Some Good Computer Habits to have

You've always been taught to cultivate good habits and avoid bad ones. The same applies to your computer use, where habits are good, bad or ugly. Good habits can maximise your IT investment and optimise your operational efficiency, while bad ones can cost you money and slow you down. The ugly ones can lead to disaster and an ugly mess. Here’s a list of computer habits you should kick start into your regular routine to keep you going – in the right direction!

1. Save frequently: To avoid any data loss in case of software or system freezing, regularly save your changes to documents. Doing so only takes a second and won’t interrupt your productivity groove. Use the keyboard shortcut “Ctrl + S”, or click on the “Save” icon – the old floppy disk in the toolbar. Don’t rely on “ Auto Save”, as it’s not a feature on every program.
2. Backup: Don’t risk losing your files by not having them backed up. With damage, loss and theft all possible, no hard drive is guaranteed to be functional forever. Recovering data is often impossible and more costly and time consuming than people think. Tireless efforts on work-related documents can be preserved by simply copying files to a few DVDs, USB drive or portable hard drive, at regular intervals.
3. Think before you print: A hard copy is required sometimes, but not every time. So before clicking “Print”, determine if you really need to hold a copy of the document in your hand. And if you do, do you really need the entire thing? Use “Print Preview” and the option of selecting a “Page range” to print only the pages you actually need. And use the double-sided printing feature where available – to print multiple pages onto only one sheet of paper. It would also be helpful to set your printer to print in black and white by default, manually choosing colour prints only when necessary. All of these printing habits will have a positive impact on your environmental initiatives and can save you money by using less ink and paper.
4. Structure folders: Where do you save your files? Is everything scattered all over the desktop or stuffed into the “My Documents” folder? Maintain some order by creating folders and subfolders while giving your files appropriate names. It will only take a few extra seconds to do so, but will save you much more time in the future by being able to easily find and sort through files.
5. Store software keys: Make a note of software licence keys and store them safely. In the event of your needing to re-install or activate a program, having its corresponding licence key handy can be the difference between completing a simple re-installation and having to go out and purchase a new one.
6. Invest in security software: Protect your IT investment, your hard work and yourself! Viruses, spyware, adware and other malicious software are topics in the news for a reason. These threats can infect your computer without your even realising it. But do you know what kind of damage they can cause? They can delete or damage files, track your online activity, steal personal information and just outright annoy you by having a poorly performing computer. Take action before they do by investing in sufficient security software. When you do, keep the software up to date and scan your computer regularly to maintain optimum performance and productivity.
7. Blink. Yes, with your eyes: Staring at a computer screen for extended periods of time can have a negative effect on your precious eyesight. Computer users tend to blink less frequently, so make it a habit to blink more often. Why? Blinking produces tears that coat the eyes, keeping them lubricated and moist. Other habits to preserve and protect your eyesight include focusing on distant objects every 15 minutes to relax your eye muscles, and to just take a break every hour or two to reduce eyestrain. Your eyes will thank you.

Classifications of Networks-Part 4

Networking Models

Peer-to-Peer(Workgroup) Model

Peer-to-Peer Model

Peer-to-Peer or simply P2P is a networking model in which each computer in the network has the same priorities or rights when communications are done. That is there is no central nodes or namely servers to manage and control other nodes in the network.  In some cases, peer-to-peer communications is implemented by giving each communication node both server and client capabilities. Because of  these reasons, the P2P is a less secure networking model.

                                            The Peer-to-peer model is also known as Workgroup Model, because the computers working in this model are said to be lied in a Workgoup (A group of computers).

Advantages

1. Easy to setup the network.
2. No dedicated nodes needed.
3. Less expensive.
4. Suitable for small networks with ten to twenty nodes.
5. Local users can control their shared resources.

Disadvantages

1. Less Secure.
2. Less Reliable.
3. Difficult to Administrate.

Client-Server(Domain) Model

Client-Server Model

This is a much secure networking model compared to P2P. In a server-client network, there must have a special computer called server and the others will be clients. A Server is typically a computer which provides service, but here we are using the term server to denote a specific node which has the ability to control and manage other nodes which we calls as clients. Clients are nodes which receives services from a server.

                                 In most conditions, servers only gives some software resources(or a Database) for the clients to use their computer under the control of the server and do their work that are allowed by the server. That is most servers are not intended to give their processing capability or storage capacity to clients. All these resources should exist in the client computer itself.

                The servers must have specific server operating systems installed on it.Some popular server OS's are Windows 2000 Server, Windows 2003 Server, Windows 2008 Server, Redhat Enterprise Linux, Ubundu Server. Clients only need any desktop level OS such as Windows XP, Windows Vista, Windows 7 or Ubundu Desktop.

Advantages

1. Having a dedicated high end machine as server will increase the network performance.
2. Highest level of security(Centralized control of data).
3. Highly expandable.
4. Easy administration compared to P2P.
5. More reliable than P2P.

Disadvantages

1. Server should be dedicated with high configuration hardwares and specific networking softwares(including OS).This is expensive.
2. Server should always be available.
3. Need a full time administrator to maintain the network.
4. Maintenance also is expensive.

Classifications of Networks-Part 3

Network Topologies

                                 A network Topology means, the physical arrangement of computers,devices and cables in a network.

Bus Topology  

In Bus topology network devices uses a common backbone in a linear shape to communicate in the network. All the devices should be attached with this single shared cable with an interface connector. The device, which wants to communicate send a broadcast message to all the devices attached with the shared cable but only the intended recipient will accepts and process that message.

Bus Topology

Advantages

1. Easy to setup a network.
2. Easy to expand.
3. Suited topology for small networks.
4. Less expensive compared to other topologies.                                  

Disadvantages

1.  Slower data transfer rate.
2. Cable length and number of nodes that can connected are limited.
3. If the backbone cable fails, the whole network will fails.
4. Heavy network traffic when number of nodes are increased.

Ring Topology 

Ring Topology

In this topology computers are arranged in a ring manner. That is every computer or devices in this network should have two neighbors for communication. All the communications will be in the same direction, either clockwise or anti-clockwise. 

                              FDDI (Fiber Distributed Data Interface) or Token Ring Technology can be used to implement Ring Technology. Ring topologies can be found in office, school or small buildings.

Advantages

1. Chances of collision is very low.
2. Better performance than a Bus topology.

Disadvantages

1. Failure of one computer or port can cause the whole network to fail.
2. Adding, moving or removing devices can affect the network.
3. Slower than Star topology under normal load.
4. It is difficult to troubleshoot a ring network.
5. Network cards are expensive compared to Ethernet cards and hubs.

Mesh Topology

Mesh Topology

In a mesh topology, each device in the network are interconnected to one another to provide an almost always up network connectivity. That is each device remains in the network even if one or two of the connections go down. As this topology is difficult and expensive to configure, it is not commonly used in most computer networks.

Advantages

1. Data can be transmitted from one node to many nodes and vice versa simultaneously.
2. Less traffic problems.

Disadvantages

1. Configuration of network is complex and expensive.
2. Difficult to manage the network.

Star Topology

Star topology is the most commonly used topology in LAN. A star topology links the computers by individual cables to a centralized connectivity device, usually a hub or switch. The commonly used cable is the Unshielded Twisted Pair (UTP) or Shielded Twisted Pair (STP).

Star Topology

Advantages

1. Easy to setup and expand the network. 
2. Adding, moving or removing devices will not affected to the entire network.
3. Better performance than other topologies.                  
4. Failure of one device or link will not affect the whole network.
5. Centralization of network will help to analyze the traffic.
6. Easy to troubleshoot.

Disadvantages

1. Dependency to the central device(Hub or Switch) is the main drawback. If it fails, the entire network goes down.
2. Expansion and performance of the network is depended on the capacity of the central device.
3. Need of the expansion devices(Hubs, Switches or Routers) will make the network expensive.

Some Basics about Computer for Starters

Computer

Personal Computer

      A computer is a programmable machine that receives input, stores and manipulates data , and provides output in a useful format.In other words a computer is a digital electronic alpha-numeric data processing machine in which we can input data, the computer will process it and give us an output.

Digital
  Computers are digital machines because they can only read information as two signals-on or off. These are called digital signals and tightly related to the binary numbers 1 and 0. Any data inside a computer is in the form of combinations of 1s and 0s and will be converted to on and off signals respectively for the devices to identify it. This method of computation, also known as the binary system.

Data
The term data refers to groups of information or a collection of numbers, characters, images or other outputs from devices that collect information to convert physical quantities into symbols, that are unprocessed.

Continued...

Computers Generations

The history of computer development is often referred to in reference to the different generations of computing devices.Each generation of computer is characterized by a major technological development which in turns changed the way computers operates, resulting in increasingly smaller, cheaper, powerful, faster, efficient and more reliable

First Generation (1940-1956)
The first computers used vacuum tube technology for circuitry and magnetic drums for memory, and were very large in size, taking up entire rooms. They were very expensive to operate and in addition to using a great deal of electricity, generated a lot of heat, which was often the cause of malfunctions.

First generation computers relied on machine language to perform operations, and they could only solve one problem at a time. Machine languages are the only languages understood by computers. While easily understood by computers, machine languages are almost impossible for humans to use because they consist entirely of numbers, which means that they can be operable only by the programmers.

The UNIVAC(UNIVersal Automatic Computer) and ENIAC(Electronic Numerical Integrator And Calculator) computers are examples of first-generation computing devices.
The UNIVAC was the first commercial computer delivered to a business client, the U.S. Census Bureau in 1951. The ENIAC, weighing 30 tons, using 200 kilowatts of electric power and consisting of 18,000 vacuum tubes,1,500 relays, and hundreds of thousands of resistors,capacitors, and inductors, was completed in 1945.

Second Generation (1956-1963)
In the second generation computers Transistors replaced vacuum tubes, but still relied on punched cards for input and printouts for output. Transistor is a device composed of semiconductor material that amplifies a signal or opens or closes a circuit. Invented in 1947 at Bell Labs, transistors have become the key ingredient of all digital circuits, including computers. Today's latest microprocessor contains tens of millions of microscopic transistors.

The transistor was far superior to the vacuum tube, allowing computers to become smaller, faster, cheaper,more energy-efficient and more reliable than their first-generation predecessors. Though the transistor still generated a great deal of heat that subjected the computer to damage, it was a vast improvement over the vacuum tube.

History of Computers

The history of computers starts out about 2000 years ago, at the birth of the abacus, a wooden rack holding two horizontal wires with beads strung on them. When these beads are moved around, according to programming rules memorized by the user, all regular arithmetic problems can be done.Another important invention around the same time was the Astrolabe, used for navigation.

Blaise Pascal is usually credited for building the first digital computer in 1642. It added numbers entered with dials and was made to help his father, a tax collector. In 1671, Gottfried Wilhelm von Leibniz invented a computer that was built in 1694. It could add, and, after changing some things around, multiply. Leibniz invented a special stepped gear mechanism for introducing the addend digits, and this is still being used. The prototypes made by Pascal and Leibniz were not used in many places, and considered weird until a little more than a century later, when Thomas of Colmar created the first successful mechanical calculator that could add, subtract, multiply, and divide.

Computer and Babbage
While Thomas of Colmar was developing the desktop calculator, a series of very interesting developments in computers was started in Cambridge, England, by Charles Babbage, a mathematics professor. In 1812, Babbage realized that many long calculations, especially those needed to make mathematical tables, were really a series of predictable actions that were constantly repeated. From this he suspected that it should be possible to do these automatically. He began to design an automatic mechanical calculating machine, which he called a difference engine.

Babbage continued to work on it for the next 10 years, but in 1833 he lost interest because he thought he had a better idea — the construction of what would now be called a general purpose, fully program-controlled, automatic mechanical digital computer. Babbage called this