Model Answer Paper & Scheme of Valuation

Model Paper

Model Paper - II

Scheme of Valuation

Scheme of Valuation - II

Info.and DataBase System - 10.9 - 10.12

Sequential or Serial File Organization
i)Data records are arranged one after another.
ii)Records are arranged and accessed in a predetermined order of their keys.
iii)Definite relationship between logical and its physical organization.
iv)Magnetic tape is the storage medium.
v)Linear search algorithm can be used to access the records.

Advantages :
i)Continuous and simple.
ii)Can be used for data processing.
iii)Record key can be used to access the data.
iv)Cheaper storage medium(Magnetic tapes)
v)Localized errors.

Disadvantages :
i)Doesn't suit for random file organization.
ii)Cannot be for low activity rate.
iii)Possible only with batched and sorted data.
iv)High data redundancy.

Direct or Random File Organization
i)Data records are placed in a random order.
ii)Related records are separated physically.
iii)Magnetic disk is the storage medium.
iv)Hashing  algorithm can be used to access the records.
v)Hashing function generates a physical storage address for a particular record key.
vi)Conflict resolution technique solve the conflicts.

Advantages :
i)Saving Storage space - no index is used.
ii)Fast access - mapping exists between record key and its physical location.
iii)Saving time - no sorting for add,delete,update.
iv)Flexibility - Both sequential and non-sequential arrangement.
v)Effective online processing.

Disadvantages :
i)Detailed programming
ii)Less efficient in the usage of storage space.
iii)Difficult file update.
iv)Costlier storage medium(magnetic disk)
v)can be implemented only with direct access devices.

Indexed Sequential Access Organization
i)Combine the features of serial and direct file organizations.
ii)Data records storage are random and their access is sequential.
iii)Can also be called as ISAM(indexed sequential access method).
iv)Has main file storage and an index table.
v)Binary search algorithm is used to access the records.

Advantages :
i)combines sequential and direct access.
ii)Suit for the files which has both sequential and direct access.
iii)Quick access is possible with high activity ratio , large no.of records , arranged index table.

Disadvantages : 
i)Expensive special software and hardware.
ii)Extra processing time for index.
iii)Extra storage for insertion.
iv)Slow retrieval when compared to random access.

10.12 INTRODUCTION TO DBMS :

              Definition : Management , maintenance and retrieval operations of data in a database.

Advantages :

1.      Less Data Redundancy –

i)With a centralized data base , various programs can access data in different data files.

ii)Need not be duplicated.

2.      Data Consistency

i)Complicated operations will be avoided.

3.      Data   Integration

 i)With a centralized data base , easy integration with minimum programs.

4.      Data Sharing

 i)With a centralized data base  , data can be shared across the application.

5.      Enforcement  of standards

 i)Easy because of single set programs.

6.      Application Development Ease

i)Easy because the developer need not consider about concurrent access , integrity , security.

7.      Better Controls

i)Because of centralized data base.

8.      Data Independence

         i)Three level architecture.(internal, conceptual, external).

ii)Operations at one level doesn't affect other levels.

9.  Reduced maintenance

i)Easy because of centralized data base.

Info.and DataBase System - 10.9 - 10.11

On-line System :
 Processing of individual transaction from their origin.

Functions:
i)Separate functions can be integrated.
ii)Information can be centralized.
iii)Information can be collected from remote sites.
iv)Computing facilities can be shared.

Examples:
Banking,Stock Exchange,Stock Control

Advantages:
i)Paper Reduction
ii)Complex task elimination.

Distributed Data Processing System
 Decentralization of computer system through multiple computers.

Applications:
i)Reservation system / Sales order.
ii)Process control application.
iii)Printing of Invoice bills.

Advantages:
i)Independent System.
ii)Reduces the load on the host / client computer.
iii)Reduction of data process delay.
iv)Less risk of system break-down.

Disadvantages:
i)Data movement is more and so the complexity increases.
ii)Increased cost for the use of many hardware components.

Files
 Basic unit of storage in a computer.

Types :
Master File---- ---->Permanent by nature.
     Example : Customer ledger , Purchase ledger.
Transaction File--->Temporary by nature.
     Example : Customer Order , Purchase Order.

File Organization :
   Organizing data into records,blocks and access structure.

General Types :
Logical Organization - i)Organized by OS on secondary storage medium.
                                    ii)Depends on type of storage.
Physical Organization-i)Organized by application program.
                                     ii)Depends on type of information.


Types :
i)Sequential or Serial.
ii)Direct or Random.
iii)Indexed.

Info.and DataBase System - 10.1 - 10.9

                                                                 CHAPTER-10

INFORMATION SYSTEM AND DATABASE SYSTEM

Data: Collection of facts which can be  processed to produce information.

Information: Processed data with definite meaning.

                      Represent  facts or statistics, which have proper meaning.

10.2 TYPES OF INFORMATION:

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	STRATEGIC	TACTICAL	OPERATIONAL
DURATION	Long	Short	Day-to-day policies
PURPOSE	Decision to expand  business/not	Decision to run business  efficiently	Stock details/unpaid bill details
OBTAINABLE	Difficult	Easy through day to day	Easy through clerical processing
VOLUME	Less	More	More than tactical
HANDLING PERSON	CEO	Middle level manager	Line manager

IV. Statutory information: Reports which are required by law to be sent to government authorities. It requires straightforward processing of data.

10.5 QUALITIES OF INFORMAITON

QUALITY	How to ensure quality?
Accurate	Ensure correct input and processing rules
complete	Include all data
Trustworthy	Do not hide unpleasant information
Timely	Give at the right time
UP-to-date	include  all  data up to the present time
Relevant	understand  the  user  needs
Brief	summarize relevant information
significance/understandable	use attractive format and  graphical charts

10.6 Data   processing:  A series of actions  that converts data into  useful information.

Data Processing system: A system which includes the resources such as people, procedure, devices and  producing  desirable output with a process.

10.7 DATA PROCESSING CYCLE AND FUNCTIONS:

            1.Data collection:

a)      Data required for an organization may be available at various places.

b)      The source may include documents such as invoices, sales  orders and purchase orders.

2. Data Input: Data Input  to the data processing system.

            3. Data Process:

1.      Classification

2.      Sorting

3.      Verification

4.      Calculation

5.      Summarization

            4. Data storage :

1)      Stored data can be used in future.

2)      Storage can be on devices such as floppy disk, hard disk, magnetic tape and print out copies.

5.Data output : i)Helps in proper decision making and in the generation of more information.

                           ii)The output of data processing system is in the form of a report.

10.8 Types of Data Processing

Manual Data Processing

i)Tasks are executed by humans.

ii)Pre-processed data can be stored on papers.

iii)Processed data can be stored in the form of reports and files.

iv)Brain acts as a control, logical and storage  unit.

v)Disadvantages are slow system and data storage in papers because of large volume of data.

Electronic Data Processing

i)Data Processing speed increased.

ii)Processed data are accurate.

iii)To process the repeated and complex tasks , no tiresome.

DIFFERENCE BETWEEN MANUAL DATA PROCESSING AND ELECTRONIC DATA PROCESSING

MANUAL DATA PROCESSING	ELECTRONIC DATA PROCESSING
1. Large amount of paper.	No paper
2. Limited speed and accuracy	High-speed and greater accuracy
3. Limited data process and storage.	Large volume of data process and storage.
4.Cost of processing is high	Cost of processing is low.
5.Repeated tasks reduce the efficiency	Doesn't Reduce.

10.9TYPES OF DATA PROCESSING SYSTEM:

1.      Batch processing systems

2.       Real time systems

3.      On-line systems

4.       Distributed data systems

BATCH PROCESSING SYSTEM:

Definition: Data collected in batches, and the results obtained periodically

Applications :

a)      Payroll

b)      Financial accounting.

c)      Budget management

d)      Production planning  and control  

e)      Periodic sales analysis

          Advantages :

1.       Large volumes of data can be processed efficiently because of no interventions.

2.      Speed of data processing is determined by the speed of the computer in use and not by the speed of the operator.

Disadvantages of batch processing systems are:

1.      Increased turn-around time because of wait in line at each step

2.      Difficult to provide the desired priority scheduling.

Real time systems:

Definition: Responds to events before the events become obsolete.

            Applications:

1.      Banking systems.

2.      Air and ground traffic control

3.      Automatic radar connected defense systems.

           Advantages:

1.      Detection and correction of input errors

2.      Immediate error messages.

3.      Help-Messages to correct errors

4.      Available Source documents during errors.

Disadvantages :

1.Direct access devices have to be used.

2.Elaborate controls and backup procedures.

3.Input errors may damage the file.

            4.Difficult control checks.