Saturday, October 6, 2012

The Differences between the NetBIOS Naming System and DNS

The Differences between the NetBIOS Naming System and DNS
                                                                                                      The naming system used by DNS is a hierarchical namespace, called the DNS namespace. The DNS namespace has a unique root. The root can contain numerous subdomains. Each subdomain also can contain multiple subdomains. The DNS namespace uses a logical tree structure wherein an entity is subordinate to the entity which resides over it. Each node in the DNS domain tree has a name, which is called a label. The label can be up to 63 characters. Nodes that are located on the same branch within the DNS domain tree must have different names. Nodes that reside on separate branches in the DNS hierarchy can have the same name.
Each node in the DNS domain tree or DNS hierarchy is identified by a FQDN. This is a DNS domain name that specifies the node.s location in relation to the DNS domain tree/hierarchy. A domain name can be defined as the list of labels along the path from the root of the DNS domain tree/hierarchy to a particular node. The FQDN is the entire list of labels for a specific node.
Each domain registered in DNS is connected to a DNS name server. The DNS server of a domain provides authoritative replies to queries for that particular domain.
Internet Corporation for Assigned Names and Numbers (ICANN) manages the DNS root of the Internet domain namespace. ICANN manages the assignment of globally unique identifiers which are key to the operation of Internet. This includes the following components:
  • Internet domain names
  • IP addresses
  • Port numbers
  • Protocol parameters
Below the root DNS domain are the top-level domains. These top-level domains are also managed by ICANN. The top-level domains managed by ICANN are:
  • Organizational domains: Organizational domains have the following characteristics:
    • Organizational domains can be used globally.
    • They are named via a three-character code.
    • The code defines the main function of the organizations of the DNS domain.
  • Geographical domains: Geographical domains have the following characteristics:
    • Geographical domains are usually used by organizations not residing in the United States.
    • They are named via a two-character country and region codes.
    • The codes were established by the International Organization for Standardization (ISO) 3166.
    • The codes identify a country, such as .uk for the United Kingdom
  • Reverse domains: These domains are used for IP address to name mappings. This is called reverse lookups.
The additional top-level domains defined by ICANN in late 2000 are:
  • .aero; for the air transportation industry
  • .biz; for businesses
  • .coop; for cooperatives
  • .info; for information
  • .museum; for museums
  • .name; for individual names
  • .pro; for credentialed professions such as attorneys.
The common top-level domain names used are:
  • .com; commercial organizations
  • .edu; for educational institutes.
  • .gov; for government.
  • .int; for international organizations.
  • .mil; for military organizations
  • .net; for Internet providers, and networking organizations
  • .org; non-commercial organizations
  • .uk; United Kingdom
  • .us; United States
  • .ca; Canada
  • .jp; Japan

Troubleshooting DNS Errors

Troubleshooting DNS Errors
Users may sometimes try to connect to a system by name and get a DNS error because the name did not resolve to the proper IP address. There are several causes for this:
  • The DNS server is down
  • IP connectivity gets lost and thus the DNS cannot resolve it
  • DNS cache poisoning
  • Update and zone issues
  • The DNS server does not have network connectivity to the root servers
There are a number of ways to find out whether a system is resolving properly, nslookup can be used to verify name resolution. The nslookup command can be used to find various details relating to a particular DNS (Domain Name System) such as IP address, MX records, etc.
Go to the command prompt and type in nslookup host_name server_IP_address. Replace the actual host name to be resolved for host_name and the IP address of the DNS server for server_IP_address then press enter.
This allows the user to verify if an error is on the server, if there is a widespread resolution error, or if the server is possibly down. Nslookup will also display the various types of DNS records, not just primary (A) records, or all records for a domain. Users can then ping with the switch to also verify if DNS resolution is working fine.
Troubleshoot the dns client since most problems start with failed queries at the client. If a dns server provides incorrect data to queries that it successfully answers, then the most likely causes are:
  • Resource records (RRs) were not dynamically updated in a zone.
  • An error was made when manually adding or modifying static resource records in the zone.
  • Stale resource records in the DNS server database left from cached lookups or zone records not updated with current information or removed when they were no longer needed.
If the DNS server does not resolve names for external networks, then the possible causes could be:
  • The recursive query times out before it can be completed.
  • A remote DNS server fails to respond.
  • A remote DNS server provides incorrect data.
  • DNS server recursion has been disabled.
Also troubleshoot the connectivity to the root servers. Verify that the DNS server used in a failed query can ping its root servers by IP address. If a ping attempt to one root server fails, it might indicate that an IP address for that root server has changed.

DNS

DNS
Domain Name System (DNS) is an Internet Engineering Task Force (IETF) standard name service which enables applications and users to connect to hosts in TCP/IP based networks by specifying a name. DNS makes it possible to assign domain names to organizations independent of the routing of the numerical IP address. DNS is a hierarchically distributed database that creates hierarchical names that can be resolved to IP addresses. The IP addresses are then resolved to MAC addresses. DNS therefore provides the means for naming IP hosts, and for locating IP hosts when they are queried for by name.
The protocols and standards of DNS provide the following key components:
  • The method for updating address information in a DNS database.
  • The method for querying address information in a DNS database.
  • The schema of the DNS database.
  • The ability of replicating address information between DNS servers in the DNS topology.
The HOSTS files were used to resolve host names to IP addresses before DNS was in existence. The HOSTS files were manually maintained by administrators. The HOSTS file was located on a centrally administered server on the Internet. Each site or location that needed to resolve host names to IP addresses had to at regular intervals download a new copy of the HOSTS file. The size of the HOSTS file grew as the Internet grew. The traffic that was generated from downloading a new copy of the HOSTS file also grew. This led to the design and implementation of Domain Name Service (DNS) in 1984, the hierarchically distributed database that can resolve host names to IP addresses.

The main design requirement of DNS provides the following key features over the HOST file.
  • A hierarchical name space
  • Hostnames in the DNS database can be distributed between multiple servers
  • The database has an unlimited size.
  • Extensible data types
  • Together with supporting host name to IP address mappings, different data types are supported as well.
  • No degrade in performance as more servers are added . the database is scalable.
  • Distribution of administration . naming can be managed individually for each partition.

Monday, October 1, 2012

differences between 32-bit versions of Windows Vista and 64-bit versions of Windows Vista


A description of the differences between 32-bit versions of Windows Vista and 64-bit versions of Windows Vista

  • Kernel Patch Protection
  • Support for hardware-backed Data Execution Protection (DEP)
  • Mandatory driver signing
  • Removal of support for 32-bit drivers
  • Removal of the 16-bit subsystem
One of the greatest advantages of using a 64-bit version of Windows Vista is the ability to access physical memory (RAM) that is above the 4-gigabyte (GB) range. This physical memory is not addressable by 32-bit versions of Windows Vista.

Depending on the version of Windows Vista that is installed, a 64-bit version of Windows Vista supports from 1 GB of RAM to more than 128 GB of RAM. The ability to address more physical memory lets Windows Vista minimize the time that is required to swap processes in and out of physical memory. Therefore, Windows Vista can manage processes more efficiently. This memory management feature helps improve the overall performance of Windows Vista.

Advantages when you install a 64-bit version of Windows Vista

  • Increased memory support beyond that of the 4-GB addressable memory space that is available in a 32-bit operating system
  • Increased program performance for programs that are written to take advantage of a 64-bit operating system
  • Enhanced security features

What to consider when you install a 64-bit version of Windows Vista

  • 64-bit device drivers may not be available for one or more devices in the computer.
  • Device drivers must be digitally signed.
  • 32-bit device drivers are not supported.
  • 32-bit programs may not be fully compatible with a 64-bit operating system.
  • It may be difficult to locate programs that are written specifically for a 64-bit operating system.
  • Not all hardware devices may be compatible with a 64-bit version of Windows Vista.

The main differences between the 32-bit versions of Windows Vista and the 64-bit versions of Windows Vista

Collapse this tableExpand this table
ArchitectureWindows Vista, 32-bit versions Windows Vista, 64-bit versions
System requirements1-gigahertz (GHz) 32-bit (x86) processor or 64-bit (x64) processor, 512 MB of RAM 1-GHz 64-bit (x64) processor, 1 GB of RAM (4 GB recommended)
Memory accessA 32-bit version of Windows Vista can access up to 4 GB of RAM.A 64-bit version of Windows Vista can access from 1 GB of RAM to more than 128 GB of RAM.
Memory access per editionAll 32-bit versions of Windows Vista can access up to 4 GB of RAM.Windows Vista Home Basic - 8 GB of RAM
Windows Vista Home Premium - 16 GB of RAM
Windows Vista Business - 128 GB of RAM or more
Windows Vista Enterprise - 128 GB of RAM or more
Windows Vista Ultimate - 128 GB of RAM or more
DEP32-bit versions of Windows Vista use a software-based version of DEP.64-bit versions of Windows Vista support hardware-backed DEP.
Kernel Patch Protection (PatchGuard)This feature is not available in 32-bit versions of Windows Vista.This feature is available in 64-bit versions of Windows Vista. Kernel Patch Protection helps prevent a malicious program from updating the Windows Vista kernel. This feature works by helping to prevent a kernel-mode driver from extending or replacing other kernel services. Also, this feature helps prevent third-party programs from updating (patching) any part of the kernel.
Driver signingUnsigned drivers may be used with 32-bit versions of Windows Vista.64-bit versions of Windows Vista require that all device drivers be digitally signed by the developer.
32-bit driver support32-bit versions of Windows Vista support 32-bit drivers that are designed for Windows Vista.64-bit versions of Windows Vista do not support 32-bit device drivers.
16-bit program support32-bit versions of Windows Vista support 16-bit programs, in part.64-bit versions of Windows Vista do not support 16-bit programs.

 

Windows Vista-Advantages & Disadvantages


Windows Vista Advantages:
1. Improved Graphical User Interface, the Aero:
There is an entire new GUI for Windows Vista. The appearance of window, desktop, start button, start menu, taskbar, everything got a new look. Now, the window in Windows Vista looks similar to that of in Mac OSX. Minimize, maximize and the close buttons wore an entire new strange look. The windows can be made to appear in translucent, 3D modes, if the new Aero is applied. The start button has been modified to give a new look. The word “start” has been removed. Only the new Windows logo gets appear in start button. Start menu also got a new look. The desktop wallpapers got a new look too. The desktop contains a side bar, which shows a clock, and some of the widgets. Widgets are small programs, which is equivalent to standard short cuts.
2. Surf the net, without much worry about security
Browsing the net, without any security measures invites a major danger. Windows Vista enable one provide high level of security measures. Windows Vista has come with a latest version of Internet Explorer which is version 7.0. This provides a higher degree of security to the system, as well as, the operating system environment. It also warns strictly against visiting some fake sites. It includes phishing filter to provide higher security while surfing the net. Protection against spamming is also provided. The other security measures include tools such as Windows defender, advanced firewall, Encryption/Decryption of data, support for NTFS partitions, auto backup. The Windows Defender is a program which blocks suspicious programs which tries to do some illegal activity in the computer system. Advanced firewall provides security to both incoming and outgoing data.
3. Manage your knotty kids, using parental controls:
One can control kids by using parental controls in Windows Vista. Parents can now deny access to certain programs especially, the games. Through separate child account, parents can now keep track of what all activities done by the child. It also enables parents to control the activities by blocking certain activities such as running a game program, blocking some sites that, the child might have visited etc. For this to work, parent must setup separate account for the child with different password.
4. Play multimedia contents using latest media player:
The latest version of Windows Media Player bundled with Windows Vista. The Windows Media Player 11 enhances video, audio quality when playing sound, music, videos. It has got new look and has got a series of rich features. These features include URGE services from MTV digital music services, Simplified Library, Library layouts. The newest URGE services provide access to the huge collection of online music, song collections. The simplified library improves customization options. Whenever, one plugs some of the latest media player compatible devices, the media player detects the device and installs the drivers associated with the device automatically.
5. Improved search, Windows Explorer:
In Windows Vista, you will get the search result as and when you type some letters of a particular word. The explorer shows a list of all files in the folder by default. When one types in, the few letters of words in the search box, the files will get filtered out according to the letters. Suppose, if one searches for filenames of “govt. services”, the search will filter out and displays only files with filenames with the name “gov”, if you type “gov” in the search text box. It will further filter the filenames, when you type full form. Also, the look of Windows Explorer got changed rapidly. More sorting options are also provided. Different kinds of listing is also got introduced.
6. Date and time, know the difference in time across the world:
In earlier Windows operating systems, it was indeed difficult to know the time difference across the two countries. It proved difficult for online chat users. In Windows Vista, one can add additional clocks, to show the time of some other country. For example, if you want to know the time of London, then you can add clock of London to the additional clocks tray. The tray comes up for display, when one moves mouse over the time shown in the task bar.
7. Manage your photos using photo gallery:
Windows Vista has got an inbuilt tool called as Photo Gallery to manage digital photos. Using it, one can modify the photos. It has got ability to show previews of movie files, a feature, which was not there with Windows XP. Using this tool, one can transfer or share the photos from computer to devices such as mobile phones, PDA’s, etc. The photo gallery also has the ability to work high precision, high quality images, which are produced by latest high quality cameras.
8. Total different world, new experience:
Windows Vista brings you the new world of new experience. It starts from amazingly changed desktop, which goes beyond imagination. All icons look better this time around. The 256x256 resolution icons made Vista world to feel like you have got a computer from heaven. Networking aspect has improved further in Windows Vista, with the introduction of further security enhancements. Performance wise, vista makes life better, when compared with its predecessors.


Vista Disadvantages:
1. Requirements high, too hot deal:
Windows Vista, the next generation operating system requires superb computer to install. It consumes a lot more resources than its predecessor windows XP. For vista Aero to work, you need to invest something more than what you would have expected to invest before. The graphics card requirement is quite high. The graphics card must be of DirectX 10 supported. The required minimum graphics memory on the graphics card is 128 MB. For better performance, graphics memory must be of 256 MB. The minimum hard disk space required is 20 GB for installation of Windows Vista. Processor speed is also expected to be high for Aero to work smoothly without causing any hiccups. The memory requirement for Windows Vista system is high. The system will work smoothly when one has got RAM of about 2 GB installed. Totally, I would like to say that, Windows vista eats up lot of resources, than its predecessor, the Windows XP.
2. Regarding price, sucking your hard earned money:
The price of Windows Vista Ultimate edition seems to be too high. Ordinary user cannot thus, have a look into all the features of Vista, which is only available in the Ultimate Edition. Microsoft seems to be not so interested in country wise markets. The prices are set according to the US market. However these prices are on higher side for developing asian countries. Microsoft should set the price of Vista as per the market. It is the time for Microsoft to think over this aspect, having introduced stricter validation process.
3. Replace the oldies, another way of extracting:
This is a usual problem, which always exists whenever new operating system gets released, and you have an old system or have some old components in the system. If one decides to install windows vista in the old system, then they should check the compatibility of system components, checking whether Vista supports them or not. Some manufacturers will still provide Vista support for the oldies by providing the latest drivers for the same. If manufacturers are not providing the latest drivers, you need to purchase a new device as a replacement for the existing device. Before, you purchase a new device you need to check out for Vista compatible or Vista ready logo, which is put up on the device.
4.Window appearance. Did you like the different look?
In Windows Vista, the window appearance underwent lot of unwanted changes. The windows in Windows Vista, the window appears similar to that of MAC OSX. The Minimize, Maximize, and Close buttons, wore a different look. The three buttons got reduced in their sizes, making them unclear to aged people, people with eye sight problems. The minimize, maximize, and close buttons have reduced in sizes. The icon in the other end has disappeared, which makes the window slightly dull in appearance.
In overall, the new operating system, Windows Vista is said to be an ideal replacement to its predecessor, the Windows XP.

Friday, September 28, 2012

Windows 8-Features



10 Key Features in Windows 8: 

                                                                      Released just last week in Developers Preview mode, Windows 8 already contains more than 300 new features. At its Build developers conference, Microsoft pointed to plans to keep adding more new capabilities until Windows 8 evolves into a shipping product. Which of the existing features are most important to get to know about right now?
While no list like this can even approach 'all inclusiveness', our list of ten key features in Windows 8 ranges across new jargon such as "charms" and "snap muti-tasking," to first-time operatibility on ARM-based tablets, to major improvements around support for USB 3.0, touch keyboards, file copying, and more. Here, in no particular order of importance, is the list of ten:
1. Support for both x86 PCs and ARM tablets
Windows 8 is the first edition of Windows to operate on both ARM-based tablets and traditional x86 PCs based on ARM processors from Intel and AMD.
“Support for ARM-based chipsets, touch, and sensors makes Windows 8 work beautifully on your choice of a full spectrum of devices, such as 10-inch slates with all-day battery life, ultra-lightweight laptops, and powerful all-in-ones with 27-inch high-definition screens,” Microsoft contends, in a Windows 8 Guide distributed with Windows Developer Preview
In addition, the ARM edition of Windows 8 includes a new mode dubbed “always on, always connected,” designed to let tablets act like smartphones. Tablets can remain in standby mode without disconnecting from the Internet, and then wake up instantly.
Windows 8 is designed to work seamlessly across both PCs and ARM tablets. Yet until developers get a real start on apps for Microsoft’s still empty Windows Store, it’s tough to tell whether that will be universally true.
2. Touch-centric, Tiles-based User Interface (UI)
Although Windows 8 might look and feel like an entirely new “user experiemce,”, Microsoft is actually layering a new animation-enabled user interface (UI) on top of an only somewhat upgraded Windows 7.
The Windows 8 Start Menu is customizable through a mosaic of tiles, which differ from traditional desktop icons by letting you view live information from Windows 8 Metro style apps without actually accessing the apps.
In demoing the tile-based UI at last week’s Build conference , Microsoft showed how the tile for a Windows 8 weather app is able to display the current temperature in a city – along with projected temperatures for the next two days – without requiring you to open up the app. A tile for Windows Live Mail will show you your latest message, while a tile for a social networking app will show you notifications.
 “The [Metro] apps are full-screen. They’re beautiful.They’re designed for touch, but of course, they work great with a mouse and keyboard as well if that’s what you have. We wanted to make it really fast and fluid for you to switch between them,” according to Jensen Harris, lead program manager on the Microsoft Office User Experience..
Windows 8 users are also able to access Windows 7 apps. “Everything that runs on Windows 7 will run on Windows 8,” maintained Steven Sinofsky, president of Microsoft’s Windows and indows Live division, during a keynote at the Build conference. However, in order to access Windows 7 apps, you need to switch to a different built-in UI.
3. Charms
In large part, ‘charms’ is a new implementation of the traditional Windows start bar. Charms can also be used to quickly configure settings for individual apps. On an ordinary non-touch PC, charms are accessed by dragging the mouse to the bottom-left corner of the screen, to the same spot as the old Windows start button. On a tablet, you swipe from the right side of the screen to bring up charms.
Microsoft recently applied for a trademark on charms. The charms sidebar offers five sets of options, supporting both app-specific settings and system settings such as volume and brightness. The options include Start, Search, Share, Devices, and Settings. The Start option returns the user to the home screen. The Devices option presents a list of connected devices. Under the Share option, users can see social network sharing apps.
4. Snap Multi-tasking
‘Snap multitasking” is designed to make it easy to run two apps in Windows 8 side-by-side, to resize them, and to switch between them. On the right-hand side of the screen, you can snap an app into place.
You can make an app smaller or larger by dragging the bar for the app. To switch between apps in Windows 8, you swipe from the left-hand part of the screen.
However, Windows 8 does not allow you to view all of your running apps on a single screen.
5. Windows 8 Control Panel
Beyond revamping the Windows task manager, Microsoft has also redesigned the control panel for Windows 8.  New options include Personalize, Users, Wireless, Notifications, General, Privacy, Search, and Share.
As Metro style apps become available, you'll be able to use the Personalize menu to customize the Start menu with tiles for calendar, music, e-mail, Netflix, and much more.
In a demo at Build, Julie Larson-Green, Microsoft's corporate VP of program management for Windows, showed how you’ll be able to position these Metro apps on the screen, and also to combine them into groups such as friends and games.
6. Web Navigation by Touch
The Internet Explorer (IE) 10 browser built into Windows 8 is designed to offer faster browsing through greater hardware acceleration, along with rapid gesture-based zoom, pan, and Web site navigation.
As in other areas of Windows 8, you can quickly access Windows 8 charms, as well as the two keyboards described below.
7. Two Touch Keyboards
Windows 8 also contains two soft keyboards: an “enhanced” traditional keyboard, plus a new thumbs keyboard for non-touch typists.
In efforts by Microsoft to make typing on a virtual keyboard faster and more accurate, the revised edition of the conventional keyboard suggests words on the screen as you type. You can then tap to selected a suggested word.  Microsoft also provides a spellcheck-like feature designed to automatically correct mistyped words – although like any other spellchecker, this feature carries the potential to cause its own errors.
The keyboards are also aimed at automatically adjusting to whaever human language you choose for Windows. These language settings will automatically apply to the entire computer, instead of only to specific apps
8. ‘Enhanced Copy Experience’
Windows 8 also introduces the ability to perform all current copy operations into a single dialog box, instead of requiring you to perform file copying in separate dialog boxes for each app.
The new dialog box for file copying lets you pause, resume, and stop each sopy operation currently under way. It will also warn you if you’re beginning to copy one version of a file on top of another.
Microsoft has also added a realtime throughput graph. “Now each copy job shows the speed of data transfer, the transfer rate trend, and how much data is left to transfer. While this is not designed for benchmarking, in many cases it can provide a quick and easy way to assess what is going on for a particular [copy] job,” noted Alex Simons, director of program management with the Windows 8 management team.
9. Native USB 3.0 Support
New USB 3.0 ports operate at speeds up to ten times faster than )SB 2.0. To better support these speeds, Microsoft is outfitting Windows 8 with native USB 3.0 drivers.
Meanwhile, though, USB 3.0 will purportedly continue to work under Windows 7, through the use of third-party drivers.
“By 2015, all new PCs are expected to offer USB 3.0 ports, and over 2 billion new ‘SuperSpeed’ USB devices will be sold in that year alone,” said Dennis Flanagan, director of program management for the Windows 8 Devices and Networking Group, in a blog post. “There are also billions of older USB devices that Windows must remain compatible with.”
10. Better Support for Multiple Monitors
Windows 8 also brings increased support for multiple monitors, The Developers Preview of the new OS includes first-time capabilities for extending the taskbar across two PCs, without any need for third-party apps. You can also stretch wallpaper across two monitors, or display the Start screen on one PC and the desktop on the other, for instance.
It's also easy to switch between multiple monitors. The primary monitor has a start button, and the secondary monitor has a switcher button. Clicking or tapping on the switcher button will swap it out for the start button, allowing you to turn the secondary monitor into the primary one.