Dis
tribu
ted
Obj
ect-B
ased
Sy
stem
s
Cha
pter
9
Ove
rvie
w o
f CO
RB
A
The
glob
al a
rchi
tect
ure
of C
OR
BA
.
Obj
ect M
odel
The
gene
ral o
rgan
izat
ion
of a
CO
RB
A sy
stem
.
Cor
ba S
ervi
ces
Ove
rvie
w o
f CO
RB
A se
rvic
es.
Prov
ides
the
curre
nt ti
me
with
in s
peci
fied
erro
r mar
gins
Tim
e
Mec
hani
sms
for s
ecur
e ch
anne
ls, a
utho
rizat
ion,
and
aud
iting
Secu
rity
Faci
litie
s fo
r exp
ress
ing
rela
tions
hips
bet
wee
n ob
ject
sR
elat
ions
hip
Faci
litie
s fo
r per
sist
ently
sto
ring
obje
cts
Pers
iste
nce
Faci
litie
s to
pub
lish
and
find
the
serv
ices
on
obje
ct h
as to
offe
rTr
adin
g
Faci
litie
s fo
r ass
ocia
ting
(attr
ibut
e, v
alue
) pai
rs w
ith o
bjec
tsPr
oper
ty
Faci
litie
s fo
r sys
tem
wid
e na
me
of o
bjec
tsN
amin
g
Faci
litie
s fo
r atta
chin
g a
licen
se to
an
obje
ctLi
cens
ing
Faci
litie
s fo
r cre
atio
n, d
elet
ion,
cop
ying
, and
mov
ing
of o
bjec
tsLi
fe c
ycle
Faci
litie
s fo
r mar
shal
ing
and
unm
arsh
alin
g of
obj
ects
Exte
rnal
izat
ion
Adva
nced
faci
litie
s fo
r eve
nt-b
ased
asy
nchr
onou
s co
mm
unic
atio
nN
otifi
catio
n
Faci
litie
s fo
r asy
nchr
onou
s co
mm
unic
atio
n th
roug
h ev
ents
Even
t
Flat
and
nes
ted
trans
actio
ns o
n m
etho
d ca
lls o
ver m
ultip
le o
bjec
tsTr
ansa
ctio
n
Faci
litie
s to
allo
w c
oncu
rrent
acc
ess
to s
hare
d ob
ject
sC
oncu
rrenc
y
Faci
litie
s fo
r que
ryin
g co
llect
ions
of o
bjec
ts in
a d
ecla
rativ
e m
anne
rQ
uery
Faci
litie
s fo
r gro
upin
g ob
ject
s in
to li
sts,
que
ue, s
ets,
etc
.C
olle
ctio
n
Des
crip
tion
Serv
ice
Obj
ect I
nvoc
atio
n M
odel
s
Invo
catio
n m
odel
s sup
porte
d in
CO
RB
A.
Cal
ler c
ontin
ues
imm
edia
tely
an
d ca
n la
ter b
lock
unt
il re
spon
se is
del
iver
ed
At-m
ost-o
nce
Def
erre
d sy
nchr
onou
s
Cal
ler c
ontin
ues
imm
edia
tely
w
ithou
t wai
ting
for a
ny re
spon
se
from
the
serv
er
Best
effo
rt de
liver
yO
ne-w
ay
Cal
ler b
lock
s un
til a
resp
onse
is
retu
rned
or a
n ex
cept
ion
is
rais
ed
At-m
ost-o
nce
Sync
hron
ous
Des
crip
tion
Failu
re s
eman
tics
Req
uest
type
Even
t and
Not
ifica
tion
Serv
ices
(1)
The
logi
cal o
rgan
izat
ion
of su
pplie
rs a
nd c
onsu
mer
s of
eve
nts,
follo
win
g th
e pu
sh-s
tyle
mod
el.
Even
t and
Not
ifica
tion
Serv
ices
(2)
The
pull-
styl
e m
odel
for e
vent
del
iver
y in
CO
RB
A.
Mes
sagi
ng (1
)
CO
RB
A's
callb
ack
mod
el fo
r asy
nchr
onou
s met
hod
invo
catio
n.
Mes
sagi
ng (2
)
CO
RB
A'S
pol
ling
mod
el fo
r as
ynch
rono
us m
etho
d in
voca
tion.
Inte
rope
rabi
lity
GIO
P m
essa
ge ty
pes.
Part
(frag
men
t) of
a la
rger
mes
sage
Both
Frag
men
t
Con
tain
s in
form
atio
n on
an
erro
rBo
thM
essa
geEr
ror
Indi
catio
n th
at c
onne
ctio
n w
ill be
clo
sed
Both
Clo
seC
onne
ctio
n
Indi
cate
s cl
ient
no
long
er e
xpec
ts a
repl
yC
lient
Can
celR
eque
st
Con
tain
s lo
catio
n in
form
atio
n on
an
obje
ctSe
rver
Loca
teR
eply
Con
tain
s a
requ
est o
n th
e ex
act l
ocat
ion
of a
n ob
ject
Clie
ntLo
cate
Req
uest
Con
tain
s th
e re
spon
se to
an
invo
catio
nSe
rver
Rep
ly
Con
tain
s an
invo
catio
n re
ques
tC
lient
Req
uest
Des
crip
tion
Orig
inat
orM
essa
ge ty
pe
Clie
nts
Logi
cal p
lace
men
t of i
nter
cept
ors i
n C
OR
BA
.
Porta
ble
Obj
ect A
dapt
or (1
)
Map
ping
of C
OR
BA
obj
ect i
dent
ifier
s to
serv
ants
.a)
The
POA
supp
orts
mul
tiple
serv
ants
.b)
The
POA
supp
orts
a si
ngle
serv
ant.
Porta
ble
Obj
ect A
dapt
or (2
)
Cha
ngin
g a
C++
obj
ect i
nto
a C
OR
BA
obj
ect.
My_
serv
ant *
my_
obje
ct;
// D
ecla
re a
refe
renc
e to
a C
++ o
bjec
tC
OR
BA::O
bjec
tid_v
ar o
id;
// D
ecla
re a
CO
RBA
iden
tifie
r
my_
obje
ct =
new
MyS
erva
nt;
// C
reat
e a
new
C++
obj
ect
oid
= po
a ->
activ
ate_
obje
ct (m
y_ob
ject
);//
Reg
iste
r C++
obj
ect a
s C
OR
BA O
BJEC
T
Age
nts
CO
RB
A's
over
all m
odel
of a
gent
s, ag
ent s
yste
ms,
and
regi
ons.
Obj
ect R
efer
ence
s (1)
The
orga
niza
tion
of a
n IO
R w
ith sp
ecifi
c in
form
atio
n fo
r IIO
P.
Obj
ect R
efer
ence
s (2)
Indi
rect
bin
ding
in C
OR
BA
.
Cac
hing
and
Rep
licat
ion
The
(sim
plifi
ed) o
rgan
izat
ion
of a
DC
S.
Obj
ect G
roup
s
A p
ossi
ble
orga
niza
tion
of a
n IO
GR
for a
n ob
ject
gr
oup
havi
ng a
prim
ary
and
back
ups.
An
Exam
ple
Arc
hite
ctur
e
An
exam
ple
arch
itect
ure
of a
faul
t-tol
eran
t CO
RB
A sy
stem
.
Secu
rity
(1)
The
gene
ral o
rgan
izat
ion
for s
ecur
e ob
ject
invo
catio
n in
CO
RB
A.
Secu
rity
(2)
The
role
of s
ecur
ity in
terc
epto
rs in
CO
RB
A.
Ove
rvie
w o
f DC
OM
The
gene
ral o
rgan
izat
ion
of A
ctiv
eX, O
LE, a
nd C
OM
.
Obj
ect M
odel
The
diff
eren
ce b
etw
een
lang
uage
-def
ined
and
bin
ary
inte
rfac
es.
Tape
Lib
rary
and
Reg
istry
The
over
all a
rchi
tect
ure
of D
CO
M.
DC
OM
Ser
vice
s
Ove
rvie
w o
f DC
OM
serv
ices
in c
ompa
rison
to C
OR
BA
serv
ices
.
Non
eN
one
Tim
e
SSL,
Ker
bero
sAu
thor
izat
ion
Secu
rity
Dat
abas
e ac
cess
Non
eR
elat
ions
hip
Dat
abas
e ac
cess
Stru
ctur
ed s
tora
gePe
rsis
tenc
e
Activ
e D
irect
ory
Non
eTr
adin
g
Activ
e D
irect
ory
Non
ePr
oper
ty
Activ
e D
irect
ory
Mon
iker
sN
amin
g
-Sp
ecia
l cla
ss fa
ctor
ies
Lice
nsin
g
-C
lass
fact
orie
s, J
IT a
ctiv
atio
nLi
fe c
ycle
-M
arsh
alin
g ut
ilitie
sEx
tern
aliz
atio
n
-C
OM
+ Ev
ents
Not
ifica
tion
-C
OM
+ Ev
ents
Even
t
Dis
tribu
ted
Tran
sact
ion
Coo
rdin
ator
CO
M+
Auto
mat
ic T
rans
actio
nsTr
ansa
ctio
n
-Th
read
con
curre
ncy
Con
curre
ncy
-N
one
Que
ry
-Ac
tiveX
Dat
a O
bjec
tsC
olle
ctio
n
Win
dow
s 20
00 S
ervi
ceD
CO
M/C
OM
+ Se
rvic
eC
OR
BA
Ser
vice
Even
ts
Even
t pro
cess
ing
in D
CO
M.
Clie
nts
Pass
ing
an o
bjec
t ref
eren
ce in
DC
OM
with
cus
tom
mar
shal
ing.
Mon
iker
s (1)
Bin
ding
to a
DC
OM
obj
ect b
y m
eans
of f
ile m
onik
er.
Ret
urns
inte
rface
poi
nter
of o
bjec
t to
clie
ntM
onik
er7
Load
s its
sta
te fr
om fi
leO
bjec
t6
Inst
ruct
s ob
ject
to lo
ad p
revi
ousl
y st
ored
sta
teM
onik
er5
Cre
ates
obj
ect a
nd re
turn
s in
terfa
ce p
oint
er to
m
onik
erC
lass
obj
ect
4
Load
s cl
ass
obje
ctSC
M3
Look
s up
ass
ocia
ted
CLS
ID a
nd in
stru
cts
SCM
to
cre
ate
obje
ctM
onik
er2
Cal
ls B
indM
onik
er a
t mon
iker
Clie
nt1
Des
crip
tion
Perf
orm
erSt
ep
Mon
iker
s (2)
DC
OM
-def
ined
mon
iker
type
s.
Ref
eren
ce to
an
obje
ct in
a re
mot
e pr
oces
sPo
inte
r mon
iker
Ref
eren
ce to
a m
onik
er in
a c
ompo
sitio
nIte
m m
onik
er
Ref
eren
ce to
a c
ompo
sitio
n of
mon
iker
sC
ompo
site
mon
iker
Ref
eren
ce to
a c
lass
obj
ect
Cla
ss m
onik
er
Ref
eren
ce to
an
obje
ct c
onst
ruct
ed fr
om a
UR
LU
RL
mon
iker
Ref
eren
ce to
an
obje
ct c
onst
ruct
ed fr
om a
file
File
mon
iker
Des
crip
tion
Mon
iker
type
Act
ive
Dire
ctor
y
The
gene
ral o
rgan
izat
ion
of A
ctiv
e D
irect
ory.
Faul
t Tol
eran
ce
Tran
sact
ion
attri
bute
val
ues f
or D
CO
M o
bjec
ts.
Nev
er jo
in a
tran
sact
ion,
eve
n if
told
to d
o so
DIS
ABLE
D
Nev
er jo
in a
tran
sact
ion
NO
T_SU
PPO
RTE
D
Join
a tr
ansa
ctio
n on
ly if
cal
ler i
s al
read
y pa
rt of
one
SUPP
OR
TED
A ne
w tr
ansa
ctio
n is
sta
rted
if no
t alre
ady
done
so
REQ
UIR
ED
A ne
w tr
ansa
ctio
n is
alw
ays
star
ted
at e
ach
invo
catio
nR
EQU
IRES
_NEW
Des
crip
tion
Attr
ibut
e va
lue
Dec
lara
tive
Secu
rity
(1)
Aut
hent
icat
ion
leve
ls in
DC
OM
.
Auth
entic
ate,
inte
grity
-che
ck, a
nd e
ncry
pt d
ata
pack
ets
PAC
KET_
PRIV
ACY
Auth
entic
ate
data
pac
kets
and
do
inte
grity
che
ckPA
CKE
T_IN
TEG
RIT
YAu
then
ticat
e al
l dat
a pa
cket
sPA
CKE
TAu
then
ticat
e cl
ient
at e
ach
invo
catio
nC
ALL
Auth
entic
ate
clie
nt w
hen
first
con
nect
ed to
ser
ver
CO
NN
ECT
No
auth
entic
atio
n is
requ
ired
NO
NE
Des
crip
tion
Aut
hent
icat
ion
leve
l
Dec
lara
tive
Secu
rity
(2)
Impe
rson
atio
n le
vels
in D
CO
M.
The
serv
er c
an in
voke
rem
ote
obje
cts
on b
ehal
f of t
he c
lient
DEL
EGAT
E
The
serv
er c
an in
voke
loca
l obj
ects
on
beha
lf of
the
clie
ntIM
PER
SON
ATE
The
serv
er k
now
s th
e cl
ient
and
can
do
acce
ss c
ontro
l ch
ecks
IDEN
TIFY
The
clie
nt is
com
plet
ely
anon
ymou
s to
the
serv
erAN
ON
YMO
US
Des
crip
tion
Impe
rson
atio
n le
vel
Prog
ram
mat
ic S
ecur
ity
a)D
efau
lt au
then
ticat
ion
serv
ices
supp
orte
d in
DC
OM
.b)
Def
ault
auth
oriz
atio
n se
rvic
es su
ppor
ted
in D
CO
M.
(b)
Auth
oriz
atio
n us
ing
DEC
Priv
ilege
Attr
ibut
e C
ertif
icat
es (P
ACs)
DC
E
Auth
oriz
atio
n ba
sed
on th
e cl
ient
's id
entit
yN
AME
No
auth
oriz
atio
nN
ON
E
Des
crip
tion
Serv
ice
(a)
Kerb
eros
aut
hent
icat
ion
GSS
_KER
BER
OS
Win
dow
s N
T se
curit
yW
INN
T
DEC
aut
hent
icat
ion
base
d on
pub
lic k
eys
DC
E_PU
BLIC
DC
E au
then
ticat
ion
base
d on
sha
red
keys
DC
E_PR
IVAT
E
No
auth
entic
atio
nN
ON
E
Des
crip
tion
Serv
ice
Glo
be O
bjec
t Mod
el (1
)
The
orga
niza
tion
of a
Glo
be d
istri
bute
d sh
ared
obj
ect.
Glo
be O
bjec
t Mod
el (2
)
The
gene
ral o
rgan
izat
ion
of a
loca
l obj
ect f
or
dist
ribut
ed sh
ared
ob
ject
s in
Glo
be.
Glo
be O
bjec
t Mod
el (3
)
Inte
rfac
es im
plem
ente
d by
the
sem
antic
s sub
obje
ct o
f a
Glo
beD
oc o
bjec
t.
Rep
lace
the
cont
ent o
f an
entir
e do
cum
ent
PutA
llCon
tent
Rep
lace
the
cont
ent o
f an
elem
ent w
ith a
giv
en a
rray
of b
ytes
PutC
onte
nt
Ret
urn
the
cont
ent o
f an
elem
ent a
s an
arra
y of
byt
esG
etC
oten
t
Des
crip
tion
Met
hod
Con
tent
Inte
rfac
e
Ret
urn
a re
fere
nce
to th
e ro
ot e
lem
ent
Get
Roo
t
Set t
he ro
ot e
lem
ent
SetR
oot
Ret
urn
a lis
t of t
he e
lem
ents
cur
rent
ly in
the
docu
men
tAl
lEle
men
ts
Rem
ove
an e
lem
ent f
rom
the
Web
doc
umen
tD
elet
eEle
men
t
Add
an e
lem
ent t
o th
e cu
rrent
set
of e
lem
ents
AddE
lem
ent
Des
crip
tion
Met
hod
Doc
umen
t Int
erfa
ce
Glo
be O
bjec
t Mod
el (4
)
Inte
rfac
es im
plem
ente
d by
the
sem
antic
s su
bobj
ect o
f a G
lobe
Doc
Obj
ect.
Get
a li
st o
f ele
men
ts th
at a
re c
urre
ntly
che
cked
out
Get
Che
cked
Elem
ents
Che
ck in
a s
erie
s of
mod
ified
ele
men
tsC
heck
InEl
emen
ts
Che
ck o
ut a
ser
ies
of e
lem
ents
that
requ
ire m
odifi
catio
nC
heck
Out
Elem
ents
Des
crip
tion
Met
hod
Lock
Inte
rfac
e
Prov
ide
a lis
t of (
attri
bute
, val
ue)-p
airs
for a
n el
emen
tSe
tPro
perti
es
Ret
urn
the
list o
f (at
tribu
te, v
alue
)-pai
rs o
f an
elem
ent
Get
Prop
ertie
s
Des
crip
tion
Met
hod
Prop
erty
Inte
rfac
e
Proc
ess-
to-O
bjec
t Bin
ding
Bin
ding
a p
roce
ss to
an
obje
ct in
Glo
be.
Glo
be S
ervi
ces
Ove
rvie
w o
f pos
sibl
e G
lobe
impl
emen
tatio
ns o
f typ
ical
di
strib
utes
-sys
tem
s ser
vice
s.
Yes
Impl
emen
ted
per o
bjec
t com
bine
d w
ith fa
ult-t
oler
ant s
ervi
ces
Faul
t tol
eran
ce
Yes
Impl
emen
ted
on a
per
-obj
ect b
asis
Rep
licat
ion
Yes
Impl
emen
ted
per o
bjec
t, co
mbi
ned
with
(loc
al) s
ecur
ity s
ervi
ces
Secu
rity
Yes
Impl
emen
ted
on a
per
-obj
ect b
asis
Pers
iste
nce
No
Sepa
rate
ser
vice
, im
plem
ente
d by
a c
olle
ctio
n of
dire
ctor
y ob
ject
sPr
oper
ty/T
radi
ng
Yes
Sepa
rate
ser
vice
, im
plem
ente
d by
a c
olle
ctio
n of
nam
ing
obje
cts
Nam
ing
No
Impl
emen
ted
by e
ach
obje
ct s
epar
atel
yLi
cens
ing
Yes
Sepa
rate
cla
ss o
bjec
ts c
ombi
ned
with
per
-obj
ect i
mpl
emen
tatio
nsLi
fe c
ycle
Yes
Each
obj
ect i
mpl
emen
ts it
s ow
n m
arsh
alin
g ro
utin
esEx
tern
aliz
atio
n
No
Sepa
rate
obj
ect p
er g
roup
of e
vent
s (a
s in
DC
OM
)Ev
ent/N
otifi
catio
n
No
Sepa
rate
obj
ect r
epre
sent
ing
a tra
nsac
tion
man
ager
Tran
sact
ion
No
Each
obj
ect i
mpl
emen
ts it
s ow
n co
ncur
renc
y co
ntro
l stra
tegy
Con
curre
ncy
No
Sepa
rate
obj
ect t
hat h
olds
refe
renc
es to
oth
er o
bjec
tsC
olle
ctio
n
Ava
ilabl
ePo
ssib
le Im
plem
enta
tion
in G
lobe
Serv
ice
Com
mun
icat
ion
Invo
king
an
obje
ct in
Glo
be th
at u
ses a
ctiv
e re
plic
atio
n.
Glo
be S
erve
r
Ope
ratio
ns o
n a
Glo
be o
bjec
t ser
ver.
Get
the
stat
us o
f a s
peci
fic lo
cal o
bjec
tSt
atLR
Ret
urns
a li
st o
f all
loca
l obj
ects
for a
giv
en o
bjec
tsLi
stD
SOR
etur
ns a
list
of a
ll lo
cal o
bjec
tsLi
stAl
lLe
ts th
e se
rver
rem
ove
all l
ocal
obj
ects
of a
giv
en o
bjec
tU
nbin
dDSO
Lets
the
serv
er re
mov
e a
loca
l obj
ect o
f a g
iven
obj
ect
Rem
oveL
RLe
ts th
e se
rver
cre
ate
a lo
cal o
bjec
t for
a n
ew d
istri
bute
d ob
ject
Cre
ateL
RLe
ts th
e se
rver
bin
d to
an
obje
ct, e
ven
if it
is a
lread
y bo
und
AddB
indi
ngLe
ts th
e se
rver
bin
d to
a g
iven
obj
ect,
unle
ss it
is a
lread
y bo
und
Bind
Des
crip
tion
Met
hod
Obj
ect R
efer
ence
s and
Con
tact
Add
ress
es (1
)
The
repr
esen
tatio
n of
a p
roto
col l
ayer
in a
stac
ked
cont
act a
ddre
ss.
Ref
eren
ce to
a fi
le in
a c
lass
repo
sito
ryIm
plem
enta
tion
hand
leA
prot
ocol
-spe
cific
add
ress
Prot
ocol
add
ress
A co
nsta
nt re
pres
entin
g a
(kno
wn)
pro
toco
lPr
otoc
ol id
entif
ier
Des
crip
tion
Fiel
d
Obj
ect R
efer
ence
s and
Con
tact
Add
ress
es (2
)
The
repr
esen
tatio
n of
an
inst
ance
con
tact
add
ress
.
Strin
g th
at is
use
d to
initi
aliz
e an
impl
emen
tatio
nIn
itial
izat
ion
strin
g
Ref
eren
ce to
a fi
le in
a c
lass
repo
sito
ryIm
plem
enta
tion
hand
le
Des
crip
tion
Fiel
d
Glo
be N
amin
g Se
rvic
e
Itera
tive
DN
S-ba
sed
nam
e re
solu
tion
in G
lobe
.
Rep
licat
ion
(1)
The
inte
rfac
e of
the
repl
icat
ion
subo
bjec
t as
mad
e av
aila
ble
to th
e co
ntro
l sub
obje
ct.
Indi
cate
that
the
invo
catio
n on
the
sem
antic
s ob
ject
has
com
plet
edIn
voke
dPa
ss th
e m
arsh
aled
invo
catio
n re
ques
t to
the
repl
icat
ion
subo
bjec
tSe
ndIn
dica
te th
at a
new
met
hod
invo
catio
n ha
s be
en lo
cally
requ
este
dSt
art
Des
crip
tion
Met
hod
Rep
licat
ion
(2)
The
beha
vior
of t
he c
ontro
l su
bobj
ect a
s a fi
nite
stat
e m
achi
ne.
Exam
ples
of R
eplic
atio
n in
Glo
be (1
)
Stat
e tra
nsiti
ons a
nd a
ctio
ns fo
r act
ive
repl
icat
ion.Nex
t sta
teM
etho
d ca
llA
ctio
n to
take
Stat
e
STAR
TN
one
Ret
urn
resu
lts to
cal
ler
RET
UR
N
RET
UR
NIn
voke
din
voke
loca
l met
hod
INVO
KE
INVO
KESe
ndPa
ss m
arsh
aled
invo
catio
nsSE
ND
SEN
DSt
art
Non
eST
ART
Mod
ify m
etho
d
STAR
TN
one
Ret
urn
resu
lts to
cal
ler
RET
UR
N
RET
UR
NIn
voke
dIn
voke
loca
l met
hod
INVO
KE
INVO
KESt
art
Non
eST
ART
Nex
t sta
teM
etho
d ca
llA
ctio
n to
take
Stat
e
Rea
d m
etho
d
Exam
ples
of R
eplic
atio
n in
Glo
be (2
)
Stat
e tra
nsiti
ons a
nd a
ctio
ns w
ith p
rimar
y-ba
ckup
repl
icat
ion.
STAR
TN
one
Ret
urn
resu
lts to
cal
ler
RET
UR
N
RET
UR
NIn
voke
din
voke
loca
l met
hod
INVO
KE
Nex
t sta
teM
etho
d ca
llA
ctio
n to
take
Stat
eIN
VOKE
Star
tno
neST
ART
Mod
ify m
etho
d at
prim
ary
repl
ica
Nex
t sta
teM
etho
d ca
llA
ctio
n to
take
Stat
e
STAR
TN
one
Ret
urn
resu
lts to
cal
ler
RET
UR
N
RET
UR
NSe
ndPa
ss m
arsh
aled
invo
catio
nSE
ND
SEN
DSt
art
Non
eST
ART
Mod
ify m
etho
d at
bac
kup
repl
ica
STAR
TN
one
Ret
urn
resu
lts to
cal
ler
RET
UR
N
RET
UR
NIn
voke
dIn
voke
loca
l met
hod
INVO
KE
INVO
KESt
art
Non
eST
ART
Nex
t sta
teM
etho
d ca
llA
ctio
n to
take
Stat
eR
ead
met
hod
Secu
rity
(1)
The
posi
tion
of a
secu
rity
subo
bjec
t in
a G
lobe
loca
l obj
ect.
Secu
rity
(2)
Usi
ng K
erbe
ros t
o es
tabl
ish
secu
re d
istri
bute
d sh
ared
ob
ject
s.
Sum
mar
y (1
)
Com
paris
on o
f CO
RB
A, D
CO
M, a
nd G
lobe
.
No
No
yes
Trad
ing
serv
ice
No
Yes
Yes
Dire
ctor
y se
rvic
e
Obj
ect d
epen
dent
Har
d-co
ded
Flex
ible
(PO
A)O
bjec
t ser
ver
No
Yes
Yes
Mes
sagi
ng
No
Yes
Yes
Even
ts
No
Yes
Yes
Cal
lbac
ks
No
Yes
Yes
Asyn
c. c
omm
unic
atio
n
Yes
Yes
Yes
Sync
. com
mun
icat
ion
Bina
ryBi
nary
IDL
base
dIn
terfa
ces
Few
From
env
ironm
ent
Man
y of
its
own
Serv
ices
Dis
tribu
ted
obje
cts
Rem
ote
obje
cts
Rem
ote
obje
cts
Obj
ect m
odel
Scal
abilit
yFu
nctio
nalit
yIn
tero
pera
bilit
yD
esig
n go
als
Glo
beD
CO
MC
OR
BA
Issu
e
Con
tinue
d �
Sum
mar
y (2
)
Com
paris
on o
f CO
RB
A, D
CO
M, a
nd G
lobe
.
Glo
beD
CO
MC
OR
BA
Issu
e
Mor
e w
ork
need
edVa
rious
mec
hani
sms
Vario
us m
echa
nism
sSe
curit
y
No
By tr
ansa
ctio
nsYe
sR
ecov
ery
supp
ort
By re
plic
atio
nBy
tran
sact
ions
By re
plic
atio
nFa
ult t
oler
ance
No
Yes
Yes
Tran
sact
ions
Sepa
rate
sub
obje
ctN
one
Sepa
rate
ser
ver
Rep
licat
ion
supp
ort
Onl
y in
tra-o
bjec
tTr
ansa
ctio
nsTr
ansa
ctio
nsSy
nchr
oniz
atio
n
True
iden
tifie
rIn
terfa
ce p
oint
erO
bjec
t's lo
catio
nO
bjec
t ref
eren
ce
Yes
No
No
Loca
tion
serv
ice
Yes
Yes
Yes
Nam
ing
serv
ice