ma*ine

" Elli",e i, a "ro*e,,. #$are -a*totum "ro*e,,e,

" %$are te "ie*e, an+ "roxie, o- a +i,tribute+ "rogram.

;e autenti*ation ,er!er i, one o- ,e!eralre"o,itorie, -or u,er, ,e*urity in-ormation tat-a*totum "ro*e,,e, *on,ult a, reuire+.e*,tore i, a ,are+ re,our*e -or ,toring "ri!atein-ormation ,u* a, ey, -a*totum *on,ult, it -or te

u,er +uring boot,tra"

Capa0ility for (arallel (rogramming


46/57

Cernel provides a simple process model and a 4ew

care4ully designed system calls 4or synchroniationand sharing.

9arallel "rogramming language *alle+ Ale- ,u""ort,*on*urrent "rogramming.

Altoug it i, "o,,ible to /rite "arallel "rogram, in 7#Ale- i, te "arallel language o- *oi*e.

Ale- u,e, a ,y,tem *all *alle+ ren+eM!ou, to "ro!i+e,a /ay -or "ro*e,,e, to ,yn*roniMe.

Structure


47/57

%ain arts

" 2ile ,er!er," 79U ,er!er,

" ;erminal, (u,er a**e,, "oint,).

;y"i*ally *entrally lo*ate+ -ile

,er!er, an+ 79U ,er!er,

# !erversile !ervers

Eigh !peedetwork

#entrally located multiprocessor machines with largememories and high 8andwidth point to point interconnects.


48/57

J7ample: Jcho !erver

$%&' ()*+ &,-.+,+/0' 1 02-&31.$(4 .&'0+/+56

70 1//)8/3+' &0'+.9 .&'0+/' 9)5 3)//+30&)/': 1/* 9)5;'

1 /+< -5)3+'' 9)5 +13%6$%+ /+< -5)3+'' +3%)+' *101 )/

0%+ 3)//+30&)/ 8/0&. 0%+ 5+,)0++/* 3.)'+' &06

$%+ =>= &/ 0%+ '2,?).&3 /1,+,+1/' 0%+ 1//)8/3+,+/0 &' @1.&*9)5 1/2 1**5+''+' ?)8/* 0) 0%+,13%&/+ 0%+ -5)A51, &' 58/ )/6

+sing (lan )


49/57


1.;nnounce',

2.>isten',

K.;ccept', LL &e5ect',

*.rocess',M.

3.#lose',M


50/57

(lan )4 +sing (lan ) J7ample: Jcho !erver

1. ;nnounce', &eturns open 4ile descriptor 4or the

ctl 4ile o4 a connection and 4ills dirwith the path o4 the protocoldirectory 4or the announcement.

int announce'char Naddr char Ndir,

;ddr is the sym8olic name/addressannounced( i4 it does not contain aservice the announcement is 4or allservices not e7plicitly announced.


51/57


2. >isten', >isten returns an open 4ile

descriptor 4or the ctl 4ile and 4ills ldirwith the path o4 the protocoldirectory 4or the receivedconnection.

t is passed dir 4rom theannouncement.

int listen'char Ndir char Nldir,


52/57


K. ;ccept', and &e5ect', ;ccept and re5ect are called with

the control 4ile descriptor and ldirreturned 8y listen.

!ome networks such as Datakitaccept a reason 4or a re5ection(networks such as ignore thethird argument.

int accept'int ctl char Nldir,

int re5ect'int ctl char Nldir charNreason,

+sing (lan )


53/57


1.;nnounce',

2.>isten',

K.;ccept', LL &e5ect',

*.rocess',M.

3.#lose',M

Significance


54/57

ul4ills de4inition o4 Distri8uted !ystem

:94 U,e, me,,age "a,,ing to *oor+inate a*tion,

9ro!i+e, -or te maCor +e,ign *on,i+eration, a,outline+

&eterogeneity, 'penness, Security, Scalability,#ailure handling, oncurrency, ransparency


55/57

Renassance

Reference


56/57

ni7 and eyond: ;eme, in O"erating y,tem,

e,ear*# enni, $. it*ie# Bell 3aboratorie,#Al*atel 3u*ent ('00G)

9lan : -rom Bell 3ab,4 eal orl+ i,tribute+O"erating y,tem 7a,e tu+y# Bryan =inney#

7om"uter *ien*e an+ Engineering# 7ri,to"erNe/"ort Uni!er,ity ('00&)


57/57

tt"40xlab.org

Documents

plan9-review-1plan 921128013725-phpapp02