Friday, May 28, 2010
Thursday, September 14, 2006
LATEX, written as LaTeX in plain text, is a document preparation system for the (TeX) typesetting program. It is used mainly by mathematicians, scientists, and engineers in academia. It is also widely used by people outside of these fields as a primary or intermediate format (e.g. translating DocBook and other XML-based formats to PDF) due to the quality of typesetting achieved by TeX.
It offers programmable desktop publishing features and extensive facilities for automating most aspects of typesetting and desktop publishing, including numbering and cross-referencing, tables and figures, page layout, bibliographies, and much more. LaTeX was originally written in 1984 by Leslie Lamport and has become the dominant method for using TeX—few people write in (plain TeX) anymore. The current version is (LaTeX2e). Both LaTeX and TeX are free software.LaTeX is usually pronounced [ˈleɪ.tɛx] or [ˈlɑ.tɛx] (that is, not with the [ks] pronunciation English speakers normally associate with X). The last character in the name comes from a capital χ (chi), as the name of TeX derives from the Greek τέχνη (skill, art, technique). While TeX's creator Donald Knuth promoted the /tɛx/ pronunciation, Lamport has said he does not favor or deprecate any pronunciation for LaTeX. It is traditionally printed with the special typographical logo shown on this page. In media where the logo cannot be precisely reproduced in running text, the word is typically given the unique capitalization LaTeX to avoid confusion with the word “latex”.
Posted by Vinay Shukla at 11:21 PM
An Oracle database consists of a collection of data managed by an Oracle database management system. Popular generic usage also refers to the DBMS management software, but not necessarily a specific database under its control.
One can refer to the Oracle database management system unambiguously as Oracle DBMS or (since it manages databases which have relational characteristics) as Oracle RDBMS.
Oracle Corporation itself blurs the very useful distinction between:
data managed by an Oracle RDBMS
an Oracle database, and
the Oracle RDBMS software itself
when it refers nowadays to the Oracle RDBMS (the software it sells for the purpose of managing databases) as the Oracle Database. The distinction between the managed data (the database) and the software which manages the data (the DBMS / RDBMS) relies, in Oracle's marketing literature, on the capitalisation of the word database.
Oracle Corporation produces and markets the Oracle DBMS, which many database applications use extensively on many popular computing platforms.
Larry Ellison and his friends and former co-workers Bob Miner and Ed Oates - who had started a consultancy called Software Development Laboratories (SDL) - developed the original Oracle DBMS software. They called their finished product Oracle after the code name of a CIA-funded project they had worked on while previously employed by Ampex.
An Oracle database comprises an instance and data storage. The instance comprises a set of operating system processes and memory structures that interact with the storage. Typical processes include PMON (the process monitor) and SMON (the system monitor).
Oracle users refer to the server-side memory structure as the SGA (System Global Area). The SGA typically holds cache information like data buffers, SQL commands and user information. In addition to storage, the database consists of online redo logs (which hold transactional history). Processes can in turn archive the online redo logs into archive logs (offline redo logs), which provide the basis (if necessary) for data recovery and for some forms of data replication.
The Oracle RDBMS stores data logically in the form of tablespaces and physically in the form of data files. Tablespaces can contain various types of segments, for example, Data Segments, Index Segments etc. Segments in turn comprise one or more extents. Extents comprise groups of contiguous data blocks. Data blocks form the basic units of data storage. At the physical level, data files comprise one or more data blocks, where the blocksize can vary.
Oracle keeps track of its data storage with the help of information stored in the SYSTEM tablespace. The SYSTEM tablespace contains the data dictionary - and often (by default) indexes and clusters. (A data dictionary consists of a special collection of tables that contains information about all user objects in the database). Since version 8i, the Oracle RDBMS also supports "locally managed" tablespaces which can store space management information in bitmaps in their own headers rather than in the SYSTEM tablespace (as happens with the default "dictionary managed" tablespaces).
If the Oracle database administrator has instituted Oracle RAC (Real Application Clusters), then multiple instances, usually on different servers, attach to a central storage array. This scenario offers numerous advantages, most importantly performance, scalability and redundancy. However, support becomes more complex, and many sites do not use RAC. In version 10g, grid computing has introduced shared resources where an instance can use (for example) CPU resources from another node (computer) in the grid.
The Oracle DBMS can store and execute stored procedures and functions within itself. PL/SQL (Oracle Corporation's proprietary procedural extension to SQL), or the object-oriented language Java can invoke such code objects and/or provide the programming structures for writing them.
Older Oracle database installations (pre-10g) traditionally came with a default schema called scott. After the installation process has set up the sample tables, the user can log into the database with the username scott and the password tiger. (The name of the "scott" schema originated with Bruce Scott, one of the first employees at Oracle (then Software Development Laboratories), who had a cat named Tiger.)
Posted by Vinay Shukla at 11:12 PM
Linux (also known as GNU/Linux) is a Unix-like computer operating system. It is one of the most prominent examples of open source development and free software; unlike proprietary operating systems such as Windows or Mac OS X, all of its underlying source code is available for anyone to use, modify, and redistribute freely.
Initially, Linux was primarily developed and used by individual enthusiasts on personal computers. Since then, Linux has gained the support of major corporations such as IBM, Sun Microsystems, Hewlett-Packard, and Novell for use in servers and is gaining popularity in the desktop market. It is used in systems ranging from supercomputers to mobile phones. Proponents and analysts attribute its success to its security, reliability, low cost, and freedom from vendor lock-in
In 1983, Richard Stallman founded the GNU Project, with the goal of developing a complete Unix-like operating system composed entirely of free software. By the beginning of the 1990s, GNU had produced or collected most of the necessary components of this system—libraries, compilers, text editors, a Unix-like shell—except for the core component, the kernel. The GNU project began developing a kernel, the Hurd, in 1990, based on the Mach microkernel, but the development of this Mach-based design proved difficult and proceeded slowly.
Meanwhile, in 1991, another kernel was begun as a hobby by Finnish university student Linus Torvalds while attending the University of Helsinki. Torvalds originally used Minix on his own computer, a simplified Unix-like system written by Andrew Tanenbaum for teaching operating system design. However, Tanenbaum did not permit others to extend his operating system, leading Torvalds to create a replacement for Minix.
Originally, Torvalds called his kernel "Freax" for "free" and "freak" and with the often-used X in the names of Unix-like systems. The name "Linux" was coined by Ari Lemmke, who administered an FTP server belonging to the Finnish University Network; he invented the name Linux for the directory from which Torvalds' project was first available for download.
At first a computer running Minix was necessary in order to configure and install Linux. Initial versions of Linux also required another operating system to be present in order to boot from a hard disk, but soon there were independent boot loaders such as LILO. The Linux system quickly surpassed Minix in functionality; Torvalds and other early Linux kernel developers adapted their work for the GNU components and user-space programs to create a complete, fully functional, and free operating system.
Today, Torvalds continues to direct the development of the kernel, while other subsystems such as the GNU components continue to be developed separately (Linux kernel development is not part of the GNU Project). Other groups and companies combine and distribute these components with additional application software in the form of Linux distributions.
Posted by Vinay Shukla at 11:07 PM
When a winner makes a mistake, he says, "I was wrong;"When a loser makes a mistake, he says, "It wasn't my fault."
A winner works harder than a loser and has more time;A loser is always "too busy" to do what is necessary.
A winner goes through a problem;A loser goes around it, and never gets past it.
A winner makes commitments;A loser makes promises.
A winner says, "I'm good, but not as good as I ought to be:"A loser says, "I'm not as bad as a lot of other people."
A winner listens;A loser just waits until it's his turn to talk.
A winner respects those who are superior to him and tries to learn something from them;A loser resents those who are superior to him and tries to find chinks in their armor.
A winner feels responsible for more than his job;A loser says, "I only work here."
A winner says, "There ought to be a better way to do it;"A loser says, "That's the way it's always been done here"
Posted by Vinay Shukla at 10:55 PM