Seven Basic Principles of Software Engineering

22 Pages·2003·2.28 MB·English

neveS cisaB selpicnirP of Software gnireenignE
yrraB W. Boehm
TRW Defense Systems Group
sihT repap attempts ot llitsid eht egral rebmun fo -dividni sihT is eno fo a seires fo stroffe at WRT ot enifed
lau smsirohpa no doog erawtfos gnireenigne otni a llams hcus a tes fo ,selpicnirp gninnigeb htiw a tes fo evif -nirp
tes fo cisab .selpicnirp neveS selpicnirp evah neeb -reted selpic detalumrof yb ecyoR ni 1970 I[ ,1 and denifer
denim hcihw form a ylbanosaer tnednepedni dna com- otni tnereffid sets fo selpicnirp yb dlognaM ni -esbus
etelp .tes esehT :era ( 1) eganam gnisu a desahp tneuq stroffe .]2[
elcyc-efil ;nalp (2) perform suounitnoc ;noitadilav (3)
niatniam denilpicsid tcudorp ;lortnoc (4) esu nredom pro-
gramming ;secitcarp (5) niatniam raelc ytilibatnuocca rof AIRETIRC FOR A TES OF CISAB SELPICNIRP
:stluser (6) esu retteb dna rewef ;elpoep dna (7) -niam
yhW dluohs eno redisnoc eht evoba neves selpicnirp as
niat a commitment ot evorpmi eht .ssecorp ehT llarevo ra-
a cisab ?tes ehT airetirc rof a tes fo cisab selpicnirp
elanoit dniheb siht tes fo selpicnirp si ,dessucsid dewollof
yb a more deliated noissucsid fo hcae fo eht .selpicnirp dluohs eb ralimis ot esoht rof a tes fo basis srotcev rof
a rotcev :ecaps
1. yehT dluohs eb .tnednepedni
NOITCUDORTNI
2. ehT eritne ecaps fo( lufesu erawtfos )selpicnirp
What seod ti ekat ot erusne a lufsseccus erawtfos -ed
dluohs eb elbatneserper ro( )deilpmi yb -anibmoc
tnempolev ?tcejorp fI uoy wollof eno ro owt cisab -nirp
snoit fo eht cisab .selpicnirp
selpic ,.g.e( “Use nwod-pot derutcurts ”,gnimmargorp
“Use a wef doog ,)”syug lliw that eb hguone ot -raug ehT ecnednepedni fo eht selpicnirp swollof morf eht
eetna a ,evisnopser elbailer tcudorp depoleved nihtiw tcaf that on noitanibmoc fo xis fo eht selpicnirp seilpmi
eludehcs and ?tegdub rO od uoy deen snezod fo -kcehc eht .htneves ,rO ot tup ti rehtona ,yaw erawtfos stcejorp
lists htiw snezod fo smeti ni ?hcae nac eb nur using yna xis fo cisab ,selpicnirp tub -iv
sihT repap stroper no emos tnecer stpmetta ot -noc gnitalo eht gniniamer .eno
esned ylhguor 30,~0,~0 ruoh-nam fo erawtfos -leved ehT ssenetelpmoc fo eht ~lpicn~p t’nac eb -nomed
tnempo ecneirepxe at WRT otni a small rebmun fo detarts .yletulosba ehT tseb that ev’ew neeb elba ot od
cisab selpicnirp hcihw edivorp eht syek ot a lufsseccus has neeb ot ekat revo a 100 lufesu erawtfos selpicnirp
erawtfos .troffe hguorhT this ,ecneirepxe ew evah dnuof and wohs that yeht nac eb ,deilpmi ylriaf ,ylbicudorper
that r eono owt hcus selpicnirp era tneiciffusni ot -raug morf snoitanibmoc fo eht neves cisab .selpicnirp
eetna hcus a lufsseccus .emoctuo tI won sraeppa that at A trohs elpmaxe is nevig ni elbaT 1. ,ereH ew koot
tsael neves cisab selpicnirp era .devlovni esehT :era Ward’s ytnewT“ stnemdnammoC rof lacitcaT -tfoS
eraw ”noitisiuqcA ]3[ and evag meht ot eerht tnereffid
1. Manage using a desahp elcyc-efil plan.
elpoep ot enimreted yltnednepedni eht tnetxe ot hcihw
2. mrofreP suounitnoc .noitadilav
yeht erew deilpmi yb eht evoba neves cisab .selpicnirp
3. Maintain denilpicsid tcudorp .lortnoc
nI elbaT 1, hcae ksiretsa setacidni that eno fo eht
4. esU nredom gnimmargorp .secitcarp
stnednopser deredisnoc that eht gnidn~~rroc Ward
5. Maintain raelc ytilibatnuocca rof .stluser
tnemdnamm~ was deilpmi yb eht elpicnirp ni eht -ni
6. esU retteb and rewef .elpoep
detacid .nmuloc ,suhT all eerht slaudividni deredisnoc
7. Maintain a tnemtimmoc ot evorpmi eht .ssecorp
eht tsrif ,tnemdnammoc enO“ emirp ”,rotcartnoc ot eb
deilpmi yb elpicnirP 5, “Maintain raelc ytilibatnuocca
rof ”.stluser llA eerht deredisnoc eht dnoces -dnammoc
sserddA correspondence to .B Boehm, TRW Defense smetsyS
,tnem oN“ ”,gnissecorpitlum as elbissopmi ot ecuded
Group, Software Information smetsyS and ,noisiviD One Space
Park, Redondo Beach, AC 90278, morf eht neves tub-selpicnirp yeht osla deredisnoc
ehT lanruoJ fo smetsyS dna erawtfoS 42-3.3 )3891(
3
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4 yrraB W. mheoB
Table 1. Seven Basic Principles vs Ward’s “20 commandments”
eganam-l suounitno~2 tcudorp-3 evorpmi-7
stnemdnammoC ot nalp noitadilav lortnoc PPM-4 ytilibatnuocca-5 elpoep-6 ssecorp rehtO
.1 enO emirp rotcartnoc ***
.2 oN gnissecorpitlum ***
3. .pednI depoleved smetsysbus . ** .*
4. retupmoC margorP noitargetnI
noitatnemucoD tI* *
5. nommoC cexe rof all sretupmoc **
6. deifinU WS-WH tnemeganam *** I
.I retupmoC margorp tnempoleved
nalp ***
8. suounitnoC noitargetni .* **
l
9. tseT snalp
10. remotsuC sah retupmoc strepxe **. ** ” .*
11. esolC rotcartnoc-remotsuc noitaler *. *
** I
12. lacinhceT eciffo sah retupmoc
strepxe * .
13. hguorohT ngised sweiver . .**
14, remotsuC setarepo sretupmoc ***
15. esU srotalumis ***
16. citsilaeR tset soiranecs * ***
17. digiR noitarugifnoc lortnoc ***
.81 HW rednu noitarugifnoc lortnoc ***
19. WS steg edispot noitnetta * *
l
setacidni elpicnirp seilpmi ,tnemdnammoc gnidrocca ot eno .tnednopser * setacidni elpicnirp si detalerroc htiw ,tnemdnammoc gnidrocca ot eno
Note: *
.tnednopser
that this was ton an elbatpecca lareneg tnemdnammoc ,woleb dewollof yb a yrammus gnitacidni eht stluser fo
morf rieht ,ecneirepxe ecnis emos stcejorp evah -cus using erom and erom fo eht selpicnirp revo evif -reneg
yllufssec desu rossecorpitlum .serutcetihcra ehT stod ni snoita fo gnipoleved a ralucitrap enil fo egral dnammoc
elbaT 1 etacidni that a tnednopser deredisnoc that and lortnoc erawtfos .stcudorp
ereht was a noitalerroc neewteb eht tnemdnammoc and
eht ,elpicnirp tub less than an .noitacilpmi
elbaT 1 shows a gnorts eerged fo ytiminanu gnoma ELPICNIRP :1 MANAGE GNISU PHASED -EFIL
eht eerht ,stnednopser gnitacidni that elpoep nac esu ELCYC PLAN
eht selpicnirp ylriaf ylbicudorper ot ylpmi rehto lareneg
ecivda no doog erawtfos .ecitcarp ,rehtonA[ erom etaerC and Maintain a elcyC-efiL Project nalP
amusing, tcaf that ew derevocsid ni gnitareneg elbaT 1
ecnatropmI of eht tcejorp .nalp woH tnatropmi is
was that eht ytnewT ,stnemdnammoC hcihw erew
ti ot evah a tcejorp ?nalp regzteM ]4[ seog as raf as ot
derebmun )a( hguorht )s( ni Ward’s ,repap yllautca
yas that fo all eht lufsseccusnu stcejorp fo hcihw eh had
derebmun ylno ]!91
,egdelwonk ylhguor %05 deliaf esuaceb fo roop -nalp
lanoitiddA noitaroborroc fo eht ssenetelpmoc fo eht
.gnin siH list fo snosaer rof eht eruliaf fo erawtfos -jorp
neveS cisaB selpicnirP is nevig ni elbaT 2, hcihw shows
stce skool ekil this:
snoitalerroc and snoitacilpmi neewteb eht neveS cisaB
selpicnirP and rehtona noitceles morf ruo noitalipmoc rooP planning
fo selur rof doog erawtfos .ecitcarp Again, eht -icnirp denifed-llI tcartnoc
selp ylriaf ylbicudorper ylpmi eht selur fo doog -carp
rooP planning
,ecit htiw emos snoitpecxe ni eht aera fo lacitcat selur
elbatsnU melborp noitinifed
rof doog gnidoc ,ecitcarp hcus as ezilaitinI“ selbairaV
roirP ot Use,” ,suhT eht selpicnirp t’nod evig all eht -na rooP planning
srews rof all lacitcat erawtfos ,snoitseuq tub yeht -orp decneirepxenI tnemeganam
ediv ,doog ylbanosaer etelpmoc ecnadiug no eht -arts
rooP planning
ciget ,snoitseuq erehw ereht is eroiu egarevel rof gib
lacitiloP serusserp
savings ni tcejorp .ecnamrofrep
eroM liated no hcae fo eht selpicnirp is won nevig rooP planning
cisaB selpicnirP fo erawtfoS gnireenignE 5
elbaT 2, neveS Basic selpicnirP sv rehtO Software selpicnirP
eganam-l suounitnoc-Z tcudorp-3 evorpm47
rehtO erawtfos selpicnirp ot nalp noitadilav lortnoc PPM-4 ytilibatnuocca-S elpoep-6 ssecorp rehtO
oD a etelpmoc yranimilerp ngised *
evlovnI eht remotsuc dna resu *
*
,tnerruC etelpmoc noitatnemucod
enilpicsiD tset gninnalp * *
elbatseT stnemeriuqer *
eraperP rof lanoitarepo srorre *
deliateD ecruoser lortnoc & data
* *
noitcelloc
*
esU detamotua sdia
stnemeriuqeR ytilibaecart *
*
esU elbarusaem senotselim
*
esU derutcurts edoc
latnemercnI nwod-pot
tnempoleved *
*
esU a feihc remmargorp l
esU a margorp yrarbil
esU shguorht-klaw *
*
esU & ezylana melborp stroper
diovA ”evaw-namuh“ hcaorppa *
elbaecrofnE sdradnats
tinU tnempoleveD redloF
*
ylraE data esab ngised
selbarevileD nalp
noitisnarT dna revonrut nalp
tnednepedni tset maet * *
tcejorP krow snoitazirohtua *
ezilaitinI selbairav roirp ot esu *
ylraE gninilesab fo stnemeriuqer *
hguorohT stnemeriuqer c8 ngised
sweiver *
:etoN * setacidni elpicnirp selpmi ,tnemdnammoc gnidrocca ot eno tnednopser
ekoorb 3-3-83
Essentials fo a software tcejorp .nalp ehT -nesse tasks ot eb yletarapes dellortnoc yb boj ;srebmun a
tials fo a erawtfos tcejorp plan era nevig ,woleb desab resource management plan gnitacidni woh eht -xe
yltrap no esoht nevig yb regzteM ]4[ and nosmarbA erutidnep fo all lacitirc secruoser gnidulcni( hcus
[51- things as eroc yromem and noitucexe )emit lliw eb
,deludehcs ,derotinom and ;dellortnoc and a
project
A yrammus fo eht tcejorp that nac plan gniyfitnedi eht cidoirep
Project overview. and milestone review,
eb daer yb enoyna yas( a level-hgih )reganam ni a and enotselim ,sweiver and all fo eht detaler -nesse
wef setunim and that lliw evig mih eht slaitnesse fo tials ot gnimrofrep eht weiver yb( ,mohw rof ,mohw
eht .tcejorp ,nehw ,erehw what, and woh ot ,eraperp ,mrofrep
Phased milestone .nalp A noitpircsed fo eht stcudorp and wollof up no eht .)weiver
ot eb depoleved ni hcae ,esahp and fo eht detaicossa sihT plan seifitnedi eht rojam
Product control plan.
tnempoleved seitivitca and .seludehcs rojaM -dorp seitivitca devlovni ni erawtfos tcudorp ro -arugifnoc
stcu fo hcae esahp dluohs eb deifitnedi as etercsid noit noitarugifnoc-lortnoc ,noitacifitnedi -ugifnoc
,senotselim ni hcus a yaw that ereht nac eb on -ma noitar ,lortnoc noitarugifnoc status ,gnitnuocca and
ytiugib tuoba rehtehw ro ton a enotselim has neeb noitarugifnoc dna-noitacifirev woh eseht seitivitca
.deveihca ehT tnenopmoc seitivitca ni hcae esahp evlove hguorht eht erawtfos .elcyc-efil oslA dedulcni
dluohs eb deifitnedi ni emos .liated A doog elpmaxe rednu tcudorp lortnoc plans era a
traceability plan
fo a tsilkcehc fo tnenopmoc seitivitca is that nevig gnirusne edoc-ngised-stnemeriuqer ytilibaecart and
yb notrevloW ]6[ and nwohs ereh as erugiF 1. a gnitacidni nehw all tcartnoc ro(
deliverables pfan
sihT plan setacidni eht )lanretni selbareviled era ,eud ni what ,mrof and
Project control plan. project
and detaicossa seitilibisnopser dna( woh yeht lliw eb .deraperp sihT tcejbus lliw eb dis-
organization
woh eseht yam evlove tuohguorht eht ;)tcejorp a dessuc ni erom liated rednu elpicnirP 3 .woleb
gniyfitnedi all tcejorp sihT plan srevoc hcum erom than
work breakdown structure Validation plan.
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Figure 1. Activities as a function of software development and plans
.esahp yti ,snoitarepo tuptuo ,noitanim~~id margorp and
data esab ,ecnanetniam gnidulcni detaicossa -moc
,retup ,ytilicaf ,lennosrep and troppus erawtfos
.stnemeriuqer
eht usual tset“ plan,” and is dessucsid ni erom liated
rednu elpicnirP 2 .woleb ehT skoob yb eciH te al. ]7[ and ehtrowsuaT ]8[
6. Operations dna ecnanetniam .nalp sihT sedulcni an niatnoc doog selpmaxe fo eht liated ot eb dnuof ni -tfos
weivrevo fo eht tpecnoc fo noitarepo rof eht ,metsys eraw tcejorp plans.
7
cisaB selpicnirP fo erawtfoS gnireenignE
enifnoC snoitareti ot evisseccus stages.
Figure 2.
ehT ecnatropmi fo doog stnemeriuqer specifica-
tneirO eht nalP dnuorA a desahP tnempoleveD .snoit ehT tsom tnatropmi esahp stcudorp ni this -er
hcaorppA drag era eht metsys and erawtfos stnemeriuqer
ehT desahp hcaorppa snaem that eht rojam stcudorp fo :esuaceb
hcae esahp must eb ylhguoroht ,dootsrednu and -ferp
.1 yehT era eht tsedrah ot xif up ro evloser .retal
ylbare ,detnemucod erofeb gniog ot eht txen ,eno as -ni
2. yehT era eht tseisae ot yaled ro diova gniod
detacid ni eht ”llafretaw“ trahc ni erugiF 2. nehW this
.ylhguoroht
t’nsi ,enod eht tluser is eht yltsoc tnairav nwohs ni -giF
sediseB eht xif-ot-tsoc ,smelborp ereht era rehto lacitirc
eru 3. nI this ,esac smelborp era detceted ni retal phases
smelborp gnimmets morf a kcal fo a doog stnemeriuqer
yllausu( edoc and ,tset tub yltneuqerf neve gnirud -po
.noitacificeps esehT :edulcni
,)snoitare hcihw dluoc evah neeb detceted ylisae ni
ylrae phases and detcerroc ylevisnepxeni at that .emit 1. nwod-poT ngised is ,elbissopmi rof kcal fo a -llew
gnitcerroC meht ni retal phases snaem that a egral -ni deificeps .”pot“
yrotnev fo ,ngised ,edoc ,noitatnemu~d gniniart -etam
,lair ,.cte must eb dekrower dna( ,)detseter gnivlovni
hcum retaerg sesnepxe and syaled ni tcejorp .seludehcs erugiF 3. selpmaxE fo esahpitlum noitareti .spool
8 yrraB W. mheoB
2. gnitseT is ,elbissopmi esuaceb ereht is gnihton ot tset eht tnempoleved fo a -tfos
Incremental Development.
against. eraw tcudorp ni lareves gnidnapxe stnemercni fo
3. ehT resu is nezorf ,tuo esuaceb ereht is on raelc lanoitcnuf ,ytilibapac as a yaw fo gnigdeh against
tnemetats fo what is gnieb decudorp rof .mih tnempoleved risks, fo gnihtooms tuo eht s’tcejorp
4. tnemeganaM is ton ni ,lortnoc as ereht is on raelc lennosrep ,stnemeriuqer and fo gnitteg gnihtemos
tnemetats fo what eht tcejorp maet is .gnicudorp lufesu gnikrow .ylrae
,netfO eht smelborp htiw stnemeriuqer snoitacificeps Scafilding. eht ylrae tnempoleved fo erawtfos deriuqer
era elpmis snoissimo ro .srorre eroM ,netfo ,hguoht eht ot troppus eht ,tnempoleved ,noitargetni and tset fo
smelborp era esoht fo seitiugibma hcihw kool evitinifed eht lanoitarepo tcudorp ,.g.e( ecafretni ,srotalumis
tub hcihw edivorp a ediw edutital rof gnitcilfnoc -retni tset ,srevird elpmas ,selif ecnereferssorc ,srotareneg
,noitaterp hcihw is ylno derevocsid hcum .retal enO standards ,srekcehc citsongaid and gniggubed aids).
yrev evitceffe erusaem rof gnitceted hcus suoidisni -ma
ehT stluser fo a tnecer tcejorpitlum tnemirepxe -moc
seitiugib is ot kcehc rehtehw eht stnemeriuqer era
tesf- gnirap eht gniyficeps-erup and gnipytotorp-erup ap
as deifilpmexe ni elbaT 3.
able, sehcaorp detacidni that a xim fo eht owt sehcaorppa
Making erus eht stnemeriuqer era elbatset is -emos
was elbareferp ot rehtie hcaorppa desu yb flesti .]9[
gniht that nac eb enod .ylrae tI seod eriuqer emos -da
rehtruF noissucsid fo eseht stnemenifer fo eht llafretaw
lanoitid drah gnikniht and noisiced making, hcihw is
ledom fo erawtfos tnempoleved is dedivorp ni sretpahC
eno fo eht snosaer eht ssecorp is os netfo .denoptsop -nA
4 and 33 fo .]OI[
rehto is that yb gniyrruh no ot gningised and ,gnidoc ehT ecnatr~mi fo elpicnirP 1 is dezirammus ni -giF
eno setaerc eht noisulli fo dipar na-ssergorp noisulli eru 4, hcihw shows eht stluser fo 15 1 tnemeganam -ua
that is yllautriv syawla .eslaf dits fo smelborp ni eht noitisiuqca and esu fo retupmoc
smetsys ni eht .S.U tnemnrevoG .]ll[ ehT audits
,gnipytotorP latnemercni ,tnempoleved dna scaf- dewohs that seicneicifed ni tnemeganam planning
.gnidlof ehT emphasis evoba no desahp tnempoleved dnuof( ni %15 fo eht audits) and lortnoc )%43( erew
seod ton ylpmi that a tcejorp dluohs refed all gnidoc yltnacifingis regral secruos fo smelborp than erew -hcet
litnu yreve last liated has neeb dekrow tuo ni a tes fo ygolon srotcaf )%51( ro rehto noitisiuqca and egasu
stnemeriuqer and ngised .snoitacificeps erehT era -ves .srotcaf elpicnirP 1 flesti is llew dezirammus ni eht -lof
lare stnemenifer fo eht llafretaw hcaorppa hcihw -er gniwol eceip fo ’srotaiva :ecivda
plan the flight and fly
eriuq edoc ot eb depoleved .ylrae esehT :era
the plan.
eht ,dipar ylrae tnempoleved fo lacitirc
~rototyp~ng.
snoitrop fo eht erawtfos tcudorp as a snaem fo resu
esU eht nalP ot eganaM eht Project
stnemeriuqer noitanimreted ,.g.e( fo ecafretni-resu
sihT is eht laer hcnurc ,tniop
serutaef hcus as ,syalpsid dnammoc egaugnal -po where textbook manage-
,snoit deriuqer inputs and }stuptuo ro stnemeriuqer ment looks so easy and real-world project management
noitadilav ,.g.e( fo eht emit-laer ecnamrofrep -apac is ni tcaf so hard. ehT tcejorp reganam must dnetnoc
htiw a launitnoc maerts fo snoitatpmet ot xaler his -orp
seitilib fo eht .)metsys
s’tcej yllaicepse-enilpicsid nehw yeht era detaitini yb
eht remotsuc ro his tcejorp .sroirepus emoS lacipyt -xe
selpma :edulcni
eibaT 3. Make eruS stnemeriuqeR erA elbatseT
A remotsuc tseuqer ot add “a wef small ”seitilibapac
elbatsetnoN elbatseT ot eht tub-tcudorp tuohtiw gnignahc eht tegdub ro
.eludehcs
ycaruccA llahs eb tneiciffus ot 1. noitisoP llahs :eb
troppus noissim gninnalp 5 50’ gnola tibro An noitacidni that rehgih tnemeganam t’now leef
5 20’ tibro&o
that ssergorp is gnieb edam litnu yeht ees emos edoc
metsyS llahs edivorp emit-laer 2. metsyS llahs dnopser
esnopser ot sutats seireuq :ot .decudorp
epyT A seireuq ni s 2
A noit~ggus ot ecuder eht epocs fo eht ngised weiver
set
epyT B seireuq ni I ni redro ot ekam up emos .eludehcs
10 tes
A tseuqer ot ekat no emos lennosrep ohw era -eb
epyT C seireuq ni 52
nim neewt stcejorp and dnif gnihtemos lufesu rof meht ot
metsyS llahs edivorp etauqeda 3. metsyS llahs edivorp na .od
eroc yticapac rof htworg dedda 25% suougitnoc
.snoitpo eroc yticapac rof A tseuqer ot yrt tuo a lufrewop wen gnimmargorp
htworg snoitpo aid hcihw hasn’t neeb yletelpmoc .deggubed
cisaB selpicnirP fo erawtfoS gnireenignE 9
L
erugiF 4. smelborP htiw retupmoc metsys
NOITISIUOCA
noitisiuqca and esu ni .S.U ,tnemnrevoG SCINAHCEM
.6791-5691
YGOLONHCET
SROTCAF
EDIW-TVOG
TNEMEGANAM
-
0 10 20 30 40 50
TNECREP FO OAG 5TROPER GNIYFITNEDI MELBORP
erehT era yllausu a tol fo evisausrep snosaer ot traped
melborP Symptoms
morf eht tcejorp plan and etadommocca hcus .stseuqer
ehT ysae gniht ot od is ot eb a ecin yug and og gnola enO fo eht tsom tnelaverp and yltsoc mistakes edam no
htiw ,meht s’tI a tol redrah ot ekat eht artxe emit ot erawtfos stcejorp yadot is ot refed eht ytivitca fo -ed
enimreted eht tcapmi fo eht tseuqer no eht tcejorp plan gnitcet and gnitcerroc erawtfos smelborp litnu etal ni
and ot etaitogen a gnidnopserroc egnahc ni plans, eht ,tcejorp ,.e.i ni eht tset“ and ”noitadilav esahp retfa
,seludehcs and .stegdub tuB evoba all ,esle s’ti eht gniht eht edoc has neeb .depoleved erehT era owt main -aer
that tsom netfo slleps eht ecnereffid neewteb lufsseccus snos yhw this is a :ekatsim )1( tsoM fo eht srorre evah
and lufsseccusnu .stcejorp ydaerla neeb edam erofeb gnidoc ;snigeb and )2( ehT
retal an rorre is detceted and ,detcerroc eht erom -xe
evisnep ti .semoceb
ELPICNIRP :2 MROFREP SUOUNITNOC erugiF 5, desab no stluser deniatbo htob at WRT
NOITADILAV [ 121 and at MBI [ 13,141, setartsulli eht reilrae .tniop
erehT is eno elgnis egassem tuoba gnipoleved elbailer On egral ,stcejorp and netfo no rellams ,seno -eriuqer
erawtfos hcihw shgiewtuo all eht ,srehto tI is ot teg eht stnem and ngised srorre rebmuntuo gnidoc .srorre
srorre tuo .ylrae sihT is eht rojam tsurht fo elpicnirP 2,
mrofreP“ suounitnoC ”.noitadilaV ehT snoitces woleb
discuss yhw this is os tnatropmi and what nac eb enod erugiF 5. tsoM errors ni egral software smetsys are ni the
tuoba .ti ylrae stages.
M
PER@NT
TOTAL
SIMRRE
TRW TRW MBI MBI
C&C cat
TNEMPOLEVED ECNANETNIAM TNEi:OLEVED ONA TNEMP;;OLEVED
ECNANETNIAM
yrraB W. mheoB
10
elbaT 4. ngiseD sv gnidoC Errors yb yrogetaC erugiF 6, desab no stluser deniatbo at WRT [ 161,
MBI [ 131, ETG [ 171, and lleB sbaL [ 181, setartsulli
No. fo rorre sepyt
eht dnoces tniop :evoba that eht regnol uoy wait ot -ed
rorrE yrogetac ngiseD gnidoC
tcet and tcerroc an ,rorre eht erom ti stsoc yb-uoy a
Mostly design error sepyt gnol .tohs elpuoC that htiw eht stcaf evoba that tsom
Tape gnildnah 24 0 srorre era edam ylrae and uoy nac ees eno fo eht main
erawdraH ecafretni 9 0
draC gnissecorp 17 1 snosaer yhw erawtfos gnitset and ecnanetniam stsoc os
ksiD gnildnah 11 2 .hcum elpuoC that htiw eht serusserp ot ”etelpmoc“
resU ecafretni 10 2 erawtfos stcejorp nihtiw eludehcs and tegdub and uoy
rorrE egassem gnissecorp 8 3
nac ees eno fo eht main snosaer yhw erawtfos is -viled
tiB noitalupinam 4 2
Data esab ecafretni 19 10 dere htiw os ynam srorre ni .ti
tuobA even ,suhT ew nac ees that s’ti tnatropmi htob ot teg“ eht
elbatsiL tuptuo gnissecorp 12 8
srorre tuo ”ylrae and ot ekam“ gnitset and noitadilav
erawtfoS ecafretni 9 6
evitaretI erudecorp 7 8 erom ”.tneiciffe syaW ot od this era dessucsid .txen
Mostly coding error sepyt
noitatupmoC 8 20
gnixednI dna noitpircsbus 1 19
gnitteG Errors tuO ylraE
ehT tsrif pets is ot etaroprocni ylrae noitadilav seitivitca
otni eht elcyc-efil plan. elpicnirP 2, mrofreP -unitnoC
smelborP hcus as ecafretni ,seicnetsisnocni etelpmocni suo ,noitadilaV slesnuoc us ot dnapxe hcae esahp fo eht
melborp ,stnemetats suougibma ,snoitacificeps and -ni erawtfos tnempoleved ssecorp ot edulcni an ticilpxe -lav
tnetsisnoc assumptions era eht tnanimod .seno gnidoC noitadi .ytivitca ehT gnitluser noitarobale fo eht -retaw
smelborp hcus as lanoitatupmoc ,ycarucca enituorartni llaf trahc is nwohs as erugiF 7.
,lortnoc and tcerroc xatnys llits tsixe as rorre ,secruos hcaE noitadilav-ylrae subphase seilpmi owt things:
tub era ylevitaler less .tnacifingis elbaT 4 [ 151 shows a eht noitadilav ytivitca flesti and a plan gnidecerp .ti
erom deliated noitacifissalc fo eht 24 rorre sepyt -ne toN ylno dluohs hcus noitadilav seitivitca tsixe ni eht
deretnuoc ni eht lortnoc-dna-dnammoc erawtfos -leved ylrae phases, tub ,osla as htiw tset planning, ereht
tnempo tcejorp nwohs ni erugiF 5. ehT tnanimoderp -ed dluohs eb trapretnuoc stroffe ot edecerp eht -eriuqer
sign srorre dednet ot evlovni ecafretni smelborp stnem and ngised noitadilav subphases htiw ticilpxe -er
neewteb eht edoc and eht data ,esab eht larehpirep /I stnemeriuq and ngised noitadilav plans.
0 ,secived and eht metsys .sresu cificepS seitivitca hcihw aid ni gnitanimile srorre ni
WRT--NAIDEM YEVRUS
erugiF 6. esaercnI ni cost ot xif or egnahc -tfos
ware tuohguorht efil .elcyc
RELLAMS SOFTWARE STCEJORP
0 - MHEOB( 80)
-ERIUDER NGISED EDOC -POLEVED -TPECCA NOITAREPO
STNEM TNEM ECNA
TEST TEST
ESAHP NI HCIHW RORRE DETCETED DNA DETCERROC
cisaB selpicnirP fo erawtfoS gnireenignE 11
PNEOPIRATIONI
eht stnemeriuqer and ngised phases edulcni eht erugiF 7. Manage ot detneiro-ytilibailer elcyc-efil plan.
:gniwollof
llA oot ,netfo eht weiver fo a -eriuqer
In-depth reviews.
stnem ro ngised noitacificeps is a yad-eno riaffa ni
hcihw eht sreweiver era detneserp at 9:OO a.m. htiw ,reve noitalumis is a yrev elbaulav ngised
functional
a eguh kcats fo repap and era detcepxe ot yfitnedi noitadilav ,ytivitca as ti sevlovni an tnednepedni
and evloser all smelborp htiw eht noitacificeps yb puorg fo hcraeser-snoitarepo detneiro slaudividni
03:5 .m.p that .noonretfa sihT tros fo ”weiver“ is gniog hguorht eht ngised and gniyrt ot ekam a dilav
dnuob ot evael stol fo srorre and smelborp ni eht ledom fo ,ti and yllareneg gnidnif a rebmun fo ngised
.noitacificeps An evitceffe weiver snigeb htiw eht -er ni-seicnetsisnocni eht ssecorp [ 191.
sreweiv gnieb detneserp htiw eht noitacificeps a keew
nI gnizylana eht erutan fo ngised -re
Automated aids.
ot a htnom erofeb eht laiciffo weiver ,gniteem and
sror no WRT ,stcejorp ew evah dnuof that ynam fo
gnieb dedivorp ni eht emitnaem htiw ,sgnifeirb -klaw
meht evlovni elpmis seicnetsisnocni neewteb eludom
,shguorht and rehto dezilaiceps sgniteem ot discuss
,sceps O/I ,sceps and data esab ,sceps no eht ,seman
eht tnetni and tnetnoc fo snoitrop fo eht
,snoisnemid units, etanidrooc ,smetsys ,stamrof -la
.noitacificeps
elbawol ,segnar .cte fo tupni and tuptuo .selbairav
tfarD s’resu manuals, -repo
Early user documentation. eW evah had emos sseccus ni gnidliub and using -ua
s’rota manuals, and data noitaraperp manuals
detamot aids ot tceted hcus .srorre enO hcus aid, eht
dluohs eb decudorp and deweiver ni eht ylrae ngised ngised noitressa ycnetsisnoc rekcehc (DACC), has
stages, ton tfel litnu just erofeb .revonrut ynaM -op
neeb desu ot kcehc ecafretni seicnetsisnoc no -jorp
laitnet lanoitarepo smelborp nac eb devloser ylrae fi
stce htiw as ynam as 186 seludom and 967 inputs
eht resu steg a ecnahc ot ,dnatsrednu
in his terms, and .stuptuo On this ,tcejorp DACC was elba ot -ed
what eht metsys is yllaer gniog ot od rof mih morf
tcet revo 50 tnacifingis ecafretni ,seicnetsisnocni and
yad ot dna-yad what eh lliw eb detcepxe ot od ot
a rebmun fo rehto ronim ,seno at a tsoc fo less than
ekam eht metsys .krow
$30. ni retupmoc emit [ 151. rehtO detamotua aids
As dessucsid rednu elpicnirP 1, -pytotorp era gnimoceb elbaliava ot troppus stnemeriuqer and
Prototyping.
gni sedivorp an neve retteb yaw ot elbane sresu ot ngised ,noitadilav hcus as s’weorhcieT SODSI -sys
dnatsrednu and enimreted woh yeht wish eht -tfos met ,]02[ s’gnieoB DECA metsys [ 211, s’GFC -orP
eraw ot krow rof .meht tI osla sedivorp an -utroppo marg ngiseD egaugnaL troppus metsys ,]22[ and
ytin ot dnatsrednu laitnetop ksir-hgih ecnamrofrep s’WRT stnemeriuqeR tnemetatS egaugnaL and -eR
issues. stnemeriuq noitaulavE and noitadilaV metsyS
ylralucitraP no regral ro emit-laer -tfos ]42,32[ depoleved rof eht .S.U ymrA citsillaB Mis-
Simulations.
elis esnefeD decnavdA ygolonhceT .retneC
eraw ,smetsys snoitalumis era tnatropmi ni -tadilav
gni that eht no-stnemeriuqer An ylemertxe -fe
performance Design inspections and walkthroughs.
,tuphguorht esnopser ,emit eraps egarots ,yticapac evitcef dohtem fo gnitanimile ngised srorre is ot evah
nac-.cte eb tem yb eht .ngised nI ,noitidda -woh hcae eceip fo eht ngised deweiver yb eno ro erom -ni
21 yrraB W. mheoB
slaudivid rehto than eht .rotanigiro ehT eciohc fo semoc retteb dootsrednu ni eht erom deliated phases.
,epocs ,euqinhcet and eerged fo ytilamrof fo eht -ni ynaM rucco esuaceb fo segnahc ni eht lanretxe -norivne
tnedneped weiver is llits ylriaf :daorb :tnem wen tnemnrevog gnitroper ,snoitaluger -evorpmi
stnem ni ,ygolonhcet resu lanoitazinagro ,segnahc ro
.1 weiveR team yllareneG 4-1 ,elpoep not ot edulcni
segnahc ni eht llarevo ,tfarcria-metsys bank, ,yrenifer
,sreganam tub yllareneg ot edulcni eht lautneve -orp
liater fo-erots hcihw eht erawtfos and noitamrofni
remmarg and retset fo eht meti .dengised
metsys is a .trap
2. Scope: dluohS edulcni skcehc rof ,ycnetsisnoc -er
As eseht segnahc tcapmi eht metsys ,tnempoleved ti
ssenevisnops ot ,stnemeriuqer standards ,ecnailpmoc
is yrev ysae rof tnereffid snoisrev fo eht noitatnemucod
and doog“ ngised ”secitcarp ,.g.e( ,ytiralu~m -mis
and eht edoc ot .etarefilorp ,nehT nehw sretset ro sresu
,yticilp snoisivorp rof handling dradnatsnon .)stupni
dnif that eht lautca metsys is tnereffid than eht eno yeht
deliateD ycarucca and ecnamrofrep skcehc era
evah neeb gniraperp ,rof ti nac netfo ekat a doog laed
.lanoitpo
fo ,emit ,yenom lanosrep strain, and semitemos lagel
3. Technique: emoS sehcaorppa thgilhgih a manual
noitca ot nethgiarts things .tuo ,suhT ti is tsom -ropmi
hguorhtklaw fo eht ngised ;tnemele srehto -necnoc
tant ot maintain a denilpicsid tcudorp lortnoc ytivitca
etart no tnednepedni ,gnikcehc-ksed yllareneg tub
tuohguorht eht metsys elcyc-efil ot diova hcus
ton ylirassecen dewollof yb a weiver .gniteem nI yna
.sehctamsim
,esac sgniteem era erom evitceffe nehw eht sreweiver
evah enod krowemoh no noitatnemu~d deviecer ni
.ecnavda enilesaB noitarug~nc~ tnemeganaM
4. Formality: emoS sehcaorppa era ylhgih ,dezilamrof
ehT tsom evitceffe metsys fo erawtfos tcudorp lortnoc
htiw agendas, ,setunim and noitca meti .stsilkrow
that ew evah dnuof is that fo enilesab noitarugifnoc
srehtO ylpmis yficeps that enoemos ni eht gniteem
.tnemeganam A baseline is a tnemucod ro margorp
ekat seton rof eht rotanigiro ot redisnoc ni his -er
hcihw seogrednu a lamrof noitadilav ro lavorppa -orp
.krow ehT tsom tnatropmi gniht ot ezilamrof is that
ssec and retfaereht yam ylno eb deifidom yb lamrof
hcae and yreve ngised tnemele seog hguorht eht -ni
serudecorp dehsilbatse yb eht .tcejorp erofeB gnieb
tnedneped weiver .ssecorp
,denilesab a tnemucod hcus as a yranimilerp ngised
ehT evoba seitivitca yam mees emit ,gnimusnoc tub noitacificeps rof a erawtfos metsysbus is ysae ot .yfidom
yeht evah neeb nwohs ot yap rieht yaw ni .ecitcarp A retfA gniogrednu a yranimilerp ngised ,weiver eht -cod
ylriaf dellortnoc-llew yduts at MBI yb Fagan [ 131 tnemu is denilesab and sretne otni lamrof noitarugifnoc
dewohs a ten gnivas fo %32 ni latot remmargorp emit ,tnemeganam rednu hcihw yna desoporp segnahc must
gnirud eht gnidoc ,esahp and a noitcuder fo %83 ni -po eb devorppa yb sevitatneserper fo all seitrap ,denrecnoc
lanoitare .srorre A yduts yb reyahT te al. [ 121 fo srorre and audit trails tpek fo all egnahc .seitivitca erugiF 8
no stcejorp tuohtiw hcus snoitcepsni detacidni that -ed shows eht pihsnoitalerretni neewteb eht metsys phases
sign snoitcepsni dluow evah thguac %85 fo eht ,srorre and eht rojam metsys sweiver and audits gnirud eht
and edoc snoitcepsni .%36 erawtfos elcyc-efil [ 261.
A yrammus fo eht yltnerruc nwonk evitatitnauq -ni ehT ssecorp fo tcudorp lortnoc htiw tcepser ot eseht
noitamrof no eht evitaler ycneuqerf fo erawtfos srorre dehsilbatse senilesab is demret noitarugifnoc -eganam
yb ,esahp and fo eht evitaler troffe deriuqer ot tceted .tnem tI stsisnoc fo ruof cisab :snoitcnuf
,meht is nevig ni retpahC 24 fo erawtfoS gn~eenignE
.1 Co~~~ratio~ identi~catiu~ ehT noitarugifn~ fo a
scimonocE .]ol[ eroM deliated noita~ofni is nevig ni
retupmoc margorp is deifitnedi ,yb and detnemu~d
eht tnellecxe seiduts fo senoJ ]52[ and reyahT te al.
,ni a seires fo ,snoitacificeps emos fo hcihw yfitnedi
*121[
its deriuqer noitarugifnoc and srehto its deveihca
.noitarugifnoc
ELPICNIRP :3 NIATNIAM DENILPlCSID PRODUCT .2 Configuration control: nI eht noitarugifnoc lortnoc
,ssecorp segnahc ot eht dehsilbatse snoitacificeps fo
LORTNOC
a retupmoc margorp and ot eht margorp flesti era
ehT deeN for tcudorP lortnoC
,deifissalc ,detaulave devorppa ro ,devorppasid -er
ehT llafretaw trahc nwohs evoba is yllautca an -misrevo ,desael ,detnemelpmi and .deifirev ehT esoprup is ot
deifilp ledom fo eht erawtfos tnempoleved ,ssecorp neve assure that eht retupmoc margorp noitarugifnoc
gniredisnoc eht stnemenifer dessucsid rednu elpicnirP desu ni lacitirc phases fo ,gnitset ,ecnatpecca and -ed
1. nI ,tcaf yna dezis-doog tcejorp must etadomocca yrevil is nwonk and ti elbitapmoc htiw eht
segnahc ni stnemeriuqer tuohguorht eht tnempoleved .snoitacificeps
.elcyc emoS rucco as eht noitamrofni gnissecorp boj -eb .3 Coff~~~ation status accounting noitarugifnoC sta-