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
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.
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.
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
Architecture
Windows Vista, 32-bit versions
Windows Vista, 64-bit versions
System requirements
1-gigahertz (GHz) 32-bit (x86) processor or 64-bit (x64) processor,
512 MB of RAM
A 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 edition
All 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
DEP
32-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 signing
Unsigned 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 support
32-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 support
32-bit versions of Windows Vista support 16-bit programs, in part.
64-bit versions of Windows Vista do not support 16-bit programs.
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.
