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Articleswhat is Blu-ray ?Blu-ray is an optical disc format designed to display high definition video and store large amounts of data. Blu-ray is the successor to DVD. The standard was developed collaboratively by Hitachi, LG, Matsushita (Panasonic), Pioneer, Philips, Samsung, Sharp, Sony, and Thomson. It became the default optical disk standard for HD content and optical data storage after winning a format war with HD-DVD, the format promoted by Toshiba and NEC. The format's name comes from the fact that a blue laser reads from and writes to the disc rather than the red laser of DVD players. The blue laser has a 405 nanometer (nm) wavelength that can focus more tightly than the red lasers used for writable DVD. As a consequence, a Blu-ray disc can store much more data in the same 12 centimeter space. Like the rewritable DVD formats, Blu-ray uses phase change technology to enable repeated writing to the disc. Blu-ray's standard storage capacity is enough to store a continuous backup copy of most people's hard drives on a single disc. Initially, the format had a 27 gigabyte (GB) single-sided capacity and 50 GB on dual-layer discs. Single-sided Blu-ray discs can store up to 13 hours of standard video data, compared to single-sided DVD's 133 minutes. In July 2008, Pioneer announced that they had found a way to increase capacity to 500 GB by creating 20-layer discs. These discs are not, however, expected to be commercially available in the near future.  WHAT IS ROLE OF .DLL FILES IN WINDOWS ?In a nut shell, a dynamic link library (DLL) is a collection of small programs, which can be called upon when needed by the executable program (EXE) that is running. The DLL lets the executable communicate with a specific device such as a printer or may contain source code to do particular functions. An example would be if the program (exe) needs to get the free space of your hard drive. It can call the DLL file that contains the function with parameters and a call function. The DLL will then tell the executable the free space. This allows the executable to be smaller in size and not have to write the function that has already exists. This allows any program the information about the free space, without having to write all the source code and it saves space on your hard drive as well. When a DLL is used in this fashion are also known as shared files. The advantage of DLL files is that, because they do not get loaded into random access memory (RAM) together with the main program, space is saved in RAM. When and if a DLL file is called, then it is loaded. For example, you are editing a Microsoft Word document, the printer DLL file does not need to be loaded into RAM. If you decide to print the document, then the printer DLL file is loaded and a call is made to print. All in all a DLL is an executable file that cannot run on its own, it can only run from inside an executable file. This would be like having a car without an engine, where as an executable has an engine. To do load a DLLl file, an executable needs to declare the DLL function. A DLL may have many different functions in it. Then when needed the call is made with the required parameters. Here is what a Declaration and call might look like in a executable file. This example is simplified so that you might understand it better: * Declare GetFreeSpacex, Kernel32.dll (Drive_Letter, Buffers_If_Any, Value_Returned) Now lets run a program and make the call. The DLL is not loaded into RAM until the next line. * GetFreeSpacex "C",Buffers_If_Any, Drive_Letter Now let's tell the user how much free space is on drive C * Use a MessageBox = "The free space on drive C: is ", Value_Returned, "bytes" & This call required 3 lines of code. Where as if you did not call the DLL file it may have taken you 30 or 40 lines of code. After knowing about .dll files one more question comes in mind . Why there are no .dll files in linux ? hope we will find answer of it and post it soon.
ALL ABOUT REGISTRYWhat Is The Registry ?The Registry is a hierarchical database within later versions of Windows (95/98/NT4/NT5) where all the system settings are stored. It has replaced all of the .ini files that were present in Windows 3.x. The data from system.ini, win.ini, control.ini, are all contained within it now, along with hundreds of other system settings. Additionally, all Windows specific programs are now to store their initialization data within the Registry instead of in .ini files in your Windows folder. How the Registry is stored ?* In Windows 95, 98, and Me, the Registry is contained in two hidden files in your Windows directory, called USER.DAT and SYSTEM.DAT.
* In Windows 2000 and Windows XP, the Registry is stored in several Hives, located in the \windows\system32\config and \Documents and Settings\{username} folders. Structure of the Registry The Registry has a hierarchal structure, like the directories on your hard disk. Each branch is called a Key. Each key can contain other keys, as well as Values. Each value contains the actual information stored in the Registry. There are three types of values; String, Binary, and DWORD - the use of these depends upon the context. There are six main branches (five in Windows 2000 and Windows XP), each containing a specific portion of the information stored in the Registry. They are as follows: * HKEY_CLASSES_ROOT - this branch contains all of your file types as well as OLE information for all your OLE-aware applications. * HKEY_CURRENT_USER - this branch points to the part of HKEY_USERS appropriate for the current user. * HKEY_LOCAL_MACHINE - this branch contains information about all of the hardware and software installed on your computer. Since you can specify multiple hardware configurations, the current hardware configuration is specified in HKEY_CURRENT_CONFIG. * HKEY_USERS - this branch contains certain preferences (such as colors and control panel settings) for each of the users of the computer. In Windows 95/98/Me, the default branch here contains the currently-logged in user. In Windows 2000/XP, the default branch here contains a template to be used for newly-added users. * HKEY_CURRENT_CONFIG - this branch points to the part of HKEY_LOCAL_MACHINE appropriate for the current hardware configuration. * HKEY_DYN_DATA (Windows 95/98/Me only) - this branch points to the part of HKEY_LOCAL_MACHINE, for use with Windows' Plug-&-Play subsystem. This is all basic information about registry. WHAT IS DIRECTX ? Gaming and multimedia applications are some of the most satisfying programs you can get for your PC, but getting them to run properly isn’t always as easy as it could be. First, the PC architecture was never designed as a gaming platform. Second, the wide-ranging nature of
the PC means that one person’s machine can be different from another. While games consoles all contain the same hardware, PCs don’t: the massive range of difference can make gaming a headache. To alleviate as much of the pain as possible, Microsoft needed to introduce a common standard which all games and multimedia applications could follow – a common interface between the OS and whatever hardware is installed in the PC, if you like. This common interface is DirectX, something which can be the source of much confusion. DirectX is an interface designed to make certain programming tasks much easier, for both the game developer and the rest of us who just want to sit down and play the latest blockbuster How it works At the most basic level, DirectX is an interface between the hardware in your PC and Windows itself, part of the Windows API or Application Programming Interface. Let’s look at a practical example. When a game developer wants to play a sound file, it’s simply a case of using the correct library function. When the game runs, this calls the DirectX API, which in turn plays the sound file. The developer doesn’t need to know what type of sound card he’s dealing with, what it’s capable of, or how to talk to it. Microsoft has provided DirectX, and the sound card manufacturer has provided a DirectX-capable driver. He asks for the sound to be played, and it is – whichever machine it runs on. From our point of view as gamers, DirectX also makes things incredibly easy – at least in theory. You install a new sound card in place of your old one, and it comes with a DirectX driver. Next time you play your favourite game you can still hear sounds and music, and you haven’t had to make any complex configuration changes. Originally, DirectX began life as a simple toolkit: early hardware was limited and only the most basic graphical functions were required. As hardware and software has evolved in complexity, so has DirectX. It’s now much more than a graphical toolkit, and the term has come to encompass a massive selection of routines which deal with all sorts of hardware communication. For example, the DirectInput routines can deal with all sorts of input devices, from simple two-button mice to complex flight joysticks. Other parts include DirectSound for audio devices and DirectPlay provides a toolkit for online or multiplayer gaming. How antivirus software works?Full featured Anti-Virus software consists of several important modules like, Scanner, Real Time Protection, Email Protection, Memory scanner etc. Combination of all these modules gives complete protection to the system. At the core of all these modules there is Anti-Virus engine which serves the purpose of virus scanning. It’s a very powerful multi-threaded, multi-tasking engine that can scan file/folder/buffer for any kind of malwares and threats in very efficient way.
Each of these modules are quite complex in functionality and integrates with the respective part of the operating system to provide protection. Like Real Time Protection is based on file system driver at its core. It intercepts all the file activities happening in the system and makes sure that the file that is being accessed is clean. Email protection is based on network and communication driver at its base which intercepts the email communication to scan all the emails that are being sent or received. Most important component the Anti-Virus Engine consists of lots of modules like file format identification and parsing, un-archivers and un-packers, signature scanners, emulators etc. In simple words AV Engine’s primary task is to scan a file for virus and presence of other malwares by, first scanning it for presence of virus definitions (signatures). After that engine also applies various scanners on the file based on the type of the file and the contents of the file. Like polymorphic virus detection engine, generic malware symptoms detection etc. Also there is a component in most of the AV engines called as heuristic scanner which is also applied on the file for detection of new unknown malwares. Google Search TechnologyGoogle's core search technology has been widely proven and accepted to be the finest in the industry with Google now handling 70+% of all web searches. Utilizing the same exact underlying search technology and code base as used on Google.com, the Search Appliance "crawler" not only has proven to discover a greater percentage of content than any competing product, but Google's patented search algorithms deliver end users unrivalled ranking and relevancy of the search results. The software behind Google's search technology conducts a series of simultaneous calculations requiring only a fraction of a second. Traditional search engines rely heavily on how often a word appears on a web page.Google uses PageRank™ to examine the entire link structure of the content and determine which pages are most important. It then conducts hypertext-matching analysis to determine which pages are relevant to the specific search being conducted. By combining overall importance and query-specific relevance, Google is able to put the most relevant and reliable results first. PageRank Technology PageRank performs an objective measurement of the importance of pages by solving an equation of more than 500 million variables and 2 billion terms. Instead of counting direct links, PageRank interprets a link from Page A to Page B as a vote for Page B by Page A. PageRank then assesses a page's importance by the number of votes it receives. PageRank also considers the importance of each page that casts a vote, as votes from some pages are considered to have greater value, thus giving the linked page greater value. Important pages receive a higher PageRank and appear at the top of the search results. Google's technology uses the collective intelligence of the web to determine a page's importance. There is no human involvement or manipulation of results. Hypertext-Matching Analysis Google's search engine also analyzes page content. However, instead of simply scanning for page-based text (which can be manipulated by site publishers through meta-tags), Google's technology analyzes the full content of a page and factors in fonts, subdivisions and the precise location of each word. Google also analyzes the content of neighboring web pages to ensure the results returned are the most relevant to a user's query. Why We Require Device Driver's ?A device driver is a program that controls a particular type of device that is attached to your computer. There are device drivers for printers, displays, CD-ROM readers, diskette drives, and so on. When you buy an operating system, many device drivers are built into the product. However, if you later buy a new type of device that the operating system didn't anticipate, you'll have to install the new device driver. A device driver essentially converts the more general input/output instructions of the operating system to messages that the device type can understand. Some Windows programs are virtual device drivers. These programs interface with the Windows Virtual Machine Manager. There is a virtual device driver for each main hardware device in the system, including the hard disk drive controller, keyboard, and serial and parallel ports. They're used to maintain the status of a hardware device that has changeable settings. Virtual device drivers handle software interrupts from the system rather than hardware interrupts. A device driver simplifies programming by acting as an abstraction layer between a hardware device and the applications or operating systems that use it. The higher-level application code can be written independently of whatever specific hardware device it will ultimately control, as it can interface with it in a standard way, regardless of the underlying hardware. Every version of a device, such as a printer, requires its own hardware-specific specialized commands. In contrast, most applications utilize devices (such as a file to a printer) by means of high-level device-generic commands such as PRINTLN (print a line). The device-driver accepts these generic high-level commands and breaks them into a series of low-level device-specific commands as required by the device being driven. Furthermore, drivers can provide a level of security as they can run in kernel-mode, thereby protecting the operating system from applications running in user-mode.
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