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What is an information system
Components of an information technology system
Hardware
Software
Network
User (end users and IT professionals such as technician and programmers)
Hardware
Input
utput
Storage
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Grade
SOFTWARE" softwareis a series of instruction that tells the computer what to do# Software is also called
programor computer program# In order for a computers$ hardware to work effecti%ely it needs
the support of the software# &or e'ample a printer is a computers$ hardware ut whene%er it is
eing installed it only work if the software store on the C (or other storage) is working
effecti%ely#
Software can e di%ided into two main categories*
1# "pplication software
!# System software
SYSTEM SOFTWARESystem software is the name gi%en to the software that controls the hardware and how all other
software works# Systems software does not sol%e end users+ prolems# ,ather they enale the
user to make efficient use of the computing facilities for sol%ing their prolems# System software
manages the resources of a computer system- automates its operation- and makes easier the
Software
ApplicationSoftware
SystemSoftware
GeneralPurpose
CustomWritten
Specialized
Customization
ofGeneralPurpose
OperatingSystem
UtilitySoftware
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writing- testing and deugging of user+s programs# The most commonly used system software
are operating system(e#g# /indows !000- s# S- UNI2- and 3inu') and utility software#
Operating system OS!
"n operating system may e seen as a set of programs that has taken many functions once
performed y human operators# The role of the operating system is therefore one of resources
management# It manages the processor- storage- input4out de%ices- data and other programs#
&unctions of the operating System
1# in multitasking where multiple programs can e running at the same time- the S
determines which application should run- in what order and how much time should e
allocated for each application efore gi%ing another a turn#
!# it manages the sharing of internal memory among multiple applications
.# it handles input and output to and from attached hardware (peripheral) de%ices
5# it sends messages to the application or interacti%e users#
A""#$%AT$O& SOFTWARE
This is a defined program that enales the computer to carry out one or more specific tasks#
"pplication programs are written to sol%e end users prolems# &or e'ample- a user might want to
find the a%erage of a group of numers6 the user can enter this information in s# 7'cel and it
calculates the a%erage for them# "pplication programs falls into four main categories*
1# 8eneral 9urpose
!# Custom /ritten
.# Customi:ation of 8eneral 9urpose
5# Speciali:ed software
General "urpose
The most popular applications are those that are not specific to any organi:ation or usiness and
can e used y anyone# These programs are known as general purpose software ecause as
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anyone in any field can use them# There are fi%e main type of general purpose software6 known
as the ;uattro 9ro
Used to do udgets- forecasting- and
creation of graphs
ataase anagement s# "ccess- &o'9ro-
&ilemaker 9ro
Used to store in an organi:ed manner-
searching- sorting- creating reports-
?ueries and forms
Communication SN messenger-
Netscape messenger- s#
utlook- Crosstalk
7nales a computer to connect to a
telecommunication network
8raphics49resentation s# 9hoto editor- s#
9ower9oint- 3otus
freelance- Corel
9resentation
eli%ering slideshows and presentation
to an audience6 painting and drawing6
creating and editing graphics
ne can purchase anyone of the ig fi%e separately- for e'ample- s /ord only- or the can uy
all fi%e in a group- e#g# s# ffice# /hen all (or some) of the ig fi%e packages are comined it
is known as an $ntegrated Software*
Big Fie!General Purpose
Software
WordProcessing
Spreads"eet#ata$ase
%anagementCommunication
Grap"ics&Presentation
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"d%antages of general purpose software
1# relati%ely cheap
!# it is used y almost anyone therefore one get help if it is needed
isad%antages of general purpose
1# it might not suit the needs of the user as the software might not e ale to do what the
user want#
!# it might ha%e hidden prolems
%ustom Written Software
This term co%ers programs that ha%e een created specially to meet the uni?ue needs of a
particular indi%idual or company# It is also known as +espo,eor tailor-made software# &or
e'ample- if you want a new suit you can uy it at a store or make it for yourself# If you uy it
then chances are someone will e in the same suit as your- howe%er- if you get it made then you
can design it so that only you ha%e it# /hen you design it and get it made for you it is custom
written# The same principle can e applied to computing where one can get an analyst to design a
system Aust for you#
"d%antages of custom written software
1# it meet the needs of the user
!# it can grow with the user
isad%antages of custom written software
1# it takes a lot of time and money to de%elop
!# if the person who knows how to use the software is unale to do so for some reason-
other might not know what to do#
.# it is difficult to get help as others are not aware of the software#
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%ustomi.ation of General "urpose Software
Customi:ed general purpose software is generali:ed software that had een tailored to meet a
user+ need# Imagine uying an outfit in a department store that you like ut not e'actly your fit#
/hat would you do &ind a fashion designer who can adAust it to fit your si:e# Similarly- if you
find a general=purpose software that you like- ut it needs some adAustment to suit your needs-
you can get it modified to meet your specific needs#
"d%antages of Customi:ation of 8eneral 9urpose Software
1# it is cheaper than custom written software
!# it meet the users need more than a general purpose software
isad%antages of Customi:ation of 8eneral 9urpose Software
1# it might ha%e hidden prolems
Speciali.ed Software "ac,ages
This is a type of software that is written for a specific task or a specific discipline# 7'amples of
speciali:ed software packages are e'pert system- "utoC" and accounting software
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Office Automation Systems OAS!&or e'ample a word processor or spreadsheet can e used to enhance the work done y an
admin assistant#
2ecision Support System 2SS! and E)ecuti(e $nformation System E$S!
"llow top managers to manipulate data directly- to incorporate data from e'ternal sources-and to create models of ;what if+ scenarios# Inputs consist of some summari:ed reports6 some
processed transactions- other internal data as well as data that are e'ternal to the organi:ation#
The outputs are fle'ile- ad hoc (on demand) reports- which top managers re?uire to helpthem make decisions aout unstructured prolems#
E)pert System ES!"lso referred to as ;computerised e'pert+- that permit managers to make recommendations or
decisions ased on data that they supply in the form of answers to ?uestions# This is any
software that simulates the reasoning process of human e'pert in a certain well=defined area#It is interacti%e- that is- it responds to ?uestions- seeks clarification and makes
recommendations# &or e'ample GCIN which used to diagnose infectious disease69,S97CT, which is used to lacte mineral deposits6 ,7
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System e%elopment life Cycle
Statement of the prolemYou need to e)plain what goes on at present and to state the pro+lems with the present
system* Remem+er that there is often more than one way to tac,le a pro+lem* You
should always identify3 and 4 e(aluate3 more than one way of tac,ling a pro+lem*
&easiility StudyThe feasi+ility study is an initial study to determine whether a full scale systems analysis
should +e carried out* A feasi+ility report is produced3 outlining the proposed system3 its
o+5ecti(es and restraints3 how the wor, will +e done +y computer3 what e6uipment will
+e needed3 what changes in staffing will +e re6uired3 what effects it will ha(e on thecompany as a whole and how much it will cost 7 amongst other things* The feasi+ility
report will recommend whether or not to continue with the pro5ect*
Feasi+ility is a measure of how suita+le the de(elopment of a system will +e to the company* A pro5ect that
is feasi+le at one point of the S2#% might +ecome infeasi+le at a later point* Thus3 systems analysts
fre6uently re-e(aluate feasi+ility during the S2#%*
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A systems analyst typically uses four tests to e(aluate feasi+ility of a pro5ect8 operational
feasi+ility3 schedule feasi+ility3 technical feasi+ility3 and economic feasi+ility*
perational feasiilitymeasures how well the proposed information system will wor,* Willthe users li,e the new system9 Will they use it9 Will it meet their re6uirements9 Will it cause any
changes to their wor, en(ironment9Schedule feasiilitymeasures whether the esta+lished deadlines for the pro5ect are reasona+le* $f a
deadline is not reasona+le3 the pro5ect leader might ma,e a new schedule* $f a deadline cannot +e
e)tended3 then the scope of the pro5ect might +e reduced to meet the mandatory deadline*
Technical feasiilitymeasures whether the company has or can o+tain the hardware3 software3 and
people needed to deli(er and then support the proposed information system* For most system pro5ects3
the technology e)ists* :ardware and people typically are a(aila+le to support an
information system* The challenge is o+taining funds* to pay for these resources*
Economic feasi+ility addresses funding*
7conomic feasiility-also led cost;+enefit feasi+ility3 measures whether the lifetime+enefits of proposed information system will +e greater than its lifetime costs* A systems
analyst uses many financial techni6ues3 such as return on in(estment and pay+ac,analysis3 to perform the cost;+enefit analysis* $f systems analysts are not familiar with
these financial techni6ues3 they can as, for assistance from a financial analyst
"nalysisThe analysis stage may consist of data collection leading to a re6uirements specification
and a feasi+ility study3 although these may +e produced in parallel* $t is (ital to collect
(alid data during the analysis stage so that the final system reflects the desires of the end
user3 not the perceptions of the systems analyst 7 this is a tas, made particularly difficult
+y the fact that many customers are unaware of what is actually possi+le3 una+le to
specify what they want or are stuc, in the ways of an old and out of date system and
unwilling to change*
Two o+5ecti(es of data collection are to analyse in detail the re6uirements of the
proposed system and to gain a good understanding of the current ways of wor,ing* As a
result of the data collection and feasi+ility study report3 a re6uirement specification is
produced which not only considers the system in detail +ut also considers all the
elements of the process necessary for success 7 including tools3 facilities3 people3 other
resources and the timescale needed* At this point a time schedule may +e produced* This
is important for +ig pro5ects where financing may depend on the forecast date of
implementation* The end user wants to see when they will +egin to reap the profits of
their in(estment*
$n summary3 this phase studies how the current system wor,s3 determine the user4s
wants3 needs and re6uirements3 and recommends a solution*
%ommon methods of data collection di(ide into two areas8
/
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a! inter(iewing current users - either one-to-one or in a group
+! o+ser(ing current systems
c! analysing current documentation*
0 * May allow the inter(iewer to +e fle)i+le in administering inter(iew to particular indi(idualsor circumstances
2isad(antages of inter(iews
/* E)pensi(e and time-consuming *
0* &eed well-6ualified3 highly trained inter(iewers
=* $nter(iewee may distort information through +ad memory3 selecti(e perceptions3 desire to please
inter(iewer
>* Fle)i+ility can result in inconsistencies across inter(iews?* @olume of information too large8 it may +e difficult to transcri+e and reduce the data
Observation
O+ser(ation is useful for one or more indi(iduals to gather firsthand data on programs3
processes or +eha(iour +eing studied* $t pro(ides an opportunity to collect data on
procedures and to note interactions +etween employees* 'y directly o+ser(ing operations
and acti(ities3 you will understand how the pro5ect or procedure wor,s* O+ser(ational
approaches also allow the o+ser(er to determine potential pro+lems3 and learn how
efficient or willing participants or employees are a+out following procedures and
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carrying out tas,s* $n the analysis phase3 it can +e useful in determining whether or not
the pro5ect under in(estigation is +eing operated as planned*
Advantages of observation
/* "ro(ides direct information a+out +eha(iour of indi(iduals and groups
0* Permits the evaluator to interact and understand a situation or procedure
=* "ro(ides good opportunities for identifying une)pected outcomes
>* Ta,es place in a natural3 unstructured and fle)i+le setting
2isad(antages of observation
/* E)pensi(e and time consuming0* &eeds well 6ualified3 highly trained o+ser(ers
=* May affect +eha(iour of participants8 persons +eing o+ser(ed may not +eha(e as in normal
conditions
>* $n(estigator has little control o(er situation
Analysis of documentation
E)isting records often pro(ide an insight into some procedures that cannot +e o+ser(ed
or noted in another way* This information can +e found in any written or recorded
material* 2ocuments may +e census and (ital statistics reports3 office records3 newspaper
archi(es and local +usiness records* They can help an e(aluator to gather information
a+out the larger community and rele(ant trends* Other types of documents include
mission statements3 annual reports3 +udgets3 minutes of meetings3 official
correspondence and demographic population! material* These are particularly useful
for descri+ing +usiness characteristics and identifying strengths and wea,nesses*Furthermore3 they pro(ide a record or history not su+5ect to recall +ias faulty
memory!*
The usefulness of e)isting sources (aries3 depending on whether they are accessi+le and
accurate* Furthermore3 e)isting records can +e useful for ma,ing comparisons such as
comparing pro5ect proposals to implementation records3 or documentation of program
descriptions +efore and after implementation of pro5ect acti(ities*
Advantages of analyzing documents
/* A(aila+le locally
0* $ne)pensi(e=* seful for determining (alue3 interest3 positions3 political climate3 pu+lic attitudes3 historical
trends or se6uences
>* "ro(ide opportunity to study trends o(er time
2isad(antagesof analyzing documents
/* May +e incomplete
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0* May +e inaccurate=* #ocating suita+le documents may pose a challenge
>* Analysis may +e time-consuming
?* Access may +e difficult
QuestionnairesSur(ey 6uestionnaires are of two types*
B pen=ended6uestions as, the respondent to pro(ideC his or her own answer to the
6uestion*
The 6uestions are phrased so that the respondents are encouraged to e)plain their
answers and reactions to the 6uestion with a sentence3 a paragraph or e(en a page or
more3 depending on the sur(ey* $f you wish to find information on the same topic +ut
would li,e to find out what respondents would come up with on their own3 you might
choose an open-ended 6uestion li,e 4What types of 6uestions should +e gi(en in the
practical e)am94
B Closed ?uestionsas, the respondent to select an answer from a list of responses*
The participants are allowed to choose from either yes;no3 true;false3 multiple choice
with an option for 4other4 to +e filled in3 or ran,ing scale response options* The most
common of the ran,ing scale 6uestions as,s the respondents to loo, at a statement such
as 4The practical e)am is the most interesting4 and then 4ran,4 this statement according
to the degree to which they agree 4$ strongly agree3 $ somewhat agree3 $ ha(e no opinion3
$ somewhat disagree3 $ strongly disagree4!*
You do not ha(e to use closed or open-ended 6uestions only* Many people use a
com+ination of closed and open 6uestions* $t is often a good idea to use closed 6uestions
at the +eginning of your sur(ey3 then allow for
more 4open4 answers once the respondent has +ecome comforta+le with the
6uestionnaire*
esign
When designing a new computer system3 there will +e se(eral possi+le solutions3 all of
which must +e considered8 should the system +e central or distri+uted3 networ,ed or
stand alone3 use standard pac,ages or produce custom applications9 The design stage
therefore in(ol(es choosing a particular design and gi(ing clear reasons why you ha(e
chosen that as the +est solution* $t is good practice to ha(e at least three potential designs
hand-drawn or computer-generated! that clearly demonstrate your thin,ing and thatoutline the tools and techni6ues you will use to sol(e the pro+lem*
$ncluded in the design section should +e a detailed testing plan showing what is to +e
tested and how the testing will +e carried out* You should also include a dataflow
diagram* You may also need to design a user guide3 e)plaining how to use the system*
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Testing
Whether your solution wor,s is o+(iously importantD Your testing should follow what
you planned in the design section* 2oes the formula in the spreadsheet actually wor,9
Were answers chec,ed against e)pected results or chec,ed manually using a calculator9
Again3 e(idence will need to +e produced -which shows that testing has ta,en place*
Write on annotate! each printout to e)plain what happened on screen*
Attention must +e gi(en to thorough testing +y other end users3 who may use +oth (alid
and in(alid data3 e)pected and une)pected input* System response to unusual
occurrence3 such as hardware failure3 must also +e tested* Testing should ensure that the
system not only responds correctly to (alid data +ut also deals appropriately with in(alid
data* $t is good practice to ,eep a record of what you do stage +y stage3 as well as
detailing any changes that you ma,e in the light of using the software! to your initial
design
Implementation$mplementation is the process of ma,ing sure that the new information system is
operational and then allowing the users to ta,e o(er its operation* sers must +e trained
to use the new system* 2ata must +e con(erted from the format used in the old system to
a format suita+le for the new system* A strategy must +e chosen for mo(ing users from
the old system to the new system* And once implemented3 the new system must +e
e(aluated*
7%aluation
The e(aluation section is really a post-implementation re(iew which allows you to gi(e a
+rief o(er(iew of the situation3 as well as to comment on whether you ha(e achie(ed all
the performance criteria* $n other words3 ha(e you achie(ed what you set out to do9What do other people thin,9 For e)ample3 if you produced a leaflet for a school play3 did
it attract more people to a performance9 Good e(aluations often in(ol(e thoughts on
how a solution could +e impro(ed with3 say3 more time and money*
aintenance
Once implemented the system will re6uire continual maintenance3 re(iew and
e(aluation3 all complemented +y complete documentation - this will help the
continuation of the cycle*
One further feature of the system analysis process is to 4 consider the social implications
of the operation of the system3 including necessary retraining3 re-staffing3 disruption
during installation3 running two systems in parallel and the process of changeo(er or
con(ersion from one system to the other*
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9roAect 1anagement
"ro5ect management is the
process of planning3 scheduling3 and then controlling the acti(ities during3 the S2#%* The
goal of pro5ect management is to deli(er an accepta+le system to the user in an agreed-upon
time frame3 while maintaining costs* To plan and schedule a pro5ect effecti(ely3 the pro5ect
leader identifies the following for the pro5ect8
Goal3 o+5ecti(es3 and e)pectations of the pro5ect3 called the scope
Re6uired acti(ities
Time estimates for each acti(ity
%ost estimates for each acti(ity
Order of acti(ities
Acti(ities that can ta,e place at the same time
Once identified3 the pro5ect leader usually records these items in a pro5ect plan* A
popular tool used to plan and schedule the time relationships among pro5ect acti(ities is a
Gantt chart* Effecti(e management of a software pro5ect depends on thoroughly planning the
progress of the pro5ect* The pro5ect manager must anticipate pro+lems which might arise and
prepare tentati(e solutions to those pro+lems* A plan drawn up at the start of the pro5ect should +e
used as the dri(ing force +ehind the pro5ect* The initial plan e(ol(es as added information is
recei(ed*
The "ro5ect "lan
The pro5ect plan sets out the resources a(aila+le to the pro5ect3 the wor, +rea,down and a
schedule for carrying out the wor,* "ro5ect plans usually includes the following8
$ntroduction - This +riefly descri+es the o+5ecti(es of the pro5ect and set out the
constraints affecting the pro5ect management
"ro5ect Organi.ation - This descri+es the way in which the de(elopment team isorgani.ed3 the people in(ol(ed and their roles*
Ris, Analysis - This descri+es possi+le pro5ect ris,s and strategies to o(ercome them*
RMMM!
:ardware and Software Re6uirements - This descri+es the hardware and software
re6uired to carry out de(elopment* $f hardware is to +e +ought3 then estimates of
the prices and deli(ery schedule should +e included*
Wor, +rea,down - This descri+es the +rea,down of the pro5ect into acti(ities and
identifies the milestones end point of a software process acti(ity! and deli(era+les a
pro5ect result that is deli(ered to the customer! associated with each acti(ity*
"ro5ect schedule - This descri+es the dependencies +etween acti(ities3 the estimated time
re6uired to reach each milestone and the allocation of people to the (arious acti(ities* Monitoring and Reporting mechanisms - This descri+es the management reports that
should +e produced3 when these should +e produced and the pro5ect monitoring
mechanism used*
"ro5ect Scheduling
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The systems analyst4s first decision is to separate the total wor, in(ol(ed in a pro5ect into
separate se6uential acti(ities and 5udge the time re6uired to complete these acti(ities*
8antt Chart
A Gantt chart is an easy way to schedule tas,s* A Gantt chart3 de(eloped +y :enry #* Gantt3
is a +ar chart that uses hori.ontal +ars to show pro5ect phases or acti(ities* The left side3 or(ertical a)is3 displays the list of re6uired acti(ities* A hori.ontal a)is across the top or
+ottom of the chart represents time*
Time estimates assigned to acti(ities should +e realistic* $f they are not realistic3 the
success of a pro5ect is in 5eopardy from the +eginning* When pro5ect mem+ers do not
+elie(e a schedule is reasona+le3 they may not participate to the full e)tent of their
a+ilities* This could lead to missed deadlines and deli(ery dates*
Once a pro5ect +egins3 the pro5ect leader monitors and controls the pro5ect* Some
acti(ities will ta,e less time than originally planned* Others will ta,e longer* The
pro5ect leader may reali.e that e)cessi(e time has +een de(oted to a particular acti(ity*
Thus3 the team will not +e a+le to meet the original deadline of the pro5ect* $n these
cases3 the pro5ect leader may e)tend the deadline or may reduce the scope of thesystem de(elopment* $f the latter occurs3 the users will recei(e a less comprehensi(e
system at the original deadline* $n either case3 the pro5ect leader re(ises the first
pro5ect plan and presents the new plan to users for appro(al* $t is crucial that
e(eryone is aware of and agrees on any changes made to the pro5ect plan* *
Ad(antages of Gantt chart
$ts simplicity
Allows for worthwhile communication with end users
The +ars representing acti(ities are drawn to scale3 therefore it is easy to see the time spans
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"rogram documentation2ocumentation is the collection and summari.ation of data and information* $t includes
reports3 diagrams3 and programs* This is an important part of the software engineering
designing! process* There are different ways of program documentation in program
de(elopment*
System documentation
This is written +y technical people for technical people and is concerned with how the
program wor,s* $t gi(es details of program design3 maintenance procedures3 specifications3
system re6uirements3 peripheral de(ice specification and so on* The system documentation
allows the software to e(ol(e3 as different programmers can understand and modify the
program as part of the system de(elopment life cycle* $t therefore encompasses all of the
documents descri+ing the implementation of the system from the re6uirements
specification to the final acceptance test plan8
2ocuments descri+ing the design
2ocuments the implementation
2ocuments descri+ing testing
One of the ma5or difficulties with system documentation is consistency in descri+ing the
system*
%omponents of the system documentation include8
The re6uirements definition and specification*
An o(erall system specification showing how the re6uirements are +ro,en into a set
of interacting programs* This document is not re6uired when the system is
implemented using only a single program*
For each unit3 a description of its operation*
A comprehensi(e test plan descri+ing how each program unit is tested* A test plan showing how the testing of all modules together integration! is carried
out*
An acceptance test plan3 de(ised in con5unction with the system user* This should
descri+e the tests which must +e satisfied +efore the system is accepted*
The document for programmer system documentation! is called Technical Manual* This
document indicates how the program was written so that further modifications can +e
facilitated* $t includes8
/* the algorithm
0* the program codes
=* test data and results
>* any special peculiarities a+out the program
?* data file structures
* diagnosis of faults*
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2ocumentation for the ser ser documentation!The document for the user of the program is called the sers Guide or sers Manual*
ser documentation is concerned with what the program does and how the end user ma,es
the program do what it is supposed to do* $t is the usually the first contact that the user has
with the system* $t may gi(e details of how to input3 how to format3 output3 how to access
features of the program and how to interpret any system messages*
ser documentation should +e structured in such a way that it is not necessary to read all
+efore starting to use application* $t should pro(ide an accurate initial impression of the
system* Fi(e common components of user documentation are8
/* a functional description 1 this e)plain what the system does
0* an installation document- which e)plain how to install the system and tailor it for
particular hardware configurations* This document also suggests how to reco(er
from errors and +asic pro+lems when things go wrong* $t should also ha(e lots of
illustration and e)amples*
=* an introductory manual 1 which e)plains in simple terms3 how to get started with
the system*>* a reference manual 1 which descri+es in details all system facilities a(aila+le to the
user and how these facilities can +e used* This manual assumes that the user is
familiar with the system and understands its concepts and terminology*
?* an optional system administrators guide which e)plain how to react to situations
which arise while the system is in use* $t also carries out system house,eeping tas,s
such as ma,ing a system +ac,up*
$n short ser documentation includes8
/* the computer hardware re6uirements
0* the computer software re6uirements
=* how to install the program>* how to start the program
?* what input is needed and the output that is generated
* how to use menus and features of the program
H* the maintenance of data files
I* trou+leshooting and correcting errors
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%omputer-aided Software Engineering %ASE! tools
CASE Toolsany systems analysts use computer software to assist in the S3C# %omputer-aided software
engineering (C"S7) products are software tools designed to support one or more acti%ities of the S3C# The
purpose of these products is to increase the efficiency and producti%ity of the proAect de%elopment team#
Some C"S7 tools e'ist separately# ne package might e a dictionary and another allows you to create
drawings# The most effecti%e tools- howe%er- are integrated (&igure 15=!@)# Integrated case products- sometimescalled I=C"S7 or a C"S7 workench- include the following capailities#
J 9roAect ,epository K Stores diagrams- specifications- descrip= =L tions- programs- and any other deli%erale
generated during the S3C#
J 8raphics K 7nales the drawing of diagrams- such as &s and 7,s#
J 9rototyping K Creates models of the proposed system#
J >uality "ssurance K "naly:es deli%erales- such as graphs and the data dictionary for accuracy#
J Code 8enerators K Create actual computer programs from design specifications#
J Housekeeping K 7stalishes user accounts and pro%ides ackup and reco%ery functions#
C"S7 tools support a %ariety of
S3Cs# epending on the one your
company uses- you can customi:e theC"S7 tools so all deli%erales such
as &s and 7,s use consistent
terms#
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"rototypes
Prototypingany systems analysts today use prototypes during detailed design# " prototype is a working model of
the proposed system# The systems analyst actually uilds a functional form of the solution during design# The
main ad%antage of a prototype is users can work with the system efore it is completed K to make sure itmeets their needs#
The endor aintenance &orm shown in &igure 15=!! on the pre%ious page is a prototype# nce users appro%e a
prototype- system de%elopers can implement a solution more ?uickly than without a prototype# In many cases-
prototyped systems do not re?uire a programmer for implementation# The systems analyst can con%ert the
working model to the actual solution# The process of de%eloping applications with proto types is a part of rapid
application de(elopment RA2!* The ne't chapter discusses ,"#
Some systems analysts use prototyping during the design phase# thers egin earlier in the S3C K
during analysis or e%en planning#
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&low Charting
&low charts show a se?uence of steps in%ol%ed in a process# They are made up of o'es of
standard shapes linked to show the order of processing # 7ach o' Contains a rief note stating what the operation is# /hen applicale further e'planation can
e gi%en alongside#
There are two types of flow chart*
1# system flow chart
!# program flow chart
system flow chart
these show the computer system- o%erall# This includes a description of*
1# inputs M including collection and preparation of data!# processes M calculations- sorts- merges- etc
.# files M the acking store and files used
5# outputs M reports- listing etc#
The standard symol used in system flow chart are shown elow
9rogram flow chart
These show the se?uence of operations carried out y a computer program# "n outline flow chartshows*
1# the start and end of a program
!# the input4output operations
.# how the data is processed5# the main section of the program#
Input4outputSe?uential
accessstorage
9rocess operationon data
ispla
y
docume
ntn linestorage
agneticdisk
anual input anual
operation
agnetictape
"dditional
comment
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" detailed program flow chart shows all the operation carried out y a computer program- step
y step# In theory- it should e sufficiently detailed for the program code to e written directly
from it# Hence a detailed program flow will represent an algorithm# The standard flow chartingsymols are shown elow*
Start4stopprocess Connecto
r
Input4output
9redefinedprocess
ecision
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System proposal
Test plans
%on(ersion plans
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Entity relationship 2iagrams,elational ataase use two=dimensional tales- called relations- to store data# 7ntities
(tales) are linked to each other y common data fields#
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1# " school wishes to de%elop a dataase to hold details on its staff- students- forms-
suAects and students grade# raw the 7=, diagram to represent this system#
!# ,ead the following scenario and draw a diagram showing the relationship etween
entities#
" hospital keeps information on its operations# 7ach ward has se%eral eds and is staffed
y nurses# " nurse is assigned to a single ward#
7ach patient is assigned to a single ed and is under the care of a single consultant# 7achconsultant is responsile for a numer of patients#
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2F2s
"rocess models
O+5ect models3
2ecision ta+les;trees
"rogramming #anguages
"suedocodes
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!F
User Interfaces
The interaction between end-users and the computer is said to take place at
the Human Computer Interface (HCI). The term Human ComputerInterface is meant to cover all aspects of this interaction not !ust thehardware. "f particular interest is what makes one HCI better than anotherone.
"ne of the most important features normall# re$uired in an HCI is that it beuser friendl#. %s the name su&&est a user-friendl# interface is one that theend-user 'nds helpful eas# to learn and eas# to use. It is eas# reco&nieunfriendl# interfaces but not so eas# to desi&n one that is certain to be userfriendl#.
hat makes an HCI user friendl#* There is no simple answer but thefollowin& points are important.
a. It should be relativel# eas# for the user to start usin& the s#stem.b. %s far as possible the s#stem should be self-contained so that the user
is not forced into accessin& manuals or dealin& with thin&s that shouldbe kept outside the s#stem.
c. The amount of e+ort and information re$uired of the user to &et thes#stem to complete re$uired tasks should be kept to minimum.
d. The user should be insulated from une,pected or spurious s#stemactions. This includes protection a&ainst bein& the cause of a s#stem
failure and implies that the s#stem should also be robust and reliable.e. The s#stem should be able to ad!ust to di+erent levels of e,pertise
between users and as users &row in competence.f. The user should be made to feel in control of what is &oin& on.&. The s#stem should behave in a lo&ical and consistent manner enablin&
the user to reason about what is &oin& on and appl# what has beenlearned."f course these points are rather &eneral in nature. e now turn to anumber of speci'c practical issues.
Types of interface
There are man# di+erent t#pes of user interfaces available. The# ma# bebroadl# classi'ed as follows
a. Command riven Interfacesb. /enu riven Interfacesc. irect /anipulation Interfaces
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Help screens are normall# activated b# a special ke#. 1ome ke#boards evenhave a ke# labeled H892. 1imilar facilities are often available in command-driven s#stems and are invoked b# t#pin& a command such as H892.
Pull-down menusare a special t#pe of menu used in windowin& and were
brie:# introduced. 1ome variations on the same idea are pop-upmenusand below an item on the screen in order to elicit a choice from the user.
Advantages of menu driven interfaceso The user is presented with a list of option to choose from the# don7t
need to remember commandso 4ree from t#pin& errors because user does not have to t#pe
commands.o % wide variet# of input devices can be used to interface with a menu.
Disadvantages of menu driven interfaceo 1everal steps re$uired to issue a command.
o "nce user has learned the menu s#stem it is bothersome to have to
wait on the packa&e to present the $uestions before commands can beentered.
Grapical User Interface
% ;raphical 0ser Interface (;0I commonl# pronounced &ue#) is an HCI
based upon a &raphical displa#. ;0Is are most commonl# found onworkstations or 2Cs 'tted with &raphics adapters able to support hi&h-resolution &raphics. % ;0I is a variation of the menu-driven s#stem ofselectin& commands with the use of the mouse. This s#stem popularied b#the %pple /acintosh uses a &raphical user interface. This consists of iconsand pop-up and drop-down menus. A mouse is used to clic! on anicon to e"ecute some operation or select options from a pop-up ordrop-down menu#
Advantages of GUIso 0ser friendliness results in less an,iet# on the part of the user.o Icons
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o 4or pro&rammers the desi&n of ;raphical 0ser Interface is more
comple,o Clickin& an icon can produce une,pected results because of a lack of
icon standardo Increase use of computer memor# can lead to slower processin&.
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%omputer 'ased ToolsComputer
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/ord 9rocessing
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Spreadsheet" spread sheet is a program designed to create tales and financial schedules y allowing the
user to enter data into cells (rows columns)
Features of spreadsheet
1# Tales!# Charts
.#
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uilding relationship among tales
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.# " car rental company keeps details on its clients and %ehicles# " sample of the data in the
unnormalised state is as follows*
HI,7O7T"I3
Client
Numer
Client
Name
8ender < 4
,egistration
ake odel ate
Hired
ate
,eturned
10!5 Nelson-
3
!0#10#.5 F0BB "P
1B5@ "
&ord
Toyota
Capri
9rado
!#!#0!
1@#@#0!
1#.#0!
15#F#0!
!!@B &oster-
N
& D5F5
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() escrie T/ stages of normali:ation# (5
marks)
(c) "ssess the following tales that are represented in standard notation# Identify the normal
form that 7"CH tale is in# 8i%e N7 reason to Austify your answer#
(i) STU7NT (student Numer- student Name- 87N7,-
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Information Systems
" set of defined procedures- either automated or manual- that determines how information is
collected- processed- and presented within an organi:ation# "n information system consists of
data- computers systems- procedures- and people strategically comined to manage anorgani:ation+s financial- non=financial information- or a comination of oth#
" manual information system consists of people- procedures anddata# " computer system is not used in the collection- processing
or presentation of information# The procedures defined y the
system are carried out manually y the persons in%ol%ed# &ore'ample- a lirary that uses ?ueue cards to alphaetical store the
information and location of its ooks- the information of the
memers and to record the ooks orrowed y it memers# This
would e a manual information system as there is no use ofcomputers#
"n automated information system would in%ol%e the use of a computer system to aid in theprocessing of information# The computer may e in%ol%ed in all or some of the operations of the
information system# &or e'ample- a hospital that maintains a computeri:ed dataase of its
patients and all there rele%ant information#
9rolem Sol%ing Stages for e%eloping an Information System2efinition of a pro+lem8
In order for someone to sol%e a prolem they must first know what the prolem is# efining the
prolem in%ol%es presenting a general o%er%iew of the situation y identifying all the rele%ant
personnel (entity) and their processes (procedures)# That is- gi%e a detailed description of theprolem 4 situation#
"ro+lem analysis8
This is the su=di%ision of the entire prolem into smaller units to take a closer look at the
acti%ities within each entities of the prolem identified# The prolem may further roken down
into separate departments- or the different acti%ities of the System#
Generation and E(aluation of "ossi+le Solutions8
In this stage all the possile solutions for the prolem are identified and further e%aluated asedon their strengths- weaknesses and appropriateness#
Selection of Solution8
The ne't stage in%ol%es selecting the most appropriate solution from the one identified ande%aluated in the pre%ious stage#
$mplementation8
The final stage of prolem sol%ing is to implement the solution identified- either in modules of a
full implementation all at once# "fter Implementation the solution is tested to ensure full
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functionality# This stage also in%ol%es an ongoing maintenance of the information system after
full implementation#
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Pro$lem %olving %tages for Developing anInformation %ystem
9rolem sol%ing deals with how organi:ation inefficiencies and how they can e impro%ed to
increase output within a company y de%eloping an information system# 7%ery company already
has an information system- e%en if they don+t ha%e any computers or technological e?uipment
(manual information system)#An information system is a set of predefined procedures that determines
how data is passed within a company. The information system
determines how data is collected, processed and then presented.Technically- you might e upgrading rather than de%eloping# 7ither way the following fi%e stage
model is used to guide the de%elopment process of an information system#
2efinition of a pro+lem8
In order for someone to sol%e a prolem they must first know what the prolem is# efining the
prolem in%ol%es presenting a general o%er%iew of the situation y identifying all the rele%antentity and their processes#
"n entity can e representati%e of an indi%idual 4 customer- employee or department# " process is
a predefined procedure that is carried out y employees 4 departments# " process can also e%iewed as the relationship etween the entities#
The prolem definition should e'plain allrele%ant usiness operations to show how
information is collected- processed- and
dispensed within the company to highlight the
inefficiencies of the current system#
"ro+lem analysis8
"naly:ing the prolem is to further su=di%ision
of the entire prolem into smaller units to take a
closer look at the acti%ities within each entity ofthe within the usiness to ha%e a etter
understanding of the prolem# This should gi%e
you an idea of whatis eing done y eachdepartment 4 employee and how they are doing
it# The prolem usually lies in the how#
Generation and E(aluation of "ossi+le
Solutions8
In this stage all the possile solutions for the
prolem are identified and further e%aluated ased on their strengths- weaknesses andappropriateness# The rele%ant hardware- software and networking components will e e'amined
to determine there appropriateness#
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The ne't stage selection of solutionin%ol%es selecting the most appropriate solution from the
one identified and e%aluated in the pre%ious stage# The most appropriate hardware- software and
networking components will e selected for implementation#
The final stage of prolem sol%ing is to implement the solution identified- either in modules of a
full implementation all at once# "fter Implementation the solution is tested to ensure fullfunctionality# This stage also in%ol%es an ongoing maintenance of the information system after
full implementation#
$dentifying a pro+lem
Identifying an organi:ation with an information
system prolem can e an easy task if you know
what to look for# The prolem may e'ist in one of
three areas within the company* technology-organi:ation- or people# The prolems eing
e'perienced is not necessarily limited to one area-
it might e a comination of any two or all three
areas#
Technological prolems can arise as a result ofoutdated e?uipment- inappropriate networking- or
lack of technology within the company- a manual
information system# Inappropriate software as a
result of poor design or a comple' user interfacecan also e considered a technological prolem#
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$nformation Technology - Grade /0
Module / 1 $nformation Systems
2O%ME&TAT$O& OF $&FORMAT$O& SYSTEMSSe%eral tools are a%ailale for documenting the flow of information within an organi:ation- from
a simple descripti%e method to a diagrammatic model# &or e'ample- using short statements to list
the set of acti%ities to e performed within a department of an organi:ation is an e'ample of asimple descripti%e method#
2ata Flow 2iagrams 2F2s!
" data flow diagram- also known as &- is a graphical representation of the information flow
within a system# It is an e'ample of a diagrammatic model# " data flow diagram can also e used
for the %isuali:ation of data processing (structured design)# It is common practice for a designerto draw a conte't=le%el & first which shows the interaction etween the system and outside
entities# This conte't=le%el & is then Re'plodedR to show more detail of the system eingmodelled# /ith a dataflow diagram- users are ale to %isualise how the system will operate- what
the system will accomplish and how the system will e implemented# ld system dataflowdiagrams can e drawn up and compared with the new systems dataflow diagrams to draw
comparisons to implement a more efficient system# ataflow diagrams can e used to pro%ide
the end user with a physical idea of where the data they input- ultimately has an effect upon thestructure of the whole system from order to dispatch to restock how any system is de%eloped can
e determined through a dataflow diagram#
Types of 2F2
In analysing a usiness- se%eral sets of &s are drawn# Initial &s might model the e'isting
system (flaws and all)- while later &s may model a solution to the prolem eing analysed#&or these solution &s a logical and physical & is drawn# 9hysical &s represent physicalfiles and transactions- while logical or conceptual &s can e used to represent usiness
functions or processes#
%omponents of a 2F2
" data flow diagram illustrates the processes- data stores- and e'ternal entities in a usiness or
other system and the connecting data4resource flows#The four components of a data flow diagram (&) are*
7'ternal 7ntities (represented y a s?uare or o%al)
9rocesses (represented y a rounded rectangle)
ata Stores (represented y an open ended narrow rectangle) ata &lows (represented y an arrow)
,esource &lows
2ata Flow 2iagrams 1 2iagram &otation
There are only fi%e symols that are used in the drawing of usiness process diagrams (data flow
diagrams)# These are now e'plained- together with the rules that apply to them#
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This diagram represents a anking process- which maintains customer accounts# In this e'ample-customers can withdraw or deposit cash- re?uest information aout their account or update their
account details# The fi%e different symols used in this e'ample represent the full set of symols
re?uired to draw any usiness process diagram#
E)ternal Entities
"n e'ternal entity is a source (where the data comes from) or destination (where the data go) of a
data flow which is outside the system ut interacts with the system (e#g#- person- department ororganisation)# /hen modeling a &- the designer is not interested in the inner workings of the
e'ternal entity- ut only what data is produced4needed y the entity# The symol used to
represent an e'ternal entity is a s?uare or o%al#
Diagrams used to represent external entities
"rocess
" process shows a transformation or manipulation of data flows within the system#" process is a
manual or computeri:ed routine that changes data y performing a calculation- updatinginformation- sorting a list- and so on# There are two ways in which a process is represented- one
with a rounded rectangle- which is numered and laeled with a %er phase (e'cept for the
process numered 0- which gi%es the system+s name)# Two- with a rectangle that has three partsan identification numer- a location that appears to the right of the identifier which descries
where in the system the process takes place and a descripti%e title placed in the centre of the o'#
The process shows a part of the system that transforms inputs into outputs6 that is- it shows howone or more inputs are changed into outputs#
Diagrams used to represent a process
Student Customer
!
7nroll
student
,
,
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2ata Store
" data store is a holding place for information within the system# It is represented y an open
ended narrow rectangle# ata stores may e long=term files such as sales ledgers- or may eshort=term accumulations* for e'ample atches of documents that are waiting to e processed#
7ach data store should e gi%en a reference followed y an aritrary numer# It could represent
the data eing held manually or on a computer#
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"rocesses
/hen naming processes- a%oid glossing o%er them- without really understanding their role#
Indications that this has een done are the use of %ague terms in the descripti%e title area = like$process$ or $update$# The most important thing to rememer is that the description must e
meaningful to whoe%er will e using the diagram#
2ata Flows
oule headed arrows can e used (to show two=way flows) on all ut ottom le%el diagrams#
&urthermore- in common with most of the other symols used- a data flow at a particular le%el ofa diagram may e decomposed to multiple data flows at lower le%els#
2ata Stores
7ach store should e gi%en a reference letter- followed y an aritrary numer# These referenceletters are allocated as follows*
$$ = indicates a permanent computer file
$$ = indicates a manual file
$T$ = indicates a transient store- one that is deleted after processing#In order to a%oid comple' flows- the same data store may e drawn se%eral times on a diagram#
ultiple instances of the same data store are indicated y a doule %ertical ar on their left handedge#
Rules go(erning how the diagram components relate to each other
2ata Flows
&or data flows the rules are as follows*
ata flows and resource flows are allowed etween e'ternal entities and processes# ata flowsare also allowed etween different e'ternal entities# Howe%er- data flows and resource flows are
not allowed etween e'ternal entities and data stores#
"rocesses
&or processes the data flow rules are as follows*
ata flows and resource flows are allowed etween processes and e'ternal entities and etweenprocesses and data stores# They are also allowed etween different processes# In other words
processes can communicate with all other areas of the usiness process diagram#
2ata Stores
&or data stores the data flow rules are as follows*ata flows and resource flows are allowed etween data stores and processes# Howe%er- these
flows are not allowed etween data stores and e'ternal entities or etween one data store and
another# In practice this means that data stores cannot initiate a communication of information-they re?uire a process to do this#
2ata Flow 2iagrams 1 %onte)t 2iagrams #e(el J 2iagram!
The first step in constructing &s is to draw a conte't diagram# " conte't diagram is a top=le%el%iew of an information system that shows the system+s oundaries and scope# To draw a conte't
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diagram- you start y placing a single process symol in the centre of the page# The symol
represents the entire system- and you identify it as process 0# Then you place the entities around
the perimeter of the page and use data flows to connect the entities to the central process# Gou donot show any data stores in a conte't diagram ecause data stores are internal to the system# In
drawing the conte't diagram you should only e concerned with the most important information
flows#Remember that no data flow process diagram is the definitive solution - there is noabsolute right or wrong.
Data Flow Diagrams Context Diagrams
%onte)t 2iagram E)ample
The conte't diagram shown on this screen represents a ook lending lirary# The lirary recei%es
details of ooks- and orders ooks from one or more ook suppliers#
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The le%el 1 diagram shows the main functional areas of the system under in%estigation# "s with
the conte't diagram- any system under in%estigation should e represented y only one le%el 1diagram#
There is no formula that can e applied in deciding what is- and what is not- a le%el 1 process#3e%el 1 processes should descrie only the main functional areas of the system- and you should
a%oid the temptation of including lower le%el processes on this diagram# "s a general rule no
data flow diagram should contain more than 1! process o'es#
The le%el 1 diagram is surrounded y the outline of a process o' that represents the oundaries
of the system#
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.# /hat action is done to ill amount
5# /hat is ill amount
@# How many data stores are in the diagram
B# Name an e'ternal entity#
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E)ample of a 2ata Flow 2iagram
This data flow diagram represents a system used in a %ideo rental store#
ideo &ile1
ideo
emer
1
8et ideo
etails
1
Compute
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$nformation Technology - Grade /0
Module / 1 $nformation Systems
Opportunities arising from the use of information technology learning = disco%ering knowledge
Training M
7ntertainment
Communication
Career opportunity
$mpact of $nformation Technology
rganisational impact
automation
Introducing information Technology
Societal impact
Po skills
Po opportunity
,etraining
9ri%acy M mo%ie enemy of the state with will smith
Sur%eillance
Security
Commercial transaction 7ntertainment
Culture
7conomic opportunities
9olitics
7commerce
7=usiness
7=go%ernance
7=learning
7=surgery
7thical- legal and political consideration
Copyright
Intellectual and property
9roprietary data and software
9ropaganda
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