Archive for the ‘Uncategorized’ Category

COMPILER

February 28, 2008

THE FIRST COMPILERA Compiler is a computer program (or a set of programs) that translates text written in a computer language (the source language) into another language (the target language). The original sequence is usually called the source code and the output called the object code. Commonly the output has a form suitable for processing by other programs, but it may be human – readable text files.Towards the end of the 1950’s, machine-independent programming languages were first proposed. Subsequently, several experimental compiler were developed. The first compiler was written by Grace Hopper, in 1952, for the A-0 programming language. The FORTRAN team led by John Backus at IBM is generally credited as having introduced the first compiler, in 1957.COBOL was an early language to be compiled on multiple architectures, in 1960.Early compilers were written in assembly language. The first self-hosting compiler which was capable of compiling its own source code in high- level language was created for Lisp by Hart and Levin at MIT in 1962. Since the 1970s it has become common practice to implement a compiler in the language it compiles, although both Pascal and C have been popular choices for implementation language. Building a self-hosting compiler is a bootstrapping problem- the first such compiler for a language must be compiled either by a compiler written in a different language, or (as in Hart and Levin’s Lisp compiler) compiled by running the compiler in an interpreter.

NORMALIZATION

February 12, 2008

Name
emial_id
phone_no
late_fine_outstanding
book_isbn                  
library_catalog_no  
book_title
book_author
book_price
quality_of_book
no_of_copies
issue_date
return_date

UNNORMALISED                                                                                                                                                                                        

 

       

NORMALISED                                                                                            

STUDENT            

roll_no                           PK
name
emial_id
phone_no
late_fine_outstanding

                                                                                                                                                                                                                                                                                                                                  

     

                                    

ISSUE_DETAILS

issue_id                             PK
roll_no                               FK
library_catalog_no        FK
issue_date
return_date

 

 

 

 

 

 

 

 

 

 

 

BOOK

book_isbn                     PK
library_catalog_no    FK
book_author
book_title
book_title
BOOK_LIST
library_catalog_no        PK
quality_of_book
no_of_copies

                                                                               

System Architecture

February 4, 2008

Well, it was evening when after my tea I sat to complete my S.E Assignment , one of my friend who missed her 1st S.E class came to me and asked me to explain her what was taught in the class. Teaching I.T was one of the most difficult tasks I have ever faced but I tried…….

Me: Okay, let me explain you what System Engineering is?

Friend: Ya……. Definition 1st.

Me: Well, Let’s break it into System and Engineering. Systems (from Latin syastema), is a set of interdependent entities, real or abstract forming an integrated whole. Engineering is the discipline of acquiring and applying scientific and technical knowledge to the design, analysis and for construction of works for practical purpose. Systems engineering can be thus defined as applying technological knowledge to your system to run the system fast and efficiently to fulfill your purpose.

Friend: That’s quite clear…….. could you explain me the slides…….

Me: Sure………. See……… Just as Computer Science has two components i.e. Data structure which describes what is to be processed and Algorithms specifies how it is to be processed. On a similar note, Information System Engineering has two Components database and applications having the same purpose. But one important point is that data and application should be distinct from eachother i.e. they should be kept separately.

Friend: okay……… what are the different types of architecture?

 Me: well, there are various types. The single tier system, in which all the data and the application(includes processing and presentation) are on a single machine/server. The two tier system where data is stored in a server using Oracle, mySQL, SQL Server or DB2. The application comprising business logic and presentation logic is stored on individual machines and The LAN connects client machines to the server using TCP/IP protocols. In a three tier system, along with data now Business logic is also kept centrally so that changes can be done at one location and the presentation logic is kept locally In a multi tier system, the end-user’s browser communicates with Web. All the presentation logic occurs on standard server.

Friend: ok…… but if I am making my data web enabled than intruders may comeup…. So do we need a firewall protector?

Me: Obviously, and that’s what there is in the next slide.

Friend: hmm…… And how are the complexities managed in this system???

Me: Ya……… the 1st one is the RDBMS i.e. Relational Data Base Management System which leads to no duplication and inconsistency of data across location or time periods and it is even easier to manage. And the 2nd is the implementation of an Integrated ERP System which is faster and easier to manage and maintain. Moreover there is no separate activity required to synchronise data and it can be purchased as a single package from an established vendor.

Friend: ok……… and how is the development of Application System done?

Me: The Database Design and Development is based the Relational Model using oracle, SQL Server, MySQL or ZOHO whereas the Application Design and Development is done using Java / C++, Visual Basic, Ruby-on-Rails or Zoho.

Friend: Thanks dear…….. It is now really clear.

Me: It’s ok. Now complete your assignment and lets watch a movie……

Friend: Sure…… byee

 Me: byeee

Hello world!

February 4, 2008

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