The average computer user is familiar with the basic use of a computer but may not really understand what goes on behind the scenes. We understand that data is an important feature but how it is stored and what happens with it are things a lot of us are clueless about. We even use the terms hard drive, software, server etc. without too much thought about what each is. As long as the computer functions, we are happy to be ignorant.
Appropriate software is the core of the system that makes a computer function. A piece of hardware is referred to as the server but, actually, what it means is that this hardware is running one or more pieces of server software. Requests are sent to a server by a “client”. An example of a client is the garden variety Web browser, typically used as client to a Web server. The Internet and Intranets have resulted in a wide variety of servers. In fact, networks are the backbone of client/ server relationships.
Types of Servers
Typically, there are different kinds of servers, each dedicated to a particular role. There are Web servers, Application servers, Proxy servers, e-mail servers, DHCP servers, fax servers and firewalls. It actually sounds more complicated than it is and the average user needs to understand just the basic functioning of servers.
A Web server functions in a very straightforward manner. A client makes a request, perhaps for a file, and the role of the Web server is to get the file and send it to the client. The Web server is usually not conditioned to read or scan the file but just transfers it to a client, when a request is made. However, modern Web servers are more sophisticated and can multi-task at great speed.
An application server is also known as an information server. These servers have an amazing capacity to process information. The applications server’s potential is maximised by using it with existing technologies. An open source developer might connect an Apache Web server with PHP scripting language. Simply put, however, an application server is a bundled solution that contains all the necessary component technologies needed. Application servers are useful for some organizations as it eases development by unifying development models.
Proxy servers do not require a client to have Internet access at all. Proxy servers are a popular way to bridge a local network to an external network. This is possible as long as one computer, which is running the proxy server, is linked. Proxy servers can be configured to allow or deny particular types of network requests. It takes on the guise of a firewall and can inspect each piece of data that passes through its defined territory.
RAID stands for Redundant Array of Independent Drives or Redundant Array of Inexpensive Drives. It refers to computer data storage schemes. These schemes divide and replicate data among multiple hard disk drives. The focus of RAID is to increase data reliability and increase input/ output performance. Originally, there were five standard levels of RAID but newer variations have increased the number.
RAID uses special hardware or software to combine physical hard disks into single logical units. RAID drives are presented as single drive applications by software solutions which are implemented in the operating system.
There are three definitive concepts in RAID. They are -- mirroring, striping and error correction. Mirroring refers to the copying of data to more than one disk. The splitting of data across more than one disk is known as striping. Error correction refers to redundant data being stored to allow detection and resolution of problems. Depending on system requirements, different RAID levels use one or more of these techniques. RAID ensures reliability, data protection and speed.
RAID Data Recovery
Reconstructing RAID is not easy. There can be many reasons that lead to the software being unable to create the correct setting to ensure a properly constructed array. However, luckily, there are always solutions to most technological problems. There are software available in the market that will be able to recreate the correct settings. Even if one is not familiar with RAID parameters like drive order or block size, there are software available that can analyze the drives and determine correct values. Once this is done, a user will be able to create a copy of the reconstructed RAID on a physical drive.