1. Components of Information Systems.pdf

Information System

1. CONCEPTS AND
COMPONENTS OF
INFORMATION SYSTEM

2. What is a system?
Asystemisdefinedasetofinterrelatedcomponents,witha
clearlydefinedboundary,workingtogethertoachievea
commonsetofobjectivesbyacceptinginputandproducing
outputs.
Ithasthreebasicfunctions:
INPUT
PROCESSING
OUTPUT

3. INPUT:involvescapturingandassemblingelementsthatenter
thesystemtobeprocessed.
Ex-raw materials, energy and data.
PROCESSING:involvestransformationprocessesthatconvert
inputintooutput.
Ex-manufacturing processes, mathematical calculation.
OUTPUT:involvestransferringelementsthathavebeen
producedbytransformationprocesstothereultimate
destination.
Ex-finished products, human services.

4. FEEDBACK AND
CONTROL
The system concept becomes more useful by including to
elements, feedback and control. A system with feedback and
control functions is called a cybernetic system.
FEEDBACK: is data about the performance about the system.
Ex-data about sale performance are feedback to sales manager.
CONTROL: involves monitoring and evaluating feedback to
determine whether a system is moving towards the
achievements of its goal.
It makes necessary adjustments to a system input and
processing components. Ex-a sales manager exercise control
when reassigning sales person to new sales territories

5. INFORMATION SYSTEM
Amodelthatexpressesafundamentalconceptualframework
forthemajorcomponentsandactivitiesiscalledITsystem.it
highlightedtherelationshipsamongthecomponentsand
activitiesofinformationsystem.Italsoprovidesaframework
thatemphasisconceptsthatcanbeappliedtoalltypesof
informationsystem.

6. INFORMATION SYSTEM
RESOURCE
PEOPLE
RESOURCES
NETWORK
RSOURCES
DATA
RESOURCES
SOFTWARE
RESOURCES
HARDWARE
RESOURCES

7. PEOPLE RESOURCE
Peoplearetheessentialingredientforthesuccessfuloperation
ofallinformationsystem.ItincludesendusersandIS
specialist.
ENDUSERSarepeoplewhouseaninformationsystemorthe
informationitproduces.Theycanbecustomers,salesperson
arefoundatalllevels.
ISSPECIALISTarepeoplewhodevelopandoperate
informationsystem.Itincludessystemanalysts,software
developersetc.

8. HARDWARE
RESOURCES
Itincludesallphysicaldevicesandmaterialusedin
informationprocessing.Itincludesnotonlymachines,suchas
computersbutalsoalldatamedia,i.e.tangibleobjectson
whichdataisrecorded.Ex-
COMPUTERSYSTEM:consistofcentralprocessingunits
containingmicroprocessorsandavarietyofinterconnected
devicessuchasprinters,scannersetc.
COMPUTER PERIPHERALS:aredevicessuchas
keyboard,electronicmousefortheinputofdataand
commands,avideoscreenorprintersfortheoutputofthe
information.

9. SOFTWARE RESOURCES
It includes all sets of information processing instructions. This
generic concept includes not only the sets of operating
instructions called programs which direct and control computer
hardware but also the set of information processing instruction
called procedure that people need.
Example:
System software
Application software
procedures

10. DATA RESOURCES
Thisconcepthasbeenbroadenedbymanagersandinformation
systemprofessionals.Theyrealizethedataconstitutevaluable
organizationalresources.Itresultedinvarietyofchangesin
modernorganization.Underthisdatacantakemanyforms
includingtraditionalnumericdatacomposedofnumbersetc.
Thedataresourcesofinformationsystemaretypically
organized,stored,accessedbyavarietyofdataresource
managementtechnologiesinto:
Data base that hold processed and organize data.
Knowledgebasesthatholdknowledgeinavarietyofforms
suchasfacts.

11. NETWORK RESOURCES
Itemphasizesthatcommunicationstechnologiesandnetworks
arefundamentalresourcecomponentsofallinformation
system.Itincludes:
CommunicationMedia-includestwistedpair
wire,microwave,cellularwirelesstechnologies.
NetworkInfrastructure-emphasizesthatmany
hardware,softwareanddatatechnologiesareneededto
supporttheoperationsanduseofcommunicationnetwork.
Ex-communication processors such as modems.

12. TYPES OF COMPUTER SYSTEMS
There are three categories of computer systems:
Microcomputer systems
Midrange systems
Mainframe systems

13. COMPUTER
HARDWARE

14. MICROCOMPUTER
SYSTEMS
Microcomputers are the most important category of computer
systems for both business people and consumers.
Microcomputers have become powerful networked
professional workstations for business professionals.
Examples: personal computers, networked
computers, technical workstations, information appliances.

15. MIDRANGE
COMPUTERS
Midrange systems are primarily are high-end network servers
that can handle the large scale processing of many business
applications.
Midrange systems first became popular as minicomputers for
scientific research, engineering analysis, instrumentation
systems, and industrial process monitoring and control.
Midrange systems are used as front-end servers to assist
mainframe computers in telecommunications processing and
network management.
Examples: network servers, minicomputers, web servers and
multiuser systems

16. MAINFRAME COMPUTER
SYSTEMS
Mainframe systems are large, fast and powerful computer
systems.
They have large primary storage capacity.
They handle the information processing needs of major
corporations and government agencies with high transaction
processing volumes or complex computational problems.
Examples: enterprise systems, super servers, and super
computers.

17. PERIPHERALS
Peripheralsisagenericnamegiventoallinput,outputand
secondarystoragedevicesthatareapartofacomputer
system.
Peripheralsdependondirectconnectionsor
telecommunicationslinktothecentralprocessingunitofa
computersystem.

18. INPUT TECHNOLOGIES
Input technologies now provide a more natural user interface
for computer systems you can enter the data directly & easily
into computer through pointing devices like electronic mice
and touch pads and with technologies like optical scanning
, handwriting recognition , voice recognition .

19. Pointing devices
Pointing devices are used for issuing commands , making
choices .
They include devices such as electronic mouse, trackball and
touch pads .
Electronic mouse: It is most popular device used to move the
cursor on the screen to issue commands and make selections .
Touch pads: It is a small rectangular touch sensitive surface
usually placed below the keyboard the cursor moves in
direction your fingers move on pad.

20. Pen based computing
Instead of using keyboard or clipboard you can use a pen to
make selections, send e-mails, draw or write.
Various pen devices are available such as digitizer pen and
graphics tablet.

21. Speech recognition systems
Speech recognition systems analyze and classify your speech
and sound patterns . Software compares your speech patterns
to a database of sound patterns and passes the recognized
words to your application software
Devices in workplace allow operators to perform data entry
without their hands on keys .

22. Optical scanning
Optical scanning devices read text or graphics and convert
them into digital input for your computer .
OCR (optical character recognition) is also a type of optical
scanning technology . OCR scanners can read characters and
codes on product labels, airline tickets etc

23. STORAGE TRADE-OFFS
Computer users depend on memory circuits and secondary
storage devices of computer systems to meet storage
requirements.
Progress in very-large-scale integration (VLSI), which packs
millions of memory circuit elements on tiny semi-conductor
memory chips, is responsible for continuing increases in main
memory capacity of computers.
High speed storage media cost more per byte and provide
lower capacities.
Large capacity storage media cost less per byte but are slower.
Primary storage circuits use RAM chips, which loose their
contents when electrical power is interrupted while secondary
storage devices provide a more permanent type of storage
media.

24. Computer storage fundamentals
Data are processed and stored in a computer system through
the presence or absence of electronic or magnetic signals in
the computer circuitry or in the media it uses.
This character is called two-state or binary representation of
data because the computer and media can exhibit only two
possible states or conditions, similar to a common light
switch: “on” or “off”.
The smallest element of data is called bit, which can have a
value of either zero or one.
The capacity of memory chips is usually expressed in terms of
bits.
A byte is a basic grouping of bits that the computer operates as
a single unit.
Storage capacities can be measured in
kilobytes, megabytes, gigabytes or terabytes.

25. There are four types of storage trade-offs-
oSemiconductor memory
oMagnetic disks
oOptical disks
oMagnetic tape

26. Direct and sequential access
Primary storage media such as semiconductor memory chips
are called direct access memory or random access memory.
Secondary storage media such as magnetic tape cartridges are
known as sequential access devices.
The concepts described by Direct and sequential access are as
follows-
An element of data or instructions can be directly stored and
retrieved by selecting and using any of the locations on
storage media.
Each storage position has a unique address and can be
individually accessed in approximately the same length of
time without having to search through other storage positions.

27. Semiconductor memory
The primary storage of a computer consists of microelectronic
semiconductor chips.
It provides with the working storage a computer needs to
process applications.
Attractions of semiconductor memory are-
oSmall size
oGreat speed
oShock resistance
oTemperature resistance

28. Two basic types of semiconductor memory are-
Random Access Memory(RAM): These memory chips are
most widely used primary storage medium. Each memory
position can be both sensed(read) and changed(written), so it
is called read/write memory. This is a volatile memory.
Read Only Memory(ROM): Non-volatile memory chips are
used for permanent storage; ROM can be read but not erased
or overwritten.

29. Magnetic disks
Magnetic disks are the most common form of secondary
storage for a computer system.
They provide fast access and high storage capacities at a
reasonable cost.
Data are recorded on tracks in the form of tiny magnetized
spots to form the binary digits of common computer codes.
Thousands of bytes can be recorded on each track, and there
are several hundred data tracks on each disk surface, thus
providing us with billions of storage positions for software
and data.

30. RAID storage
Redundant Arrays of Independent Disks(RAID) combine from
6 to more than 100 small hard disk drives and their control
microprocessors into a single unit.
RAID units provide large capacities with high access speeds
because data are accessed in parallel over multiple paths from
many disks.
They provide a fault-tolerant capacity, in which their
redundant design offers multiple copies of data on several
disks.
If one disk fails, data can be recovered from backup copies
automatically stored on other disks.

31. MAGNETIC TAPE
Tapestorageismovingbeyondbackup.Althoughdisk
subsystemsprovidethefastestresponsetimeformission-
critical;data,thesheeramountofdatathatusersneedto
accessthesedaysaspartofhugeenterpriseapplications,such
asdatawarehouse,requiresaffordable(magnetictape)
storage.
Ongrowingbusinessapplicationofmagnetictapeinvolves
theuseofhigh-speed36-trackmagnetictapecartridgesin
roboticautomateddriveassembliesthatcandirectlyaccess
hundredsofcartridges.
Othermajorapplicationsformagnetictapeincludelong-term
archivalstorageandbackupstorageforPCsandother
systems.

32. OPTICAL DISKS
Optical disk technology has become a necessity. Most
software companies now distribute their elephantine programs
o CD-ROMs.
It is a fast-growing type of storage media.
Examples :-CD-ROM, CD-RW, DVD, DVD-ROM etc.

33. Business Applications
One of the use of optical disks in mainframe and midrange
systems is in image processing, where long-term archival
storage of historical files of document images must be
maintained.
Interactive multimedia applications in
business, education, and entertainment area another major use
of optical disks.
Financial institutions, among others, are using optical
scanners to capture digitized document images and store them
on optical disks as an alternative to microfilm media.

34. RADIO FREQUENCY
IDENTIFICTAION
One of the newest and most rapidly growing storage
technologies is radio frequency identification [RFID] a system
for tagging and identifying mobile objects such as store
merchandise, postal packages, and sometimes even living
organisms.
Using special device called an RIFD reader, RFID allows
objects to be labeled and tracked as they move from place to
place.

35. RFID technology works using small pieces of hardware
called RFID chips. These chips feature an antenna to transmit
and receive radio signals. These are of 2 types passive and
active.
Passive chips do not have a power source and active chips
are self powered and do not need to be close to the reader to
transmit their signal.
The RIFD systems were created as an alternative to common
bar codes.

36. RFID Privacy Issues
The use of RFID technology has caused considerable
controversy and even product boycotts by consumer privacy
advocates who refer to RFID tags as spy chips.
The 2 main privacy concerns are:
1. Since the owner of an item will not necessarily be aware of
the presence of an RFID tag, and the tag can be read at a distance
without the knowledge of the individual, it becomes possible to
gather sensitive data about an individual without consent.
2. If a customer pays by a credit card, then it would be
possible to deduce the identity of the purchaser indirectly by
reading the globally unique ID of that item.

37. Enhancing Security using RFID
RFID presents the potential for enormous efficiencies and
cost savings.
It also presents significant challenges to privacy and security.
example-Chennai air port