module 2 info processing and pres study guide

8/10/2019 Module 2 Info Processing and Pres Study Guide

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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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!1

"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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!B

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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!D

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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.B


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.F


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.E

.# " 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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50

() 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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51

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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5.

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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5@

$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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5B

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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5D

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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5F

"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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@0

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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@1

.# /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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@5

$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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module 2 info processing and pres study guide

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