21

Evolucdo de software

ObjetivosOs objctivos deste capitulo sao Jµresenldr d evulu~ao Je sullware 11 desm1vl!I

uma sene de maneiras de corno rnod1f1lar urn scltware. Aµos h11 este cepnulo, voce.

ii cornpreendera que 11s mucfant11s ~i\o 1nPv1tilve1~ pnrn CJUC cs m1cm.1sdi! software perm11ne~11m ute1s e 1111r. o rlP.Sl'nvolv1m!'nto c a l'volu~Ao do softw<1re pndem ser lntegr11nm rm um morlrlo cm e~piral,

111 lera <1µre11J1do )Ollre duerentes upos de rnanutencao de software e fatores que illl!liml OS tuSlU) Ull manutencac:

111 e\tllril r1r.ntr rlo\ rrocr~~m onvolvldos na cvolucfio d!' software, cntrc eles o prn<l'sso rle rrl'ng1?nh.ir1;i rl!' sottw.1m;

111 compreendera corno os suternas le941dos podem ser avali11dosp11ra decidlr se devem ser dcscartados, manudos, sofrer reengenhana ou ser substituidos

Conteudo21.1 D1nJim1ca da evolu~ao de prograrnas21.2 Mdnuten~ao JI! sullwarl!21 .3 Processo de evotuceo21.4 Lvolu~ao de sistemes leqados

J)cpnls de m ,,~1c111a~ rercrn ~ld11 1111pl.111l:hl•"· l'lc~ devem 111c\1L,1ll'l111cnte 111111la1 1'·113 pcr rnanecercm ilte1s. A1i1'1s P M•ll\\ ire ~cl c11lm:.1J1• c111 us«, no\l" 1cq111,11u, •111~c111 c '" 1e<1111'lll" cxlstemes mudam r.tud.111<;.1s Ill" m:g11~111> lfrquelll<'ll1C11ll'i,:<'rn111 nmn' n.:<1111s1111• p.11111> s111l\\.r1e l'XI iemc Panes do ,ofl\\.ue p0Je111 ser 1,111th!it·ada' 1•.11,1 (11111i;11 cuos descobcuos dur.uue <11:1 operJ~no. para ,11l.1p1a In .11J111,1111"•' p1'11.1lo111t.1 e p.11.1 IJ'1111111rar <cu dt·sc111pt·11l1u e outr,« <·II•""tensllt\l~ 11~11 fUllt°ion,11s () dl''l"ll\t oh 11111:11111 de wl 1 II WC. pon.nuo, II o p.ua ljU.1mJ11 um "'IClllllt! enuegue par 1 t•pcr 1i;.111, 111.1' l'il'"''j:llc .111 h111i;11 Jo t1do d1· 11d.1 d11 1,u:in.1

,\ c\l1l11~·.c1cl1 s11f111a1c t! llllpnrlan(<' pm' "1ng;11111,1\0C' Ulu.11' '·'" rm1110 dcpendeutes dos'l'ICm.ts nos qu,11, m1.:<111.11111111lh11r:',,, dPlan:~. Scus .,,lcmJ\ S,11) unportanrcs .ill\t" de llC~•Xlll<e dcve haver mvesrunentos l.'111 111ud.1r1\·" p.u.1<1uc11 1,1!111 J,,, am••' se1a rn ntulo \ 111, 101 p.irte rfo Of\':HI c.·1110 n.t"li~1,111dC"'i cmpre ....b c dl"q111.tda •• UhtllUll'll\al• de lrri1Sl('111.t\t... xrsterue«, e n.\u liC\C'flH}'.\

fit.11 surpre us 1·11111 "llla\•lCb i.:1111111 " 111<1'llo1d.1' Jll>1 I rl1~h (I rl1~h. lOOOJ, que ~ugcre que 'JO du' t11stnb de M•ll'' 11c c'IJ1111.1C'\11111\10 I ~1<tc grnndc 1.1rrn,ao nesse pcrvcntu.d, ,omudo, um 1l'el que 1 lie ~1.1 d1'>lllljlUl:lil ''' •U."U' di': cvohl\••O do• .te 111o1n111c11~.t<'.

<'umo explieo 111.11~ i11lr.1111t·, ·" mud 111~ a< p6' 11npl .111tll\ .10 11 o c~tlin rel a, I• •11ad.1< ~ nip I smente

•om reparos de tkh:1to no onw.ue Am 1011~ d,1< r1111J.111~as ~ ,nnsCtjll~n,11 de novos rcqu1•ll<l~~cr.111< s c1111c,pu u :i, 111ud.111~as ""' 11 "''"' •'U 11c'c"1d d s lo• u<udno< l C'll<•'ljllen!cmcr:1c,

324 iii l:ngenhana de software

Figura21.1I

0

21.1 Dinamica da evolucao de programas

Caprtulo 21 Iii Evolu1;ao de souware 325

T•bela21.1 le de I ria11

(Ju ilu o '1s e111a uhrJpa"·' dc1c1111111.11lu tamanho ck s~ t11111a 1hhL1l 1k• ah,·1.11 <'111n11 c gran.le e l'11111plex11, 11 ~ s1c111J ~Ji: t>el ,01111nc,·11J1do, cos p111g1.uu;11li•1c' licuru llLJI\ JlfllJIC'l'°' .1 c11111tlc1c111>•c1111111\huu dclL·11os 1111 isterna.Assim,

po. euas muda.t1\a' evnam a dn1w1u1\•'" da ,1111l1.1h1h1l.1dt:: "" '"te•11a ll111a •1.1mJ.., 11111d.1111;a 1111 1'1r111a provavelmenrcIll 11;l 111u11<K Ill'"'' dcte1h>• que 1111,,larao ,1 uulukul Ila 111ud.1111a euuegue 111 1111,,1 verv u do s1ri:11t1

S1 l 11 ' de i;r.1111lc JK•llc '·"' pn w.lu1, do' p1 •r i;r.1111Jc, "' ~.11111,1~ • ..., 1. n111 u 111.1 I •u 1 .., ""'a 1111c111a q 11c leflne os 11r1 .tlllL'lllU• n,J p.11.1 c da srrcma e 1.u11twl.1 "' p1111.C'"'' de d''"'·'" 'k":i' 11n1da11~;1, \s 01i;an11.a\l'1C' devern ln111.ir de1.·1s&·s en nscos, valoies das 111udai11.1 e cusios envolvidos, J,u, Je.is11e' 1011111111 lc1111~• Durante esse 1c111p11

ou1r.1~\ab. de 11 .11or p1 rorulade, podem M.·1 prllf" "'a l'udc sci 11C(c\s~1111 dc1 '·" a\ 111111!;111\ as 1 •n 111 1 par.1 mais iardc. < h os d t.a111ada de dc11sil<.'' J s 1•1i;.1111£m0c .. , J1t11111, ll<•ll.111111, ,, l,1xn de m111.IJ111•" Jo MM<llla

A qu IJ lei de Lehman 'lllJflC •jllC .t "';i111r1.1dos11r.1111les l'l"JCl11s tit• pwgi.1111.11511 '" uec e 110 que ele de1111111in.1 c,t,1llo' Ou seia, uma rnudaueu lie rccui 11s nu lie pessoul '' ru clc111" 11111•c11.t•pllle1 11.1 ''"''"~.to 11<1 ,1,tt•111.1 110 longo

I 1 c '"n" Lente •••111" terccua ler, que •u11c:1c quc .1 cvolu,.111 do pw111.1111.1 c 111JqJC11Jc1111· o.l.1> Jc,,,,....., g1·1't'11n;11,,IC nurnu <jUCas CljUl[)C' Jc descnvotvnncnto de g1:10dCS ~1slc111,1• de Molt\\'311: ,,Ill ruun S \C/CS lllllllllJllll\," J'lllljUll heads de comumc .1~ao dommam o trab.ilho da equrpc.

A qui ta IC'1 de 1 ehmau esta 1clac1(111aJ.1 ao, mcrcmcun« <k mud;m\·'' em c 1Ja release du M•1c111a \o .1Jll 11>11.11 11m.t',w""""'"'J.1llc• ao srstemn, 1111°\ llll' clrnente ,,10 111trmJunJos uovos dclcttos (Ju. ntu 111.m I""' 11111al ul.rdcs s.111 1111, 11du11d,1s,

d euos suo mserido» i\"1m. um gr.111Jc mcremcnro 111 l11n<1co11ahd,1Jc J,• 11111 rck.1•c ''" '"tcm.t Mgn1h1..1 <JUC havcr.i ase postenor na qcal Ill' novos <klc:to• •erln repar dos l<cl.111' uncme, pllu1.a h1tl1.1rn1,ol1l1.11lc sci ...11un11.1J.1 uesseA lei sugere que '"'c n '' deve on;nr g1. ndes 111,rcmc11to' de Iuncron 1hd «te sem lev tr c111 •<>nt.1 1 neccssnl.ulc Jc

C<,ilO de>• defeuos

326 Engenhana de softw;ire

"'•'ln:I 1 amewo, .01111:i;ado Jc rec un.ns \~·· rn 11 c 1·~ na de mu111" 111cs 1hyk' <k me 111•na1' di• um prnces :ul11r 111:11 rJ1ll 1 tune u mu ua t:\ulu~<10 P•" cc conn 111/l~r 1 qunna cu qu1111a lers 1lt: I ch111,111. I c1nt111h1 11•1w1t11 que e se 1•111i;1amJ

J• exnu m nte uiua sequcncra de rc\1§/\cs d, nm pm£rn11111 dc •1ud<11 comum N,1 vcut 1d,. 11 nome fol 1n:1111Juo pordr mercado e ,, 1nui;1i111H1 IOI reescruo <' rc·1· 1ri1111nut11 mats <k uma vet. dcvde o I Ll\UllWnln il1• cu relcas u11i; i:il

21.2 Manuten~ao de softwareI\ manurcuca« de software c urn pm<'• ~~u c~rnl de 111ud.lfl\·ls de uni s1s1e11w dcpo1s que le t5 entreg

1 rnn rnlmerue ~ aplicudo ao sotrw.ue sob cn,·nmrndn 1111 qu;il i;1ul"" de 1k,cnv11h1111en111 srp 1rndc~ silo envolv ulf<'• r dcpnl da emrega d" srsterna A' m11dan\.1S 1, 1111~ no 011w.11c podn11 ser mud,m~"' ,11nple~ pnrn cmngu euu odifk n,.no, podem ser 111ud.111i;as mai' cH<'ns." pnrn cnrrigir c1111~ de projctos ou mclhon 1' s1g111t1c 111\,1~ paru 1:01 1 rro de 1••pcc11icJ~au ou para , cornodar n 1\0, r1 •j111'llm !\s 11111J.111\,t' '·"' 1mpl1!111c111,1.tn~ pm nir111 de 11111d1l1<a\' omponenic de bl 11.:ma e ..1\lcnt~· c. 4u:111<10 O('<l'~'ilrlO. I"" 1111.'lll da llli\.ll1 de 1111\ll\ <fli)lJ'<lllrllll'S an ~I 1r111a

F .r ICm trJ!~ Up." drtercntes Jc nl ll\Ultlll;' I(\ 1lo• llilWolll!

Mcu 111r11ra • paru 1.pnm tk: drl< uos J, w/11111n. A corru;~"de' 1·1111s de crnhl1c.1\.10 c 111111111lincnh: h.11 ta; o • de projetos <.10 ma1s earns pois podcm euvulver a recs, 11111 <k ,,1110~ ,·,1111p1nwnr,•s J11s p1og1u111a;, I 1 ros de re 1111 fio ma1 ouero os para sercm re p r.ulns pois 1111\lc ";:1 neccssano •> rq>r•ll to d,1 <1s1cma cxisreute

2 ll111111/rn11fo pa» i adaptor o ~t!fhttrr" a 11111 1mil11r11I< operac: "'"/ d1/11~111r I ssc Iii'" de 111a11u1c11., 1<• ~ ncccquaudo ali;um ..ispc1:10 do runh e111e 1lll s1•1c11111. ,011111 o Ii rrdwarc, pl.11.1fomrn 1111 '"''"ma 11pc1 1,·mnal 1111 outro vii ware de 1po1<1111ud.11n u" 1e1111 da 11pl1t·n,.in deve scr 111..d1i11.: "I'' para lid.11 com' ~s.1• 1111111.111\ 1 de .1111h11:111c stanuu nrcw I'"'" 11d1• um tr f1111111111a/11/11.!1 '"' 11111 ma ''" 1111•d1/1<, /,, Evse 11p11 dr m.111111c111;.111 c uece s.i11.1 11u. no reqursuu J<• "'tcma mud.uoi <':Tl r1·spm1.1 h~ muda!l\.1' 0111.11111.l•lllllfth nu '" 11• I''"'"" I\ escula du 111udn < <' <Jina para o sol1wa.rc c 11111110 111.m11 do q11<' cm 11u1r11s tip1" de 111.111u1,11, 10

deste cap 1ul •Pcsquts s (C'lf 1 pm 1 rentz e Swanson (l 1cntl c :.w.m"•n l'IXllJ e N11,.:k c l'i1h1a 1Nu,d. c l',11\la, l'l'.lO) "'l'•'flm 11ue

arn ~1111.rd Oll'llll' ti~ d.1s manulCll\l.lC' est.Ill n:lacu>n,1da' I 11npit'll1l'llia\;lll1 dc ""'"' 1c4u1Mh"· II!' .• 11111<1.111\IL' 1'11 SI1cm~ p.ira 1 I pt In .i um 110\u ;i111l11.,111e ''llClJ• 101r.1I c , 7 • n 1•01r1 •11 d 1,•i1 .. , du M'li.:111.1 <I l),'llrJ 21 'I l'ur.1 1\1• 111." ~ 1bc"'om oda n 1h rnhut\aode Cll,il1S a11111.i" «•rrcta 111x1111<11111p<1r1.i111c nnu" II IX:l«lllU.11cs1)<'<lfi<ll,111ns I) l.1111 .1, qucorcparo Jc d1 lclln\ ,111 1icmJ 11011" u111a .111, 1daclc de 01anull'11\;1o 1111r111su. 1'111111<>1 ,·r .1 cv.1111,•"' dn s"11111a p.un hd,11 comn "c" mb ntrs ens 1111\os 1c4u1bth1b ou a alt.:rj\.11) dc,1rs, .,11,ome111 111,11~ cslo1~11 Jc m.111u1cn,.11)

O usto• de m.inutem,nu <lllllll 1•.1llc dos •U•I<>• d• d1'\l'll\C•hrn1c11111 1a1i.1111 de urn lolt\11111> 1h! .1pl1< .11; n p.110 ou1n1Gu1mar ' ((iu11n.1rll<''· 1981) 'tll:CIC 4uc ~ .u,h>S .1, m 111111rn\;)11 de 1sk11t•1> de apl1cn,.10 Jc 11cg1'1. IM snc\ h,1<,1,1111c """

\ u no~ r11 10<, de dc:;emuh11ucnh• de "'i.ina.' l'.11J s1si.·m.1' Je 1c111p11 1<.11111cvrp<•r11h1S,"' <'"'"'~de m.in111c11\a•1 podcrn "r rt< q11.11rn \Cl.C 111'11' altu do 411c '" ~\1'111\ clc• 1lr~1·mol\1111c1110. 0 rc:4u1'1l0>de 1ha 1nh11~1,•1 r "'''l.'fllj)l.'llho dc•"'S 1st ma.~ fo1cm com qu.: •cus 1110dulos tcnh 1111 .tr s.;r 111111111 un>plaJu, c. pvr 1''"· J111cc' ,ti!" r~in mo.lilic.1u<>S.

(, rulm ntr ~ henlHku 111\c,lu .:~IOr\o nu pw1cto c n.1 inipk111l'nra~a11 d<' u 11 •1,lcn1.1 p.11a 1ul1111r '''.ti tu' di: manurcn~. o Ad11'11 n.11 nmus fu11u1utahd:ides depo" dn n1r• 1•a clo si.1c111a L' 111t<'1UM• 1"''4"e \()(< pn·u"1 r111p1,•ga1 c fol\O~par <nmrn nclcr o Mslc111a c analt~ill o 1mpad<1 <I 'm11dan,as pmposla.' A•Mn1, o 1111b 1lh•• <\u 11t11<tn cl11r.mrc 11 de,<:11\\11\Ill l'llh> p;1rn !Omar ll MJh\\3JC 111,11~ f,,11 de ~Cf <'C\lll(ll•<'ll1hd!1 C alh;tUJll lllOlllhUI p.1ra I chlllr cl~ l'llSlll~ de r11a1lUICl!\aU Uo:i~ tt<rm ~de en cnhar1a de wllwarc, ,omn C•ll('• Iii< n~tl..·s prcci'·"· 11 u d.11•11cnt.r\11111 oh1 '"'no 1l1•st•mol\illlc1t10 ~ m·nl't mrmu de .unligurn\'OC•, '"ntnbuem p:mi r.. lu~an rln' cu,J11s de 111.111u1en,.1"

A F1i;unr 21 '.\ n usu.i. \.Omo <'S Cl""" de I >do c1 <"1dn 11<' '111.1 po<lcm dnnnnm qu 1n1lo m "' •'•lllf'4' fm d1.:,1>c11\hdl!durnnrl' o \lesen' oh 11nc11tu pa• 11mJu11r um s1 r,•ma f.11 11 tic m,1111er J>~, 1du ~" po>len.. .il de f"('.\t1\'n11 le , usros 11.1 1:0111p1c

Capitufo Evoluc;ao de software

erto

Sl~ttm~ I

t--~"T""~~~~~~..-~"T""~-r~--.~~..-~"T""~-r.~..o so 100 150 200 2SO 300 350 400 4~0 500 S

Custos de decnvo1v1mento n l.U\IOS de manu1cn~~o

lise e testc, existc um ereuo m11l11pl1,,1J1•1 s1~11,h<.1ln11 q11.:imlu u "'lc111a I! d sem .. h1d11 •1•11>1dci.111<.l11 se .i 'U" Jc de m nutcn ao l'ArJ o S1s1e11m I, o custo extra <le deseuvulv1111c11t1• tic :l5 mil J1•lmc\ 6 mvesud« paru 11•111u u

a1• l.11:11 de manrer h'<• rc•ulta <ITI uma cconomra de JOO nul Jula11.'' c111 cu•tos lie r11.11 ut 11~,1u 1h11a111c ludo,,'d;1 do souware. Supc.ic se quc 11 pcr.cnt..i h Jc uumcnt« 1111s cusros de dc'<·moh1111c1110 u:s..ih.:i cu 11111 dc•1t,,·M111

wr ...111UJI comp: rlhcl em custo- gl1>h,u• J11s1tcm1razlto rmportarue Jc os cusu», Je 111.mulcn, es •111:111 alto•~ 411e e 111a1s oncros» ,1d1..aonar I.in• 1111 111!,11.lc J1•p111'

1 I a cstA cm opera, 10 do que d 1mple111e11t,1,,1n d.1 111c,111a lunc11111,1l1J.11lc durante I/ de e11\,.J11mc ''" (h l.11111.:s1rn~1nc11u1s que J1,tmg11e111 u desenvoivunem« e u ma11Ul<1l\,10 e que levam .i 111.1101<s cusios de inallu'C'l\·10 s<1n

billdadr 1/11 rq1111•1 lkpms qui' um ~ist<"nrn 101 1•111ri·i.:111• c norm 1l q1w 1 rq1111w <'Jll ,1, t.·111 c s pc'"'' s 11.1

cm m novos pri11 tos A rn\.1C<JlllJll'11u s pcss ..;i., r<,llllll,~\<'I' p<·l.1 111a111111·J1\' ".Im "'1e11 s !11<) cntendernI ma ou 1 base da' dc.i"'\c' ,JC' projeto .1pJi,.ad." a,, s1ic111.1 l\1u1ht csh>1\o durante 11 processo de mJ11111c11,.111

ndrdo 1>a1.t compreende. o "'te111a cxrvrcutc ,11111•• de 1111pi<111c11r.11 as 11111d.t11\.I'ibtlidad« contnnual C) i.:<intr.llu p,ar.t 111.1n1er um ~1:--.ll'JO.t ger rlmcntc ~ "'cp,u.1J1r..> dn ~unl!.110 de dcvcn

ento deste O conuato de 1t1Jnutc111,,111 pode ~c:1 .1111,c:J11.ht ,1 urua <•11111c•.1 1iilc:1e111e da 11uc 1k\C:ll"•hc11 ma. b.sc C,tlUf, juntu llllll I IJll;1 de C,l,1h1l1tladc d.1 cqurpe, indica 4U•' 11;111 Ji~ tucenuvo para que umu

re de de Cll\(11\ unentu C.'i\.TCIU um .1t111.1r,• 1.1c1I 11,• ..... 111od1l1c.1tl11 Se pudercm ser t.•11ns s1111pl1t11 H\O!'S

1 poup. r t"sfou;o durunte n •I• ••·m111\ 1mrn1n n rqutpr I ;r.1 ts'" lll<:S111P 11·.111c1 ndu uum lllll 1111' Cll\111' dt•

('r.1Jm,·n11 ' rncxp n nit' "'111 l.11111li.ar11J,11I 1111n n dommio ,1,,Am nutcn~ 10 tern uma un agent ntun cntrc ns engcnheiro« 11<· •ott w, ue I ta e vrsta l•>mc urn processo quc

e me e>• hab.lrdadc do que n desenvolvuucuto d< 'l•l<'11>,1 e, 111111tas \CIC , ' aloe nln u111 pc•H>.il 111c:n11' nl'cl Al Ill diss«, ~l\lc111a' di lil!US JM><lc111 ICI '"'" C'lllh" c111 li11gu.l"l'llS de I'"' •r 11tt.l\\l\l ohs1•kl,1•. 0 P<'\S11,1l de

n~ o pode ttllo rer tantn C\jlCflcnci.r em 1lc•.l'11111J\1111a:n111 ne~su• hn •1111gen e d \C1n npn·nd~ I" pnru r~··1·111arCOii' n fin '1~1rm.1

rutura do l''"f;rama i\ 111cJ1tl.1 que '" piugna111.1 c111elhc1.c111 1111 c tru1111.1 1t•ndc .1 sc d1•rr,11J.u fl('I ~tom ndo l>r' a~•llTI r 11.1 \!'/ 11i.i1s .lolkd ,J, "'r 111mprr1·1111,.1 t t11<J<htii I \l 1111~ '"h in~' li1r;11111lc 1'n

Mm as mod ma• lcCn><U de cn11cnh1111 J,• ,11f1\\,arc I k~ po<lcrn nun, lcr s1du bcrn c'ln11ur11los c 11lvc1.

328 ii Engcnharra de ~oftwdre

tcnham s1do orirnlzado levumlo sc cm l:On111 ,1 ctkil'1K1:i l'lll \Cl du fu~il1d;11h: <le '""'l"c:cns.o A docu 1 nt ~~ d s1 tcma podc tar ri·rctul 1 nu sr-r rm on rsteme S1~1cma~ anugos po1k111 nan IL'I fildo '11h1111.111Llos 111 i;cr 11~a.1111 11 de configurn,,ul de mod» que ~ dc,pcrth\ 11!11 r1111i1 1 trmpn p.1rn 1•n1•0111r.tt us wl"l\1•' c11rrc1a' clns compon m

lhlClll u 'I: cm modrncados

21 2.1 Previsao de manutencao

o, t"n mes d te tnm urpr as, e pee rahneute "Cl clu' rcsultain 1:111 ill<••' "'Lo mespcrudo \u.C: devc tcn1.ir1111111.m\ de srstemn '• o l" peruda c qu.us p.ut<fi do "'''"'" '·'" '" 11011~ d 11_.·1 de sotrerem mJ.lllllCll\llo

di•\ t mht'm tentnr esnrnar os cu tos gl(1ha1 de 111anu1cn~llo I"'' .i o stc111.1 eru J,1du 1x: 1 tLl\l•> de 1"n1•• A I 1~111 .1 21 4' ' r"'' 1sl'oe.o; e a.~ ljllC..\lile'i .1~o;oc1.11fas

rn \lsf>e." 1·q~o ohvtarnerne 1t'la1.111nuJa.o; a.

'Se urna mud11111,.i de •1slc111a deve ser a.:<·11.1 '~"' 11q:><·nd1· ol, '' n m.1111"1m cL1 l.11ll1d1de ii•• rn.111111c11~1io dos c11111

pun 11 ' de ~1,lcu1a ulcrados por e••a mud,in,.11l~gr 111.ir •111 1·,1ru1111 rcdullmln uss.m 1111 f.1.il1J.cdc de 111.111u

custo de manurencaodcpcndcru do 'lU1111ro> 1k rnu.lnnc s c os C'lhll'~ ii•• 1111pk111en1n\aO de 111uJan\U depcndcmIacrhdade de manuteo,ao dos ''"''~'n<ntes do •l'k ID 1

1 dn ndmeru le 1;11hl1la\l'lc de 111uda11~a p1 uut s •tc111J reque: uma 1:omp1cc11s.10 du relacronamento entre"' m e seu mbicrue exierno r..l runs fil,lc11~1~ Ll!m urn relac.uu mc111u h.1•tante ""1111lc~o com seu umbrcruc externo itm, n se amh enter ulunu cu1111c,11.i~c1h1·1ud :i,.,~ 11c 1'1c111.1 Paru ft\,1hJr u rd.1 1n11.1111cnl•> cutrc o "'1<m.1 c

mh n \oce dcve 1'al1a1

V nus "' e CJ 1 •111111 xulad« •W• 1111 r{CJ< es d« '"" 111<1 (,.111 in1n rn 111r •> m11111·ro 11(• 1111t·rl ll'l'S' qunnto rnms complcvu-,s ptu\.i\CI ~c1lio d' dcmundas qu mlo 1 mud: n.,:.,.

Qu•l1 JJlrtm do 11\lem4 111uv•nlme11twM!rloma" •'•tadas pela•"'1 rllA(Oes de mudan~7

Que p.11 I•• Cl<J 11\lema•Nii() m•1l rll<Jl~llr11Mft,

para montcr1

Oua t scrlo as cusies cltrn;i •Ul~n~Jv <lu• ant" o 1 ..mpo

rl~ virla c1M•e 1111em• I

Owntas solleita~Oes de mudan~ l)Odom .. , JJ"1'•da17

{lun 1,PrA() n\ r11\to1 ee m<mutcn\ao eesse 1l1tcma

no pr6:111n10 •no?

CClµ1lulu 21 ii t::voluyao de 3

ni tit- 1 qmsu •1 <I• sis« "'" 111<'1 ntrtu, nt, vo] "'" C onrorme cxphqu l 1111 (•II tuhet m pol!cicas e 11111~J1111i.:111• ,, <>r11.1111L.i. 1 111n" <.10, pr••\ we lmc l\C. m 1" \ol1\ll'I dn qm o

, ti•rl I c,1, de dornh1os estavers.

orrcm

o 1111'11• n ,i. , nmp11m 111cs nfc1.1do' pelun r,, nfl•1ud11'i e

ml ntcs dt 1111u/a11111 I 111 11111w111" desse 11<1111c10 c om 1• 1e111p,, IX"' 1nd1car ,l(d1111c11111

~"''' d previsausobrc ,\S "'lllila\<>C:<; de mudanps C "'hl'C I [.1t11iil.1<h' d1• 'llnllllh'l1~ 11 1!11 'l'i(Clll.1 'all

pr1'\ r o• cu "'' 11•· m.11tUIL'11,a11. A "'""" .i th•• ~·rcncc, cnn1t>111.1 css 'i 111fn11n \''''' ll'i 1ml11 a 1111u1i,.111 e .1I p rn esum r ll'i custn» 0 nnxlelo de etuuauva de c usto l I)('( 1\11)" \111\i Jim l'I .1! 20(~1) explicud« 11116 u err que una es11m.111~adu i.:slur~o Jc m.1nu1c11i,.111 de '"II" ,,. ('<\ill' S• h.t'<'•"'·I 1111 csfori;o p.u.. '"'nrruh 0 CX stcme C 1111 ,ju11;11 pa1.i 1k<c11\o!lcr um novo ~od1g<1

21.3 Processo de evolucao

330 iii Engenhana de software

Figura 21.5Prorl"i ;o; t1 10 r• r. ~."lo de da c;a I! NO i;ao

P'Utt'))O <l~ ttvvh.i\d ;..1

de $0t1w8re

pl nejam mo de relc seq 1 o<hq .1\ mud 'I\'•" pmp.1i I' 1rep.1rn .l d1•k1tos. udnptll\clc' c 110\11 lu11~1011,1h1l.11h.:sl '!l' 1:u1ll 1d1" l 111.1 dccrsao 1·11110 101111.Jn ~c1hr, qu Ji. 1111111.1111,•11 .lcvem ser 1mpk111c111<111,1., 11.1 p11h1111u •c"' u ,Ju •1•11·1111 Amu1fani;nq \.10 mpkm•''ltadas ~ '1hd cl s r um nmo release 1!11 srsiemu ~ hl>.:i.1do 0 pr•"c"u ~ 11·111:1c 1:<1111 um 1 'comunto 11< mud O\ll'i rmposlll rmn o 1mh1mn release A h •ur.1 21 6, uJJptud.1 de i\11hu 11\11111.:· l'IX!\), 1111"l1J u I

\ '' 1 • r I ck Si pmct'S"'1() pr(l('('s..o dr implcrnem 1\llO di" 111111fa111;n ~ e~senunl1111·1111•, 11111a 111·1,11,··"' 1h• p101:c' o Jc ilc11·11111h 1111c11to 11J qu I

l'C'\l'il'li's clo s1s1cma sno pr<lJ!'lnda.s. lmptcmu11,1ilas e 1c,1.1J,,, (\111111011, u ua il1k1c11\.t 11111kJ1t 1111c e que 11c't~g1u1111ci1r1pl<"mrnr.1, n il1' m1ul.111\ll.s ~ 1 rmnpreensao dn progrunu Dur.utte c'"' lase. \111c ueve 1:1 end 1 ~111110 " p111i;rJ

st eetrnrurndo r cumo cle enrrega sua fun,1n11ul1d.Hlc \11 1111ple111c11t.11 u111.1 111uda11\•'• \Ui;c u•a c'M: c111c11d11n<11I•• p1r~'" ur r que .1 mudancn uuplernentnda n.111 pre111di1:.11<1 u 'isic111a cxrsreure

nr prrt1"n"n11.1 '1,•,14gm1le m1plernenw~l!ti Lie rnui.l;1111;.1s de ,,,. p11>< C'"' dcve mvd11t,,11 n cspcc 1hlo1~ 111, o p111Jctn c1 mplc'll('nlll\l!O 1 to 1s11•111.1 parn re 11 cur us 111uda11.;a.' 110 \lslc:11 i;1 ( hgu 1 u 21. 7) /\t1HJ' 1 e11ur- '''' que rct letcu. " 11iuJ,1n\ a no 1 tern 1 slln propo tos, 111whsuuus e \Ulitl,1ilos (h 1·11111p11m·11tcs de srstcm ilo rq1r0Jct.1do• e 1111plc111cnt,1J1>s. e c

1 t m ~ rrte: tadn (' so 1pro1m.11lo. pode i;c1 re.11i1u1la a p101o!Jp.1~o1u da<. 111udan,a• prop•"tJ' corn« p.ute J1> proves •de n. h

Quanclo o.: orre uma mudanen no ~llll\\ arc. a<• d ~11\oh 1d111. sue es "ns rele se' do •1•1c 11 I ssc• rele ses • 1n ,01111~ ''~0\11 v r.;.ies de cumponemes do ''b(C(lla. Vu~ deve .uxunpuuhur .. H'l»UC' pm.i l:•llollltll <JUC .lb \Cn>ilc:•" ""·''Lins C(>

('(lO n e Ifill endo UsaJ.is em <•hla release 1lu ~"(CIJ~I.() 1,;C:ltlll;lollllC:lllu dell nugu ol\•>C' bC:IJ burd,1do110 Lap1tuh> ;,.90 mntC 0 processo Je cn>lU\ilO, ll~ ~"<llllSltll' 'a" u11ahsad1" cu 1ktiilhcs C:, Ircquentctucntc, •111gc111 1mpl1l,1,1<' II 0

tes n 1 111f•ll> Jo prwc so de .1114hw II." 1111111.m~a;, l"u ,1.,.11111,,1 1111c .is 11111d.111~n' p11•po•t '' poucm ,,., 1lterJd.1s e (\c;, po nenores cum u d11·111c po1k11 c:r • ecevsauus .11111·• yuc •" 11111d.111\•" ej.un 1rnpk·111c11tJd.1'

Sn! .11n\l\c' Jc mud.111\a' ruuiu.' \Cle:<> e'la11 1cl.1~11111.1d.1s a p1 .. hk 111.1, dn s1,k 111.1 'I"'' p1c<1s:irn ~er rc•oh 1d<" urgcntern me

Anih)~dr ~mpncf()'I

11 lbtorn\AO

do mrnma

Figura 21.7

AMII\.- tlrllQUIS1tOI

ii Fvolu~:loclP 3(npirnlo

Ocorrcu um dcfeuo grnvc do ,i,temn quc dcvc sl't reparudu pat;i pcunitir .1,·0111111u11l,tJc11,1 111ier.1\:l1• m•1111al2 I Ieiu s 11cspcrnd11~ de 111ud.111\a.' 110 .1111l>1<11lc Ju s1,tcm.t 1•p.:1,i.1u11.d qui: 111lc1111111pcn1 u 1•11t'tJ\ o 11• n .11

Ocorrerarn mudancas t[llple\1•11" n.1 e111presa<JUC Utlitl.l 11 <t't~tn t (01110 llJl1,Jtill< fl: 0< l provoc Ill I por "< vos

~· ncuucutes ou a 111twdu\ ao de uma 1111\ .1 k111,l.1<;U•'

seven w.. o necr,,id.t1lc 1lc 0111<1.lll\US nlplda~ 'ign1h,.1 que prnlL• nno '''t pn"l\d ,,,•i;1.1tr 11 procud 11\·I' fm \C7 de modificur os rcquisuos 1111 o plllJClc>. ,,...,.(1 d1·,·c lall·r utn.t lollc\m> de erner •c11ua nn p111grn111a

<;01\('• 11 prohlemn t'.'lled1n10 tl·1r11rn 21 lh C'1111tt1J11, 11 l'<'tigo C que llS IC'lllt\,111'· ti projero Jc i;.1rt\\ 111.1 C I <Wth.:a\anOm m grndntivnmcme mconstsrcmcs I JJ(!llUJllO\'11,·(l cstn rcmundu dll\'lllllCttl,11 a llllllhlll\ I nos rcq11J llos C 1111 prurero.

trn orr~i;nc., emcrgcncnns no nnwnre podcm ~et necessdrius, l•l.1~ 1ct11 p1i1111t.l.1dt.: '"f)lc a d1.1cu111 111ui,:1u. l.nc11111.il111,•111c.11 l ~11 nriginal ~ e quc idu c 11 d1><:umc111.t.;n,1 e u <'tkligo nuuva '" 111111,1111 .:1111i,11·1111·•·Im ourro problerna com o> reparos cmc1geu.1rus de ,j,1e111u e que eles p1c,1~a111 •c1.,ortdu[duso111.11' rJp1d11 p11"1'd.

e olhe uma solu~BP de nlp1,l.1 implernentaoln e111 ver d.1 ruclhor ,.,111.;il11 d., p1111111 di! 't\W da esttulu1a Jo ~1,11·111J1 cetera o euvclhecimento uo i;.11l\\UTI! de 1111•t.lt• que "111uJ:11t,·.t, l111u11" •c 111111at1t p111g1e\•t\a111 lilt' 111at' dd11ct' ecu ns tie man .. 1en,:i11 nu111c111.1111Preferenctilrnente. qunn.lo ..Uo rc.tli1.ados n·pams 1·111i:ri;1·11i.:11us de i;11d1i;,11. 1 ~11l1~tta\at1 J.i t1111Jan\ ••le' j.>i:t111anc~c1 •• t1111

pendente JJll" a ..n11e,,·a1• du> Jclcltm Jo l<i<.hgo Ela tllldi.:14 !<CL 1L·11111'lt:1ti\'t1t.Hla 1lq1111• de ia 11 11 c 11i;11, <t11d.1Jmaturulmeme, u c6J1gv Jo reparo pode ser 1cU!>;hlo. l 111.1 ,.,111,~11 Jlt1·111a11,u e m.u ndci111.1J;i I• rt 1111 bl 111 pode .·1 u1·,.

ibena quando houver 111.1i 1cm1~• lli>1)l•ntvcl p.ua mahsc. N.1 p111t~.1. \ot1J11d11. u 4uas 111 vr vcl 1111c ~ s 111111t.in,.1s tcuharn~a pnomhtdc ,•. depots 11u.: 11u1ti1• 11111d.11t\~ de ~ ~ti:111a lu1,·111 teuas, 11au ~··11 1eJlt•W rd.11~1 '' r p

21.3.1 Rcengenharia de srstemas

Cnnformr- 1·xph.1<l11 na sr,.)n ,1111< rlor, 11 fl"'"''So de c\ul11~~11 cuvolvc u comprccns h• do p1,1g1.111i.1 .t scr k'prn~ n 11nplrmrn1n,.10 tfn, mud ncus Cnnt11tln rnuuo- 1'1cm.1s, t>Jl<'L:t11l111<•11tc os s1,tc1m1 leg.tdo> m.us a1111gos

p 1 ulos nn C'npl111l11 ~I s.1n <Ill iccrs ilr compreen.ter e ,J,• m111l.1r Os pmgm111.1s l"'<kni t\'I •td11 1111g1n:d 1111·111c nil 11111ad11sI worreer n desempcnho 1111 u11h1.11;011de1•sp.t~o de mcmona h ,.11,1.1 J,1 fo.ilid.ulc de compreen ,111 1H1. cum 11 1c111p11,JI "1 tnlrt ti do f'rllftnflln pode h'I Si<lll C'llfflln1['td,1 por lllll.J l'<~rie lk' lltlldnt11;.t'

Pn a 1mphlk r n~ pnihll'mos di' m11clnn\,1 1lr. st"<'mJs h'ga1los. 1111rn l'lltp1c•.;1 prn.k d,1·llltr fu1c1 1 rc,·111w11h;ma dcss~sm s p m .1p111nnr tr su.1 ,•,·truturn e 1 f.1r1ltdD1k .te n1n1prct•n,:iu. A t cc11genh.1tr.t tie i;. •Ii\\ arc c•t.1 1el.u:11 •n .i.1 .1 1c1111plc

1 ode 1sttm. ~ lri:111lo' para tnrn.1 lo,; m.11s 1lkc1• de 111.111tcr. \ 1,•,·ng1·nltJrta p111.k l'll\1•1'•·1 um.1 nm,11l11~11111c111.11;;111,11\' or rr• stnt1t11n~o cln 1,u•m:i c·1111\r.n;!Jo do ~1stc111.1 em 11111a l111g1.1.1gc111111u1s 1n11de111a c 11111thh•u~·ao c i1l1t.tlt1i10,nu

tnn m r do'' Im•s 1l11s 1l.1dn' 111• s1 1i.:m.t. \ lun, 1011:thd,1dc dll r;ult\\Ult.: nno ~ ahc1ad.1 e. 110111i.1l111c111,•, .1 11q1111e1ur.1 em 1.1m~m fl<'' m.uw. c n mesm.t

A re. h1n,no <Ir ll'• nt••nhann 1lt• 11111 ~1,tem.1 J,, sull\\.trc 1c111 du.ts \,m1.1~i.:11s l1111dail1e11u11s •nlirc .1s .1honlai;c11' 111a1~ti 11 dr <'\olu.,nn de srsu•111;1·

Nm, rcd11 1cJ,, I \tsle alto rl!l1<• no reJ1·.:11H•h llll(nto de uni •••llw.1rc crf11,·11 d1• 1w,,:or111' 1'11<1,•Jll ~er <llil1<'1ido, erms llJ c~pcctlic;1~1>cs 1ln s1•h:ma ou pu1lc l1.<1•t pu•hlcn1.1s de de<•llhlh 1mi:nto 1\tt.1•0< 11a 111tn11IU\•l" do nmo oft\\Orc pndem ~ gn1ficar ll penl.1 dt.> 11cg1\i.:ios e Ut.11n·ta1 ,u,tos L·>.tta.' 1'111 nc111plu, c111 ll!'l'l. u111.1 i:r.111,k e111pt<'·1

norte .1mt."11rnna d1• nlimrni.1~ 111 tso11 t 1111ro.tu.,~o ilo 1111\0 ~1'1<'111.l 1k 1icdttllls pm,01·.111<111 ,111a."" 11as cllll<'gas deprciduh s C(jUJ\,1lc111c' a llMI nulho,s ,t,• di\lar.s ,1•11.1111<· 11111 p1<·1111,11rmp11rndn d1• \t'lld.is

ru ltl rtd11 1.Jn () ~U<IO d4 rr<'ll['.l'llh,mn ~ '1g1111lc;J11\,tlllCtlll' Jllt•1t1>t du (1111! o Cll,10 dl' dcsl•Jl\oh1111c11l111k 111111111111 (nftwall.' Uln<h (l ln.h l'll/tlj • l'R 11111 ··xr1npln 1lr 11111 'is11•mn <'111111·" t.tl ent 'Iii<' ns Mt tns de r1•1111ph•111c111,1\ao h•rdlll e'l1111JJos cm •Cr•J lie :>O 1mlh1ies de dol,11~• O ,j,i.r11a p t\S(llt llllt ntnJ t cngcnh.111.1 licm '"' dtda ,1,• I'1111l11(lC\ d lfula1l'.s. 'iuspe1tll 4uc, ,utll 11llldt·111a' IC1t111l11i,:tJ\ 1IC •<1lt1,,rc, ll LUM(• 1cl,J11\1• Jc 1c1mplc11i<'lll.t~ Ill •Ca mcnnt do que c' c. rna' allld.t J,~1111 c~n·11L•t i ,.1.1,11kta\cli11<'t1te "' <ll''"' de 1n:ngc1iha1t.1

A d1•t11 \ o pnnupal cntrc 11·cn,grnh.1n 1 c ,1.,.. mnl\ 111u·1110 dr 11111 11<11n s.111w 111• 1< o po11111 de p mdn pnr.1n,test•11111ll1m to I m \t'Z d C•\JllC'\ 11 o <1,•..,·11w1I\ m<'nto ,•om 11111a "'l'•'<'1lt1.1irn1•,,;.11111, o ~tstcmu nn11g11 I u11, i.111n , nmo 11111.1 c'1ie.11l

''trm.1 c h1k•'f'h r C'r•''~tf'h1k111'k} r Crnss, l'>'XI) tll•nnm1nur.tm o desc11111l\111w11111 comflll'to11nl de

F1gu1a 21.8

p ~!.() d IUd

An•h•••<6d1go lonle

Mod f1<•1 c6d190 tont~

332 ii Engenharid tie ~oflwdrt:

Figura 21 9

l a e rt' lJt'nhhl)e<lfl<d~~"

t:f,. .,,,,t,.m11 Pro)eto e1mplt!mf'nt.l~~n .. [ Novn <1'1,.ma

5,,,1,.ma dti ""tt"A"11r1~

C!>1'1rntoc nmpr,.,.n<no

c tr.1nsformJt3o'i1ucma de

r eenge11har11

Rccngcnh<1r a de software

rn nhari 1 dircta parn d1 ungur lo d.1 reengenhan.r de ~oJt\\,llC l•ssa d"llll\<IO c:stll 1lt"t"1da llJ l 1gu1.i ll 'I \ engen hma un~J corn uma e'Jlt'<lli<a\llo de '1stem11 c C!J\1>1\e u lll•!Jcl" ca uuplcmcut •~·"' d., 110\0 "'tc:,1 A rcen enh omt\ <Pm um ~I tcma existeme, e 1> p1l11.CsM> de 1Jc,c11,111\1111c11tu p.u.1 ;i •11l"1Jlu1~.1n l1a!.C1a se na cornprecnsao e

tr f• nn.11;o do Mstcma oni;inalI\ I t uru 21.1 (} ilusua o priK:c\so lie 1ccni;c11h;111a \ cull ada du 111•11.c~''' e u 11 prog .1111.1 lcj,\a•IO , a ud 1 t um 1 •

tnnuruda e n uJular J(111 c 11111 p1ul!1a111a l>u1J11Lc d ILC:ugc11ha11.1du1•11•i.:1.1111J '''dados dn rstem 1p.odcm1,11n!JC1t1 ppor reengenhana A a 1\ idadc uesse pu11.c "' de 1cc11i,:c11h.111sa.su.

( 1mrrt, ( (ft' C •dlRO [ont« I) progrnn .1 c 11111\1111.fo 1ft' Jllllll lrn 110 '<Ill um: d de ptt> rumay hi paru urna vers lmars modems d.1 mc•111J lmgu: gem vu p.1r.1 urn 1 11111111.iµ• 111 ·hh rent.

2 Ln1<errhnna mer~,, (J progrnrna ~ .111 hs.uln r sl1n rx1rnfdn~ lnl.irn111i,·1'1t•s 1h•l1•zn.,.10 e fun.ion.ihua<k

11 llJUdll n do•1J111 ntnr ua 1 1 .r111

l Aprm111mmr11rro du e11ru111m ,f,, ,,,,,li"'m" A, 'tm1111 ,1, < 0111rc1I<! tin pmr1·,u11~ ~ 1111ul1~1dJ e moditlc.ula p.11,1 l.1ciln.ir.1 lenur .1 e a comprcenvao

4 M1 tulari: 11110 dr ,.,.,,~rmna \s pnrtes r. Inc nnn.-1.is do prugr 1111a ~no ag1up.1d,1~ e, quaml 1 .1p11•p11.1do, 1 1cdu11d;ui,,,., ' o remov rd." I 111 ,ol11uns cn~o~. c we csulgrn fl<kk envnlvcr 1r n~lnmin\f••'" 1lr .11111111rr11r.1 rm q11r nm s1•1cm:icentrahz d11, pl, llCJaJ,1 paru 11111 umco \.tllllfllJ!,tdor, c modificado p.1 ..1 ll()< rm en uma pl ll,1h•rl11 111 lnhu(da

5 Rc>r111:1nlwr1<1 de d11dM lh .1 d11s prc1c:es~ ... los '"" nh1 ruin~ parn n-Iletir '' m11dnn,_.,, do pmrr ma

Figura 21.10 roe de

DocumcntJ~ao do P•C>\1••111•

Engtntulrtall'VNSI

Pr0<1ram•Mt utur1dn Oad01'1 r~ IM""'""'

par rtnngcnhar a

Iii Evolw;lio de 3Capitulo

F gura 21.11 flcestrutt" a~o.-ulo•n•tl.t4cJtJ Ju µ1v~r•1t••

Rccsiruture~o deJ.HV.,,l.llht\ • J•JO\

~I t! I lctl d

Corwer~o •ulvf1'1tiza<J. Ree>truturo\Ao .,utomatrz•d•dr rhrt19..,..fnntr cnm mud11n<;11• manu~"

Re"1trutur•tlo ma11 mlldantiK de uqu tttuta

SU>' dJ reengenhana dependcm oh\ iamente da <'xte11s.10 <Ill trabalho quvers p.tru a reengenhan« confonne lll<>~lraJo na hgur.1 21 11 th cu tns 1111n nt 1111 d 1

sun a .on\Cl,UOJc ~·..h~n e """"'"' 111.11, h.irut.1 A I Tlll\l'llh.1rrn. com« p.utc c.l.1 1111 ird1 \8

pend nte d.1 extensa« da re(ll):(llh.1n,1 '" pnncipa« I 1tr1n•s q111• <'lnlll os ustc" cll'ln u

A qualidadc do ojnwrr q111 dcvr passar pct« 11111i:c11/1111u1. ()uaJllo 111c111>1 .14uiLIHl,1d (!., ullw.i11: e de: ma JJXU·nt \no ... ,~oc1acl.1 l•·•'n rx1M,1) 111,1111n·s erao os cusios de re,·111w11h,1na

0 upou) de Ierrammtus 1lt11}(111firt1 pam 11111i:111/w1ia r.111111.1l111t·11te. 11.10 ulequ Jo em I 1 11 J vu 10 la1e1 Jre n enh inn cir 111 ~1s1r11111 dt' sof•v.ilrt', u rnenos que \cl<.c ""' l<'ir.tme11t1L'> CASI paramud n il\

F::rr n lln da <11m1111711 de dados Se 11 rccngcnhana e,1 •i1 que grundes \oh1111c'i de ll.ulos 1:).1111" 111c1t1dr>•, u .:11,111ti p ocevso umcntnri s1gn1!k Ill\ 1'11.:ontr

A di po111/1/lidcrdr 1/0 prHoa/ rrprua/1•t11/11 'il' o pes,oal 1c.:'1~•11s,l\ei pclu 111.111ute11,.1u <lu 1.t 111a 11.10 p11<k1 't'I n\ol\ do no proces o .tr r,1·n1•1·nh.1nn n~ !'11,1ns .1111ncn1.1r,10, p11i., us engcnheirn de 1stc111.1 re p<>ns~\cls pclJ re enh 1n.i tcrno de emprcgnr m1111e1 1, mpo p1r 1 1 comprc: 11' ii dn •1st1 11111

21.4 Evolu~ao de sistemas legados

Pam 11u1'U~ .rslt'llla' des< m11h 1dos por ruero de p11 .. ess .. s 1111 ..lcrnos d eugcnh.mn Je rnflv..1rc, ,01110 o'•h111 c1110 iterauvu e <'BS!:., 6 po,shd pl.incJn comu mtegra: o desenvolvuncnto c n c1L•l11\i<• de ~l'tcmn l.1,la

t'1 lp1C'•" C\laCI <'\Ill C:\aildll a comprccudcr <jUC I• I'll'<'"" de UC•Cl1HllV1menlO de 'l~IC111, prossegue por h._ln t>

vsda e quc u111a \cpa1.ii,:lio aruhcral cutrc n uescnvolvuneruo c .1111nn111cn,.11) de "'fhhll< ~ 111utr! lonru,lo, .:'lslcnlun 1'te111a' leg.1Jo> quc "i" ''"lc111.1s "Ill«••'" 11egf..:111s. I ~ses •tslcm" pn:,1s.11n ~r• ,11npl11Jo' e ad 1p1 tuns a,,

\ da~ I 11it11.:a.;; Jc e busiuc ~A llf~ .,,~:> com u11 01~:i111e1110 l111ut:iJ11 p rJ mautcr e ,111111.ltl.u •cits •t,lrm." 1c:i,i.1do~ prcc1• 1111dtc1J1r1.011111 obtcr o

lb tomo » bre seu lll\CS11111c1110 Ivso s1g1111,,, quc cl 1' dcveru taver uma n,.1h,1.,,111 r .1lrs1a <le•<''" s1,lu11.1s kt1·"''" ed.x1d11rm <jual ta 1·•lrJICJ.:IJ 111m• .1p111prr.da p.ua a rvolU\•'" <l•J' "'tc.111a• I ~"le111 ljU llrn "1"1'"'' de e,1ra1~gi.1

I> 1rtm n <rftnnn '0111rl1 rnmrmr I •\s: 11p.,a11 1lcvr <.1•r l'!ic:nllmla qu.mrl11 '' sl ll'llta nllo estlt mais l'1•11111h111ndo dic1c:ntc111ente com 11.<. pro1.c~'"' at, nq:61 io hso 11o.·1)111. qu.1111!11 os pnl< <'~~ns cl 111• I\<"' rn111lnr.1111 d<'Mle <IU•' n

1tem;i Im mst. l.1do c nan s 1• ma1s c •lllplctan1en1e dcpendc11tes do "s1en1a ! "1 "1u.1, •> 1111 mu110 c111n11f11 c1u nc.Jo t n1111a1~ Jc 111:1111ha111c lnialtl sul>sltlufJ,., IK•I I'(.'• c solt\.\a11:• ~omcrc1nl\ hu 1m 11J.ipl 1dos nes.• • 1116.tmn11.• par.1 ftmL'CCr 11rn1 upmo l'mnputu•l<mul :i_, 11cccs~1d.i.lc' ,i.1 111"c"" Jc 11ci;o1:111

l Dt<u11r '' 111/tmli «m 11/111111•ut'1u11t111111u tom 1111u11u11c111110 r11111/<11. [:"a npo,;i(l 1!c'c ~er c ,, Ih11lJ qu111Jo1 u:ma 6 111nJa m.:cc: ~u. mas liru tantc eM;bc.:I. c "' u'uJ11111> J,. Mbk111a 1e111 rdJU\u111<11h: pouc ~·•IK1t \i'le de

1111111.m\ll

1

334 11 Engenhariade \oftwar~

N1cllJ:tlllu.111u'11• s1ur111a 1•a11111pr111 1rt11 \Ua "' litdtult tlr nuutrtlt'ft\llfl I ,~.1 UJt\,10 dcve ser u c~colh1J.1qu tndo quahdade do s1,tema 101 dr:gra1L1d.1 por nuulnn\n~ rf'['lll.ur~ e qua min essas 11111da11~·a.s ~1mla <. o nece • 1.1~ l ontorme c~1,l111u••· evse procevso pocle nc lurr '' 1k,emoh1111l'nln 111' """" (·nmpnm•n11•, de 1111,·rl.11.e le •11 .. i.. que u "'te1Lm On IOUI !11l S:1 cpcrur com l•Ullllb b!Slcnr.1~ 111,11' 111\\l)S

1 ~ul ~1111111 tudo u« /Ji.'" tlo u,1111111 p1·1 u111 n1uo \t\f' "'" I "''•l llf'\'l'iodl'\C'ser l!'s.:olhida qu,111t.lu\1UltO~ l,th>f!..!\,

como urr novo hardw.ue, rllll""~1l11l tam que « sistern« anugo pos~.1u1111i11u.1r1•111 opl'r.1\ln ou quundo l\lc11i.1s (Unt<'1ll;11s p<'rm111·1r qut" um nmn 1qt.'m.t seja di:set1•01\1<h• a um <.11,10 r.11<1.l\CI [111 n1111111s <I''" .11• 1r.11<'1•1.11l• suh 111u1i;~• C'• u on4ria pod1· <.1'1 n1io111.tn qunnd« n~ (lll!lpu11e11l<'' 111111< 1p.11s Jo '1ste111.1 '·"' '""'111111.!1•~ por '' h'I"

1s '0111t'r, 1"'

, • n outros c unponentes rL'1>\,1do• sc1•1pn• que f'<''~f1 cl

N urul IC'Ote. ci•.t.' "ll\''Ch uao sao excludcnres e, a."11'1, 111111ndo 111•1,1'1t'll1111' rumpn,to lllli vunu pwi;1m11a.,, d1l<r1:11le~~lk' dc1c111 ser 11phl.11fa ad terentes panes J,, «~te111.1

An a11hJr um M'le111.1 ki,:.1do. 11x;c devc obscrva o do pontn tc '1'1.1 1lns nec•~nn e tla JlCl">llClll\ 1tc<111•a1\\J1rcn,19Ql'> Do p111110 de 1i.1.1 de n e1,Jdo, voce prc'i'a tlcc1dit se n e111prt''a n·nl1111•11tL' precisa 1h• ~"!1'1a I),, l'''"l'<'dn~ ti!l'!lll3. VUl:C pre••'•' avah,u a quJI J,,d< do souw.u al.1 pill' I\·"'<' n ,01m,1rr e IM11IYo11H de up1110 du' 'tcua.1 V<>\:C usa, pnnJnlll. uma •11mb111a~:lo <I<' 1Jh1r de mere: doc: de quali.la I< dn "~1t·ma pnr.1 f11ndn111.r111r sua de< 'li•• sobre o que lo11ercorn o istcma lei;a<lo

P01r.1 1lust1JI 1'h\.1, vamos super que 11111J org 11111.1\ 111 h'nlld 1lr1 vt 11·111.1' lci;udos \ 11ual11l.1Jc c ,, 1alu1 rlc 111e1<.1d,1 Jcrn<la um Ja.>oe' ~1Slcrna' suo .11.1h.idos e compar ''"' l'<llll olllirll' 11111 tlll'lll tic grulkos quc 1110,11.1111 l! val .. r rcl.urvo Jcmereado e ot ljUa!JJ de Jc •1•Lcm:i I""~ mnstr 1do I' 1 I 1 11r 1 , I I"

Observando a hi:u ,, .!I.I.!, \ll<:e pode v rtfic rr q1r. ""'"'m qu.atm .1 •reg.1,·i\1•, de !.l'lt·ma

Baixa q11a/1o/,11/,• haLw valor 1k mctrudo ;\ 111a11ul•·n~5" do•. "'lcm.1' cm <•(1Crl\' 11 S<:111111,1wn1h11~u <' .1 tn~a derctorno para o 11rgoc1n <l<'r.1 hn,1111111• ('l'•llll!na l·"c' ~1s1c111a' dc•c111 'Ci des1.,utado'

2 fl"" 1 q..alidatl, alto valor ,Je 1m n 11</o. I '!.Cs Hstc111 ' ,1•nl11huc:in Jc n1. t1<1n1 11n111111 1111• p r.1 n cmpre~a c nl11

potJe111 "··r •k•~nnn.to1 ( 11111111!0 sua huh 1 qu.1l1d.ulc: ~1g111ti1.a 4uc c d1'p<ndtu'o 111.1111< Ins I ssc.' '1icm 1s d1·,r111 otrer 1<engcnh ana par.1 .1pr11nor.1r su t q11al11l 1t!c 1111 ,,.r,•111 suh,111ut<l11~ '·"'' u111"'l<'llla1.0111c11.1JI 1dcyu <do c'l<'tad1spo11t\l:I

J \Ira q1tt1l1dt1<lr b'"'" 11/M 1/e 1111·11 ado I ~,,., s1q,·m.1~ sn11 '" 4uc 11au .i•11ll li1t1c111 ma1\ p a a c111prcs.1, 111a, 1.ua manut O\au u o <' 111u110 <h•penJ10s.1. Nin \.1k n p<·n•.1 "'h"1111f lo' ill! 111111!11 '{11\lll' 111u11u1•·11~i'lc' 11u1111a1, pudem pl i;egutr de de '{U 11<·11hu111a muJ:m~.1 J1,pcnd1<"•' sq.1 llc.<'SS ria 1' 11 hn11!Yo.1rl' dn S• •IClll.l CMeJ,I 11pcr.1<·11111.1I Sc mu I. n s d, pen tm:.a\ forcru nc:1.·e".u1a..,, '" .itcm.is J..:vcr.10 scr d<' c 1rt. 1ln•

4 Alt<t qualidudr ''''" 1e1lo1 dt "'' 1 wl • h•sc:• ~1Ste111 " do:' c111 '' 1 naJ11t 11ln' rm npt"r.l~On 111.1' sun 111i.d1<1.11J.., ~1g111l 1,a<l \fl((• ruin dcve 10\c ltr e111 1ran,lo1t1ia\aO uu >11h,t111u~·"'· ,, 1111ou1cn~ lu 11111111.11 d1·1't' prns<;epu1r

l'a ,, ,l\al ar o 11lor de mere !101 (I, um 1 r.•11111 \irl .i,\c 1dc11lillta1 11s '1.1~clitoldt1s du "stc111a, ,omo 11' 11'111n•" lin.11~ ccu< gcrcntc• e fcirmul 1r 111na ~nr 111' (]II slf>i s snhie 11 ~1·.1<·111a. l•1t1,1c111 qu ''" 1111cslil..·, "·"'''" <1ur: d~c."111 •er .l"c1111.ln.'

I "' d 11~trmu Sc o~ 1,tcma.,' "u • d" l>1..1•11m,1l111c11k <111 por u111p1•q111·11111Hlmr1111lr pes 1i.1s, clcs p111k111 tcr umb t~O \ 1!nr dr m rcodO. l Ill ,j,ll!llla ltg.1<111 pvdt": kl Sldll d 'C:l11<>l\11lo p;ira olk 11dc1 I llT11n llCCt's<;a,l,111~ 1!01 l'lllj'ICStl

I.Jiit' muJou ou 11111· ori pmlr •l'r ntemhd.1 11i.11' l'li< rc111~ 11c:111c de u111l.1s 111.111c11u.<

Figura 21.12 Altn •• nr 11.. mr.rcndn(Bal•3 qu3tldade)

-'\~~I

Ba1xo valor de mt!r<"doUIA ·~ q ••l•dddrl

Altn v•lcord• m.,codo(Alta qualld~del

B11xo v1lot rifl O'lf"rCAdo(AltA <Jlllhd•dt)

QualtJad" do \lltPm&

I'

<.ap1tulo .l1 ii tvoluceo de 3

2

If )\.C~"'-OS,

I cont) ibtltdad« do fl<f• 11111 \ C'1111tinh1l1d.ut.· .tu ,._.,•1nn 11.11> •' 1pl'n" um p1<1hlem.1 11!u1tu1 1n;1 tnm~m um prohlerna de IlCg<XIO~ C um Si,ICnt.1 11d I 1(1r contiave: C th problem I~ nrctarem iillC'I 1111CI' Ill 111< 011j;lfClll <jUC llC"lla' •Clalll Jcs\l.tJ,I' Jc suns l,lfd.ts f131U revolver C'SCS r11 f1ic111 I\. <1 'ISICl!lU ICm f:i,11X•' \,1lnr Jrncrcado,

1 A1 suidus d11 ~11/em11 A questao Iund.unental m1111 ~a 1'111w11.111cia J,,~ s.11Ja.~ J,, '' icma fl iru '' fu11c11•11.a111cn10 !lcm ucedido da empresa Se a cmprcsu ,f,·p•·mt.: <k,,a.~ "'f,J 1~. 11 M'tc111a tern um .111 .. valor Jc 111cr,t1•lo l'or outr« l.1Ju, sr r\s" s.11cll1< purlerem ser facllmcnrc ger;1,f.t, de algumu ou11.1 m:111••i1,1out:e11'1Mc111a1•wdu11 'ald,1~ 1.i1a111cnh.: U!>l das, seu ' 1lnr de m rcado pod ••·r bnixn

P r outr 1 lado, dig irnos que a .:mrn·x.1 desenvolvcu urn s1'1~111.1 q111• 111.11111 m n .w111np 11th.1ner10 cl!" 1<1d11s n' p~1hdo' res de chenre e c111 n""" aut<•n1<111c , 1111cn1c p.ira q111• 11s elienn-s pt ~nm n~ p111th111• 1111\1111w111,• '"" rc'ulut eut

w~as de pedidos repcudos e 111.1111,·111 <'~ , hultc• •nlr~fr 1lc\\ pc1rq11< ,•I ~ I'''" l'l•1 rn qur n J.1m~1 edor r Iii cu-nte 1lc .11.1'1d.1des ~' '11J.1, Jc t.11 MStl'll)..I ,,,,, 11111 to 11'1ponanh s pnr.1 n c•1'lpr.•"1' I"S"" srsremn tern ponnnro 11111 .ih11 val Pr UC'

(1,1

"arc e de ~oft" ire (I,• nr1110 S!" •""' s fnmru•dnrr~ nno rstn11 mui' atuando 1111 111en:.1d••. 11mlc 11a11 h.1wr .1p1111> JcO\" c para OS Shit 111 • .

pr B\ 1111111 c111ali.t 1l<' 1t1cntC'n 1h• 1 m s1 It ma de uplt,,1,nn 1111:(\ ilcve Uh1h:1r \Jlllls lat•11cs 1 f,1locl.1 21 I) 1cla1:11111.1d11, ilmcmc II' onflnhllhtn.t: 110Sl'lt'm1 h' 11tfo·11ld.ulcs ;1,. 111u11111cn~.10 do ~.1c111.1 c a 1h•<·1111w111.1,.a11 <k vrstcrua \.,,~ mbc m , oletar d.ulns <11inn11111111m 'l"•' ·•JUrl.irfio .1 j11Ira1 ;o qualuladc do '"1c111.1 I l'>C111plu, J1· duJu 11u.111111a11111,

pod m ser oll'tnt111' o:

0 n11m1 r • d1 w/11 rlll\ "' s tit 11111(/1111111 111• ""' 11w. "' r11ud.111i;.1s 1c11dc111 .1,·nrrrnnp:1 r csmuurn .to st<.lt rna c rornnrnmu lam;J~ tutums 111.11~ d1ff.r1' Quu111o1 ma~' ,1110 Ior esse '·''"r· 111.11• h.11,,1 sc:r.1a•111.1l1d1,1~ do '"l<llli\

l U numerv dl' 111/< 1}111,' '"111 •• 1111lrl'I I •le ~ 11111 iator 1111pnrt.m1e cm ,,,t,•m s h sc ... 10, <'Ill fm 111uUJi11, • m qur.

cada formul4nu pode scr i.:111tstdc1111lu ct111111 uma 111kil ice ·~p.11.1J.1coin"11•u6nu. Qu.mto ma" 1111<11.tC••. m.1111r ~ n prnh.1h1lidndl' <It• 1m·nnslst~m u" ,. rt"<lundnn,·111.'

\ 0 volume dt dados usudos p1 /11 \1 •It mu. ()1..1111<1 111al\11 n vol11111c 1k ,lad'" (n11111c1" de 114u '"'· I 11111111!0 ,111 bancotlr dadns rte l mm~ , omplcxo '<'111 o .s1e111u

336 iii E11ye11har1a de sottware

Tnbefa 21 2 Fat rr u dos na JwJ1 u d

Fntor Ouestoes

T11bef11 21 3

F11tor Qucstacs

hnrdwnre 1 u pode C1.l!_:ll" ,u!),111u1~.io J,,, •istc111.1' tic apii<J~,111 ..,,. 11o10, Xl'I< llf\' 11w11111 1f1spun1\cl jJ.tlll 11 11uns[1•r maeno de rstemas cm dc1~111 mado ,1110. ,, manutcn\!o de si''' rnas ['1<.•dr prnsq(' 111 'lle~mo qu,• I~'" resulte l'l'I 11!~

-PONTOS·CHAVE

•

EXERCICIOS21 1

21.221 l21 4

21 5

Caprtulo 21 ii Evolu1,CJ0 de ~uflWitll! 337

21 6

21711 8

1cl 'uu r Q~• "e e ue

219

21 10

1111

2112