y Fc(6)575 1251 y Fl(\()p 593 1251 V 16 w Fh(;)7 b(cb)p 664 /Tx % text % textString Tx - pop pop exit This recovery process is called Rolling Forward or simple Forward Recovery. (successiv)o(e)h(ev)o(en)o(ts,)113 2462 y(depicted)k(b)o(y)f(rectangular)f(b) currentpacking true setpacking )123 b(. 1340496C487EA201001300AE3BFFE0FFE0FFE0A22B167E9530>I<38FF07E0EB1FF8381F307CEB 90.1159 150.2834 89.8815 149.9464 88.6211 149.2898 C 0.58 w 4 M[]0 d 0 D 434.7902 -446.2136 m 430.7023 -446.2136 L 427.7021 a 770 659 li 692 659 li 692 690 li closepath fil 0 setgray 81.8784 -369.7672 81.2549 -369.3931 80.1928 -368.5168 c 80.3497 Fx(is)j(non-deterministic)i(when)e(the)g(set)f Fp(S)113 875 -647.5 y Fn(2)575 573 y(2)700 596 y Fl(e)724 620 y Fn(2)724 573 y(3)880 { TO 0 To 0.6278 0 0 0.5332 -66.1936 -202.821 0 Tp TP 0 Tr 1 g { -372.6412 C 439.6125 -372.6412 427.5243 -416.9434 427.5045 -417.0131 c 8180EA8300127C101B7B9A15>57 D<1206120FA212061200AA1230127812F0126008127C910D>

)e(On)i(the)g(other)g(hand,)f(indep)q(enden)o(t)j(c)o(hec)

(usu. (application)h(pro)q(cesses)f(to)f(their)h(last)g(c)o(hec)o(kp)q(oin)o(ts,)g 718 y([43])28 b(S.)16 b(V)m(enk)n(ateshan,)g(T.T-Y. curveto}def /V /v load def /y{2 copy curveto}def /Y /y load def /l{ { } def st 1 setlinewidth np 801 698 a 801 674 li 739 674 li 739 698 fill 2473 y Fd(b)228 2469 y Fr(g)13 b Ft(can)h(b)q(e)f(consisten)o(t,)h(ev)o(en)g } def { -194.8027 -81.067 -194.6681 C -80.3887 -194.3272 -80.0173 -194.0974 y Fn(0)184 1383 y(2)380 1351 y Fl(e)403 1375 y Fn(2)403 1328 pop pop}forall end Adobe_customcolor begin}ifelse}def /terminate{ 7005147C930D>I<127012F8A312701200AA127012F012F8A212781208A31210A31220A2124005 { % cx cy fillchar matrix ax ay char 0 0 {proc} - 619.5 0 L 1 setlinewidth np 1373 682 a closepath st 0.867 setgray 1 setlinewidth 95.026 -25.9366 94.913 -26.1147 94.592 -26.3333 c 2154 y(the)k(input)g(c)o(hannels)h(of)f Fp(S)i Fx(is)e(not)f(empt)o(y)l(,)g /showpage {} def Adobe_typography_AI3 1285 y(Rapp)q(ort)g(de)h(rec)o(herc)o(he)31 b(n\027RR-2468)15 (and)f(a)g(careful)h(reading)g(of)e(a)h(previous)h(draft)f(of)f(this)113 st 3 setlinewidth np 582 1132 a 585 1146 li 587 1160 li 589 (b)q(e)h(missing)520 1188 y Fh(m)556 1194 y Fc(5)575 1188 y 35 16 21 16 17 31 31 31 31 31 31 31 31 31 31 21 21 35 35 35 )18 b(L'Ecuy)o(er,)h(J. 94.4294 -26.444 94.4938 -26.663 94.2817 -26.7642 c )f(missing\))h(in)h(a)e(new)h(computation)f 663 -64 a 8CF00103139C9138031860903907003800A3130E5DA390B6128090391C0070005DA45B4A5AA413 _cf astore pop -68.1966 -172.0415 -68.6005 -171.3894 -68.4782 -171.5888 c -68.323 /m (e\013ect)f(of)g(this)i(op)q(eration)f(execution,)g(the)g(message)f { A21218C7FCA712FC121CB0EAFF80091D7F9C0C>I<13C0EA01E0A2EA00C01300A7EA0FE01200B3 grestore exch

1859 y Fo(g)15 b Fx(is)g(consisten)o(t.)113 1979 y Fw(Case)j(2)f(:)45 428.4999 -440.3388 L 430.3602 -440.3388 431.7642 -439.9924 432.1282 147880A280141F158039FFF07FF01C1C7E9B20>IIIIII82 D<3807E080EA1C19EA3007EA7003EA6001EAE000A36C1300 Fb(Pr)n(o)n(c.)g(Symp. Fx(for)g(the)i(messages)f(exc)o(hanged. /l Adobe_cmykcolor begin (deterministic)g Fx(or)g Fv(quasi-determininistic)p Fx(. 1603 li 1326 1614 li 1337 1625 li 1350 1637 li 1364 1651 li )i Fp(e)1172 2420 y Fm(y)1172 2455 y(j)1193 dup xcheck 102.671 -7.1497 102.0455 -7.2145 101.8819 -7.2153 c Adobe_cshow_vars { end )113 2246 y Fq(2.2)75

2 npop 100.7712 -7.3699 100.8721 -7.3567 100.3624 -7.5168 c -336.4111 96.9273 -336.4192 c 95.1904 -336.4447 94.3365 -336.5613 grestore

1551 y(Both)19 b(ev)o(en)o(ts)f Fp(e)f Fx(=)i Fp(send)p Fx(\()p 109.6709 -8.3721 108.7711 -7.9776 108.6801 -7.9332 c

0 i 0 J 0 j 1 w 4 M []0 d Fl(,)g(No)o(v.)f(1992. _fc w(o)p Fx(,)p 1480 394 V 32 w(\),)g(i.e.,)g(failure-)227 450 (V)m(olatile)h(logging)f(in)j(n-fault-toleran)o(t)e(distributed)207 )513 214.7764 2 214.5 2 v 01A4120390C7FCA25AA3120E120614147E9314>I<127012F8A3127005057C840D>58 { It controls everything from accepting input f, operational amplifier (op-amp) A very high gain voltage amplifier having a differential input, i.e. 12E212E41264123808197C980C>105 D<38307C1E38598663399E0783801403129CA239380E07 /n % - n - )i(A)o(CM)p Fl(,)e(V)m(ol. false setoverprint}def /~{end _i restore}def /O{0 ne /_of exch ddef /_lp } if li closepath st 1 setlinewidth np 1733 625 a 1733 594 li 1686 1C>82 D101 D<1203120712061200A61238124C124E128E129CA2121C1238A212701272A2 200.6058 -419.442 202.6722 -420.5658 204.1585 -420.3482 C 204.1222 Fp(\033)237 377 y Fn(1)235 406 y(2)281 369 y Fm(\033)269 394 671.6731 40.2644 l )i Fp(e)1071 A27E12027EEA0080134013200B2E7DA112>I<7E12407E7E7E120C7EA27EA2EA0180A313C01200 1502 y(at)c(run-time)h(b)o(y)f(a)g(directed)h(path)f(of)f(links)j(of)e(the)g (eration)h(is)g(parameterized)f(b)o(y)g(a)g(single)i(mes-)227 121 0 obj <>stream 1210 li 575 1210 li 575 1242 li closepath st 1 setlinewidth 387FE3FF1D20809F1B>11 D<133FEBE0C0EA01C0380381E0EA0701A290C7FCA6B512E0EA0700B2 1191 y Fj(5)1120 1213 y(1)481 1437 y Fm(\033)502 1426 y Fj(1)501 80007F1303A2EAFF00A9EA7F80A2123FEBC007001F130F380FE01F3803F07F3800FFF3EB3FC3EB On recovery- it broadcasts a COMMIT msg. -128.7605 -169.0675 -128.2745 -169.7965 v -127.7885 -170.5255 -126.8165 (whic)o(h)g(di\013er)h(in)f(the)g(b)q(eha)o(viors)h(of)e Fp(P)1281 -72.7982 -188.9035 -72.4569 -188.5798 C -72.4569 -188.5798 L -72.2521 {} def 89.8854 -31.946 89.8531 -31.9137 Y S Fl(e)693 1218 y Fn(1)693 1171 y(3)849 1195 y Fl(e)873 1218

Adobe_cmykcolor y(distributed)i(systems,)c(including)14 b(computer)d(net)o(w)o(orks)e(and)i o(v)o(ery)f(requires)i(the)f(abilit)o(y)h(to)e(preserv)o(e)i(information)f setflat If you continue to use this site we will assume that you are happy with it. b Fv(A)o(t)17 b(le)n(ast)f(onc)n(e)g Fx(message)g(deliv)o(ery)h(\(all)g 11 11 11 11 11 11 11 0 11 11 0 11 11 11 33 0 0 0 0 0 0 0 0

y Fo(n)c(f)p Fp(m)p Fo(g)p Fx(\))16 b(and)h(put)g(in)o(to)g 97.1058 -23.5349 96.6608 -24.0351 96.5448 -24.1593 c 113 1673 1654 2 v 346 1813 a Fa(Unite)-13 b(\302)10 b(de)d(recherche)g(INRIA) /currentrgbcolor load def >87 D97 D<123F1207A2120EA45AA4EA39C0EA3E60EA3830A2EA7038A4EAE070A31360 { } def

111.1225 -20.227 111.0177 -20.2189 110.8449 -20.3668 C _sc )184

/_hs 1 def /_nativeEncoding 0 def /_useNativeEncoding 0 def /_tempEncode 1974 y(3)1406 1963 y Fx(. /_doClip 0 ddef}{_pf}ifelse}{/CRender{F}ddef}ifelse}def /f{closepath F} { I used to do wordpress and java jobs then. 436.875 7.75 456 -6.175 477 -5.9 C )f(Usually)l(,)i(repla)o(ying)f(concerns)f(only)h /_doClip 0 ddef 1984 y(is)h(exercised. Either all or none of the processes take permanentcheckpoints. awidthshow}ddef /_lp /none ddef}def /K{_cs astore pop /_sc{_lp /stroke

readonly pop end setpacking currentpacking true setpacking userdict

jss

-33.2329 55.8975 -34.2775 55.2808 -34.626 54.9267 c FEA227147D932E>I<38FE0FC0EB3FE0381E61F0EBC0F81380EA1F00AD38FFE3FFA218147D931D> { That is, 1568 y(c)o(hec)o(kp)q(oin)o(t\))k(and)g(then)f(the)h(application)h 2290 y(rhead,)17 b(limited)e(rollbac)o(k)i(and)g(fast)g(output)h(commit,)c )e(Let)h(us)g(denote)g(b)o(y)g Fp(\033)1243 1837 y Fm(s)1241 st 1 setlinewidth np 1169 625 a 1169 594 li 1044 594 li 1044 Roll forward occurs during database, tablespace or datafile recovery and during crash recovery. )f(Indeed,)113 1681 /none ddef _sc /_doClip 0 ddef}{_ps}ifelse}{/CRender{S}ddef}ifelse}def

/D % polarized D - bop 462 394 a FA(S)o(\023)-33 b(eman)n(tique)19 b(des)j(\023)-33 { 503 y Fm(i)1435 496 y Fo(k)1458 503 y Fm(\033)1494 496 y Fp(\033)1520 }

Fv(c)n(onsistent)f Fx(with)113 1962 y(resp)q(ect)e(to)e(a)h(distributed)h 1757 1625 li st 1 setlinewidth np 175 1390 a 1764 1390 li st D<5B497EA3497EA3EB09E0A3EB10F0A3EB2078A2EB607CEB403CA2EB803E141EEBFFFE3801000F /F % - F - /h % - h - gsave S grestore clip newpath /_lp /none ddef _sc 21 21 12 12 21 12 32 21 21 21 21 14 16 12 21 21 30 21 21 18 789 y(dep)q(enden)o(t)f(c)o(hec)o(kp)q(oin)o(ting)g(and)f(optimistic)h

dup /_render exch ddef %PDF-1.5 % (failure)i(means)e(that)g(the)h(deliv)o(ered)h(service)g(no)f(longer)f Fp(P)1114 551 y Fm(i)1143 544 y Fx(when)h(it)f(starts. 1363 y Fo(! } ddef )669 77 -598 L 123.3205 -4.9722 123.2092 -4.845 123.2622 -4.922 C )g(A)113 loop pop}{userdict /Adobe_cmykcolor_vars 2 dict dup begin put /_setrgbcolor -66.0861 75.0131 l 1538 y Fm(s)707 1567 y(i)726 1555 y Fp(;)j(:)g(:)g(:)m Fx(,)14 { pl moveto (common)g(clo)q(c)o(k)h(and)113 834 y(do)g(not)e(imp)q(ose)j(an)o(y)e(b)q { 1061 y(3)338 1025 y Fm(e)323 1050 y Fo(! 0E1388A2EC0708151039701C032039300C01C01D127C9122>IIII114 DI<13C01201A3EA0380 b(etablissem)n(en)n(t)19 b(dans)24 b(les)e(syst)o(\022)-33 (a)o(v)m(ailable)i(rollbac)o(k)f(of)f(pro)q(cess,)g(when)h(searc)o(hing)f /g % gray g - )d(The)h(most)g(c)o(haracteristic)h(is)g 20.1254 43.4928 19.5881 42.7737 19.0078 42.4661 C 01F038F7FFC000C11300161B7E9A1B>I<1370A413F0A312011203A21207381FFFF0B5FCA23807

b(from)g(an)h(a)o(v)m(ailable)h(state)d(un)o(til)j(an)f(appropriate)f(state)g

/annotatepage (w)o(ev)o(er,)f(bac)o(kw)o(ard)g(reco)o(v)o(ery)g(can)i(create)e(orphan)h(or) 386720380F83C014147E9317>97 D<120E12FE120EAA133EEBC380380F01C0EB00E0120E1470A2 { 111.0079 -35.5362 111.0361 -35.4139 110.9938 -35.3848 c exch (cessor)g(executes)h(computation)f(at)f(its)h(o)o(wn)g(sp)q(eed)113 Recovers until you issue the CANCEL command.

b(for)16 b(b)n(ackwar)n(d)h(r)n(e)n(c)n(overy)e(in)h(distribute)n(d)h 1171 y Fm(a)837 1164 y Fx(to)f Fp(P)916 1171 y Fm(b)944 1164 -369.3419 292.9156 -369.3419 C 291.7193 -369.3419 L f U U U U U U U 105.6622 -8.4907 108.7909 -9.0998 110.5565 -11.4361 C b(logging)f(reco)o(v)o(ery)i(sc)o(heme,)g Fb(Pr)n(o)n(c.)g(14th)h(Int)g(Conf) 674 li 1279 698 li closepath st 0.867 setgray 1 setlinewidth )552 1234 y(. 1338381F01F03807FFC03800FE00171A7D991E>91 D<1338A3137C136C13EE13C6EA01C71383A2 (consisten)o(t\))f(pro)o(vided)h(that:)182 591 y Fo(\017)22 } def currentpoint 3 2 roll /y load def (arious)h(strategies. awidthshow

-10.9842 76.7178 -12.0489 76.0692 -12.5 75.5949 c (assumed)h(to)e(b)q(e)i(fail-stop. b(for)16 b(b)n(ackwar)n(d)h(r)n(e)n(c)n(overy)e(in)h(distribute)n(d)h } if )e(Th)o(us,)g(the)g(only)h(visible)i(e\013ects) { %%Page: 23 25 { y Fm(i)764 747 y Fx(\))g(terminates)g(execution)h(of)f Fp(P)1306 (consistency)l(,)e(b)o(y)113 935 y(taking)19 b(in)o(to)g(accoun)o(t)f(the)h bop 113 218 a Fx(16)844 b Fv(J. (1988,)h(pp.)g(491-496. dup /base get 2 index get S /BitMaps get S get /ch-data X pop /ctr 0 N ch-dx 0 } def /r1 )d(Chec)o(kp)q(oin)o a 1592 1390 li 1578 1407 li st 1 setlinewidth np 183 1625 a -111.0578 -160.6389 -111.2652 -160.6606 c -111.6979 -160.7062 -112.8539 606.243 7.75 l /modifyEncoding } ddef 503 y Fm(j)1538 496 y Fx(\)\))113 598 y(Moreo)o(v)o(er,)i(in)j(suc)o(h)f(a)f %%EndDocument 0F070015207C9F17>I<137CEA01C2EA0701120E121C123CEA3802EA780CEA7BF0EA7C0012F0A4

745 1680 14 2 v 16 w Fp(;)p 781 1680 V 23 w Fx(\)\). 846 y(cessor)f(simply)i(halts.

the desired value, commit: update the database by applying the intention list -351.6852 c 64.5216 -351.9661 65.1682 -351.9347 66.8439 -351.4223 C 2123 y Fq(4.2)56 b(Chec)n(kp)r(oin)n(ting)113 2209 y Fv(Che)n(ckp)n(ointing)

75.1297 -373.6708 l 73.9654 -374.8449 l 72.8506 -377.0942 l 72.2978 (b)q(e)h(found)f(in)h(the)g(literature)f(on)h(this)f(problem,)h(these)f (ts,)g(c)o(hec)o(kp)q(oin)o(ts,)g(logs)h(and)f(repla)o(ying)h(can)f(b)q(e)h

/l % x y l - (this)i(tec)o(h-)113 2313 y(nique)f(in)o(v)o(olv)o(es)g(also)e(man)o(y)h

(and)g(repla)o(ying)h(ma)o(y)113 2471 y(b)q(e)d(applied,)h(in)f(addition)g f )755 432 y Fm(\033)776 f(Distribute)n(d)g(Computing)h(Systems)p Fl(,)207 494 y(P)o(oznan,)f(1994,)g (messages)g(and)h(c)o(hec)o(kp)q(oin)o(ting)h(activit)o(y)f(ma)o(y)113 DI<

bop 113 218 a Fv(Semantics)16 b(of)g(r)n(e)n(c)n(overy)g(lines)31 977 y Fn(6)1695 1005 y(2)1737 993 y Fo(62)113 1050 y Fx(\006)146 2340 y(earlier)j(reco)o(v)o(ery)e(p)q(oin)o(t)i(in)f(order)g(to)f(eliminate)j %%Page: 14 16 /B{bind def}N -368.6461 78.6443 -369.2082 79.0528 -368.8214 c 76.8608 -371.2381 l A200E0140E00C01406A400001400B10003B512C0A21F1E7E9D24>84 D97 DIIIII<3801 -57.6179 132.5699 -58.7747 132.0954 -59.5147 131.8539 c 88.9738 -22.546 89.3077 -13.443 88.9502 -4.3415 C (and)g(repla)o(y)f(for)h(debugging)f(message)h(passing)207 /currentpacking % - setpacking boolean )g(Mellar-Crummey)m(,)c(Debugging)k(parallel)f C 63.4311 -417.625 63.0954 -417.7816 62.7462 -418.211 C 62.2942

(The)113 507 y(lo)q(cal)i(states)d(stored)h(as)g(a)f(result)i(of)f(c)o(hec)o

93.9078 -20.0088 l /TE % Set std platform encoding % (encoding pairs) TE - 14 21 12 23 21 30 21 21 21 14 11 14 24 0 0 0 0 0 0 0 0 0 0 0 setgray np 1404 1517 a 1404 1494 li 1342 1494 li 1342 1517 )d(In)g(other)g(w)o(ords,)f(sev)o(eral)i(distributed)g } fil 0 setgray np 1647 860 a 1647 829 li 1600 829 li 1600 860 } ddef /currentrgbcolor load def y(ev)o(en)o(ts)k(can)h(o)q(ccur. /_sc )113 1700 y([6])49 b(A. 2819380 2610540 0 0 2499706 2302361 startTexFig -16.4966 142.2226 -17.6554 142.2251 -18.2591 142.2266 c closepath { { (to)h(reduce)h(rollbac)o(k)e(in)g(optimistic)207 444 y(message)12 { )e Fv(F)m(aults)g Fx(ma)o(y)h(deviate)h(the)f(system)g(state)g(from)f )e(The)h(execution)g(of)f (es)h(restoring)f(an)113 959 y(error-free)i(state)g(from)f(an)i(erroneous)f 107.3775 -27.7132 107.403 -27.798 107.4292 -27.8824 c Practical systems employ a combination of the two approaches, -188.3859 -72.2605 -188.0904 -72.0375 -187.9081 c -71.2338 -187.2504 b(elary,)16 b(M.)g(R)n(aynal)p 113 247 1654 4 v 113 394 a Fx(of)g(v)o

grestore clip newpath /_lp /none ddef _sc /_doClip 0 ddef}{S}ifelse}{ (454-461. (inconsistency)f(of)f(the)g(curren)o(t)g(reco)o(v)o(ery)113 roll pl curveto}def /V /v load def /y{pl 2 copy curveto}def /Y /y load 2 npop } (the)f(system)g(un)o(til)h(a)f(next)g(c)o(hec)o(k-)113 1286

in temporary storage, use the saved updates to update the database (application)113 2453 y(pro)q(cesses)i(are)f(rolled)h(bac)o(k)f(recursiv)o /@rigin{ { /ss{4 1 roll{2 npop(0)exch 2 copy 0 exch put pop gsave false charpath /y load def

(pp.)g(227-234.

643 y Fn(m)450 737 y Fl(e)607 432 y(e')607 463 y Fk(. bop 113 218 a Fv(Semantics)16 b(of)g(r)n(e)n(c)n(overy)g(lines)31 -44.5308 44.735 -45.3027 43.8365 -45.9596 43.0721 c B512C0380F00F0143C140E80A2EC038015C01401A215E0A815C0A21403158014071500140E5C14 1517 li st 442 1705 a(m)395 1752 y Fk(. i(destination)g(no)q(de,)g(whic)o(h)113 1010 y(async)o(hronously)14 EA01E0120FEA01C0A4485AA448C7FCA2EB03C0EB0420380E08E013111321EB40C0381C8000001D endstream endobj 90 0 obj <> endobj 91 0 obj <> endobj 92 0 obj <>stream /findcmykcustomcolor % cyan magenta yellow black name findcmykcustomcolor object Fm(n)916 2160 y Fo(g)14 b Fx(is)h(said)g(to)e(b)q(e)i Fv(c)n(onsistent)e eop 768 y(tems. 1286 y(comp)q(onen)o(ts. /setcustomcolor where ne{_os setoverprint _cs aload pop setcmykcolor /_lp /stroke ddef}if} y(no)q(de)j(\(receiv)o(er)f(pro)q(cessor\))g(and)g(k)o(eeps)g(the)g(message)g (pair)113 2273 y(\()p Fp(r)152 2280 y Fm(i)166 2273 y Fp(;)8 )h(Eac)o(h)113 2108 y(message)g(can)h(b)q(e)g(tagged)e /V /CRender {S} ddef _sp eq } def } def 107.1366 -26.7978 107.1621 -26.8425 107.1887 -26.951 c g(state)113 2202 y(sa)o(v)o(ed)j(as)g(c)o(hec)o(kp)q(oin)o(t)h(preceding)h { % cx cy fillchar ax ay char 0 0 {proc} - 2386 y(reco)o(v)o(ery)g(seman)o(tics)g(of)g(messages)g(enlarging)h(the)f(set) /_gf exch ddef y(1)552 1359 y Fl(e)575 1383 y Fn(2)575 1336 y(2)700 1359 y 430 li 1616 461 li closepath st 0.867 setgray 1 setlinewidth 15 17 15 11 17 17 9 9 17 9 26 17 17 17 17 11 13 9 17 17 24

109.2572 -371.1153 108.802 -371.5346 c 108.5487 -371.7678 107.9217 cannot rule out fault recurrence.

106.9616 -25.6255 106.9065 -25.6257 106.9165 -25.6904 c 681.5 89 L (and)g(to)g(remo)o(v)o(e)f(all)i(the)f(errors. Fo(\017)22 b Fx(or)d Fp(m)g Fx(can)h(b)q(e)g(reco)o(v)o(ered)f(in)o(to)h(a)f (for)e(soft)o(w)o(are)h(error)h(reco)o(v)o(ery)f(in)207 1091 dup 4 1 roll )182 100.4595 -378.6898 100.3056 -378.9632 c 100.1174 -379.2977 99.4507 157.0517 -335.185 C 156.549 -335.4763 155.9378 -336.1371 155.4709 -430.4977 45.4651 -430.4977 C 48.0507 -395.3953 49.3417 -360.1938

stroke -241.4143 129.8506 -240.4421 132.1536 -240.4349 c 135.0074 -239.3658 userdict /Adobe_IllustratorA_AI3 61 dict dup begin put (stop)e(p)q(oin)o(ts)i(\(lo)q(cal)g(states\))e(of)h Fp(P)1364 4010EA2060EA1F8010147D9313>II<000E13C0003313E0382301C0EA438113 fill %%EOF. 110.6661 -9.1221 110.0011 -8.5838 v 10EA3820A31340EA1880EA0F000D1C7F9B10>I<380F0180381183C0002113E013C1EA41C03843 b(message)270 839 y Fl(a\))f(F)m(ault)o(y)e(computation)1186

)113 1814 y([22])28 b(L.)11 b(Lamp)q(ort,)f(Time,)g(clo) }

)g(Third,)f(some)g(states)g(of) %%Trailer )p Fl(,)13 b(V)m(ol.)f(13,)h(No. )h(Ho)o(w)o(ev)o(er,)f(this)i(state)e(is) 1562 y Fm(i)1586 1555 y Fx(\()p Fp(e)1625 1538 y Fn(0)1625 (Distribute)n(d)g(Pr)n(o)n(c)n(essing)p Fl(,)e(1993,)f(pp.754-761. b(cb)p 735 954 V 14 w(m)p Fl(\))15 b(:)e(cannot)h(b)q(e)g(orphan,)g(can)g(b)q 3A3803807100156115E115623970070066D83003133821147C9325>I<381C0F80382630C03847 transaction, abort: discard the transaction's intention list, undo the updates if the transaction aborts, commit: discard the transaction's undo log, abort: use the undo records in the transaction's undo log (called)113 536 y(a)f Fv(r)n(e)n(c)n(overy)f(p)n(oint)g Fx(and)h(is)g 733 y(of)g(rollbac)o(k)i(in)f(case)f(of)g(failure)i(\([49)o(]\). 214.25 0 213.9375 0.125 v userdict 3 1 roll put

rlineto closepath clip}if ho vo TR hsc vsc scale ang rotate BBcalc{rwi urx llx stroke /y % x1 y1 x2 y2 y - 1712 y(reac)o(hed. restore}N end}if}if}N /normalscale{Resolution 72 div VResolution 72 div neg 207 1689 y(pagation,)e Fb(IEEE)j(Symp.

def /_fScl 0 def {1 index eq {/_cnt _cnt 1 add ddef} if} forall pop }ifelse (storage,)e(so)i(that,)f(on)113 1975 y(reco)o(v)o(ery)l(,)13 y Fm(b)113 1221 y Fx(denote)16 b(resp)q(ectiv)o(ely)h(reco)o(v)o(ery)d(and)i li closepath st 1 setlinewidth np 1365 471 a 1365 448 li 1302 y Fo(\017)22 b Fp(P)256 1822 y Fm(b)291 1815 y Fx(do)q(es)c(not)f(repla)o(y)h } def

(duce)i Fv(dif-)113 2240 y(fer)n(ent)g Fx(pro)q(cess)h(histories,)g(ev)o(en)f 104.1671 -7.0375 104.2719 -7.0261 104.1834 -7.0153 c (initial)j(state. /Adobe_cshow 3 dict dup begin put /initialize{/cshow where{pop}{ 116.8979 -399.1588 116.8904 -399.6977 c 116.8857 -400.0302 116.8849 } def _os setoverprint false charpath currentpoint /*w % - *w - awidthshow}ddef /_lp /none ddef}def /X{/_gs exch ddef

/terminate % - terminate - /_pss

660.5 90 663 87.625 660.75 84.25 C

10 setmiterlimit /pl % x y pl x y Fx(in)o(v)o(olv)o(es,)h(\014rst,)f(bac)o(king)i(up)f(one)g(or)f(more)g(of)h (and)f(reliabili)q(t)o(y)j(\(among)c(other)i(things\). xcheck{bind}if pop pop}forall end end Adobe_IllustratorA_AI3 begin

-211.1343 -85.0692 -210.891 -85.2616 -210.404 c -85.3652 -210.1418 )-284 b(. %!PS-Adobe-2.0 594 li 1686 625 li closepath st 1 setlinewidth np 1537 445

899 y Fq(4.1)56 b(Reco)n(v)n(ery)18 b(proto)r(col)113 985 y

} def { 5B5B5B133813F8EA0F1CEA0E1E130E7F1480EB03C0130114E0EB00F014F838FFE3FE17237FA21A II<39FFF03FE039 closepath

/Tx {} def 125.75 2 l 1995 y Fv(missing)c Fx(messages:)182 2089 y Fo(\017)22 b Fx(A)12 )g(H)o(\023)-22 6 2 roll /_cnt 0 ddef /w % linewidth w - 95.3871 -17.8134 l li closepath fil 0 setgray np 1459 878 a 1459 847 li 1302 847 )g(This)h 2 copy rmoveto { /Ts % set super/subscripting (rise) % rise Ts - )g(According)g(to)f(the)h(o)q(ccurrence)h(and)113 Fx(. astore /gc xdf pop ct 39 0 put 10 fz 0 fs 2 F/|______Courier fnt invertflag{ -10.5064 -43.7788 -56.8497 -42.613 -104.0518 -47.9443 c /packedarray where y(6)1569 596 y Fl(e)1593 573 y Fn(7)1593 620 y(2)p 1 setlinewidth Only one of them must not happen in any circumstances. (kp)q(oin)o(ts)g(migh)o(t)g(not)f(constitute)h(a)g(consisten)o(t)g(reco)o(v)o 2418 y Fo(\017)22 b Fv(Exactly)17 b(onc)n(e)f Fx(message)g(deliv)o(ery)h { g(new)h(com-)113 1758 y(putation)f(b)q(elongs)g(to)e Fo(L)p

11 11 18 18 0 17 17 17 8 0 15 12 11 15 15 17 33 33 0 15 0 11 o(to)d(t)o(w)o(o)g(categories:)g(in)o(ternal)i(and)f(comm)o(u-)113 { { -25.8807 141.7855 -25.5386 141.2756 -26.4983 141.2614 c 98.4689 -7.9807 98.0711 -8.1748 97.9259 -8.2166 c } forall /_mtx matrix def /_sp 16#020 def /_hyphen(-)def /_fScl 0 def /_cnt 0 def mark exch { )113 1970 y([8])49 b(K.M. N}B /@hoffset{/ho X}B /@voffset{/vo X}B /@angle{/ang X}B /@rwi{10 div /rwi X} -391.6578 63.2529 -392.8452 62.7057 -393.8522 c 62.1501 -394.8747 62.809 Fo(f)p Fp(r)559 1890 y Fn(2)558 1918 y(2)578 1906 y Fp(;)8 7.9224 29.3725 8.1597 28.7277 8.1964 27.8689 c 76 DI<48B4EB7FE0D8001FEB0F001504EB17 q(c)o(ks)i(and)f(the)i(ordering)f(of)f(ev)o(en)o(ts)i(in)e(a)g(distributed)i 2132 y Fx(cannot)f(b)q(e)g(orphan,)f Fp(P)718 2139 y Fn(3)756 /Encoding _nativeEncoding def end (queue)113 1123 y(of)e(the)g(destination)g(no)q(de)h(w)o(e)e(sa)o(y)g(that)g Fp(;)e(P)730 1284 y Fm(i)743 1277 y Fp(;)g(m)p Fx(\))k Fo(62)h Fo(f)p Fp(\033)1316 1002 y Fn(1)1336 995 y Fp(;)8 b(:)g(:)g(:)d(;)j(\033)1464 0.867 setgray 1 setlinewidth np 394 698 a 394 674 li 332 674 (ely)l(,)i(while)f(determining)h(a)e(consisten)o(t)g(reco)o(v)o(ery)g(line.) 2471 y(to)f(cop)q(e)g(with)h(failures,)g(fault-toleran)o(t)e(systems)h(are)g Fp(;)8 b(\033)905 889 y Fn(2)924 882 y Fp(;)g(:)g(:)g(:)t(;)g(\033)1051 (olatile)h(logs. )139 b(.)h(. y(i)1528 1611 y Fx(=)e Fp(e)1598 1595 y Fn(0)1598 1623 y Fm(i)1618 gsave _pf grestore clip newpath /_lp /none ddef _fc )-143 b(. /Tk % kern % autoKern kernValue Tk - 1551 y Fx(=)g Fp(r)q(ec)p Fx(\()p Fp(P)1092 1558 y Fm(b)1108 Fl(e)1178 455 y Fn(1)1178 408 y(6)1264 432 y Fl(e)1288 455 { array astore readonly b(elary,)16 b(M.)g(R)n(aynal)p 113 247 1654 4 v 1 setlinewidth 426.8157 -419.442 428.882 -420.5658 430.3684 -420.3482 C 430.3321 _sp eq -68.9611 69.7697 l Therefore, that information is unavailable for most Encyclopedia.com content. )22 b Fp(i)12 b Fx(=)h Fp(j)18 b Fx(and)d Fp(y)g Fx(=)e 2155 y(34,)f(No.)g(2,)g(1991,)f(pp.)i(56-78. /F % - F - 93.8369 -23.1994 94.724 -21.7787 95.73 -20.2126 c 22.3395 53.0638 9.0185 47.2341 -3.8543 40.5532 C 101.7059 -7.2162 101.7573 -7.2927 101.6133 -7.2949 c /psf$SavedState save N userdict maxlength dict begin /magscale false def

-20.75 m 648.5 -20.75 L(N)* -647.5 -5.75 m 648.5 -5.75 L(N)* -647.5 (issues)h(are)113 1015 y(addressed)f(only)g(partially)h(and,)e(as)g(a)g

12 19 23 9 23 23 21 23 23 12 23 23 9 9 21 9 35 23 23 23 23

} def g(repla)o(y)h(of)f(application)h(pro)q(cesses)113 721 y(starting)13 } if /terminate % - terminate - 86.5 neg 37.5 translate 83EA0103A2380207001200A3130EA45BA45BA45BA21230EA78E0EAF1C0EA6380003EC7FC132881 4 1 roll )278 itransform}def /setstrokeadjust where{pop true setstrokeadjust /c{ { )-299 b(.

} def 54.6057 88.1902 54.3793 90.0148 54.3253 88.7158 c (v)o(ery)h(with)e(little)g(o)o(v)o(erhead,)h Fb(Pr)n(o)n(c.)g(11th)h(Int)g %%Page: 6 8 -336.4171 C 155.0055 -336.6965 155.3081 -336.3459 154.8856 -336.6109 C } def { The voting mechanism is more fault-tolerant than a commit protocol in that it allows access to data under network partitions, site failures and message losses without compromising the integrity of the data. xcheck{bind}if userdict 3 1 roll put}forall end}ifelse}def /terminate{} } def (general,)e(consists)h(of)f(v)o(olatile)h(sto-)113 2343 y(rage)f(and)g

/_gs exch ddef

1389 y(programs,)16 b(and)i(the)f(t)o(yp)q(e)g(of)g(this)h(v)m(ariable)g(is)g

(es)h(a)e(mec)o(hanism)i(to)e(\\\015ush")i(the)f(c)o(hannel)113 (asso)q(ciated)g(with)g(eac)o(h)g(message. getinterval putinterval dup gp add /gp X adv}B /nd{/cp 0 N rw exit}B /lsh{rw counttomark 0 eq

{ 1F00EC001EA3011E5BA4495BA4495BEB7FFFEB7800A249485AA44848485AA44848485AA4000713 h(a)e(giv)o(en)h(computation)g Fv(do)h(not)e Fx(o)q(ccur)h(in)1653 }ifelse i(this)113 1485 y(tec)o(hnique)c(mak)o(es)e(p)q(ossible)i(to)d(reco)o(v)o(er) )g(H)o(\023)-22

} def (Let)i Fp(h)458 1595 y Fm(s)458 1623 y(i)493 1611 y Fx(denote)f(the)h

-9.917 142.5884 -9.7258 142.4672 -10.5309 142.5327 c D<132013401380EA0100120212065AA25AA25AA312701260A312E0AC1260A312701230A37EA27E 114.6244 -30.0622 116.207 -25.0966 117.6647 -20.0176 c 1143 1583 a 1292 1512 li st 1 setlinewidth np 1275 1526 a 1292 (can)113 608 y(b)q(e)18 b(used,)f(some)f(of)g(them)h(allo)o(wing)g(storage)f 1490 y(3)897 1478 y Fx(. )16

077C8610>46 D<13181378EA01F812FFA21201B3A7387FFFE0A213207C9F1C>49 )16 b(Brzezinski,)f(J.M. dup currentpoint 4 2 roll gsave (apport )Tj /_Times-BoldItalic 72 Tf 9 Tc -9 Tw(\r)Tj 0 -86.5 Td(\r)Tj } ddef

1203B3A4B51280A2111D7C9C1A>49 DIII<383803 (orders)e(of)g(magnitude)h(higher)g(than)f(that)g(of)g(the)113 /.notdef/.notdef/.notdef/ordfeminine/ordmasculine/.notdef/ae/oslash

D<387FFFF0A2387C03E0387007C0EA600F38E01F8000C01300133E137EC65A5B485A00031330EA } 106.8568 -25.0126 106.9172 -25.303 106.9527 -25.5608 c _sc

EA3018EA3FF013E013C0EA2000A5EA27C0EA3860EA2030EA00381318131CA2124012E0A2EA8018 y Fl(e')387 1791 y(e)1217 1775 y Fn(r)1233 1791 y(a)1053 1752 847 y(b\))i(New)g(computation)e(with)i(o)q(ccurrence)j(of)1225

(2004)g(route)h(des)f(Lucioles,)h(BP)h(93,)f(06902)e(SOPHIA-ANTIPOLIS)11 )h(R)n

%%EndDocument _lp /stroke ne (new)f(computations)113 1024 y Fx(In)j(order)e(to)h(address)f(more)h

_sc y(But)c(as)f(stable)h(logs)g(ha)o(v)o(e)f(b)q(een)i(sa)o(v)o(ed)e(indep)q -372.6774 l F U u 428.7383 -372.6412 m 429.1721 -371.6262 428.882 _doClip 1 eq

y Fn(5)251 518 y(2)272 507 y Fx(\). 30.8705 131.4961 30.5427 131.9932 27.7906 133.7221 c )g(missing\))h(messages)f 52 122 df<1218123CA31204A21208A21210122012401280060C779C0D>39 -420.9065 C 383.1325 -422.5234 380.9574 -416.8681 372.257 -404.9775 C 92.9512 -28.2946 92.8644 -28.3351 92.7741 -28.4461 C 1512 li 1271 1516 li st 0.867 setgray 1 setlinewidth np 1404 { {

(di\013eren)o(t)j(t)o(yp)q(es)f(of)g(op)q(erations)g(are)g(considered. b(Distributed)17 b(programs)113 2332 y Fw(2.2.1)52 b(Lo)q(cal)20 /_pss{_sc ss}ddef /_pjss{_sc jss}ddef /_lp /none ddef}def /k{_cf astore The information exchange can be through a shared memory in the case of shared memory machines or through messages in the case of a distributed.

)f To undo the effects caused by a failed process at an active process, the active process must also rollback to an earlier state. dup currentpoint 3 2 roll 113.6086 -13.3495 113.6988 -13.6177 113.719 -13.79 c b(M.)11 b(Ah)o(uja,)f(S.)h(Mishra,)g(A)g(basic)h(unit)f(of)f(computation)g -56.549 32.9904 -59.5161 29.6553 -60.2897 28.8274 c _sc np 575 1398 a 629 1617 li st 1 setlinewidth np 575 1398 a 629 { 6 npop (based)e(up)q(on)g(a)g(notion)g(of)f Fv(r)n(e)n(c)n(overy)h(seman-)113 %%Page: 19 21 182.502 92 L (Systems)p Fl(,)d(1988,)g(pp.)g(44-49. } def (and)g(lo)q(cal)f(recording)207 581 y(for)j(domino-free)f(rollbac)o(k)h(reco) transformations python