Load balancing is the even distribution of computer processing and communication activities so that a server is not overwhelmed. Load balancing is especially important for networks where it is difficult to predict the number of requests that will be issued to a server.
Busy Web sites typically employ two or more Web servers in a load-balancing scheme. If one server starts to get swamped, requests are forwarded to another server with more capacity. Load balancing is therefore a service that is employed on more sophisticated site deployments.
Most service providers that offer managed hosting will provide load balancing services to their clients if they experience constantly heavy traffic on their Web sites. Multiplexing traffic amongst several servers permits better site availability. Load balancing therefore distributes traffic efficiently among network servers so that no individual server is overburdened.
In the early days of the technology, many load balancing solutions where implemented through customized domain name server configurations. This approach called “DNS round robin,” rotated incoming requests from Web browsers to multiple Web servers. The result was that all requests to the particular Web site were evenly distributed among all of the machines in the cluster.
The advantage of this system was that it was inexpensive, as a system administrator only needed to make a few changes in order to implement it. Its major disadvantages however was that DNS round robin did not support server affinity or high availability.
Server affinity is a load-balancing systems ability to manage a users requests, either to a specific server or any server, depending on whether session information is maintained on the server or at an underlying, database level. Without server affinity, DNS round robin could not by itself exercise control over incoming traffic without the aid of cookies, hidden fields or URL rewriting.
Due to its very nature of not being able to exercise this type of control, DNS round robin could not natively handle browser caching, since incoming requests were randomized. DNS round robin also had tremendous difficulties dealing with high availability, since the DNS system requires a large amount of time of propagate information and cache it throughout the network. As a result, DNS round robin is a more antiquated approach toward managing server load. Load balancing, however, is much more sophisticated today, because it is mainly implemented through appliances such as smart switches.
Hardware load balancers solve many of the problems faced by the round robin software solution through virtual server addressing. A load balancer shows a single, virtual server address to the outside world, which maps to the addresses of each server within the cluster. When a request comes to the load balancer, it rewrites the requests header to point to other machines in the cluster. If a machine is removed from the cluster, the request does not run the risk of hitting a dead server, since all of the machines in the cluster appear to have the same IP address. This address remains the same even if a node in the cluster is down. Moreover, cached DNS entries around the Internet are not a problem. When a response is returned, the client sees it coming from the hardware load balancer machine. In other words, the client is dealing with a single machine, the hardware load balancer.
Because one machine is dealing with the management of an entire cluster, server affinity and high availability is actually integrated into the hardware load balancer solution. Indeed, with the hardware solution, a service provider can offer fail-over services, cluster management, traffic routing and geographic load balancing across multiple sites and points of presence.
Hardware also is a much faster traffic routing solution because it is solid-state device that more efficiently processes requests than software on a server deployment can
Link load balancing is a key element in the overall network Intrusion Prevention effort. Expert Link Load Balancing guards the network against internal and external attacks such as viruses, worms, Trojans, anti-scanning and protocol anomalies. Above all hovers the ultimate link load balancing challenge and network threat – DOS - Denial of Service.
Saturday, April 3, 2010
DNS Load Balancing
How DNS load balancing works
When the request comes to the DNS server to resolve the domain name, it gives out one of the several canonical names in a rotated order. This redirects the request to one of the several servers in a server group. Once the BIND feature of DNS resolves the domain to one of the servers, subsequent requests from the same client are sent to the same server.
DNS load balancing implementation (Multiple CNAMES)
This approach works for BIND 4 name servers, where multiple CNAMES are not considered as a configuration error. Assuming there are 4 web servers in the cluster configured with IP addresses 123.45.67.[1-4], add all of them to the DNS with Address records (A Names) as below. The srv[1-4] can be set to any name you want, such as foo[1-4], but should match the next step.
The DNS server will resolve the www.domain.com to one of the listed servers in a rotated manner. That will spread the requests over the group of servers.
Note: The requests sent to http://domain.com (without www) should be forwarded to http://www.domain.com in this case to work. For BIND 8 name servers, the above approach will throw an error for multiple CNAMES. This can be avoided by an explicit multiple CNAME configuration option as shown below.
DNS load balancing implementation (Multiple A Records)
This above approach with multiple CNAMES for one domain name is not a valid DNS server configuration for BIND 9 and above. In this case, multiple A records are used.
When the request comes to the DNS server to resolve the domain name, it gives out one of the several canonical names in a rotated order. This redirects the request to one of the several servers in a server group. Once the BIND feature of DNS resolves the domain to one of the servers, subsequent requests from the same client are sent to the same server.
DNS load balancing implementation (Multiple CNAMES)
This approach works for BIND 4 name servers, where multiple CNAMES are not considered as a configuration error. Assuming there are 4 web servers in the cluster configured with IP addresses 123.45.67.[1-4], add all of them to the DNS with Address records (A Names) as below. The srv[1-4] can be set to any name you want, such as foo[1-4], but should match the next step.
The DNS server will resolve the www.domain.com to one of the listed servers in a rotated manner. That will spread the requests over the group of servers.
Note: The requests sent to http://domain.com (without www) should be forwarded to http://www.domain.com in this case to work. For BIND 8 name servers, the above approach will throw an error for multiple CNAMES. This can be avoided by an explicit multiple CNAME configuration option as shown below.
DNS load balancing implementation (Multiple A Records)
This above approach with multiple CNAMES for one domain name is not a valid DNS server configuration for BIND 9 and above. In this case, multiple A records are used.
Server Load Balancing: Introduction
Why is load balancing of servers needed?
If there is only one web server responding to all the incoming HTTP requests for your website, the capacity of the web server may not be able to handle high volumes of incoming traffic once the website becomes popular. The websites pages will load slowly as some of the users will have to wait until the web server is free to process their requests. The increase in traffic and connections to your website can lead to a point where upgrading the server hardware will no longer be cost effective.
In order to achieve web server scalability, more servers need to be added to distribute the load among the group of servers, which is also known as a server cluster. The load distribution among these servers is known as a href= http://www.xrio.com/xrionet/TechnologySolutions/ISPLoadBalancing/tabid/83/Default.aspx target= _blank load balancing. Load balancing applies to all types of servers (application server, database server), however, we will be devoting this section for load balancing of web servers (HTTP server) only.
About load balancing mechanism - IP Spraying
When multiple web servers are present in a server group, the HTTP traffic needs to be evenly distributed among the servers. In the process, these servers must appear as one web server to the web client, for example an internet browser. The load balancing mechanism used for spreading HTTP requests is known as IP Spraying. The equipment used for IP spraying is also called the load dispatcher or network dispatcher or simply, the load balancer. In this case, the IP sprayer intercepts each HTTP request, and redirects them to a server in the server cluster. Depending on the type of sprayer involved, the architecture can provide scalability, load balancing and failover requirements.
If there is only one web server responding to all the incoming HTTP requests for your website, the capacity of the web server may not be able to handle high volumes of incoming traffic once the website becomes popular. The websites pages will load slowly as some of the users will have to wait until the web server is free to process their requests. The increase in traffic and connections to your website can lead to a point where upgrading the server hardware will no longer be cost effective.
In order to achieve web server scalability, more servers need to be added to distribute the load among the group of servers, which is also known as a server cluster. The load distribution among these servers is known as a href= http://www.xrio.com/xrionet/TechnologySolutions/ISPLoadBalancing/tabid/83/Default.aspx target= _blank load balancing. Load balancing applies to all types of servers (application server, database server), however, we will be devoting this section for load balancing of web servers (HTTP server) only.
About load balancing mechanism - IP Spraying
When multiple web servers are present in a server group, the HTTP traffic needs to be evenly distributed among the servers. In the process, these servers must appear as one web server to the web client, for example an internet browser. The load balancing mechanism used for spreading HTTP requests is known as IP Spraying. The equipment used for IP spraying is also called the load dispatcher or network dispatcher or simply, the load balancer. In this case, the IP sprayer intercepts each HTTP request, and redirects them to a server in the server cluster. Depending on the type of sprayer involved, the architecture can provide scalability, load balancing and failover requirements.
Grinding Coffee is Never a Grind.
After years of collecting all the kitchen gadgets and labour-saving devices you could care to mention, I’m still prize my coffee grinder above all else. I drink gallons of coffee a week – a habit that really puts my coffee grinder through the mill, as it were, on a daily basis. You just can’t beat the taste of coffee brewed from freshly ground beans. Even the very act of grinding the beans myself is something I look forward to. It has become a ritual that connects me to my kitchen and stimulates every sense. The aroma is released, my mouth begins to water, my hands tingle as they grip the body of the grinder, my eyes are hypnotized by the whirling beans, and… well the noise is pretty awful actually. In our fast-track lives in which we often eat on the fly and seldom make the time to cook, it is a privilege to enjoy such as sensual feast in your kitchen every day.
I’m sure I’d be healthier if I drank less coffee, but I belong to a long line of coffee connoisseurs. I started my coffee drinking devotion long before I should have. I had watched my parents in the middle of a heated ‘discussion’ stop and purr as the first wonderful elixia reached made contact with the tips of their tongues. I came to associate that wonderful aroma with a sense of well-being and close-knittedness. I wanted to be part of the grinding and brewing process; I wanted to be the magician that made a brew that made everything perfect. I have my coffee, like the Japanese have their tea. If you’ve seen ‘Karate Kid,’ you’ll know where I’m coming from.
I can’t understand why coffee grinders seem to be overlooked as gift ideas. They may not make the most glamorous presents, but they always make an impact on the lives of those who use them. What could be better than a coffee grinder for Christmas? It fits snuggly into a decent-sized stocking, and just a few hours later, leaning back in your chair after dinner, you can be breathing in the aroma of freshly ground coffee as you sample your first cup. Grinders can be found at any major store or mall. There’s a grinder out there for you no matter whether you have 5 dollars to spend or fifty. My own modest grinder was bought about four years ago for 10 bucks. It has never let me down.
Giving a coffee grinder at Christmas, perhaps along with a carefully wrapped sample of premium beans, is the best gift I could imagine. I’ve given grinders to nearly all my family members over the years. As I’ve said, I come from a family of coffee drinkers, but I’ve also given coffee grinders as wedding gifts housewarming parties and even a college graduation. Funnily enough, nobody has ever bought me one. I guess they assume it’s something I don’t lack. My kitchen is more like my own café than a food production area, and my coffee grinder holds centre stage on the counter.
Eoin Beckett is a freelance writer and editor. He writes both short fiction and non-fiction for both online and print publications. Although he stems from Ireland, since his teens he has lived in countries all over the world and has forgotten many - but not all - of the Irish songs he grew up with. He currently lives and works in Copenhagen, Denmark.
I’m sure I’d be healthier if I drank less coffee, but I belong to a long line of coffee connoisseurs. I started my coffee drinking devotion long before I should have. I had watched my parents in the middle of a heated ‘discussion’ stop and purr as the first wonderful elixia reached made contact with the tips of their tongues. I came to associate that wonderful aroma with a sense of well-being and close-knittedness. I wanted to be part of the grinding and brewing process; I wanted to be the magician that made a brew that made everything perfect. I have my coffee, like the Japanese have their tea. If you’ve seen ‘Karate Kid,’ you’ll know where I’m coming from.
I can’t understand why coffee grinders seem to be overlooked as gift ideas. They may not make the most glamorous presents, but they always make an impact on the lives of those who use them. What could be better than a coffee grinder for Christmas? It fits snuggly into a decent-sized stocking, and just a few hours later, leaning back in your chair after dinner, you can be breathing in the aroma of freshly ground coffee as you sample your first cup. Grinders can be found at any major store or mall. There’s a grinder out there for you no matter whether you have 5 dollars to spend or fifty. My own modest grinder was bought about four years ago for 10 bucks. It has never let me down.
Giving a coffee grinder at Christmas, perhaps along with a carefully wrapped sample of premium beans, is the best gift I could imagine. I’ve given grinders to nearly all my family members over the years. As I’ve said, I come from a family of coffee drinkers, but I’ve also given coffee grinders as wedding gifts housewarming parties and even a college graduation. Funnily enough, nobody has ever bought me one. I guess they assume it’s something I don’t lack. My kitchen is more like my own café than a food production area, and my coffee grinder holds centre stage on the counter.
Eoin Beckett is a freelance writer and editor. He writes both short fiction and non-fiction for both online and print publications. Although he stems from Ireland, since his teens he has lived in countries all over the world and has forgotten many - but not all - of the Irish songs he grew up with. He currently lives and works in Copenhagen, Denmark.
A wonder of the modern age
Are you sick of having no room on your computer table, if so here are a few tips that might help you on your way?
If you still own one of those HUGE CRT monitors maybe it’s now a good idea to purchase one of the new more modern looking TFT monitors, they are a fifth of the size of cumbersome CRT monitors and much more aesthetic looking in the process.
Prices for a good CRT monitor have dropped considerably over the last 12 months and a 17” monitor which I find big enough for most uses can be purchased for around $200.
Other great purchases which are now the much smaller are compact keyboards, even a smaller than normal mouse can be bought for only a few dollars and are often more preferred for the female pc user.
Also you could always turn to a laptop which would be much more portable and you could have it anywhere in the home, making wireless networking a great idea, if you have broadband.
Being wireless enabled is now very cost effective and now the best thing about it is how simple it all is to put together, most laptops already come with the WIFI card built in.
Also if you travel a lot a laptop computer is a very indispensable bit of kit, they are also very versatile and extremely lightweight the Apple G4 iBook probably being the lightest one around at the moment.
I suppose the only downside to a laptop compared to a desktop is that if you are really into gaming it maybe doesn’t quite cut the mustard like the laptop, Laptops usually share memory between the CPU(central processing unit) and the GPU(graphics processing unit), saving a lot of space and helping reduce power consumption.
If you still own one of those HUGE CRT monitors maybe it’s now a good idea to purchase one of the new more modern looking TFT monitors, they are a fifth of the size of cumbersome CRT monitors and much more aesthetic looking in the process.
Prices for a good CRT monitor have dropped considerably over the last 12 months and a 17” monitor which I find big enough for most uses can be purchased for around $200.
Other great purchases which are now the much smaller are compact keyboards, even a smaller than normal mouse can be bought for only a few dollars and are often more preferred for the female pc user.
Also you could always turn to a laptop which would be much more portable and you could have it anywhere in the home, making wireless networking a great idea, if you have broadband.
Being wireless enabled is now very cost effective and now the best thing about it is how simple it all is to put together, most laptops already come with the WIFI card built in.
Also if you travel a lot a laptop computer is a very indispensable bit of kit, they are also very versatile and extremely lightweight the Apple G4 iBook probably being the lightest one around at the moment.
I suppose the only downside to a laptop compared to a desktop is that if you are really into gaming it maybe doesn’t quite cut the mustard like the laptop, Laptops usually share memory between the CPU(central processing unit) and the GPU(graphics processing unit), saving a lot of space and helping reduce power consumption.
Organize Disk Drive Partition
1. What Is Disk Partitioning?
Partitioning creates a logical file structures on your hard disk so as to divide various potions of a hard disk to be used for different purposes such as a dual operating systems, storage or organizational purposes.
2. Why Partition Your Disk?
Partitioning your hard disk helps to categorize your files into logical groupings so that you can search for files and make changes more effectively. Folders are made for the same reason too. But partitioning provides better security.
a. Security
Most default primary partition is the C drive. This is the drive which your operating system and most other software applications are installed in. A useful way of protecting your data is to store your personal information into a separate disk partition. For example, if you are using a 80GB hard disk, you might want to partition it into two drives - drive C & drive D. Drive C will contain your operating system files and software applications such as your Microsoft Office Suite, Adobe Acrobat, Antivirus, Photoshop etc. While drive D can be configured as a storage drive to store all your document files, JPEG, MP3 and other personal data.
It is understood that your most important files are those that are difficult or virtually impossible to replace. For example, if Microsoft Word would to crash, you can always reinstall the application to make it work again. However, if your document files are corrupted by a virus or worm you may need to spend money and precious time trying to recover your data. In some case, you may not be able to recover them if the damage is too severe. Statistics have shown that most viruses and worms are more likely to infect executable and system files compared to your MP3 or excel spreadsheets. Therefore, if one partition corrupts, only that partition suffers and hopefully not the whole drive.
b. Convenience
Another reason for storing your document files in a separate drive is the ease of manageability. Say in a scenario which your computer needs to be reformatted due to severe corruption, you can easily reformat drive C and be assured that all your documents in drive D remains intact. This will save you quite a bit of time trying to backup your documents, then restoring them back in your local drive after your computer is reformatted and working. In this way, should you decide to refresh your operating system or application, the stored data is not affected.
c. Dual Operating System
You may wish to install more than one operating system into your computer. For example you need to a Windows and Linux operating system. But both are unable to be installed in the same partition. By partitioning the disk, you separate two logical spaces to include each individual OS.
3. Evaluating Your Needs
Before you start, ask yourself the following questions to help you determine the kind of partitions to create:
1. Do you work more on documents than on software?
2. Does your job require you to install multiple software applications?
3. Does the size of your software exceed that of your documents?
The point here to is to study the ratio space to allocate for each partition. The choice of how you partition your disk is important because it affects both disk performance and efficiency. If you are a designer or sound engineer given a computer with 80GB of disk space, you probably would want to assign 25GB of capacity to your primary disk and 55GB to a secondary drive to contain all your media files. You can always adjust this ratio according to your needs. On the other hand, if you are a software tester or a hardcore gamer you would probably choose to assign 50GB to your primary disk and 30GB to the secondary drive for storage. Again, there is no fixed rule or a standard template and much is directly dependent on your needs and how you operate.
4. Understanding Partitions
The master boot record is the first record that resides in your hard disk. It is located at the first sector of the disk and the first program that runs each time you power up your computer. The master boot record contains 2 important structure - the master boot code and the master partition table. Both of which provides instructions and information to how your computer boots up. Due to its structure, a single hard disk is limited to 4 primary partitions. One of it will be assigned as the active partition to contains your operating system. Simply, You can create 4 primary partitions, or 3 primary partitions and 1 extended partition which can be subdivided into multiple logical partitions.
For example, you may want to spilt your 80GB disk as follows:
„h 40GB primary partition for your OS and software applications
„h 10GB for MP3 files
„h 15GB for Document files
„h 5GB for Miscellaneous files
„h 10GB for Archival files
Partitioning creates a logical file structures on your hard disk so as to divide various potions of a hard disk to be used for different purposes such as a dual operating systems, storage or organizational purposes.
2. Why Partition Your Disk?
Partitioning your hard disk helps to categorize your files into logical groupings so that you can search for files and make changes more effectively. Folders are made for the same reason too. But partitioning provides better security.
a. Security
Most default primary partition is the C drive. This is the drive which your operating system and most other software applications are installed in. A useful way of protecting your data is to store your personal information into a separate disk partition. For example, if you are using a 80GB hard disk, you might want to partition it into two drives - drive C & drive D. Drive C will contain your operating system files and software applications such as your Microsoft Office Suite, Adobe Acrobat, Antivirus, Photoshop etc. While drive D can be configured as a storage drive to store all your document files, JPEG, MP3 and other personal data.
It is understood that your most important files are those that are difficult or virtually impossible to replace. For example, if Microsoft Word would to crash, you can always reinstall the application to make it work again. However, if your document files are corrupted by a virus or worm you may need to spend money and precious time trying to recover your data. In some case, you may not be able to recover them if the damage is too severe. Statistics have shown that most viruses and worms are more likely to infect executable and system files compared to your MP3 or excel spreadsheets. Therefore, if one partition corrupts, only that partition suffers and hopefully not the whole drive.
b. Convenience
Another reason for storing your document files in a separate drive is the ease of manageability. Say in a scenario which your computer needs to be reformatted due to severe corruption, you can easily reformat drive C and be assured that all your documents in drive D remains intact. This will save you quite a bit of time trying to backup your documents, then restoring them back in your local drive after your computer is reformatted and working. In this way, should you decide to refresh your operating system or application, the stored data is not affected.
c. Dual Operating System
You may wish to install more than one operating system into your computer. For example you need to a Windows and Linux operating system. But both are unable to be installed in the same partition. By partitioning the disk, you separate two logical spaces to include each individual OS.
3. Evaluating Your Needs
Before you start, ask yourself the following questions to help you determine the kind of partitions to create:
1. Do you work more on documents than on software?
2. Does your job require you to install multiple software applications?
3. Does the size of your software exceed that of your documents?
The point here to is to study the ratio space to allocate for each partition. The choice of how you partition your disk is important because it affects both disk performance and efficiency. If you are a designer or sound engineer given a computer with 80GB of disk space, you probably would want to assign 25GB of capacity to your primary disk and 55GB to a secondary drive to contain all your media files. You can always adjust this ratio according to your needs. On the other hand, if you are a software tester or a hardcore gamer you would probably choose to assign 50GB to your primary disk and 30GB to the secondary drive for storage. Again, there is no fixed rule or a standard template and much is directly dependent on your needs and how you operate.
4. Understanding Partitions
The master boot record is the first record that resides in your hard disk. It is located at the first sector of the disk and the first program that runs each time you power up your computer. The master boot record contains 2 important structure - the master boot code and the master partition table. Both of which provides instructions and information to how your computer boots up. Due to its structure, a single hard disk is limited to 4 primary partitions. One of it will be assigned as the active partition to contains your operating system. Simply, You can create 4 primary partitions, or 3 primary partitions and 1 extended partition which can be subdivided into multiple logical partitions.
For example, you may want to spilt your 80GB disk as follows:
„h 40GB primary partition for your OS and software applications
„h 10GB for MP3 files
„h 15GB for Document files
„h 5GB for Miscellaneous files
„h 10GB for Archival files
A Brief History of Rugs and Carpets
Rugs and carpets have a rich history, only part of which is known. Ancient rugs are very rare because the earliest rugs were made of organic fibers. Organic fibers disintegrate speedily over time, thus preservation over thousands of years is extremely rare. What we do know is that the art of weaving is very old and dates back thousands of years.
Weaving began with rough, simple mats and baskets made of grasses, reeds, leaves, and other natural materials. The first true ‘rugs’ were probably rough cured skins used as floor coverings in the homes of early hunters. With tough, flexible backing and generally soft material (called ‘pile’), these rugs served to keep the home more warm and insulated.
There is evidence for weaving and the existence of rugs in ancient Mesopotamia and Turkey as far back as 7000 and 8000 B.C.E., and in Egypt (wool and cotton) as early as the third millennium B.C.E. Mongolia and China were also main players in the textile industry, and nomadic herders and Chinese weavers were among the first to develop and weave wool rugs.
Weaving developed in many other parts of the world in addition to Europe, including parts of the Americas as far back as 5500 B.C.E. Weavers began to use natural colors and gradually transitioned to using vegetable, flower, and insect materials.
Silk development in China, the ornate, intricate embroidery and designs of Turkey and Mongolia, and the development of more sophisticated looms and weaving techniques throughout the world lifted rug-making from necessity to art form.
Italian merchants first brought oriental rugs to Europe, where they were used as wall hangings and coverings. By 1600, France had developed a dominant weaver’s guild, and England wasn’t far behind. The 1700’s marked England’s emergence into the weaving industry, and by about 1830, a good portion of the wool produced in England was used for carpets.
Various machines were created to aid the process of weaving, and looms have become so sophisticated today that they run off of computer algorithms. Rugs were not widely available in the US and Europe until the onset of mass production and the invention of industrial grade machines.
The first steam-powered loom appeared in 1787, and by 1876, the invention of the Axminster loom, a machine that permitted unlimited use of color and design, boosted the production of carpets. The advent of synthetic fibers and tufted carpet (carpet manufactured by the insertion of tufts of yarn through a carpet-backing fabric) made mass production and purchase of carpets easier, faster, and less expensive.
Weaving began with rough, simple mats and baskets made of grasses, reeds, leaves, and other natural materials. The first true ‘rugs’ were probably rough cured skins used as floor coverings in the homes of early hunters. With tough, flexible backing and generally soft material (called ‘pile’), these rugs served to keep the home more warm and insulated.
There is evidence for weaving and the existence of rugs in ancient Mesopotamia and Turkey as far back as 7000 and 8000 B.C.E., and in Egypt (wool and cotton) as early as the third millennium B.C.E. Mongolia and China were also main players in the textile industry, and nomadic herders and Chinese weavers were among the first to develop and weave wool rugs.
Weaving developed in many other parts of the world in addition to Europe, including parts of the Americas as far back as 5500 B.C.E. Weavers began to use natural colors and gradually transitioned to using vegetable, flower, and insect materials.
Silk development in China, the ornate, intricate embroidery and designs of Turkey and Mongolia, and the development of more sophisticated looms and weaving techniques throughout the world lifted rug-making from necessity to art form.
Italian merchants first brought oriental rugs to Europe, where they were used as wall hangings and coverings. By 1600, France had developed a dominant weaver’s guild, and England wasn’t far behind. The 1700’s marked England’s emergence into the weaving industry, and by about 1830, a good portion of the wool produced in England was used for carpets.
Various machines were created to aid the process of weaving, and looms have become so sophisticated today that they run off of computer algorithms. Rugs were not widely available in the US and Europe until the onset of mass production and the invention of industrial grade machines.
The first steam-powered loom appeared in 1787, and by 1876, the invention of the Axminster loom, a machine that permitted unlimited use of color and design, boosted the production of carpets. The advent of synthetic fibers and tufted carpet (carpet manufactured by the insertion of tufts of yarn through a carpet-backing fabric) made mass production and purchase of carpets easier, faster, and less expensive.
What is CCTV?
CCTV is an acronym that stands for Closed Circuit Television. It is defined as the use of one or more cameras used for surveillance purposes. It was initially developed to increase bank security and has since spread to every corner of the security industry. Home security systems, businesses, corporations, organizations, and schools are several examples of locations that implement CCTV Security Systems.
When CCTV cameras first appeared in the public sphere, they were crude, low-definition cameras that only recorded in black and white. They were completely simple and lacked even the ability to pan or zoom. CCTV cameras today are smaller, sleeker, and far more technologically advanced than the cameras of yesterday.
They produce high quality, exceptionally sharp color images, and have motion sensors that track movement across an area. They can pick a person out of a crowd and lock on them, tracing their movements; they can run at night because of infrared technology. The possibilities are endless for CCTV, especially as the technology continues to develop.
Closed-circuit cameras are often used to discourage and deter crime. While they don’t necessarily eliminate crime, closed-circuit cameras do make it possible to identify events and suspects, making is easier to detect and prosecute those involved in a crime.
Another function that closed-circuit cameras serve is that of traffic monitors. Speed cameras are installed in various locations, taking a picture of your license plate and with the help of radar technology, recording your speed. In many cities in the US, you may receive a speeding ticket with a picture of your car and its clocked speed, or a picture of the exact moment you ran a red light.
They come in all shapes and sizes and can be installed anywhere, from your car and your handbag to police surveillance vans and taxis. They are ideal for purposes of security as they have the ability to recall events in real time at an accurate date and provide information that may lead to the detection and persecution of criminal activities.
Emerging technologies will make faster, quicker cameras that will be able to pick a face out of the crowd on command. They could be programmed to identify ‘criminal’ behavior by body movement that might signify a troublemaker, and zoom up on your face in an instant.
Banks, hospitals, institutions that deal in large sums of money, government buildings, and schools are several areas of the public sector where closed-circuit television cameras work well. The CCTV System is moving towards a completely computerized monitoring system that will eventually replace the current need for a CCTV operator and become a fully automated system.
When CCTV cameras first appeared in the public sphere, they were crude, low-definition cameras that only recorded in black and white. They were completely simple and lacked even the ability to pan or zoom. CCTV cameras today are smaller, sleeker, and far more technologically advanced than the cameras of yesterday.
They produce high quality, exceptionally sharp color images, and have motion sensors that track movement across an area. They can pick a person out of a crowd and lock on them, tracing their movements; they can run at night because of infrared technology. The possibilities are endless for CCTV, especially as the technology continues to develop.
Closed-circuit cameras are often used to discourage and deter crime. While they don’t necessarily eliminate crime, closed-circuit cameras do make it possible to identify events and suspects, making is easier to detect and prosecute those involved in a crime.
Another function that closed-circuit cameras serve is that of traffic monitors. Speed cameras are installed in various locations, taking a picture of your license plate and with the help of radar technology, recording your speed. In many cities in the US, you may receive a speeding ticket with a picture of your car and its clocked speed, or a picture of the exact moment you ran a red light.
They come in all shapes and sizes and can be installed anywhere, from your car and your handbag to police surveillance vans and taxis. They are ideal for purposes of security as they have the ability to recall events in real time at an accurate date and provide information that may lead to the detection and persecution of criminal activities.
Emerging technologies will make faster, quicker cameras that will be able to pick a face out of the crowd on command. They could be programmed to identify ‘criminal’ behavior by body movement that might signify a troublemaker, and zoom up on your face in an instant.
Banks, hospitals, institutions that deal in large sums of money, government buildings, and schools are several areas of the public sector where closed-circuit television cameras work well. The CCTV System is moving towards a completely computerized monitoring system that will eventually replace the current need for a CCTV operator and become a fully automated system.
Defining the World of Security Cameras
Finding the right security camera is difficult enough without having to wade through the terms and figure what the abbreviations and words actually mean. If you’re trying to do research on a security camera and frustrated with the multitude of terms that are unknown to the average user, here’s a list of the terms you’ll want to know. There are many more out there, but this is enough to get you started:
DVR: Digital Video Recorder, or ‘personal video recorder.’ Usually used when referring to a Security Camera System, you use a DVR to record broadcasts on a hard disk drive which can then be played back at a later time. The most well-known type of DVR is TiVO. They often come with standard features like motion detection, time and date stamping, and remote internet monitoring capabilities.
Motion Detection: Many cameras and DVRs are built with motion sensors to track movement securely.
Time and Date Stamping: Term used when a DVR records the date and time of an occurrence or recording.
Remote Internet Monitoring: Refers to using a camera like a Network IP Camera to record information and the ability to see that information live in real time from a distant location.
PC: Still refers to a personal computer.
PTZ: ‘Pan, Tilt, Zoom’ refers to the motion of a controllable or PTZ camera. Movement can go from left to right and up down, as well as zoom in and out on an object.
Infrared: A technology that uses heat sensors to detect objects in its surroundings. It was developed especially to ‘see’ in the dark.
Network IP Camera: refers to a type of camera that connects to the internet or a computer network via an IP address and can be viewed remotely from different locations.
DVR Card: Digital Recorder Card. Provides digital video recording capability so
that you can store video files from your security/surveillance system on your PC.
Camera Housing: Refers to the outer shell of a security camera. It serves to weatherproof, protect, and ‘house’ the camera from potential harm.
Quad Processor: four processors in one
Multiplexer: the multiplexer takes several separate digital data streams and combines them together into one data stream of a higher data rate. A multiplexer makes it easier to combine the data from several security cameras into one stream of information. This is system is a quicker and more effective way of processing information.
Multiple Output Power adaptor: a power adaptor that enables multiple outputs and is highly useful for a system that requires a good amount of power.
Security Camera Systems: General, broad term for the package that security companies often sell. They are usually a better deal than buying the items separately and come in a variety of choices. They usually include a security camera, Processor, Software, Cables, Power Adaptor, Monitor, VCR/DVR, and some come with a warrantee. This is one of the more basic kits; more deluxe options often entail other accessories.
Dome Security Cameras: Dome security cameras are ideal for use in building entrances, stores, and shopping malls; in short, anywhere you want a ‘fashionable’ camera that is designed to blend into its surrounding environment. Prettier and more appealing than its cousins, a Dome Camera offers high security and an increased surveillance capacity because of its non-invasive qualities.
PTZ (Pan, Tilt, Zoom) and Controllable Cameras: PTZ and Controllable Cameras are designed to be controlled by remote or through a DVR. They have the ability to move up and down as well as right and left. You can pan, tilt, and zoom in or out. You have all the control you want over these cameras, and they provide excellent surveillance and security.
Bullet Security Cameras: Bullet Security Cameras are a special type of small, sleek camera that that is ideal for both indoor and outdoor installation. Sealed in cylinders and totally protected, they are impermeable to water and are totally weatherproof. Mountable on the ceiling or on the wall, they provide sharp, detailed video images while maintaining low profile visibility and an unobtrusive presence.
Mini, Board and Covert Cameras: Just as they sound, mini cameras are small, tiny cameras that come in wireless options and can be used for increased, quiet security. Board cameras are tiny mini cameras set in small, flat housing, and are also highly useful in situations calling for more security and extremely low visibility. A Covert Camera is just what it sounds like. Like the mini and board cameras, covert cameras are intended for use for those that need increased security and a totally unobtrusive camera.
Pro Security Cameras: Professional Security Cameras are ideal for any and every purpose you might have. They can be mounted on ceiling brackets, on your wall, and indoors and outdoors. The professional line of security cameras, they are usually high resolution with clear, sharp image quality and detail. They come in color or black and white, and SONY is one of the better brands available.
DVR: Digital Video Recorder, or ‘personal video recorder.’ Usually used when referring to a Security Camera System, you use a DVR to record broadcasts on a hard disk drive which can then be played back at a later time. The most well-known type of DVR is TiVO. They often come with standard features like motion detection, time and date stamping, and remote internet monitoring capabilities.
Motion Detection: Many cameras and DVRs are built with motion sensors to track movement securely.
Time and Date Stamping: Term used when a DVR records the date and time of an occurrence or recording.
Remote Internet Monitoring: Refers to using a camera like a Network IP Camera to record information and the ability to see that information live in real time from a distant location.
PC: Still refers to a personal computer.
PTZ: ‘Pan, Tilt, Zoom’ refers to the motion of a controllable or PTZ camera. Movement can go from left to right and up down, as well as zoom in and out on an object.
Infrared: A technology that uses heat sensors to detect objects in its surroundings. It was developed especially to ‘see’ in the dark.
Network IP Camera: refers to a type of camera that connects to the internet or a computer network via an IP address and can be viewed remotely from different locations.
DVR Card: Digital Recorder Card. Provides digital video recording capability so
that you can store video files from your security/surveillance system on your PC.
Camera Housing: Refers to the outer shell of a security camera. It serves to weatherproof, protect, and ‘house’ the camera from potential harm.
Quad Processor: four processors in one
Multiplexer: the multiplexer takes several separate digital data streams and combines them together into one data stream of a higher data rate. A multiplexer makes it easier to combine the data from several security cameras into one stream of information. This is system is a quicker and more effective way of processing information.
Multiple Output Power adaptor: a power adaptor that enables multiple outputs and is highly useful for a system that requires a good amount of power.
Security Camera Systems: General, broad term for the package that security companies often sell. They are usually a better deal than buying the items separately and come in a variety of choices. They usually include a security camera, Processor, Software, Cables, Power Adaptor, Monitor, VCR/DVR, and some come with a warrantee. This is one of the more basic kits; more deluxe options often entail other accessories.
Dome Security Cameras: Dome security cameras are ideal for use in building entrances, stores, and shopping malls; in short, anywhere you want a ‘fashionable’ camera that is designed to blend into its surrounding environment. Prettier and more appealing than its cousins, a Dome Camera offers high security and an increased surveillance capacity because of its non-invasive qualities.
PTZ (Pan, Tilt, Zoom) and Controllable Cameras: PTZ and Controllable Cameras are designed to be controlled by remote or through a DVR. They have the ability to move up and down as well as right and left. You can pan, tilt, and zoom in or out. You have all the control you want over these cameras, and they provide excellent surveillance and security.
Bullet Security Cameras: Bullet Security Cameras are a special type of small, sleek camera that that is ideal for both indoor and outdoor installation. Sealed in cylinders and totally protected, they are impermeable to water and are totally weatherproof. Mountable on the ceiling or on the wall, they provide sharp, detailed video images while maintaining low profile visibility and an unobtrusive presence.
Mini, Board and Covert Cameras: Just as they sound, mini cameras are small, tiny cameras that come in wireless options and can be used for increased, quiet security. Board cameras are tiny mini cameras set in small, flat housing, and are also highly useful in situations calling for more security and extremely low visibility. A Covert Camera is just what it sounds like. Like the mini and board cameras, covert cameras are intended for use for those that need increased security and a totally unobtrusive camera.
Pro Security Cameras: Professional Security Cameras are ideal for any and every purpose you might have. They can be mounted on ceiling brackets, on your wall, and indoors and outdoors. The professional line of security cameras, they are usually high resolution with clear, sharp image quality and detail. They come in color or black and white, and SONY is one of the better brands available.
How to select the printer
It is a daunting task to choose a printer without deciding what type you really require. You have to choose between an ink jet and a laser printer. After that you have to decide on the printer size essential for the tasks you require it to accomplish. You have to consider factors such as printer type, size, running costs and price and service availability.
There are mainly two types of printers in the market. The laser printers and inkjet printers are the only two choices available in the market. In the laser printer a laser beam is used to print the picture on the drum which is then transferred on to the paper. In the inkjet printer, however, ink is sprayed through tiny jets on to the page forming the image on the page. The difference between the two types of printers is the basic difference in the technology involved in them.
Inkjet printers are generally fairly versatile being able to print anything from spreadsheets to brochures to word documents to photos. Inkjet printers are particularly good at printing professional but inexpensive documents on a small quantity. Inkjets are designed to cope with only small print volumes, but they are also far more affordable than laser printers.
Another advantage of ink jet printers is that they are usually small and lightweight. Some also come with carry cases for easy portability. Hence they would be optimum for laptops and PDAs and such devices that require printing facilities. Their maintenance is also very easy with its spares readily available.
But, in case your requirement is for more advanced print jobs then you should think of buying a laser printer. Laser printers are made to take voluminous workloads and print at a much faster speed. And the quality of the print is far superior to that of the inkjet printer. That is why not only the laser printers cost more but even the consumables of the laser printer are more expensive. Laser printers are portable and can be carried from one place to another.
Sometimes they come with their own hard cover carry cases for convenience in shifting them around.
The two most popular and readily available printers are the ink jet printers and laser printers. The laser printer uses a laser beam to mark an image on a drum, which then fuses this image to the printer. On the other hand, the ink jet printer sprays ink through tiny jets on to the page without any laser imaging.
There are mainly two types of printers in the market. The laser printers and inkjet printers are the only two choices available in the market. In the laser printer a laser beam is used to print the picture on the drum which is then transferred on to the paper. In the inkjet printer, however, ink is sprayed through tiny jets on to the page forming the image on the page. The difference between the two types of printers is the basic difference in the technology involved in them.
Inkjet printers are generally fairly versatile being able to print anything from spreadsheets to brochures to word documents to photos. Inkjet printers are particularly good at printing professional but inexpensive documents on a small quantity. Inkjets are designed to cope with only small print volumes, but they are also far more affordable than laser printers.
Another advantage of ink jet printers is that they are usually small and lightweight. Some also come with carry cases for easy portability. Hence they would be optimum for laptops and PDAs and such devices that require printing facilities. Their maintenance is also very easy with its spares readily available.
But, in case your requirement is for more advanced print jobs then you should think of buying a laser printer. Laser printers are made to take voluminous workloads and print at a much faster speed. And the quality of the print is far superior to that of the inkjet printer. That is why not only the laser printers cost more but even the consumables of the laser printer are more expensive. Laser printers are portable and can be carried from one place to another.
Sometimes they come with their own hard cover carry cases for convenience in shifting them around.
The two most popular and readily available printers are the ink jet printers and laser printers. The laser printer uses a laser beam to mark an image on a drum, which then fuses this image to the printer. On the other hand, the ink jet printer sprays ink through tiny jets on to the page without any laser imaging.
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