How to understand the Domain Name System

By Clare Lawrence 13th August 2004

Ever wonder why DNS systems came into existence? Efficiency. Every computer has a distinct IP address, and the Internet needed an elite method for obtaining these addresses and for managing the system as a whole. Enter ICANN.

The Internet Corporation for Assigned Names and Number manages the DNS root of the Internet domain namespace. ICANN's role is to manage the assignment of identifiers, ensuring that all users have unique names.

The DNS system is run by a series of servers called DNS servers. ICANN manages the root DNS domains, under which are the top-level domains.

It also manages:

Organizational domains

Geographical domains

Reverse domains

Beneath the top-level domains are other naming authorities such as Nominet, the UK's naming authority.

How does a DNS Query work?

The process occurs in two parts. Firstly, a name query begins at a client computer and is passed to DNS client service for resolution. When the query cannot be resolved locally, DNS servers are queried.

For example, when a web browser calls the fully qualified <a href="http://www.discountdomainsuk.com>domain name</a> www.discountdomainsuk.com, the request is passed on to the DNS client service to resolve the name by using locally cached information. If the query is held in the cache, then the process is complete.

If, however, the query cannot be answered locally, the DNS client service uses a server list (ordered in sequence) to query external DNS servers. When a DNS server receives a query, it first checks to see if it is authoritive for that domain name. If it is authoritive, it resolves the name, and the process is complete.

If the DNS server is unable to resolve the query, it in turns queries other DNS servers, using a process known as recursion. DNS servers make use of root hints to assist in locating DNS servers, which are able to provide the required result. In this way, DNS queries are minimised and the Internet is able to operate quickly and effectively.

A typical query may run as follows:

Client contacts Nameserver A looking for www.discountdomainsuk.com

Nameserver A checks its cache, but can't answer, so it queries a server authoritive for the Internet root.

The root server responds with a referral to a server authoritive for the .com domains.

NameserverA queries the the .com server and gets referred to the server authoritive for www.discountdomainsuk.com

Nameserver A queries this server and gets the IP address for www.discountdomainsuk.com.

Nameserver A replies to the client with the IP address.

Queries can return answers that are authoritive, positive, negative or referral in nature. In the event of a negative answer, another DNS server is queried.

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For all the background users, whether from the technician scene or general, hard drives are always the counterparts for the data storage. No hard drive means your system is not more than a metal box containing wires and circuits. There would be no E-mailing system, operating system use or World Wide Web without computers.

Here the importance and usage of hard drives tell how dumb the technical world would appear without the hard drives. Therefore the hard drive crash is one of the biggest problems for all those dealing with it. The reason for crash can count from the harsh hardware problem to the logical errors due to corrupt system files and threatening viruses.

The owner of the system is not always to blame. The hard drive consists of many magnetic disks, which have the ability to spin at the rapid speed, each surface having the hovered head to access and collect the data. If the motor sits back, saying no to spin the shaft connected to platters or the head fails to function, the hard drive will crash. This would need manual hard drive recovery procedures to apply.

The other way, where data loss can halt your way is the file removal from the hard drive. The system files may get corrupted, the operating system may get damaged, the user may delete any file, formatting of the hard drive may be faced; spyware or adware may delete the data and so many. These cases require the according logical hard drive recovery through software.

Well, the little alertness would let you know the difference between the mechanical and software problems i.e. which has affected your hard drive. This is necessary as the hard disk recovery procedures are typically based on these examinations only.

The system is not booting up at all, try attaching it to some other system. If it functions there, means you have no argument with the hardware. This can be easily cured through the hard drive recovery software as this could be the system software glitch or virus of some sort. However, attaching it to the system shows the same malfunction implies that only the hard disk recovery service can do.

The differences between these  hard drive recovery solutions can be listed with respect to prices, functionality, hard disk recovery mechanism, and working, cases addressed, and others. Basically, the high ending products and services would help and not with the cheap ratings.

Stellar Information Systems Limited offers you the most efficiently working hard drive recovery tools. Through the scanning ability of data recovery software and clean surroundings of Class 100 Clean Rooms, you can benefit the best hard disk recovery of the industry.

The hard drive recovery software will do a perfect scan which is available for different operating systems and under the data recovery service; you would get the apt treatment to the hard drive.

Simpson Raid is a freelancer for Stellar which offers data recovery software and file recovery programs for different OS and file system.

When you try to access data from your computer hard drive, you may encounter certain error messages and the drive is displayed as RAW. In such situations, your important files and data can not be accessed from the drive.

When your hard drive is shown as RAW, it might show you the following symptoms:

'Invalid media type reading drive.' Error message

'Sector not found' error message while accessing any file.

'Disk is not formatted. Do you want to format it now?'

File names contains strange characters.

In such situations, you need to opt for RAW Hard Drive Recovery. You can effectively achieve that with Hard Drive Recovery software that are specifically designed to meet recovery requirements of different users.

These software are capable of extracting your lost, missing or inaccessible hard drive partitions/volumes and complete data. Hard Drive Recovery software are generally easy to use and enable you to have ‘Do It Yourself’ data recovery.

You shoud only select hard drive recovery software that offers RAW Hard Drive Recovery support. RAW data recovery is used on hard drive file system’s logical structure corruption that causes serious issues (even post correction like index correction by chkdsk) or when logical structure gets overwritten. The RAW recovery process is carried out as the critical file system information about each file as name, type, size, number of clusters (for large files), location and more. In case of corrupted directory structures and missing file information, it is impossible to recover the original file and folder names as they are not available. So, the regular tools for data recovery do not work in this situation.

The scan method used by RAW data recovery incorporates sequential reading of all sectors on the drive using file signature search algorithm. Almost all file types have unique file header and at times footer signatures. It provides the great option of extracting the confined data that lies within the file header and footer.

Hard Disk Recovery software offered by Stellar Information Systems Limited are the best solutions for all your data loss problems. These software allow you to get your precious data back by carrying out RAW Hard Drive Recovery in few simple steps. With commanding scanning abilities, you would get incredible results with these software. You can get Stellar’s Hard Drive Recovery software for Windows, Mac OS, Linux, UNIX, BSD and Novell Netware operating systems.

Simpson Raid is a freelancer for Stellar which offers data recovery software and file recovery programs for different OS and file system.