Master And Transaction file and more

File

• Files are a kind of container that is  used for storing the Data of the users for a Long time Period.
• Files can contain any type of information means they can Store the text, any Images or Pictures or any data in any Format.

In this post we are going to discuss following topic:-

1. Transaction File
2. Master File
3. Relationship between Master and Transaction file
4. Difference between Master and Transaction file
5. Reference file
6. Backup file
7. Report file
8. Sort file
9. Archive file

1. Transaction file

• The data stored in these files are temporary by nature, the data in transaction files is used to update the master files.

• This file contains data, only for period of time and after that send to the master file and it is like a journal used in Account Management System.

• Any modification in data is done in transaction file and Transaction files are only used in 
  Batch Processing Systems.

• Once updating has been carried out, the transaction file may be kept in order to permit subsequent 
  recovery of the master file or for auditing purposes but is otherwise redundant

     Example: price of the products, customers order for the products, inserting new data to the database etc.

2. Master file

• The data stored in these files are permanent by nature. It is just like a Ledger used in Account Management.

• The master file contains all the data of the database (account number, address, bank balance, overdraft limit...).

•  It is updated only through recent transactions using Batch Processing System and Master file stores large amount of data.

Example: customer ledgers, student database, employee data of a company.

3. Relationship Between Master and Transaction File

In the above figure, we can see when old master file is merged with recent transaction file and process the both file using batch processing method than new updated master file is generated which contains up- to- date information.

Master file is updated periodically with latest Transaction file.

4. Difference between Master and Transaction file

5. Reference file

• A reference file is mainly used for reference or look-up purposes. Look-up information is that information that is stored in a separate file but is required during processing.

•  For example, in a point of sale terminal, the item code entered either manually or using a barcode reader looks up the item description and price from a reference file stored on a storage device.

6. Backup file

• A backup files is used to hold copies (backups) of data or information from the computers fixed storage (hard disk).

• Since a file held on the hard disk may be corrupted, lost or changed accidentally, it is necessary to keep copies of the recently updated files. In case of the hard disk failure, a backup file can be used to reconstruct the original file.

7. Report file

• Used to store relatively permanent records extracted from the master file or generated after processing.

•  For example you may obtain a stock levels report generated from an inventory system while a copy of the report will be stored in the report file.

8. Sort file

• It stores data which is arranged in a particular order.

• Used mainly where data is to be processed sequentially. In sequential processing, data or records are first sorted and held on a magnetic tape before updating the master file.

 9. Archive file

• An archive file is a file that is composed of one or more computer files along with metadata.

• Archive files are used to collect multiple data files together into a single file for easier portability and storage, or simply to compress files to use less storage space.

To read various file organisation technique Click Here

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File organization, their purpose and various file organization method

 In today post  we are going to discuss following topic:

1. File Meaning
2. File Organization 
3. File Organization Objective
4. File Organisation Technique/ Method 
5. And their pros and cons

File

• Files are a kind of container that is  used for storing the Data of the users for a Long time Period.
• Files can contain any type of information means they can Store the text, any Images or Pictures or any data in any Format.
• So that there must be Some Mechanism those are used for Storing the information, Accessing the information and also Performing Some Operations on the files.

File Organization

• File organization is a way of organizing the data or records in a file.
• It does not refer to how files are organized in folders, but how the contents of a file are added and accessed.
• File organization is very important because it determines the methods of access, efficiency, flexibility and storage devices to use.

File organization objective

Storing the files in certain order is called file organization. The main objective of file organization is

• Optimal selection of records i.e.; records should be accessed as fast as possible.
• Any insert, update or delete transaction on records should be easy, quick and should not harm other records.
• No duplicate records should be induced as a result of insert, update or delete
• Records should be stored efficiently so that cost of storage is minimal.

 File organization technique

There are Various methods of organizing files on a storage media. Some of them are:

• Sequential,
• Random,
• Serial and
• Indexed-sequential
• Heap
• Hash Clustered

1. Sequential file organization

• Records are stored and accessed in a particular order sorted using a key field.
• Retrieval requires searching sequentially through the entire file record by record to the end.
• Because the record in a file are sorted in a particular order, better file searching methods like the binary search technique can be used to reduce the time used for searching a file .
• For example, of the file has records with key fields 20, 30, 40, 50, 60 and the computer is searching for a record with key field 50, it starts at 40 upwards in its search, ignoring the first half of the set.

Pros of sequential file organization

• The sorting makes it easy to access records.
• The binary chop technique can be used to reduce record search time by as much as half the time taken.

Cons of sequential file organization

• The sorting does not remove the need to access other records as the search looks for particular records.
• Sequential records cannot support modern technologies that require fast access to stored records.
• The requirement that all records be of the same size is sometimes difficult to enforce.

2. Random or direct file organization

• Records are stored randomly but accessed directly.
• To access a file stored randomly, a record key is used to determine where a record is stored on the storage media.
• Magnetic and optical disks allow data to be stored and accessed randomly.

Pros of random file access

• Quick retrieval of records.
• The records can be of different sizes.

3. Serial file organization

• Records in a file are stored and accessed one after another.
• The records are not stored in any way on the storage medium this type of organization is mainly used on magnetic tapes.

Pros of serial file organization

• It is simple
• It is cheap

Cons of serial file organization

• It is cumbersome to access because you have to access all proceeding records before retrieving the one being searched.
• Wastage of space on medium in form of inter-record gap.
• It cannot support modern high speed requirements for quick record access.

4. Indexed-sequential file organization method

• Almost similar to sequential method only that, an index is used to enable the computer to locate individual records on the storage media. 
• For example, on a magnetic drum, records are stored sequential on the tracks. However, each record is assigned an index that can be used to access it directly.

5.Heap File Organization

•  When a file is created using Heap File Organization mechanism, the Operating Systems allocates memory area to that file without any further accounting details.
• File records can be placed anywhere in that memory area. It is the responsibility of software to manage the records. Heap File does not support any ordering, sequencing or indexing on its own.

Pros of Heap storage

Heap is a good storage structure in the following situations:

• When data is being bulk-loaded into the relation.
• The relation is only a few pages long. In this case, the time to locate any tuple is Short, even if the entire relation has been searched serially.
• When every tuple in the relation has to be retrieved (in any order) every time the relation is accessed. For example, retrieve the name of all the students.

Cons of Heap storage

Heap files are inappropriate when only selected tuples of a relation are to be accessed.

 6. Hash File Organization

• This mechanism uses a Hash function computation on some field of the records. As we know, that file is a collection of records, which has to be mapped on some block of the disk space allocated to it. 
• This mapping is defined that the hash computation. The output of hash determines the location of disk block where the records may exist.

Pros of Hash file organization

Hash is a good storage structure in the following situations:

• When tuples are retrieve based on an exact match on the hash field value, particularly if the access order is random.
•  For example, if the STUDENT relation is hashed on Name then retrieval of the tuple with Name equal to "Rahat Bhatia" is efficient.

Cons of Hash file organization

Hash is not a good storage structure in the following situations:

• When tuples are retrieved based on a range of values for the hash field. For example, retrieve all students whose name begins with the "R".

7. Clustered File Organization

• Clustered file organization is not considered good for large databases. In this mechanism, related records from one or more relations are kept in a same disk block, that is, the ordering of records is not based on primary key or search key. 
• This organization helps to retrieve data easily based on particular join condition. Other than particular join condition, on which data is stored, all queries become more expensive.

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Intranet,Its Working and Business Value

Hello friends, we are here again with new topic that is Intranet. You will definitely find question regarding Intranet its working, Business Value and Application of Intranet or may be related to Extranet in your BCA/BSC-IT semester exam. So examination point of view this topic is very important.

          Lets begin with Intranet, the road map of today's topic is as follow:-

1. Introduction
2. Working of Intranet
3. Application of Intranet
4. Advantages of Intranet
5. Disadvantages of Intranet
6. Difference Between Internet & Intranet

1.Intranet

Intranet is composed of two words Intra and net where Intra means within the organisation and net means Network. Intranet is a smaller private version of Internet can also say mini-Internet.Moreover we can define Intranet as:

• Intranet is defined as private network of computers within an organization with its own server and firewall. 

• Intranet is system in which multiple PCs are networked to be connected to each other. PCs in intranet are not available to the world outside of the intranet.

• Usually each company or organization has their own Intranet network and members/employees of that company can access the computers in their intranet.

• Each computer in Intranet is also identified by a IP Address, which is unique among the computers in that Intranet.

2.Working of Intranet

Just like user access the information on internet, The employees of the company can access the information from the company's intranet web server using a web browser. This Web server is connected to the company's Local Area Network(LAN).The working of Intranet is as follow:-

• When an employees of a company needs to access company information then he sends a request to web server using web browser.
• The web server retrieves the appropriate web page and send it to the employee's web browser and content is displayed on the employee screen.
• Employee of the company can also access the Internet from the company's Intranet by using a firewall.

3.Application of Intranet/ Business Value

Intranet applications are same as that of Internet applications. Intranet applications are also accessed through a web browser. The only difference is that, Intranet applications reside on local server while Internet applications reside on remote server. Here, we've discussed some of these applications:

Interactive communication Application

Like on internet, we have e-mail and chat like applications for Intranet, hence offering an interactive communication among employees.

Support for Internet Application

Intranet offers an environment to deploy and test applications before placing them on Internet.

Research and development

It is used by the research and development team to provide information related to the project schedule, post technical specification, get feedback from the sales staff etc.

Sales and marketing Application

sales and marketing staff requires up-to date and accurate information about the product and services which is very crucial in today's competitive environment.

Accounting Application

Intranet can help the finance department to post their objective to staff  all around the world. The company's stock prices, current status which can be viewed by various employee and associated customer.

4.Advantages of Intranet

Intranet is very efficient and reliable network system for any organization. It is beneficial in every aspect such as collaboration, cost-effectiveness, security, productivity and much more.

Effective Communication

Intranet offers easy and cheap communication within an organization. Employees can communicate using chat, e-mail or blogs.

Time Saving

Information on Intranet is shared in real time.

Collaboration

Information is distributed among the employees as according to requirement and it can be accessed by the authorized users, resulting in enhanced teamwork.

Platform Independency

Intranet can connect computers and other devices with different architecture.

Cost Effective

Employees can see the data and other documents using browser rather than printing them and distributing duplicate copies among the employees, which certainly decreases the cost.

Workforce Productivity

Data is available at every time and can be accessed using company workstation. This helps the employees work faster.

Business Management

It is also possible to deploy applications that support business operations.

Security

Since information shared on intranet can only be accessed within an organization, therefore there is almost no chance of being theft.

Specific Users

Intranet targets only specific users within an organization therefore, once can exactly know whom he is interacting.

Immediate Updates

Any changes made to information are reflected immediately to all the users.

5.Disadvantages of Intranet

1. Management Concern

• Loss of control 
• Hidden complexity 
• potentional for chaos

2. Security Concern

• unauthorized of services
• denial of services
• packet sniffing

Difference between Internet and Intranet

                           so friends this is all about Intranet.In the next post we will learn about Extranet. Don't forget to leave your comment.

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How Search Engine Works

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Search Engine, Its Working and Types-II

Hi and Welcome back  friends in TechMania. In the last Post we had learn about Search Engine their Architecture, Working and about Web Crawler if you miss that kindly read the Search Engine, Its Working and Types-I  for more clearance of this post . Today we'll continue with last topic that is Search Engine, Its Working and Types-II. In this we are going to learn .......................

• Types of search engine
• Web directory 
• Difference between search engine and web directory
• Market share of various search engine
• Play with Google

Types of search engine

Different blogger catogerize the on various basis but on the their working Search Engine Mainly classify into four category that is mention below:-

1. Crawler based search engine
2.  Meta search engine 
3.  Hybrid search engine
4.  Web directories

1. Crawler based search engine

• Crawler based search engine work with the help of web spider.
• Web spider searches a webpage, download it and analysis the information presented on the webpage and add to the search engine database
• Crawler based search engines are constantly search the internet for new webpage and updating their database
•   Example:- Google , Ask Jeeves, Aliweb, Baidu etc. 

Crawler Based Search Engine

2.Meta Search Engine 

• Take the result from other search engines and web directories like Google, MSN, Lycos etc.
• User can send one request simultaneously to multiple search engine without user intervention
• Meta search receives various result from different search engine and try to extract the most relevant hits
• Example:-Meta crawler, Dogpile, Fazzle, Bighub, kartoo, Infogrid, IceRocket etc.  

3.Web Directories

• Highly structured way of searching information on the WWW.
• Information is organised in hierarchical tree structure .
• Web directory may be organised by alphabetically or topically.
• Also known as indexes or catalogues.
• Web Directories are managed in search engine by directory staff.
• Some directory are paid while other are free.
• Goggle, Yahoo, Looksmart, Zeal, Galaxy, Index,  Apollo, Gimpsy, Excite etc. are the search engine that maintain web directory.

Difference Between Search Engine And Web Directories

4.Hybrid Search Engine

• Hybrid search engine is combination of crawler based search engine and web directory
• Result of the hybrid search engine is shown by the combination of both result
• Example:- yahoo and Bing  

Page Ranking criteria

Different search engine have different ranking criteria of web page. Their ranking criteria can be based on ...........

• Frequency of searched keyword in webpage.
• Number of links(internal or external link).
• Location of keyword either in title or page description.
• Number of clicks on particular webpage.

Market share of various search engine

In the below the market share of various search engine is given below of year 2013 and 2014. After the Google, Baidu search engine have more market share.

Note: Baidu is the China's most used search engine/Browser. In China Google is banned.

Play with Google

To know how play with google play see video!!!!!!!!!!!!!!!!!!!

So friends this is all about search engine how was this topic kindly post your comments so that I'll make more better if you want to know about any specific topic please sent topic name I'll post article on that topic in simple words.I will wait for your comments and reviews.

Good Bye and Have a Nice Day!!!!!!!!!!!!!!

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Search Engine, Its Working and Types-I

Hello friends we again here with a new and interesting topic i.e Search Engine. In many universities exam there is questions about Search Engine like What is search Engine their types Types,How Search Engine works and so many things. In Internet Application subject or Networking Exam you usually find question regarding search engine.

Apart from this we usually use Google as searching application but do we know how it works. So today's post we'll  try to explore the answer of following question:-

1. Definition of search engine
2. History of search engine
3. Working
4. Web crawler

Definition of Search Engine

• Search engine is software system designed to search information on www.
• Search engine consists of server and collection of a server.
• Server stores the link of various internet resources like webpages, images, programs etc.
• Works with the help of web crawler. 

History of Search Engine 

Here brief history regarding search engine is displayed.you can know more about it through google.

• Wandex is first search engine developed in 1993 by Matthew Gray
• In 1993 martin Koster created Aliweb search engine and still in use
• Lycos is first commercial engine started at Carnegie Mellon University as research project in 1994
• After that  Web crawler, Hotbot, Excite infoseek, inktomi, Northern light and AltaVista etc. introduce.
• In 1998 goggle is introduced by Larry Page & Sergey Brin.

Previously Used Search Engine

In the below picture three different previously search engine is shown i.e Wandex, Lycos and Archie Query Form but now days Google is considered as Knowledge hub.

Working of Search Engine

• Search Engine looks for the keyword in the index from the already constructed database 
• Then web crawler visit link to link where keyword exist and pass to database
• After completion of search database returns list of result that include URL, title of page, few lines of description

For more clearence see the following video 

I hope now you would know about search engine working and their architecture clearly.

Web Crawler

• Web crawler is a software that gathers the information in database
• It is also known as web spider /  web ant / robots or bots
• It travels across the www by following  the several links
• Pass this  engine’s indexing software

For more details regarding search engine must read our next post Search Engine, Its Working and Types-II that contain some more interesting fact and information.

Good Bye & Have a Nice Day!!!!!!!!!!!!

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Folder Which We Can't Create-II

Hello Friends, today we will continue with the last post "Folder Which We Can't Create-I". In the last post we are trying to create folder with specific word but we are unable to create that.In this post we will explore the following questions:-

• Why we can't create them
• How to create folder of that name
• How we are able to create them
• How we can delete them

So lets begin with the today's topic and try to find out the answer of above question.

Reason Why we can't create them

The reason behind that con, lpt1.......lpt9, prn, clock$, com1 etc. are the reserve words used  by DOS. These words have different definition for different devices.some of them are given below:-

                             con                 console keyboard and display devices

                             prn                  system list device for parallel port devices

                             aux                  for auxiliary Devices

                             nul                   for emplty or bit bucket device

                             com1               first serial communicator port

                             com2               second serial communicator port

                             lpt1                  first parallel printer port

                             lpt2                  Second  parallel printer port and so on.......

so if u r allowed to create such folders, there will be an ambiguity in where to write data when the data is supposed to go to the specified devices. In other words, if i want to print something, internally what windows does is — it will write the data to the folder prn (virtually u can call it a folder, i mean prn, con, etc are virtual folders in device level). So if we are able to create con folder, windows will get confused where to write the data, to virtual con folder or real one.

How can create folder of that name

After reading the above content now you would understand why folder of those name not created.But as we listen Nothing is Impossible so we can also create folder with all those name with some trick and also see how we are able to create folder with those name.

                             Lets begin and see how can we create folder with name con. we are going to do this using command prompt.

Steps to create folder with name con

1. Click start button and type cmd or command prompt.

2. After opening command prompt type following command 

                            md \\.\C:\CON

3. Now open my computer and browse the path where you created folder.

Yeah!!!!!!!!!!!!! you have created the folder named con

How we are to create it

• It just is because of UNC (universal naming convention) path. 
• UNC specifies a common syntax to describe the location of  a network resource such as a shared file, directory or printer.
• These convention didn`t exist under pure Dos.
• Syntax of UNC  \\Remote host\sharefolder\resource

How to Delete it

Try delete the folder con from the computer 

Oops…………..

You can`t delete it and see following image:-

To delete it write following command in command prompt  C:>rd\\.\c:\con

Some shortcut method to create con folder

Method1:-

               Press ALT+9999

 Metho2:-

               Press ALT+255 

Method3:-

                Press ALT+0160 

                 So friends this is all about con folder. I hope you'll understand this topic. If have any queries and suggestion regarding this you can comment.I'll eagerly waiting for your comment. we will meet with new interesting topic next time.

Good Bye and Have a Nice Day!!!!!!!!!!!!!!!!!!!!!

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