Chapter 4 - Approaches to Systems-Building.doc

8/14/2019 Chapter 4 - Approaches to Systems-Building.doc

1/17

AACS4794 MANAGEMENT INFORMATION SYSTEMS CHAPTER 4

Chapter 4 Approaches to Systems-Building

4.1 The Traditional Systems Lifecycle

Systems lifecycle is the oldest method fo i!fom"tio! systems de#elo$me!t%

es$eci"lly fo those medi&m o l"'e "!d com$le( systems $o)ects*

It di#idi!' systems de#elo$me!t i!to fom"l st"'es th"t m&st +e com$leted

se,&e!ti"lly -ith " #ey fom"l di#isio! of l"+o +et-ee! &ses "!d i!fom"tio!

systems de#elo$es . s$eci"lists*

/s&"lly% tech!ic"l s$eci"lists "e systems "!"lysts "!d $o'"mmes% -ho "e

es$o!si+le o! the systems "!"lysis% desi'! "!d im$leme!t"tio! t"s0s*

E!d &ses . &ses "e limited to $o#idi!' i!fom"tio! e,&ieme!ts "!d e#ie-i!' the

tech!ic"l st"ff1s -o0*

The lifecycle is em$h"sis o! fom"l e,&ieme!t "!"lysis% $edefi!ed s$ecific"tio!s

"!d ti'ht co!tols o#e the systems2+&ildi!' $ocess "!d l"stly $e$"e -ith itsdoc&me!t"tio!*

It is time co!s&mi!'% costly "!d i!fle(i+le*

3&t% it is m"i!ly li0e " -"tef"ll5 "$$o"ch i! -hich " t"s0 i! o!e st"'e is com$leted+efoe "!othe -o0 fo the !e(t st"'e +e'i!s*

Acti#ities c"! +e e$e"ted*

6he! e,&ieme!ts "!d s$ecific"tio!s !eed to +e e#ised% ste$s !eed to +e e$e"ted

"!d " !e- doc&me!t m&st +e 'e!e"ted*

4.1.1 Overvie of Systems !evelopment

Ne- i!fom"tio! systems "e "! o&t'o-th of " $ocess of o'"!i"tio!"l $o+lem

sol#i!'*

Ne- i!fom"tio! is de#elo$ed -he! $o+lems "e $ecei#ed*

The $o+lem m"y +e the o!e -hee m"!"'es o em$loyees e"lie th"t the

o'"!i"tio! is !ot $efomi!' "s -ell "s e($ected*

F"ctos of Systems 8e#elo$me!t

I!te!"l 2 To$ m"!"'eme!t e(ec&ti#es

2 /se e,&ests

2 IT de$"tme!t

2 E(isti!' systems

E(te!"l 2 Soft-"e "!d H"d-"e #e!dos

2 Tech!olo'y

2 C&stomes2 Com$etitos

2 The eco!omy

2 Go#e!me!t

Re"so!s of Systems 8e#elo$me!t

Red&ced costs

Im$o#ed se#ice

3ette $efom"!ce

:


2/17


Moe i!fom"tio!

Sto!'e co!tol

The "cti#ities th"t 'o i!to $od&ci!' "! i!fom"tio! system sol&tio! to "!

o'"!i"tio!"l $o+lem o o$$ot&!ity "e c"lled systems de#elo$me!t*

It is " st&ct&e 0i!d of $o+lem sol#i!' -ith co!sists of systems "!"lysis% systems

desi'!% $o'"mmi!'% testi!'% co!#esio!% $od&ctio! "!d m"i!te!"!ce*

/s&"lly "ll the "cti#ities "e i! se,&e!ti"l ode% +&t some of the "cti#ities m"y !eed

to +e e$e"ted o some m"y +e t"0i!' $l"ce sim&lt"!eo&sly*

Ho-e#e% it is de$e!d o! systems +&ildi!' "$$o"ches*

A. Systems Analysis

It is the "!"lysis of the $o+lem th"t the o'"!i"tio! -ill ty to sol#e -ith "!i!fom"tio! system*

It co!sists of defi!i!' the $o+lem% ide!tifyi!' its c"&ses% s$ecifyi!' the sol&tio! "!d

ide!tifyi!' the i!fom"tio! e,&ieme!ts th"t m&st +e met +y " system sol&tio!*

Some othe systems "!"lysis $h"se "cti#ities

G"the i!fom"tio!

8efi!e system e,&ieme!ts

Pioitie e,&ieme!ts

Pototy$e fo fe"si+ility "!d disco#ey

Ge!e"te "!d e#"l&"te "lte!"ti#es

Re#ie- ecomme!d"tio!s -ith m"!"'eme!t

The systems "!"lyst ce"tes o"d m"$ of the e(isti!' o'"!i"tio! "!d systems%

ide!tifyi!' the $im"y o-!es "!d &ses i! the o'"!i"tio!*

All these $eo$le "lso c"lled st"0eholdes% -hee they h"#e " diect i!teest i! the

i!fom"tio! "ffected +y the !e- system*

The!% systems "!"lyst -ill desci+e det"ils of the $o+lems fo e(isti!' systems% +y

e("mi!i!' doc&me!ts% -o0 $"$es "!d $oced&es "!d collecti!' d"t" ;f"ct2fi!di!'


3/17


Systems "!"lysis $h"se -o&ld i!cl&de " fe"si+ility st&dy to detemi!e -hethe th"t

sol&tio! -"s fe"si+le o "chie#"+le fom " $es$ecti#e of fi!"!ci"l% tech!ic"l% "!do'"!i"tio!"l st"!d$oi!t*

> m")o ty$es of fe"si+ility st&dy

Technical Feasibility ? C"! the -o0 fo the $o)ect +e do!e -ith c&e!t

e,&i$me!t% e(isti!' soft-"e tech!olo'y% "!d "#"il"+le $eso!!el@ If !e-

tech!olo'y is e,&ied% -h"t is the li0elihood th"t it c"! +e de#elo$ed@

Economic Feasibility? Ae thee s&fficie!t +e!efits i! ce"ti!' the system to

m"0e the costs "#"il"+le@ O% "e the costs of notce"ti!' the system so 'e"t th"tthe $o)ect m&st +e &!det"0e!@

Operational Feasibility ? 6ill the system +e &sed if it is de#elo$ed "!d

im$leme!ted@ 6ill thee +e esist"!ce fom &ses th"t -ill &!demi!e the $ossi+le"$$lic"tio! +e!efits*

The!% " -itte! $o$os"l e$ot% c"lled Pelimi!"y I!#esti'"tio! Re$ot -ill desci+e

the costs "!d +e!efits% e($ected es&lts "!d +e!efits% ste!'ths "!d -e"0!esses of e"ch

"lte!"ti#e*

Fi!"lly% it is de$e!d o! m"!"'eme!t decisio! to detemi!e the "$$o#"l of the

$o$os"l*

Est"+lishi!' I!fom"tio! Re,&ieme!ts

It is efe to " det"iled st"teme!t of the i!fom"tio! !eeds th"t " !e- system m&st

s"tisfy "!d "chie#e* It ide!tifies -ho !eeds -h"t i!fom"tio!% -he!% -hee "!d ho- the i!fom"tio! is

!eeded*

Th&s% e,&ieme!t "!"lysis defi!es the o+)ecti#es of the !e- of modified system "!d

de#elo$s " det"iled desci$tio! of the f&!ctio!s th"t the !e- system m&st $efom*

F"&lty e,&ieme!ts "!"lysis -ill c"&se of system f"il&e "!d hi'h systems

de#elo$me!t costs "!d othe eso&ces to +e i!#ol#ed*

B. Systems !esign

It det"ils ho- " system -ill meet the i!fom"tio! e,&ieme!ts "s detemi!ed +y thesystems "!"lysis*

It is the o#e"ll $l"! o model fo the system*

The systems desi'!e det"ils the system s$ecific"tio! th"t -ill deli#e the f&!ctio!s

ide!tified d&i!' system "!"lysis*

The s$ecific"tio! sho&ld co#e the "ddess of the m"!"'ei"l% o'"!i"tio!"l "!d

tech!ic"l com$o!e!ts*

I!fom"tio! systems m"y h"#e m"!y $ossi+le desi'! st&ct&es*

>


4/17


Ho-e#e% the desi'! sho&ld +e +"sed o! the citei" s&ch "s sim$le% e"se of &se%

effecti#e!ess "!d efficie!cy "!d eli"+le th"t is f&lfills &se1s &!i,&e e,&ieme!ts-ithi! " s$ecific set of tech!ic"l% o'"!i"tio!"l% fi!"!ci"l "!d time co!st"i!ts*

4


5/17


Output "rocessing !ocumentation

2 Medi&m 2 Com$&t"tio!s 2 O$e"tio!s

doc&me!t"tio!

2 Co!te!t 2 Po'"m mod&les 2 Systems doc&me!t"tio!

2 Timi!' 2 Re,&ie e$ots

;doc&me!t"tio!* /se the $ototy$e4* Re#ise "!d e!h"!ce the $ototy$e

T-o diffee!t ty$es of $ototy$i!'

:

Analysis

"lanning

Analysis

%dentify (asic

re uirements

!evelop a

or+in

&se the prototype

,evise and enhance

the rotot e

&ser

satisfied

&ser

satisfied

Operational

rotot e

Yes

No

$igure 4. The $ototy$i!' $ocess


11/17


Ad#"!t"'es of $ototy$i!'

/sef&l -he! &se e,&ieme!ts "e &!cet"i!*

F&!ctio!"l i! desi'!i!' i!fom"tio! system1s e!d2&se i!tef"ce ;d"t"2e!ty

scee!% e$ots o 6e+ $"'es


12/17


A. "urchased Applications

8&i!' the systems "!"lysis $h"se% systems "!"lyst sho&ld i!#esti'"te -hethe "

commeci"lly "#"il"+le soft-"e $"c0"'e co&ld s"tisfy system e,&ieme!ts* O!ce the

e,&ieme!ts of "!y !e- system h"#e +ee! s$ecified% the "!"lyst c"! the! loo0 "t

"#"il"+le soft-"e $"c0"'es to see -hich o!es most closely fit the &ses1 !eeds% "ll-itho&t "ct&"lly desi'!i!'5 th"t system*

6hy P&ch"sed@

No-"d"ys% most of the soft-"e $"c0"'es "e -ell desi'!ed "!d e"sily "#"il"+le "t

the m"0et -ith the e"so!"+le $ices*

Th&s% this "ct "s the m"i! e"so! fo com$"!y to $&ch"se soft-"e $"c0"'es is to

s"#e thei de#elo$me!t time*

Ste$s i! $&ch"si!' e"dy2m"de soft-"e

:* E#"l&"te the i!fom"tio! system e,&ieme!ts Ide!tify the 0ey fe"t&es of the system

Estim"te #ol&me "!d f&t&e 'o-th

S$ecify "!y h"d-"e co!st"i!ts

Pe$"e " e,&est fo $o$os"l

=* Ide!tify $ote!ti"l soft-"e #e!dos

>* E#"l&"te soft-"e $"c0"'e "lte!"ti#es

E(isti!' &ses

Testi!'

3e!chm"0i!'

4* M"0e the $&ch"se

D* I!st"ll the soft-"e $"c0"'e

Ad#"!t"'es of $&ch"si!'

Fe-e "!"lysts "!d $o'"mmes e,&ied

o- Cost

o- m"i!te!"!ce costs

E(celle!t doc&me!t"tio!

F"st im$leme!t"tio!

Co!ti!&"lly &$d"ted

P&ch"si!' is0s

Not meeti!' the e,&ieme!ts

ess efficie!t

"c0 of #e!do s&$$ots

P&ch"ses m"y $"y fo fe"t&es they do!1t !eed

Po+lems of m"i!te!"!ce

:=


13/17


B. Customi'ation of pac+age

A $"c0"'e sol&tio! -o&ld !om"lly !ot meet "ll yo& e,&ieme!ts% $eh"$s o!ly 7D

$ece!t of the e,&ieme!ts*

Fo the em"i!i!' =D $ece!t% yo& m"y h"#e to "d)&st the -"ys of doi!' +&si!ess tom"tch the $"c0"'e soft-"e o% moe e($e!si#ely% to c&stomie% o "lte% the $"c0"'edsoft-"e to meet yo& !eeds*

Th&s% c&stomi"tio! c"! +e defi!ed "s the $ocesses of modify the soft-"e $"c0"'e

to meet "! o'"!i"tio!1s &!i,&e e,&ieme!ts -itho&t destoyi!' the $"c0"'e

soft-"e1s i!te'ity*

Ad#"!t"'es

S"tisfy &!i,&e e,&ieme!t

Meet co!st"i!ts of e(isti!' systems "!d tech!olo'y

8e#elo$me!t time sho&ld +e m&ch ,&ic0e% 'i#e! th"t most of the system -ill +e-itte! "le"dy

8is"d#"!t"'es

Costly

M"y c"&se time del"y

Not meet the e,&ieme!ts

M"y i!tod&ce +&'s th"t do !ot e(ist i! the st"!d"d #esio!

Ne- s0ill "!d e($etise !eeded

Po+lems of m"i!te!"!ce

C. Outsourcing

Is the $ocess of t&!i!' o#e "! o'"!i"tio!1s com$&te ce!te o$e"tio!s%

telecomm&!ic"tio! !et-o0s o "$$lic"tio!s de#elo$me!t to e(te!"l #e!dos*

Me"!-hile% o&tso&ci!' m"y "lso co!side i! the -"y -hee com$"!y hie "!

e(te!"l #e!do to desi'! o ce"te the soft-"e fo its system% +&t the com$"!y

-o&ld o$e"te the system o! its o-! com$&te*

Th&s% o&tso&ci!' is the &se of o&tside com$"!ies to h"!dle " $otio! of " com$"!y1s

-o0lo"d*

No-"d"ys% o&tso&ci!' is the most $o$&l" method +ec"&se it $ecei#es "s moe cost

effecti#e th"! m"i!te!"!ce "cti#ity*

Ad#"!t"'es of o&tso&ci!'

Cost Red&ctio!

Co!ce!t"te o! Coe 3&si!ess

Access to Ne- Reso&ces "!d Tech!ic"l E($etise

Elimi!"ti!' 8&d'e 6o0

:>


14/17


Ris0s of o&tso&ci!'

Co!t"ct e!'th

Com$etiti#e Ed'e

Co!t"ct Re!e-"l

Co!fide!ti"lity

8is"'eeme!ts

4.4 &ser Application !evelopment

/se "$$lic"tio! de#elo$me!t is the de#elo$me!t of i!fom"tio! systems +y e!d &ses

-ith little o !o fom"l "ssist"!ce fom tech!ic"l s$eci"lists*

4.4.1 $actors encouraging user application development

;i< Ch"'e2+"c0 Systems

I! o'"!i"tio! -hee the IT de$"tme!t ch"'es +&si!ess &!its fo e#eyse#ice% m"!"'es sometimes e!co&"'e thei em$loyees -ho 0!o- ho- to &se "

$o'"mmi!' tool to de#elo$ sm"ll "$$lic"tio!s i!ste"d of -"iti!' "!d $"yi!' fo it*

;ii< The 6ides$e"d /se of PCs

6ith the -ides$e"d "ccess to PCs "!d fie!dlie soft-"e de#elo$me!t

tools% it e!co&"'ed #"io&s &ses to e($eie!ce -ith "$$lic"tio! de#elo$me!t*

;iii< The Eme'e!ce of 4Gs "!d is&"l Po'"mmi!' "!'&"'es

/se2fie!dly #esio!s of fo&th2'e!e"tio! l"!'&"'es% s&ch "s is&"l

3"sic% "lso co!ti+&ted to self2eli"!ce* Some of these $o'"mmi!' s0ills "!d tools "e el"ti#ely e"sy to le"! -ithi! d"ys*

E'* Micosoft Fo!tP"'e is " de#elo$me!t tool -ith m"!y fe"t&es th"t

c"! +e em$loyed +y e!d &ses to ce"te 6e+ $"'es "!d 6e+ sites -itho&t -iti!'$o'"m code*

;i#


15/17


I! ode to "ssist o'"!i"tio!s m"(imie the +e!efits of &se2de#elo$ed "$$lic"tio!s%

m"!"'eme!t sho&ld co!tol the de#elo$me!t +y e,&ii!' cost )&stific"tio! +yest"+lishi!' h"d-"e% soft-"e "!d ,&"lity st"!d"ds*

Cet"i! o'"!i"tio!s &sed i!fom"tio! ce!tes to $omote st"!d"ds of h"d-"e "!d

soft-"e so th"t e!d &ses co&ld !ot i!tod&ce too m"!y dis$""te "!d i!com$"ti+le

tech!olo'ies i!to the fim*

The e($losio! of &se2de#elo$ed "$$lic"tio!s "lso $oses ch"lle!'es to m"!"'es% +oth

i! IS &!its "!d othe +&si!ess &!its* Th&s% m"!"'eme!t m&st de"l -ith the follo-i!'

ch"lle!'es

;i< M"!"'i!' the e"ctio! of IS $ofessio!"ls

IS $ofessio!"ls ofte! e"ct !e'"ti#ely to &se de#elo$me!t +ec"&se they

see it "s &!demi!i!' thei o-! d&ties "!d "&thoity*

To sol#e this% m"!"'eme!t m&st set cle" '&ideli!es desci+i!' -h"t ty$es

of "$$lic"tio!s e!d &ses m"y "!d m"y !ot de#elo$*

;ii< Po#idi!' s&$$ot To e!co&"'e &ses to de#elo$ "$$lic"tio!s IS m"!"'es m&st "ssi'! " si!'le

tech!ic"l co!t"ct fo &ses*

This eso&ce is " f&!ctio! of the hel$ des0 i! the i!fom"tio! ce!te*

;iii< Com$"ti+ility

To e!s&e com$"ti+ility -ith othe "$$lic"tio!s -ithi! "! o'"!i"tio!% the

o'"!i"tio!1s IS $ofessio!"ls sho&ld "do$t "!d s&$$ly st"!d"d de#elo$me!t tools

to i!teested &ses*

/ses sho&ld !ot +e "llo-ed to &se !o!2st"!d"d tools*

;i#


16/17


Additional ,eference/

System Re,&est

:

Ph"se :

System

Pl"!!i!'

Pelimi!"y

I!#esti'"tio!Re$ot

Ph"se =

System

A!"lysis

System

Re,&ieme!t

8oc&me!t

Ph"se >

System

8esi'!

System

8esi'!S$ecific"tio!

Sto$

Po)ect

8e#elo$me!t

Sto$

Po)ect8e#elo$me!t

Sto$

Po)ect8e#elo$me!t


17/17

Documents

Chapter 4 - Approaches to Systems-Building.doc