History and Components of a Modern Mainframe Computer

Mainframe computers are crucial for some of the largest corporations in the world. Each mainframe has more than one modern processor, RAM ranging from a few megabytes to several-score gigabytes, and disk space and other storage beyond anything on a microcomputer. A mainframe can control multiple tasks and serve thousands of users every second without downtime.

The chief difference between mainframes and other computing systems is the level of processing that takes place. Mainframes are also different in terms of data bandwidth, organization, reliability, and control. Big organizations-banking, healthcare, insurance, and telecom companies, etc.-use mainframes for processing critical commercial data.

In this article, we discuss the evolution of mainframe computers and their components.

History of mainframe computers

IBM developed a crucial part of mainframe computing, the Automatic Sequence Controlled Calculator (ASCC) for arithmetic operations, in 1944. From the late 1950s through the 1970s, several companies manufactured mainframes: IBM, Burroughs, RCA, NCR, General Electric, and Sperry Rand, for example. Since then, System/390 by IBM is the only kind of mainframe in use. It evolved from IBM’s System/360 in 1960.

An Early mainframe occupied a huge space. New technologies have drastically reduced the size and cost of the hardware. A current-generation mainframe can fit in a small closet.

Components of a modern mainframe computer

Like a PC, a mainframe has many components for processing data: operating system, motherboard or main board, processor, controllers, storage devices, and channels.

• Motherboard: The motherboard of a mainframe computer consists of a printed circuit that allows CPU, RAM, and other hardware components to function together through a concept called “Bus architecture”. The motherboard has device slots for input cards and cable interfaces for various external devices. Where PC motherboards use 32- or 64-bit buses, mainframes use 128-bit buses. General instructions regarding the internal architecture help the motherboard connect to the other devices and retrieve data using binary computation.

• Processor: A CPU acts as the central processing point in mainframe architecture and includes an Arithmetic Logic Unit (ALU) for performing arithmetic calculations. It also works as a controller for the bus architecture and handles traffic and data requests. The processing power of mainframes is much higher compared to PCs, so that they can handle huge amounts of data.

• Storage devices: Storage devices are for entering, retrieving, storing, and recording data. Many are external devices, such as hard drives, tape drives, and punch card readers, all connected to terminals of the mainframe and controlled by the CPU. Their capacity for data storage can be hundred or even thousands of times that of a PC.

• Communication controllers: Communication controllers allow remote computers to access a mainframe. With the help of networks, LAN or WAN, communication controllers establish connections with various devices, perform data transmission over communication channels, and keep track of users at terminals.

• Channels: The “channels” are the cables used to connect the CPU and the main storage to other parts of the system and make sure that data is moved in a systematic way without losing its integrity.

Modern mainframes have advanced features such as expanded service management capabilities, cross-platform integration facilities, etc. and thus are suitable for critical data center operations. The cost of maintaining modern mainframes is much less compared to older models.

Four Criteria Of A Great Romance Movie

Romance movies are timeless. Everyone has his or her favorite romance movie. Most of the time, the romance movies serve a purpose, mostly, as an escapism. One thing that these movies do is that they keep the idea of romance alive. No matter how happy or tragic the ending is, romance movies are loved by its viewers for entertaining them and keeping their dream alive.

It begs a question.. what makes a great romance movie? There are some actors and actresses who are great for romance movies and some who do not. There are some stories that are simply remarkable and there are some stories that make you wonder who made it the first place. I believe that there are at least four criteria of a great romantic movie

1. Likability of the Leads

First and foremost, the leads in the movie must be ‘likable’, meaning that the target audience love them and believe that they are lovers or can be lovers in real life. Which means that they must have chemistry between them. When the chemistry is there, it makes the interactions in the movie likable and believable. And it is important for the audience to like the leads for them to ‘get’ the movie.

This factor made Meg Ryan, the romantic comedy queen in late 80s / early 90s. Her two major performance in ‘When Harry Meet Sally’ and ‘Sleepless In Seattle’, paired with two great leading men, Billy Crystal and Tom Hanks, was a major tour de force. In both movies, she ‘clicked’ with both of them, which gave the movies critical and commercial success.

2. Simple And Clear Storyline

Another important criteria is the storyline. It has to be simple and clear, so that the viewer can understand what is going on in the movie, which means, who are the parties in love and what is the situation. Romance movies are not good grounds to do plot twist and turns as it will turn off the viewers as it will interfere with the viewers enjoyment of the romance. An example of good storyline was the movie adaptation of Jane Austen’s Pride and Prejudice, in 2005. The movie did an excellent job in portraying the romance of Mr. Darcy and Elizabeth Darcy, showing the ‘games’ that both played with each other till they eventually fell in love in the end.

3. Movie Location / Background

The role of the movie location and background is to support and enhance the romance movie. It is not very important but it does play a role. The background refers to the cast that surrounds the leads, for example, family members or office mate. The movie location refers where the movie is situated. Usually, it is the movie locations that spice up the romance. A good example of the movie background is the cast of Four Weddings and a Funeral. In the movie, Charles’ set of eclectic friends complimented his ‘adventures’ in pursuing Carrie. A good example of movie location would be the location of Venice and Positano in Only You, starring Marisa Tomei and Robert Downey, where it made the romance in the movie magical, with glorious location scenes, Italian language and songs.

4. Excellent Movie Song / Soundtrack

And finally, the killer criteria would be the song or soundtrack of the movie, as it enhances and reminds the viewer of the romance movie experience. Usually, it would be a pop song sung by the popular artist and it becomes a chart topper. An obvious example would be the song “My Heart Will Go On” sung by Celine Dion from the movie Titanic. The song functions as a killer hook that drives the success of the movie and does help the commercial success of the movie soundtrack and movie itself. In the movie, the song typically appears either as a short music clip or becomes an instrumental background.

Well, those are the four criteria that I think makes a great romance movie. There might be others but these are the four main criteria and when all four criteria appear in a romance movie, it is almost certain that the movie becomes a commercial and critical hit.

Determining the Best Type of Fastener to Use For Outdoor Furniture Construction

If you want to learn about selecting hardware for your next outdoor furniture project, then you’ll want to read this article. Specifically, I’ll be telling you about what type of hardware will perform best, why the type of metal used for fasteners and the finish used are important considerations, and how properly protecting or limiting exposure of your furniture to wet and winter conditions can increase life span. After you’re done with this article you will understand that the best choice of hardware for your outdoor furniture project is dependent on furniture style, material used for construction, selected location for the furniture and budget.

Selecting proper hardware for your furniture will help ensure a long life span, as well as improve the overall appearance of your furniture. Part of the problem is knowing what hardware to select when there are so many options available at the hardware store. The typical Lowes or Home Depot carries a huge selection of stainless steel, hot dipped galvanized, bright galvanized, plain steel, coated steel and brass bolts, nuts, washers and screws. Each type of fastener is suitable for certain applications, but not all are ideal for outdoor furniture applications. 

In fact, choosing the wrong fasteners can greatly shorten the lifespan of your furniture, contribute to rot of wood furniture, cause unsightly staining, and even make your furniture unsafe to use. 

One thing that needs to be noted right up front is, do not ever use unprotected steel fasteners for outdoor furniture, They will rust very quickly, and the steel will react with the tannic acid in the wood causing streaks and staining. The tannic acid actually speeds up the corrosion of the fasteners. Have you ever seen a wooden fence with black streaks running down the boards from the nails? This fence was installed with the wrong type of fasteners. The same thing will happen to your furniture. Even worse, as the fasteners rust, they will speed up the decay process of the wood around the rusted fasteners, ruining your furniture and making it potentially unsafe to use.

Hot Dipped Galvanized

Screws and bolts treated by hot dipped galvanizing are specifically designed for use outdoors. Electroplated galvanized or bright galvanized fasteners ultimately will not hold up as well as the hot dipped galvanized hardware. Zinc is used as a coating in both methods, and acts as a barrier against the elements and the tannic acids in the wood. 

I strongly recommend only using screws or bolts in the construction of outdoor furniture, however. The galvanized finish on nails, either electroplated or hot dipped, can easily become damaged while hammering them in, exposing the nail head to the elements and allowing them to begin rusting quickly. 

Adequate care must be taken when installing galvanized screws. Drill pilot holes in hardwoods, and be sure to use a bit that is not worn and susceptible to skipping in the screw head. For whatever reason, the galvanized screws seem to not be as well tempered as other steel fasteners, and are more likely to either snap off or have the heads strip out while installing them. Due to the allowance required for the hot dipped coating, galvanized bolts do not have as tight of tolerance on the threads, and are more likely to strip if over tightened.

Hot dipped galvanized fasteners are a fine choice for many outdoor furniture applications, including Adirondack Chairs, but are not the best choice for use in woods, such as teak.

Stainless steel

Stainless steel is the best choice for use in woods with higher levels of tannic acid, such as teak. Stainless steel is an alloy or blend of steel, nickel and chrome. The ratio of the other metals with the steel determine the weather and corrosion resistance of stainless steel. Because the steel is mixed with other softer metals, the stainless steel is not as strong, so predrilling of screw holes is highly recommended in all applications, and essential in hardwoods such as teak and mahogany. The added corrosion resistance more than outweighs any shortcomings that the metal may have, especially in outdoor furniture applications. 

While stainless steel fasteners are the most rust resistant, they are also the most expensive of the options we are discussing. However, using stainless steel fasteners will add years of life to your furniture. In the respect, they are an investment that will pay out for years to come.

Brass

I have seen brass used in some commercially produced outdoor furniture, but do not recommend it. While brass does not form red rust, and is well suited for many wet applications such as toilets and sinks, it does tarnish and corrode. It is also very susceptible to the tannic acids in wood, which will cause it to fail more quickly. Brass screws in particular do not have sufficient strength for outdoor furniture applications.

Outdoor or deck screws

In the past several years a number of manufacturers have introduced outdoor fastening products specifically marketed for deck building. These will typically be green, gray, tan or brown. These screws are either ceramic or plastic coated to delay the metal reacting with the wood acids. The specific coating methods are proprietary to each manufacturer, and can be a combination of electroplated galvanizing and plastic, or a baked on ceramic.

I have used these fasteners in furniture applications and they perform just fine. Unfortunately, I have not come across bolts with this type of finish. The brand of screw I used was Deck Mate, and they were available in tan and brown, so that the color can be selected to better match the wood being used. These screws are ceramic coated, and the manufacturer provided a coated bit for installation, which was designed to not damage the ceramic coating at the screw head. If you choose this type of fastener, be sure to compare the cost with stainless steel, as the price will vary. If the stainless steel is reasonably comparable in cost, it would be the recommended fastener. 

Always be sure to read the manufacturers specifications on the box to be sure that the screws are suitable for your application. 

Other Considerations

If you are building furniture that will be located on a covered porch or patio where it will be protected from the elements, the concern will be the interaction between the wood and the fasteners, much more so than the weather. Furniture that will be exposed to the elements all year, such as a garden bench, or an Adirondack chair in the corner of your garden, will have to be constructed with much more care and concern to ensure that they hold up more than just one or two winters.

Additional considerations must be made beyond just the choice of what type of fastener to use, though this is very important. For example, fasteners should not be located where water where collect and sit on the fasteners for an extended period of time. The screws that attach the seat slats to an Adirondack chair are a prime example- typically these screws will be countersunk below the surface of the wood. This will allow water to collect in the screw holes, shortening the life span of all but stainless steel fasteners, and prolonging the exposure of the wood to water, which will increase the rate of decay. In applications where the furniture will be exposed to the elements year round the screw heads should be driven flush with the surface of the surrounding wood. 

Construction and design of the furniture are also important considerations. Are the horizontal surfaces of the furniture constructed in such a way that will allow them to shed water, rather than collect it? Think of a picnic table with a slatted or board top. The gaps between the boards allow water a way to run off the top and not pool up. 

Conclusion

Stainless steel is usually the best choice for outdoor furniture applications, though the cost may be prohibitive for some. There are other less expensive fastener options available that will perform acceptably. Do not use unprotected steel fasteners for outdoor furniture applications under any circumstances. Know where and how you intend to use your furniture and design it for the conditions it will be subjected to.

Top Ten Coolest Security Guard Movies

For as long as we can remember, films that feature bumbling, hapless or larger-than-life security guards, or protective dynamic duos, have been a fun, important part of cinematic history. Here is a list of classic bodyguard movies, or movies with super-strength security stars that we simply can’t forget.

1. Armed and Dangerous: John Candy and Eugene Levy team up and make cinematic history in this brilliant buddy comedy; the bumbling duo play a recently fired cop and amoral lawyer who suit up as security guards, only to find that they’ve unwittingly become members of a corrupt company.

2. The Bodyguard: Kevin Costner and Whitney Houston sizzle on the big screen as a former Secret Service agent acting as bodyguard to a mainstream pop singer. The film’s epic soundtrack continues to be one of the best-selling albums of all time.

3. National Security: Martin Lawrence and Steve Zahn as Earl and Hank, respectively; two guards from different walks of life that have one thing in common: the security company they work for. Their history of hating each other stems from Earl’s key role in Hank’s dismissal from the police force. This odd couple doesn’t disappoint in the laughs department.

4. Observe & Report: This dark comedy features Seth Rogen as Ronnie Barnhardt, a depressed, on-the-brink guard who is head of the security department at Forest Ridge Mall. When he fails to get into the police force and is belittled by the officer taking over his operations, he embarks on a dual mission of madness: to prove himself and catch the elusive mall flasher, Ronnie’s arch enemy and ultimate target.

5. In the Line of Fire: Clint Eastwood as Frank Horrigan, a Secret Service agent to the President. Frank famously dropped the ball when it came to saving President Kennedy, but did put himself on the front lines to take out a crafty assassin who is targeting his current client.

6. Paul Blart:Mall Cop: Kevin James holds it down as Paul Blart, who dreams of being an officer for the New Jersey State Police. However, his ample size doesn’t help his chances of being a powerhouse cop, so he has to make do with being a security guard at his local mall. Heartwarming and hilarious, this is a great film for the whole family.

7. The Pacifier: Vin Diesel as tough guy Shane Wolfe, a disgraced US Navy SEAL assigned to work as a bodyguard protecting five rebellious kids. He may soon be the one needing protecting, as he learns the hard way that nannying is no joke.

8. Night at The Museum: Larry Daley is a night guard at New York’s American Museum of Natural History in. Upon beginning his shift, he’s instructed not to let anything “in or out.” He soon comes to realize the significance of this creepy warning: The Museum comes to life at night, kicking off a bone-tingling phenomenon that delighted movie-goers of all ages.

9. Guarding Tess: Nicholas Cage as Doug Chesnic, a Secret Service agent protecting Jessica Tandy’s Tess Carlisle, the widow of a former US President. Though he holds great pride in his prestigious job, the fiesty First Lady tests his limits by treating him like a lowly servant. Have your hankie ready for this endearing tear-jerker.

10. Terminator 2: Judgment Day: Arnold Schwarzenegger returns as the ultimate larger-than-life robo-guard, a well-muscled force from the future on a mission to protect teenager John Connor. Nothing says big-screen fun like another deadly Terminator!

Surviving Missing Futon Frame Hardware Nightmares

There seems to be quite a few of us who have owned a futon frame and ended up losing the connecting hardware at one time or another. I myself bought a futon from the retail store I worked in for a number of years back in the early 1990s when futons were all the rage. Maybe you purchased your futon in college, acquired it from a friend or maybe made the purchase for a family room. If you’re lucky to live out your life in the same house or apartment there will never be a need to move your futon except perhaps to a different room or location. Obtaining replacement futon frame hardware involves several steps approached in order to locate exactly what you need.

In the first place don’t panic just yet. Without the hardware to attach everything back together you’re in some serious trouble. However there are ways to obtain what you need. At this point we could explain the many benefits of using a small bag to contain the hardware and attach it to a part of the frame with heavy packing tape so it’s easily found. Who am I kidding though? I’ve moved mine now about three times and each time I ended up missing a bolt, a barrel nut, a nylon roller here and there. Heck, I was lucky I had all the wood components show up at each new move let alone any hardware that happened to make it as well. Besides, isn’t moving your home stressful enough without having to keep track of a small bag of metal hardware among a sea of furniture, clothing, dishes, toys and appliances?

Pursuing this further we must calmly step back and think for a moment. Yes, we’re stressed out and fuming at either our spouse or the moving company for losing the futon hardware but we need to move past that now. To be sure the futon needs our help and we’re the only ones who can do it at this point. It’s time for us to go through the steps of obtaining replacement hardware and there is a specific order in which we do this to obtain the fastest results. I would suggest the following steps to start tracking down replacement hardware as soon as possible.

First – identify your futon frame.

Having worked retail, it’s quite possibly the toughest situation when a customer comes into the store needing assistance but can’t identify the product to the salesperson or service individual when requesting parts. Granted you’re going to have to do a little research by pulling your receipt when you bought the futon from the store and identify the model or name of the futon. If you inherited the futon, found it by the side of the road or bought it at a garage sale you’re in for a tough road ahead. Fear not however as the internet can be used to help you find the design and attach a name to it for use in tracking down hardware. Be aware that there are dozens of manufacturers out there using different hardware in their frames including many that have since closed their doors. Hopefully the manufacturer of your frame is still around.

Second – speak to the retailer.

Of course if you purchased your futon frame through a local retail store it’s time to head down there and see if they can track down the hardware for your frame. Bring your receipt. If you don’t have a receipt, then bring an image of the futon frame with you. Hopefully the salesperson or service representative is knowledgeable about the products they’ve carried in the past. Best case scenario, they either can provide you with the name of the manufacturer with contact information or have the parts on hand to get you back up and running. Worst case scenario the store you purchased it from is out of business or if the store is still around they have no clue about the product anymore.

Third – search online.

Supposing we’ve hit the worse case scenario it’s time to use the web to search for the manufacturer or the name of the style of futon you have. I’d suggest using Google, Bing or Yahoo and use the name adding the word futon to the search. If you weren’t able to locate a name you’re going to have to become a very good spotter and sift through the many images of futon frames till you find one that is very close to what you have. Identify the name of the style and the manufacturer and then proceed to locate the manufacturer of the futon frame.

Fourth – speak to the manufacturer.

Assuming the retailer didn’t have parts but could identify the manufacturer for you then you at least have something to go on. Perhaps you were able to locate your frame style through the search engines. Again, search online using the websites previously discussed using the name of the manufacturer. You’ll likely get some online retail stores off of the search. Filter them out visually until you find a link for the manufacturer. Most do have websites, locate a contact phone number or email address and contact them for information on obtaining hardware. If you’re unable to locate the manufacturer’s website go ahead and contact one of the many futon stores that pop-up in the search results and email them with your issue and ask if they can either sell you hardware or point you in the right direction for finding the manufacturer in hopes of tracking down hardware.

Finally – the last resort.

If you were unable to determine the name of the futon frame or the name of the manufacturer you are indeed in a tight spot. At this point your options are limited to heading down to a hardware store and seeing if you can locate some generic parts that might get you back up and running. The problem will be in the way of connecting bolts and barrel nuts and getting the right lengths if available. I would suggest taking one of the wood arms and a stretcher rail with you to the store. Begin plugging in different bolts and nuts till you find a combination that connects correctly. You’ll also need to track down connecting pins, washers and clips for the seat and back section as well as the four nylon rollers that most futon frames use on the back rest. If you’re lucky these may still be attached to the backrest deck making your job a bit easier.

In conclusion we’ve discussed the issues presented with lost futon hardware and how to go about tracking down the hardware you need. Basically identify your frame through a receipt or spotting it online. Visit the retailer store you purchased it from and obtain parts through them if they are still open. If you purchased it privately or inherited the frame track down the manufacturer using a search engine of your choice and speak to them about ordering replacements. If you aren’t able to locate the manufacturer but have found stores online contact one of them to see if they can sell you hardware. If all else fails visit the local hardware store with your wood futon sections in hand and begin trying bolts and nuts till you find some that work. I sincerely hope you’re able to obtain the needed hardware to get your futon frame back up and running. I wish you the best of luck to you and your futon.

Watch Free Movies Online and Explore Various Genres

Most people love to watch comedy, horror, action, adventure, or drama movies. These categories do well at the box office and in terms of DVD sales. There also happen to films that belong to other genres. If you ever watch free movies online, you may want to give them a try.

Classic Movies. The mid-20th century is also known as the Golden Age of Hollywood, which produced quite a number of films considered to be defining moments in cinematic history. Stars such as Bette Davis, Clark Gable, Marilyn Monroe, Humphrey Bogart, Joan Crawford, Audrey Hepburn and directors like Alfred Hitchcock and Orson Welles are just some of the legends of the cinema who dominated this era.

Biographical Movies. These movies tell the life story of real people such as entertainers, heroes, monarchs, scientists, philanthropists, etc. They do not purport to reveal every single detail of a person’s life but rather center upon a predominant theme and important highlights. Biographies are sometimes dramatized and feature reenactment scenes to further illuminate the personality life of that person. They also touch upon the various historical and social realities at the time.

Family Movies. These films focus on a wider audience, i.e. families. The scenes, themes and dialogue presented in family-oriented movies are generally wholesome and either rated PG (Parental Guidance) or G (General Audience) so as not to leave any negative influence on the children who are watching. Oftentimes, these movies impart moral lessons such as the importance of listening to your parents, the joy of being with your family, and the fact that no matter what happens to you, your family will never leave you. They also tackle family problems that the characters will need to resolve themselves in order to live happily ever after.

Fantasy Movies. These films create a sort of escape for viewers. Fantasy movies often deal with magic and the supernatural and are often filled with wonderful creatures like dwarves, fairies, leprechauns, elves, wizards, etc. They always have some element of drama and purport to teach lessons about life, love and sacrifice to heighten the plot.

Animated Films. These films appeal to children and the young-at-heart but can also be targeted at more mature audiences. Animated films are made with advanced graphics and CGI effects and feature fictitious characters dubbed by real persons, mostly famous actors. A lot of animated films are based on fairy tales and characters in comics; some go so far as to parody classic fairy tales or even retell them from a revisionist point of view. Today, you can find a lot animated films when you watch free movies online.

Wide Area Network (WAN)

Types and Characteristics of WANs

What is a WAN?

There are two prevailing definitions of a Wide Area Network (WAN). The book definition of a WAN is a network that spans large geographical locations, usually to interconnect multiple Local Area Networks (LANs). The practical definition of a WAN is a network that traverses a public network or commercial carrier, using one of several WAN technologies

What are its Main Components?

The main components for a WAN are routers, switches and modems. These components are described below in the hardware section.

CPE – Devices on the subscriber premises are called customer premises equipment (CPE).

The subscriber owns the CPE or leases the CPE from the service provider. A copper or fiber cable connects the CPE to the service provider’s nearest exchange or central office. This cabling is often called the local loop, or “last-mile”.

DTE/DCE – Devices that put data on the local loop are called data circuit-terminating equipment, or data communications equipment (DCE). The customer devices that pass the data to the DCE are called data terminal equipment (DTE). The DCE primarily provides an interface for the DTE into the communication link on the WAN cloud.

Hardware

In a WAN you will need various types of hardware components for it to function. The typical items of hardware that you will need in a WAN are:

Router – An electronic device that connects a local area network (LAN) to a wide area network (WAN) and handles the task of routing messages between the two networks. Operates at layer 3, and makes decisions using IP addresses.

Switch – A switch is a network device that selects a path or circuit for sending a unit of data to its next destination. Operates at layer 2, and uses MAC addresses to send data to correct destination.

Modem – Short for modulator/demodulator, a modem enables a computer to communicate with other computers over telephone lines. Operates at layer 1, where signals are converted from digital to analogue and vice versa for transmission and receiving.

Wan Standards

WANs operate within the OSI model using layer 1 and layer 2 levels. The data link layer and the physical layer. The physical layer protocols describe how to provide electrical, mechanical and functional connections to the services provided by the ISP. The data link layer defines how data is encapsulated for transmission to remote sites.

Encapsulation

Encapsulation is the wrapping of data in a particular protocol header. Remember that WANs operate at the physical layer and the data link layer of the osi model and that higher layer protocols such as IP are encapsulated when sent across the WAN link. Serial interfaces support a wide range of WAN encapsulation types, which must be manually specified. These types include SDLC, PPP, Frame delay etc. Regardless of WAN encapsulation used it must be identical on both sides of the point to point link.

Packet and Circuit Switching

Circuit switching and packet switching are both used in high-capacity networks.

The majority of switched networks today get data across the network

through packet switching.

Circuit-switching is more reliable than packet-switching. Circuit switching is old and expensive, packet switching is more modern.

General Routing Issues

What is a Routing Protocol?

A routing protocol is a protocol that specifies how routers communicate and exchange information on a network. Each router has prior knowledge of its immediate neighbours and knows the structure of the network topology. The routers know this because the routing protocol shares this information.

Protocol

RIP (Routing Information Protocol) was one of the most commonly uses protocols on internal networks. Routers use RIP to dynamically adapt changes to the network connections and communicate information about which networks routers can reach and the distance between them. RIP is sometimes said to stand for Rest in Pieces in reference to the reputation that RIP has for breaking unexpectedly and rendering a network unable to function.

Routing Algorithms

Distance Vector

This type of routing protocol requires that each router simply inform its neighbours of its routing table. The distance vector protocol is also known as the bellman-ford algorithm.

Link State

This type of routing protocol requires that each router maintain a partial map of the network. The link state algorithm is also know as Dijkstra’s algorithm.

IGRP

IGRP is a type of distance vector routing protocol invented by cisco used to exchange routing data in a autonomous system. Distance vector protocols measure distances and compare routes. Routers that use distance vector must send all or a portion of their routing table in a routing update message at regular intervals to each neighbour router.

Addressing and Routing

What does routing mean?

Routing is the process of deciding how to move packets from one network to another.

The directions also known as routes can be learned by a router using a routing protocol then the information is passed from router to router along the route of the destination.

IP Address’s

Every machine connected to the internet is assigned an IP address. An example of an IP address would be 192.168.0.1. IP addresses are displayed in decimal format to make it easier for humans to understand but computers communicate in binary form. The four numbers that separate an IP address are called Octets. Each position consists of eight bits. When added to together you get 32 bit address. The purpose of each octet in an IP address is to create classes of IP addresses that can be assigned within a network. There are three main classes that we deal with Class A, B and C. The octets of an IP address are split into two parts Network and Host. In a class A address the first octet is the network portion, this determines which network the computer belongs to, the last octets of the address are the hosts that belong to the network.

Sub netting

Sub netting allows you to create multiple networks within a class A, B or C address. The subnet address is the address used by your LAN. In a Class C network address you would have a subnet mask of 255.255.255.0. A subnet mask identifies which portion is network and which is host. For example 192.168.6.15 the first octet three octets are the Network address and the last octet being the host(Workstation). It is important to subnet a network because gateways need to forward packets to other LANS. By giving each NIC on the gateway an IP address and a Subnet mask it allows the gateways to route packets from LAN to LAN. Once the packet arrives at its destination, the gateway then uses the bits of the subnet portion of the IP address to decide which LAN to send the packets.

Circuit Switched Leased Lines

A circuit switched network is one that establishes a dedicated circuit (or channel) between nodes and terminals before the users may communicate. Here are some terminologies associated with a Circuit switched network.

Frame relay is a telecommunication service designed for cost-efficient data transmission between local area networks (LANs)

Basic rate interference is a service used by small business for internet connectivity. An ISDN BRI provides two 64 Kbps digital channels to the user.

Primary rate interface (PRI) is a telecommunications standard for carrying voice and data transmissions between two locations

All data and voice channels are ISDN and operate at 64kbit/s

Packet Switching

http://www.raduniversity.com/networks/2004/PacketSwitching/main.htm – _Toc80455261

Packet switching refers to protocols in which messages are broken up into small packets before they are sent. Each packet is then transmitted over the Internet. At the destination the packets are reassembled into the original message. Packet switching main difference from Circuit Switching is that that the communication lines are not dedicated to passing messages from the source to the destination. In Packet Switching, different messages can use the same network resources within the same time period.

http://en.wikipedia.org/wiki/Asynchronous_Transfer_Mode

Asynchronous Transfer Mode (ATM) is a cell relay, packet switching network and protocolwhich encodes data into small fixed-sized cells.

ISDN is used to carry voice, data, video and images across a telephone network. ISDN stands for integrated services Digital Network. Isdn also provides users with a 128kbps bandwidth. This is done through frame relay. Frame relay complements and provides a service between ISDN, which offers bandwidth at 128 Kbps and Asynchronous Transfer Mode which operates in somewhat similar fashion to frame relay but at speeds from 155.520 Mbps or 622.080 Mbps. Frame relay is based on the older X.25 packet switching technology and is used to transmit analogue signals such as telephone conversations.

PSDN stands for packet switched data network and is a data communication network. Packet switched networks do not establish a physical communication signal like the public telephone does (circuit switched network) Packets are sent on a fixed length basis and assigned with a source and a destination address. The packets then rely on the routers to read the address and route the packets through the network.

Mobile and Broadband Services

Digital Subscriber line(DSL) is mainly used to bring high bandwidth connections to homes and small business’s over a copper wire telephone line. This is can only be achieved if you stay within the range of the telephone exchange. DSL offers download rates of up to 6mbps allowing continuous transmission of video, audio and 3D effects. DSL is set to replace ISDN and compete with the cable modem in providing multimedia to homes. DSL works by connecting your telephone line to the telephone office over copper wires that are twisted together.

Asymmetric Digital Subscribers Line is most commonly used for home users. It provides a high download speed but a lower upload speed. Using ADSL, up to 6.1 megabits per second of data can be sent downstream and up to 640 Kbps upstream.

http://en.wikipedia.org/wiki/Symmetric_Digital_Subscriber_Line

Symmetric Digital Subscriber Line is a digital subcriber line which runs over one pair of copper wires. The main difference between ADSL and SDSL is the difference in upload and download speeds. SDSL allows the same upstream data rate and downstream data rate as ADSL upstream can be very slow.

[http://searchnetworking.techtarget.com/sDefinition/0],,sid7_gci558545,00.html

HDSL High bit-rate Digital Subscriber Line, one of the earliest forms of DSL, is used for wideband digital transmission within a corporate site and between the telephone company and a customer. The main characteristic of HDSL is that provides equal bandwidth in both directions.

IDSL is a system in which data is transmitted at 128 Kbps on a regular copper telephone line from a user to a destination using digital transmission.

The Local Loop enables operators to connect directly to the consumer via copper local loops and then add their own equipment to offer broadband and other services. This process involves operators accessing local exchange buildings to connect to a network of copper lines which connect them to homes and businesses. BT is an Example of a Local Exchange. The local loop connecting the telephone exchange to most subscribers is capable of carrying frequencies well beyond the 3.4 kHz upper limit.

Benefits of using DSL

DSL can provide virtually instantaneous transmission of voice, data and video over ordinary copper phone lines. A DSL connection can eliminate delays when waiting to download information and graphics from the Internet. It provides users with a cost effective high speed Internet connection. Another benefit is that a DSL connection is always on-line (like a LAN connection) with no waiting time for dialling or connecting.

There are now more than 10 million broadband connections in the UK. By December 2005 there were 9.792 million broadband connections in the UK and the average broadband take up rate during the three months to December was more than 70,000 per week.

A Great Reason Why People Need to Watch Comedy Movies

Everyone needs a good laugh from time to time. That is when we go to see a good comedy. There are many reasons why this genre of movies is good. Everyone needs a little bit of laughter at some point in their life. They have to smile because things in this life just wear us out and break us down. However, there is a good thing or two to know about comedies.

Comedies are suitable for people from all age groups. There are cartoons for kids and more matured content for adults and teenagers. Comedy is a way to keep people from all walks of life entertained. Some comedies are based on family values, therefore making it suitable for parents and children to watch and enjoy together.

Nevertheless, some of the materials used to make people laugh have been pretty controversial. There have been some comedies that are based on jokes that demean a person’s sexual orientation. Gays and lesbians have been bashed greatly in most comedy flicks. It is very common to turn on your TV to watch a movie, and to find that there is a gay or lesbian in the movie that has all the perceived characteristics associated with homosexuals.

There are also some films that make comedy out of racist jokes. People tend to laugh when they show a movie where a Mexican is driving a van recklessly when there are other drivers on the road. Some make racist jokes about black people. Contrary to what is being fought for by human rights, our society has taught us that making fun with racism is very acceptable.

There might have been times that come you have gone to watch a comedy movie and left the cinema finding that the movie is not funny at all. There are some movies that just try too hard to be funny. You probably would have seen at least one of these lousy comedies. We wonder where the directors came up with such a plot for these films. It is almost as though someone who was smoking weed had put random videos together and called it a movie.

However, there are some comedies that touch the heart and stick to you. Many favored movies that made jokes about previous movies that have been released. Many of you will remember the Scary Movies films which made fun of several horror movies. We laughed because Scary Movie made fun of other horrific and scary movies, and turned it into a light-hearted movie.

We should have a little time for comedies in our lives. It is what we need after a tough or bad day. Sometimes, we don’t want the fairy tale ending. We don’t want to think. We just want to laugh and enjoy the show. This is what top 10 comedy movies do for us. It is also the type of movie you can go to when you want to watch something alone. And at the same time, you can watch comedies together with a group of friends. Finally, comedies will be perfect if you just need to calm down and lose yourself for the moment.

Computer Hardware Course – The Advantages of Taking It

Computer hardware courses are an excellent way to learn how to manage the inevitable computer failures that you will encounter as you find yourself depending on your computer more and more everyday. While you do have the option of taking your computer to the service center it can cost you a lot of time and money. Your computer hardware course is invaluable for helping you understand the hardware requirements for your computer that will be enable you to jump to the rescue instead of trudging along to the repair shop.

It does not take an engineer or a technician to be successful in learning about computer hardware. If you are interested in engineering or technician positions however, a background in computer hardware can make you a far more valuable person in your field and can enhance your employability tremendously.

To troubleshoot your computer you can do very well with a simple computer hardware course. You can become your own specialist and forgo spending the money on an IT specialist.

The time invested in a computer hardware study program will pay off quickly when things go wrong. But, this is not the only reason taking a computer hardware course would be a good plan.

Not only will you be able to fix your computer, but you will have the knowledge to build a computer from scratch. The cost of computer parts is often far less expensive than buying a pre-made package. You will also be able to customize your computer so that it is perfectly designed for your needs.

By avoiding the cost of labor from the computer store you will have a far less expensive computer that is perfect for you. You will also no longer need to worry about taking your computer in for repairs as you will know just how to fix what goes wrong.

Computer knowledge is in high demand no matter what career you are involved in. With the information you learn in a computer hardware course you will be able to take on an IT position. Such positions are in high demand as a limited number of people have the knowledge to take on an IT role.

The time needed to take a computer hardware course is well worth the investment. Learning about software and programming can only make you even better with your computer goals. If you are limited in time, not to worry. Many courses are available online or on CD for you to do at home.

Take some time to discover exactly what will be covered in your course. The computer technology field is huge, so you will need to focus. You will never be able to learn everything about computer hardware in a single course. It takes a lifetime of study to learn, and with technology constantly changing you will need to continually work on keeping your knowledge up to date. A computer hardware course will bring you a chance to get ahead of the game and keep up with your own computer.

Louis Zhang, computerhardwarecourseit dot com

Why People Love Science Fiction Movies

Science fiction movies are one of those genres that people just cannot get enough of. They appeal to the need that people have to believe that there is something else out there besides us. When people need something to believe in they either lean towards religion or science. Those that lean towards science love these types of films.

People also like to ask, “what if…” in different ways. Science fiction movies allow people to open up their imaginations to all sorts of possibilities. What if there is life on other planets? What if that life came here to Earth? What if that life form was bad? What if that life form was good? All of these questions are things we ask ourselves and these types of movies allow us to explore the possibilities.

Science fiction movies are often full of things that we like in movies. There is suspense and excitement. There are battle scenes and sometimes even romance. The storytelling is often of high quality and thought provoking questions are addressed. These films often address issues like ethics and philosophy and can make us think for days on end.

There are many great science fiction movies out there and they appeal to a wide audience. If you have never watched sci fi flicks before check out some of these classic movies:

· The Matrix Trilogy: This trilogy of science fiction movies follows Neo and his friends as it addresses the question, What if this life isn’t real? What if we have another life and the life we think we are living is just a dream?

· The Star Wars Movies: This series of movies kept sci-fi fans on the edge of their seats for over a decade with movies that brought together love, ethics, power, the battle for right and wrong, and of course, exploration of the universe.

· The Star Trek Movies: Over the past several decades there have been many Star Trek movies made. The older movies are as fascinating as the new ones and the characters pull you in.

· Planet of the Apes: The first movie was made in 1968 made us think about what would have happened if we had not completely evolved. A remake of the original movie was made in 2001.

· E.T.: This is one of the first movies that made people think of aliens in a positive way. Children and adults alike fell in love with this sweet extra-terrestrial that just wanted to go home.