Computer

Thursday, December 15, 2011

EDVAC :- It was invented in 1947 A.D. by

John Von Neuman.

EDSAC :- It was invented in 1941 A.D. by

Prof. M.V. Wilkes.

UNIVAC – I :- It was invented in 1951 A.D. by Univac.

ELECTRO - MECHANICAL CALCULATING DEVICE

Mark - I :- It was invented in 1943 A.D. by Howard Aiken.

ABC :- It was invented in 1942 A.D. by Dr. John Atnasoff.

ENIAC :- It was invented in 1946 Dr. John W.. Mauchly &

J. Presper Eckert.

MECHANICAL CALCULATING DEVICE

Abacus :- It was invented in 3000 B.C. It was used

for calculating.

Napier’s Bone :- It was invented in 1614 A.D. by

John Napier.

Pascaline :- It was invented in 1642 A.D. by

Blaise Pascal.

Stepped Recknor :- It was invented in 1671 A.D. by

Gott Fried Wilhelm von Leibniz.

Jackquard’s Loom :- It was invented in 1802 A.D. by

Joseph Marie Jackquard.

Difference Engine :- It was invented in 1822 A.D. by

Charles Babbage.

Analytical Engine :- It was invented in 1833 A.D. by

Charles Babbage.

Hollarith’s Tabulator :- It was invented in 1877 A.D. by

Hollarith’s Tabulator.

Wednesday, June 15, 2011

A relational database management system (RDBMS) is a database management system (DBMS) that is based on the relational model as introduced by E. F. Codd. Most popular commercial and open source databases currently in use are based on the relational database model.
A short definition of an RDBMS is: a DBMS in which data is stored in tables and the relationships among the data are also stored in tables. The data can be accessed or reassembled in many different ways without having to change the table forms.

DBMS

A Database Management System (DBMS) is a software package with computer programs that control the creation, maintenance, and the use of a database. It allows organizations to conveniently develop databases for various applications by database administrators (DBAs) and other specialists. A database is an integrated collection of data records, files, and other database objects needed by an application. A DBMS allows different user application programs to concurrently access the same database. DBMSs may use a variety of database models, such as the relational model or object model, to conveniently describe and support applications. It typically supports query languages, which are in fact high-level programming languages, dedicated database languages that considerably simplify writing database application programs. Database languages also simplify the database organization as well as retrieving and presenting information from it. A DBMS provides facilities for controlling data access, enforcing data integrity, managing concurrency control, recovering the database after failures and restoring it from backup files, as well as maintaining database security.

Monday, June 13, 2011

QBASIC (Quick BASIC)

QBasic is an IDE and interpreter for a variant of the BASIC programming language which is based on QuickBASIC. Code entered into the IDE is compiled to an intermediate form, and this intermediate form is immediately interpreted on demand within the IDE .It can run under nearly all versions of DOS and Windows, or through DOSBox/DOSEMU, on Linux and FreeBSD.For its time, QBasic provided a state-of-the-art IDE, including a debugger with features such as on-the-fly expression evaluation and code modification.
Like QuickBASIC, but unlike earlier versions of Microsoft BASIC, QBasic is a structured programming language, supporting constructs such as subroutines and while loops.Line numbers, a concept often associated with BASIC, are supported for compatibility, but are not considered good form, having been replaced by descriptive line labels. QBasic has limited support for user-defined data types (structures), and several primitive types used to contain strings of text or numeric data.