Tuesday, December 25, 2007
Big folders made easy.
Every computer user knows that no matter how big your hard drive is, useful and useless information will step by step occupy all of it. Modern software and multimedia content have become really voracious in terms of gigabytes. Do you analyze disk space analysis? To make matters worse, many applications make temporary and-or system files that may be immense and hard to locate. In many cases they clean up the mess. But as time passes by, more and more non-eliminated trash starts to slow down your computer. And you have to do that again: reinstallation, disks reformatting to have a couple of months of normal work on your computer. Besides such extraordinary methods of used disk space management, you surely have come across some customary tools to organize and manage files and folders. Typical applications are fine while you use ordinary folders and execute standard operations. The problem with people, although, is that we are not that standard when it comes to our hard drive needs. We could get spontaneous when we make a folder with a tongue-twisting name. The inspiration could leave, however the file or folder we made remains. And that is when conventional programs work badly. It is not so easy to view directory size. In the first place, you are to find large files and folders and ordinary applications make this job amazingly hard-to-perform. They take years to view folder size. You may have to manually search around to find files that take the most space on your PC. Sometimes these files are so well hidden, that they are literary impossible to be located. One more problem is navigation. These days an ordinary PC has hundreds of different directories, which makes it difficult to find useful and useless information. Using conventional programs, you might have to go through a lot of screens before you get somewhere. Is there a better way? There is a small but efficient application called Directory Size that can help you manage your files much easier. Directory Size features a user-friendly interface to lead you through all these to find large files and folders. Essential benefit is that it turns useful and useless information into pictures and graphs allowing you to visualize used disk space analysis. Our mind can organize and manage visuals much faster than pure numbers and bits of text. Yet another vital issue is speed. Directory Size operates in the background. It creates a map of files and folders location. That is the reason why whenever you have to get somewhere near all that data, Directory Size presents you a navigation guide that significantly simplifies files and folders location. The program helps you save money. When you can efficiently organize your useful and useless information, you do not need to get into the hype for more gigabytes. It is much more comfortable to live in a neat apartment than in a huge but messy house where you stumble every time you want to find the remote control or even the way to the bathroom. And you know what, size does matter when we speak of files and folders on your hard disk drives. Directory Size helps you locate and keep an eye on the biggest space eaters on your computer used disk space. You can even arrange folders according to their size. Thus you can always see what programs and files occupy your precious disk space used and take appropriate action when necessary. disk space analysis
Plasma Television In The Living Room
Do you want your living room to be something special in your home? If so, consider having a 50-inch plasma television set in it.
With the numerous selections of great looking 50-inch televisions available in the market, you'll definitely find one that will give the look that you want for your living room. With a 50-inch plasma television, you'll be able to see bigger and clearer pictures when watching television.
When you want to have a great looking television, you should look into all the great name brands that are on the market today. There are so many of them. Think about different options and what is going to be better for your money.
Find something that is worth the money you're going to pay. Decide on your budget and what features you want for your television. Once you know what you want, you'll be able to decide on what to buy. Choosing the most suitable television would be much easier.
Imagine yourself looking forward to coming home each day at the end of your workday. You can hardly wait to unwind by enjoying all your favorite programs on your new television set. Your new 50-inch plasma television will enable you to watch all your movies and capture the entire essence of each movie on the big and clear screen. Don't be surprised that you'll soon be the envy of all your friends and neighbors.
Getting something that is going to be more for your money is important. There are plenty of different brands of 50-inch plasma televisions. However, the most important thing that you can do is finding the one that is going to work for your needs. When you are sure that you are getting something that you can rely on and have for many years, you will be able to appreciate the investment that you have made. It is going to be something that you will be able to use repeatedly throughout the upcoming years.
Do not forget to invite all of your friends over for that big game or the movie that you have all been waiting for. You will be able to entertain all of your guests with the beauty of your own 50-inch plasma television. You and your guests will appreciate the fact that you have the larger television that is going to give off the best quality picture that you can possibly get. You will definitely be proud of your television and you may never want to leave your home again.
With the numerous selections of great looking 50-inch televisions available in the market, you'll definitely find one that will give the look that you want for your living room. With a 50-inch plasma television, you'll be able to see bigger and clearer pictures when watching television.
When you want to have a great looking television, you should look into all the great name brands that are on the market today. There are so many of them. Think about different options and what is going to be better for your money.
Find something that is worth the money you're going to pay. Decide on your budget and what features you want for your television. Once you know what you want, you'll be able to decide on what to buy. Choosing the most suitable television would be much easier.
Imagine yourself looking forward to coming home each day at the end of your workday. You can hardly wait to unwind by enjoying all your favorite programs on your new television set. Your new 50-inch plasma television will enable you to watch all your movies and capture the entire essence of each movie on the big and clear screen. Don't be surprised that you'll soon be the envy of all your friends and neighbors.
Getting something that is going to be more for your money is important. There are plenty of different brands of 50-inch plasma televisions. However, the most important thing that you can do is finding the one that is going to work for your needs. When you are sure that you are getting something that you can rely on and have for many years, you will be able to appreciate the investment that you have made. It is going to be something that you will be able to use repeatedly throughout the upcoming years.
Do not forget to invite all of your friends over for that big game or the movie that you have all been waiting for. You will be able to entertain all of your guests with the beauty of your own 50-inch plasma television. You and your guests will appreciate the fact that you have the larger television that is going to give off the best quality picture that you can possibly get. You will definitely be proud of your television and you may never want to leave your home again.
High Definition Television Flat Screen TV
Getting a HDTV flat screen TV that fits your budget and gives you value for your money can be a tricky task, but it can also be extremely worth it as you watch your favorite movie with crisp sound and clear picture. So, how do you buy a HDTV flat screen TV that is worth the cost and will last for a long time? The truth is that there is no way to know for sure how valuable your flat screen TV will end up being or how long it will last, but you can shop smart and make good decisions with your purchasing power.
The first thing you need to know is that there is a difference between plasma TV sets and LCD screens. Both are featured with HDTV flat screen TV technology and both are rather thin and flat, making them easy to place anywhere in your home, but they feature two different technologies. Your HDTV flat screen TV comes in two different types: plasma and LCD. There is no such thing as a plasma LCD TV.
Plasma televisions are only available in the widescreen 16:9 aspect ratio. This is the standard ratio for a HDTV flat screen TV. As a rule, plasma televisions are high definition ready. Most plasma flat screen televisions range in screen size from 42 inches to 63 inches, although both larger and smaller versions are available.
LCD televisions tend to be smaller, anywhere from 15 inches to 65 inches. The smaller LCD screens are often utilized as computer monitors. The LCD HDTV flat screen TV is actually lower in price than plasma when you're dealing with the average size of display for the screen, but the larger LCD screens can be significantly more expensive.
There are some product differences between HDTV flat screen televisions that are plasma and LCD. Some of these differences include:
* LCD televisions have lower contrast levels than plasma televisions, meaning that they have a harder time reproducing dark colors and grays
* LCD televisions have slower response times, sometimes creating blurs during fast-paced action sequences in movies or in sports
* LCD televisions have a narrower viewing angle, but can be easier to view in well-lit rooms
* LCD televisions run cooler than plasma televisions
* Plasma televisions are of lower quality when paying lower prices
There are other differences between LCD and plasma HDTV flat screen TV sets. The easiest way to learn the major differences is to watch both types of television in a department or home electronics store. Sit in front of both televisions first, then change angles and view each television from the sides. This will help you to understand how each television works, and can help you decide which HDTV flat screen television best meets your needs.
The first thing you need to know is that there is a difference between plasma TV sets and LCD screens. Both are featured with HDTV flat screen TV technology and both are rather thin and flat, making them easy to place anywhere in your home, but they feature two different technologies. Your HDTV flat screen TV comes in two different types: plasma and LCD. There is no such thing as a plasma LCD TV.
Plasma televisions are only available in the widescreen 16:9 aspect ratio. This is the standard ratio for a HDTV flat screen TV. As a rule, plasma televisions are high definition ready. Most plasma flat screen televisions range in screen size from 42 inches to 63 inches, although both larger and smaller versions are available.
LCD televisions tend to be smaller, anywhere from 15 inches to 65 inches. The smaller LCD screens are often utilized as computer monitors. The LCD HDTV flat screen TV is actually lower in price than plasma when you're dealing with the average size of display for the screen, but the larger LCD screens can be significantly more expensive.
There are some product differences between HDTV flat screen televisions that are plasma and LCD. Some of these differences include:
* LCD televisions have lower contrast levels than plasma televisions, meaning that they have a harder time reproducing dark colors and grays
* LCD televisions have slower response times, sometimes creating blurs during fast-paced action sequences in movies or in sports
* LCD televisions have a narrower viewing angle, but can be easier to view in well-lit rooms
* LCD televisions run cooler than plasma televisions
* Plasma televisions are of lower quality when paying lower prices
There are other differences between LCD and plasma HDTV flat screen TV sets. The easiest way to learn the major differences is to watch both types of television in a department or home electronics store. Sit in front of both televisions first, then change angles and view each television from the sides. This will help you to understand how each television works, and can help you decide which HDTV flat screen television best meets your needs.
Building Networks
MIS, remote desktop setup, wireless encryption & intruder detection. For the techie-depraved individual, these words would probably sound complicated, nonsense even. But for a player in the industry that offers business IT services, these words bring profit. (Yes, profit.) If one is running a computer café providing Internet services, then you should know the topic at hand. For simple networking---wireless or otherwise, you need not have to hire professional computer services to link your PCs to other PCs or to the Internet.
Going wireless isn’t solely for aesthetics, it is for convenience. All you have to know are the basics. With that said, let’s start building our own computer networks---without wires. First stop, home connection defined. Said connection is produced when two or more PCs and a telephone line are properly linked together. This setup will allow you to share files, peripherals and a single Internet connection between and among your PCs.
These are the things that you’ll need: an Internet connection (preferably DSL or Cable), wireless router and wireless network cards. If your laptop already has built-in wireless capabilities, you need not purchase the third one. Now to elaborate each item. Internet Connection. This may be either DSL or cable. However, one may use dial-up modem but this is very slow (believe me, it’s s-l-o-w). The first two provide high-speed Internet access. With these in the market, the dial-up modem will prove to be ancient, anciently sluggish. Second would be the wireless router. Purchase a router that fits your preferred wireless signal. This device works in the same manner as that of the (hardwired) router, which determines the next network point to which a packet or data should be forwarded toward its destination. The cards are needed for the computer to pick up the signal. Though, as I’ve mentioned earlier, buying would depend on the requirement of the PC itself. If your laptop or PC has a wireless card built-in, you need not do the purchase.
With your wireless components, what you need to do is connect the router to the Ethernet cable and configure it together with the PCs and peripherals. The router should automatically transmit the signal from the wireless. If the modem is working, the Internet should too. When properly installed, one can create a network where all PCs and laptops can access a single broadband connection.
Now, let’s go to the serious part, securing your wireless network. I don’t like intruders, and I think that majority of the techie people feel the same way. First advice, don’t use the word password as your password. Immediately change your default passwords, to secure your wireless router. Another is to turn on the WEP encryption, or better yet, WPA. The former stands for Wired Equivalency Privacy while the latter Wi-Fi Protected Access. Between the two, I would opt for the WPA. WEP can be easily cracked. Though I’m not saying that WPA offers perfect encryption (there is always the possibility that an intruder will break your security)---it has some flaws but it sure beats WEP. Don’t forget to read the documents included in your hardware purchase regarding the configurations and settings.
These pieces of advice are ideal for a residential setting. For a business, I think that professional help is required. One cannot leave important files and documents in the open. A respected establishment will not be settling for mediocre security among the dozens of network management services. There are a lot of companies offering computer management services, you just need to know what you’re looking for.
Going wireless isn’t solely for aesthetics, it is for convenience. All you have to know are the basics. With that said, let’s start building our own computer networks---without wires. First stop, home connection defined. Said connection is produced when two or more PCs and a telephone line are properly linked together. This setup will allow you to share files, peripherals and a single Internet connection between and among your PCs.
These are the things that you’ll need: an Internet connection (preferably DSL or Cable), wireless router and wireless network cards. If your laptop already has built-in wireless capabilities, you need not purchase the third one. Now to elaborate each item. Internet Connection. This may be either DSL or cable. However, one may use dial-up modem but this is very slow (believe me, it’s s-l-o-w). The first two provide high-speed Internet access. With these in the market, the dial-up modem will prove to be ancient, anciently sluggish. Second would be the wireless router. Purchase a router that fits your preferred wireless signal. This device works in the same manner as that of the (hardwired) router, which determines the next network point to which a packet or data should be forwarded toward its destination. The cards are needed for the computer to pick up the signal. Though, as I’ve mentioned earlier, buying would depend on the requirement of the PC itself. If your laptop or PC has a wireless card built-in, you need not do the purchase.
With your wireless components, what you need to do is connect the router to the Ethernet cable and configure it together with the PCs and peripherals. The router should automatically transmit the signal from the wireless. If the modem is working, the Internet should too. When properly installed, one can create a network where all PCs and laptops can access a single broadband connection.
Now, let’s go to the serious part, securing your wireless network. I don’t like intruders, and I think that majority of the techie people feel the same way. First advice, don’t use the word password as your password. Immediately change your default passwords, to secure your wireless router. Another is to turn on the WEP encryption, or better yet, WPA. The former stands for Wired Equivalency Privacy while the latter Wi-Fi Protected Access. Between the two, I would opt for the WPA. WEP can be easily cracked. Though I’m not saying that WPA offers perfect encryption (there is always the possibility that an intruder will break your security)---it has some flaws but it sure beats WEP. Don’t forget to read the documents included in your hardware purchase regarding the configurations and settings.
These pieces of advice are ideal for a residential setting. For a business, I think that professional help is required. One cannot leave important files and documents in the open. A respected establishment will not be settling for mediocre security among the dozens of network management services. There are a lot of companies offering computer management services, you just need to know what you’re looking for.
IP Phone Features That Will Make Your Life Better
Certainly price is one factor keeping businesses at bay. IP phones, after all, are often the highest cost component in migrating from a traditional phone system to VoIP. Promising to help companies get more bang for their buck, however, are a whole host of special features included in most IP phones. The challenge is identifying these key attractions and ensuring that employees make proper use of them. While key features can vary from phone to phone, here are the ones that can make your employees’ lives better: CMC (Client Matter Code): Having trouble keeping track of your billable hours?
An IP phone can help. Professional services companies, from law offices to accounting firms, can now associate inbound and outbound VoIP calls with specific billing or tracking codes. Specified by a system administrator, CMC can track factors including the length of calls for each client – information that can later be packaged into detailed reports for accounting and billing purposes.Corporate Directory: Why keep a Rolodex when you can use your phone to search for coworkers’ and clients’ numbers? Simply press a soft key or a button to place a call to the phone number in the directory listing. These listings may range from corporatecontacts stored in Microsoft Active Directory to your personal contacts in Microsoft Outlook. Either way, searchable directories appear right on the phone’s display for convenient access. Some IP phones even go so far as to provide users with at-a-glance presence information for an entire corporate directory list so that they can instantly see which co-workers are available or on the phone.
Touch-screen Display: Whether your goal is to watch streaming video or simply monitor incoming calls, an IP phone’s backlit, pixel-based, touch-screen display can bring images to life. And by simply pressing a phone screen, you can access a full range of applications in seconds instead of pressing cryptic key codes on the number pad.
E911 (Enhanced 911): E911 is an enhanced version of the 911 emergency service that automatically delivers a caller’s personal information, such as name and address, to a local dispatch center or Public Safety Answering Point, as required by the Wireless Communications and Public Safety Act of 1999. Although increasingly incorporated into VoIP packages, E911 has long been plagued with implementation problems, so it’s worth asking your service provider what steps – and obstacles – are involved. The Federal Communications Commission has even jumped on board, issuing an order to providers to notify their customers of the limitations of E911 service.
Enhanced Voice Mail: For a modern-day road warrior, picking up voice mail messages can be a painstaking process. Pagers, cell phones, BlackBerrys, laptops – there’s simply no shortage of devices you need to check. With an IP phone’s enhanced voice mail, however, you can listen to your voice mail over the Internet using the Web interface of your VoIP service provider or receive your messages as email attachments. that’s more, the media files can be saved for future access or archiving. Enhanced voice mail also allows you to be notified of new messages wherever you are, through your mobile phone or pager. additionally, travelers can listen to their messages from any phone available.
IP Video: It may not earn you frequent-flyer miles, but video-over-IP is the next best thing to being there in the flesh. As a result, some IP phones include features such as advanced VGA resolution camera sensors, color and rotatable LCDs, video call Hold/ Transfer/Forward, video phone books, and video-capture capabilities. At least in a basic sense, you can engage in videoconferencing with geographically cattered
colleagues and co-workers.
Communications Control: So your entire California-based executive team is attending a conference in Utah? Rather than have them waste time calling in for voice mail messages, redirect all business-related calls to their cell phones using an IP phone’s communications control features. In fact, nowadays, companies can manage an entire VoIP system across multiple sites with nothing more than a browser-based interface.
An IP phone can help. Professional services companies, from law offices to accounting firms, can now associate inbound and outbound VoIP calls with specific billing or tracking codes. Specified by a system administrator, CMC can track factors including the length of calls for each client – information that can later be packaged into detailed reports for accounting and billing purposes.Corporate Directory: Why keep a Rolodex when you can use your phone to search for coworkers’ and clients’ numbers? Simply press a soft key or a button to place a call to the phone number in the directory listing. These listings may range from corporatecontacts stored in Microsoft Active Directory to your personal contacts in Microsoft Outlook. Either way, searchable directories appear right on the phone’s display for convenient access. Some IP phones even go so far as to provide users with at-a-glance presence information for an entire corporate directory list so that they can instantly see which co-workers are available or on the phone.
Touch-screen Display: Whether your goal is to watch streaming video or simply monitor incoming calls, an IP phone’s backlit, pixel-based, touch-screen display can bring images to life. And by simply pressing a phone screen, you can access a full range of applications in seconds instead of pressing cryptic key codes on the number pad.
E911 (Enhanced 911): E911 is an enhanced version of the 911 emergency service that automatically delivers a caller’s personal information, such as name and address, to a local dispatch center or Public Safety Answering Point, as required by the Wireless Communications and Public Safety Act of 1999. Although increasingly incorporated into VoIP packages, E911 has long been plagued with implementation problems, so it’s worth asking your service provider what steps – and obstacles – are involved. The Federal Communications Commission has even jumped on board, issuing an order to providers to notify their customers of the limitations of E911 service.
Enhanced Voice Mail: For a modern-day road warrior, picking up voice mail messages can be a painstaking process. Pagers, cell phones, BlackBerrys, laptops – there’s simply no shortage of devices you need to check. With an IP phone’s enhanced voice mail, however, you can listen to your voice mail over the Internet using the Web interface of your VoIP service provider or receive your messages as email attachments. that’s more, the media files can be saved for future access or archiving. Enhanced voice mail also allows you to be notified of new messages wherever you are, through your mobile phone or pager. additionally, travelers can listen to their messages from any phone available.
IP Video: It may not earn you frequent-flyer miles, but video-over-IP is the next best thing to being there in the flesh. As a result, some IP phones include features such as advanced VGA resolution camera sensors, color and rotatable LCDs, video call Hold/ Transfer/Forward, video phone books, and video-capture capabilities. At least in a basic sense, you can engage in videoconferencing with geographically cattered
colleagues and co-workers.
Communications Control: So your entire California-based executive team is attending a conference in Utah? Rather than have them waste time calling in for voice mail messages, redirect all business-related calls to their cell phones using an IP phone’s communications control features. In fact, nowadays, companies can manage an entire VoIP system across multiple sites with nothing more than a browser-based interface.
What can you do to Speed up the Internet?
The Internet’s never going to be fast enough, but follow our tips and it’ll be faster than what is was.
Anyone who has ever used their own home computer to demonstrate the Internet to a friend who’s never seen it before knows there’s one question that occurs more than any other: Why is it so slow?
As the kind person showing your friend the delights of the online experience, it’s hard not to feel a little offended. How dare they criticize your setup and the majesty of the Internet? But, of course, there’s a lot of truth in the question. The Internet is slow. Actually, it’s good to be reminded of this, because the chances are there’s a lot that can be done to speed it up. There are three main areas to consider. Hardware, software, and the phone line.
Hardware
Lets begin with your computer. Modern web browsers require lots of system resources. Any recent computer fits the bill, but what if you have to make do with something older? Adding more ram is good, especially if you have less than 256mb. Consider adding a faster hard disk. It won’t speed up downloads from the Internet, but avoids windows slowing things down by swapping files from RAM to disk, and your browser should be able to work more quickly.
Don’t forget your modem. If you’re still using a 56k modem, then perhaps it’s time to upgrade to ISDN or ADSL. It needn’t cost the earth either. Broadband Internet is becoming so popular that many home users have already upgraded to this option. Most ISP’s will throw in a free router as part of the package. If you don’t have a network card in your computer to support the router, then perhaps it is time to upgrade that old PC.
You may be thinking that it’s OK because you’ve had a 56k modem for years. But the money you’re wasting on dial-up and slow downloads could be considerably higher than if you resorted to broadband internet. Check with your local ISP about broadband packages on special. If you are going to purchase your own router, make sure your operating system and computer will support the new router. Your local computer store will most probably offer you free advice on the best way to setup your router.
Software
If you are going to stick with 56k modems, hardly anyone is happy with their speed, a dissatisfaction which has bred a brand new genre – utilities designed to speed things up. One major subcategory is the accelerator, a program which speeds up your browser in two different ways. First, they replace the browser’s cache with their own faster, smarter version. Second, they help make the most of your available bandwidth.
Normally, when you’ve downloaded a web page, your modem is idle while you read it. Accelerator programs take advantage of this, working through the links on the page, and downloading them while you read. This is known as pre-fetching. When you click on a link, if it’s already been fetched, then you see it speedily displayed from your own hard disk instead of having to wait for it to come from the Internet.
This sounds ideal, but there are a few problems. Accelerators can be intrusive, and it’s possible for all this background activity to slow you down. It’s also hit-and-miss whether the next link you click will be to one of the pages pre-fetched by the accelerator. If it’s not, you won’t see any benefit at all.
Also, Internet purists argue that accelerators can slow down the Internet for everyone because they increase Internet traffic by fetching pages that might never be viewed. Despite big claims for them of speed increases of 10 times or more, most people are unlikely to see more than 50% improvement at best and tasks such as downloading files will be no faster at all.
Another software category tries to optimize Windows Dial-Up Networking. This is normally done through the MTU (Maximum Transmission Unit). The theory behind this is complex, but basically all Internet data sent to and from your computer travels in little chunks called packets. MTU defines the maximum size of each packet and the default MTU setting isn’t suitable for modem connections – by changing it, so the theory goes, you can get a big speed increase. Is it true? Some people report improved performance, others report no change at all.
It’s important to use the right tools for the job. If you’re downloading, use a download manager to speed things up. A good download manager checks for mirror sites to see which is faster, and even switches between sites during the download to get the best performance. You can even schedule downloads for off peak hours.
Phone Line
A major bottleneck in your Internet connection is your telephone line. Standard phone technology just isn’t good enough for speedy downloads. Therefore, you should seriously consider the other possibilities, ISDN and ADSL. Logging on is very quick compared to the tedious wait during dial-up. Rental could be high, but check with a few ISP’s and you may find it’s much cheaper than you imagined. If you need improved speed, the costs may be worth it. Plus, you will have a 24 hours always-on connection.
Anyone who has ever used their own home computer to demonstrate the Internet to a friend who’s never seen it before knows there’s one question that occurs more than any other: Why is it so slow?
As the kind person showing your friend the delights of the online experience, it’s hard not to feel a little offended. How dare they criticize your setup and the majesty of the Internet? But, of course, there’s a lot of truth in the question. The Internet is slow. Actually, it’s good to be reminded of this, because the chances are there’s a lot that can be done to speed it up. There are three main areas to consider. Hardware, software, and the phone line.
Hardware
Lets begin with your computer. Modern web browsers require lots of system resources. Any recent computer fits the bill, but what if you have to make do with something older? Adding more ram is good, especially if you have less than 256mb. Consider adding a faster hard disk. It won’t speed up downloads from the Internet, but avoids windows slowing things down by swapping files from RAM to disk, and your browser should be able to work more quickly.
Don’t forget your modem. If you’re still using a 56k modem, then perhaps it’s time to upgrade to ISDN or ADSL. It needn’t cost the earth either. Broadband Internet is becoming so popular that many home users have already upgraded to this option. Most ISP’s will throw in a free router as part of the package. If you don’t have a network card in your computer to support the router, then perhaps it is time to upgrade that old PC.
You may be thinking that it’s OK because you’ve had a 56k modem for years. But the money you’re wasting on dial-up and slow downloads could be considerably higher than if you resorted to broadband internet. Check with your local ISP about broadband packages on special. If you are going to purchase your own router, make sure your operating system and computer will support the new router. Your local computer store will most probably offer you free advice on the best way to setup your router.
Software
If you are going to stick with 56k modems, hardly anyone is happy with their speed, a dissatisfaction which has bred a brand new genre – utilities designed to speed things up. One major subcategory is the accelerator, a program which speeds up your browser in two different ways. First, they replace the browser’s cache with their own faster, smarter version. Second, they help make the most of your available bandwidth.
Normally, when you’ve downloaded a web page, your modem is idle while you read it. Accelerator programs take advantage of this, working through the links on the page, and downloading them while you read. This is known as pre-fetching. When you click on a link, if it’s already been fetched, then you see it speedily displayed from your own hard disk instead of having to wait for it to come from the Internet.
This sounds ideal, but there are a few problems. Accelerators can be intrusive, and it’s possible for all this background activity to slow you down. It’s also hit-and-miss whether the next link you click will be to one of the pages pre-fetched by the accelerator. If it’s not, you won’t see any benefit at all.
Also, Internet purists argue that accelerators can slow down the Internet for everyone because they increase Internet traffic by fetching pages that might never be viewed. Despite big claims for them of speed increases of 10 times or more, most people are unlikely to see more than 50% improvement at best and tasks such as downloading files will be no faster at all.
Another software category tries to optimize Windows Dial-Up Networking. This is normally done through the MTU (Maximum Transmission Unit). The theory behind this is complex, but basically all Internet data sent to and from your computer travels in little chunks called packets. MTU defines the maximum size of each packet and the default MTU setting isn’t suitable for modem connections – by changing it, so the theory goes, you can get a big speed increase. Is it true? Some people report improved performance, others report no change at all.
It’s important to use the right tools for the job. If you’re downloading, use a download manager to speed things up. A good download manager checks for mirror sites to see which is faster, and even switches between sites during the download to get the best performance. You can even schedule downloads for off peak hours.
Phone Line
A major bottleneck in your Internet connection is your telephone line. Standard phone technology just isn’t good enough for speedy downloads. Therefore, you should seriously consider the other possibilities, ISDN and ADSL. Logging on is very quick compared to the tedious wait during dial-up. Rental could be high, but check with a few ISP’s and you may find it’s much cheaper than you imagined. If you need improved speed, the costs may be worth it. Plus, you will have a 24 hours always-on connection.
Saturday, August 25, 2007
Internet Security Software: Free Downloads To Secure
The internet is considered as the information superhighway where you can gather the information you need for school and work. In fact, the internet is so useful that people have begun to use it for businesses.
The internet can even be a great way to entertain yourself with downloadable movies, comics and music. Another benefit the internet gives is that you can do your shopping for your clothes and groceries right in the comforts of your own home. You no longer need to go out to the supermarket or to the mall to buy the things you need. All you need to do is log in to an online shopping website and purchase the items you need.
Unfortunately, useful as the internet may be, it also has its dangers. Since more and more people are purchasing goods and services in the internet, it also paved the way for new kinds of criminals. These criminals will try and get your financial and personal information and use it to steal money from you without you knowing about it until its too late.
These people develop programs or softwares that can invade your personal computer silently and will start gathering information for the developer. With these programs, they will have access to your files and know every key you type in your keyboard and every click of your mouse. Sometimes, these programs simply destroy the files inside your computer.
Here are the different programs cyber criminals use to destroy your files, or obtain your personal information:
Spyware
Adware
Viruses
Spam emails
In order to protect yourself and your PC from the different malicious software circulating the internet, you have to purchase a kind of internet security software. However, since there is a lot of security software available in the internet, you will be confused on which one you should purchase.
This is why there are trial periods for softwares in order for you to determine which software is better. Trial or demo versions of the different internet security software are free and can be downloaded instantly from the companys website. You can download it for free, install it in your computer, and test it if it would be worth your time and money to purchase the full version of the software.
However, these demo versions can only protect your personal computer at a limited time only. After the trial period expires, the software will be locked and you will need to purchase the full version of the software in order to use it again.
Some trial versions have full capabilities while others have only limited capabilities. These free software versions can also be very useful. You can try and use these versions until you find the internet security software you want. Think of it as a temporary fix until you find the right software.
So, if you are looking for a way to protect your computer from malicious software at least temporarily, you can try out the free versions of internet security software until you find the software that is right for your computer. You have to find the software that offer full capabilities against the growing threat in the internet today. It should be able to fight off viruses, spyware, adware, spam emails, and hackers.
With the right kind of software, you will be sure that you can surf the internet without worrying about the different malicious software circulating the internet today.
Deon Melchior is the Editor and Publisher of Article Click. For more FREE articles for your ezine and websites visit ArticleClick.com. Article Click is a free content article directory. You may reprint this article, as long as the article is unedited and this author box is included with it's live hyperlinks.
The internet can even be a great way to entertain yourself with downloadable movies, comics and music. Another benefit the internet gives is that you can do your shopping for your clothes and groceries right in the comforts of your own home. You no longer need to go out to the supermarket or to the mall to buy the things you need. All you need to do is log in to an online shopping website and purchase the items you need.
Unfortunately, useful as the internet may be, it also has its dangers. Since more and more people are purchasing goods and services in the internet, it also paved the way for new kinds of criminals. These criminals will try and get your financial and personal information and use it to steal money from you without you knowing about it until its too late.
These people develop programs or softwares that can invade your personal computer silently and will start gathering information for the developer. With these programs, they will have access to your files and know every key you type in your keyboard and every click of your mouse. Sometimes, these programs simply destroy the files inside your computer.
Here are the different programs cyber criminals use to destroy your files, or obtain your personal information:
Spyware
Adware
Viruses
Spam emails
In order to protect yourself and your PC from the different malicious software circulating the internet, you have to purchase a kind of internet security software. However, since there is a lot of security software available in the internet, you will be confused on which one you should purchase.
This is why there are trial periods for softwares in order for you to determine which software is better. Trial or demo versions of the different internet security software are free and can be downloaded instantly from the companys website. You can download it for free, install it in your computer, and test it if it would be worth your time and money to purchase the full version of the software.
However, these demo versions can only protect your personal computer at a limited time only. After the trial period expires, the software will be locked and you will need to purchase the full version of the software in order to use it again.
Some trial versions have full capabilities while others have only limited capabilities. These free software versions can also be very useful. You can try and use these versions until you find the internet security software you want. Think of it as a temporary fix until you find the right software.
So, if you are looking for a way to protect your computer from malicious software at least temporarily, you can try out the free versions of internet security software until you find the software that is right for your computer. You have to find the software that offer full capabilities against the growing threat in the internet today. It should be able to fight off viruses, spyware, adware, spam emails, and hackers.
With the right kind of software, you will be sure that you can surf the internet without worrying about the different malicious software circulating the internet today.
Deon Melchior is the Editor and Publisher of Article Click. For more FREE articles for your ezine and websites visit ArticleClick.com. Article Click is a free content article directory. You may reprint this article, as long as the article is unedited and this author box is included with it's live hyperlinks.
Internet security : How Secure Is HTTP Basic
With basic authentication, your server has identified who the client user is by means of a user ID and password. How sure can you be that the user really is who he claims to be? To answer this you have to consider the ways in which the ID and password may have been compromised:
The user may have voluntarily given the ID to another person.
The user may have written down the ID, and someone may be using it without his knowledge.
Someone may have guessed the password.
Someone may have intercepted the user ID and password between client and server systems.
The first three possibilities are problems which occur in any password-based system. The normal response to such issues is to suggest better user education and password rules. This is quite reasonable, and can be effective within a single enterprise, where you have some control over the users of the system. It is much less effective in the Interne environment, where the users can come from many backgrounds and locations.
The last possibility is dependent on the level of protection given to messages by the HTTP protocol. We mentioned at the start of the chapter that base64 encoding is used to protect the user ID and password. The base64 encoding system is described in the Multipurpose Internet Mail Extensions (MIME) standard (RFC1521). It is intended as a mechanism for converting binary data into a form that can be sent through mail gateways, some of which can only handle 7-bit ASCII data. The result of this conversion is to mask the contents of any text string but, although it looks as though the data is encrypted, the protection that Base64 provides is an illusion.
We will illustrate this with an example. In order to crack a message, the hacker first has to be able to capture it. There are various ways to do this through hardware and software and none of them are very difficult. What is more difficult is finding a suitable point to make the trace. There are numerous techniques that a hacker can use to divert Internet traffic through his own tracing system, although they are becoming more complex as firewalls and routing controls become smarter. Nonetheless, we can assume that this is not an impossible task for a determined hacker.
For our example we used the DatagLANce LAN analyzer to capture an HTTP packet packet that contained a request including a basic authentication header.
The user may have voluntarily given the ID to another person.
The user may have written down the ID, and someone may be using it without his knowledge.
Someone may have guessed the password.
Someone may have intercepted the user ID and password between client and server systems.
The first three possibilities are problems which occur in any password-based system. The normal response to such issues is to suggest better user education and password rules. This is quite reasonable, and can be effective within a single enterprise, where you have some control over the users of the system. It is much less effective in the Interne environment, where the users can come from many backgrounds and locations.
The last possibility is dependent on the level of protection given to messages by the HTTP protocol. We mentioned at the start of the chapter that base64 encoding is used to protect the user ID and password. The base64 encoding system is described in the Multipurpose Internet Mail Extensions (MIME) standard (RFC1521). It is intended as a mechanism for converting binary data into a form that can be sent through mail gateways, some of which can only handle 7-bit ASCII data. The result of this conversion is to mask the contents of any text string but, although it looks as though the data is encrypted, the protection that Base64 provides is an illusion.
We will illustrate this with an example. In order to crack a message, the hacker first has to be able to capture it. There are various ways to do this through hardware and software and none of them are very difficult. What is more difficult is finding a suitable point to make the trace. There are numerous techniques that a hacker can use to divert Internet traffic through his own tracing system, although they are becoming more complex as firewalls and routing controls become smarter. Nonetheless, we can assume that this is not an impossible task for a determined hacker.
For our example we used the DatagLANce LAN analyzer to capture an HTTP packet packet that contained a request including a basic authentication header.
Internet Security -- Types of Attack
The internet is home to a variety of cyberpunks who pose threats to the security of WWW communications. They may attempt a number of different types of attack, for example:
Passive Attacks In a passive attack the perpetrator simply monitors the traffic being sent to try to learn secrets. Such attacks can be either network based (tracing the communications links) or system based (replacing a system component with a Trojan Horse that captures data insidiously). Passive attacks are the most difficult to detect. You should assume that someone is eavesdropping on everything you send across the Internet.
Active Attacks In these the attacker is trying to break through your defenses. There are several types of active attack, for example:
System access attempts, where the attacker aims to exploit security loopholes to gain access and control over a client or server system.
Spoofing, where the attacker masquerades as a trusted system to try to persuade you to send him secret information.
Cryptographic attacks, where the attacker attempts to break 0your passwords or decrypt some of your data.
Denial of Service Attacks In this case the attacker is not so much trying to learn your secrets as to prevent your operation, by re-directing traffic or bombarding you with junk.
Passive Attacks In a passive attack the perpetrator simply monitors the traffic being sent to try to learn secrets. Such attacks can be either network based (tracing the communications links) or system based (replacing a system component with a Trojan Horse that captures data insidiously). Passive attacks are the most difficult to detect. You should assume that someone is eavesdropping on everything you send across the Internet.
Active Attacks In these the attacker is trying to break through your defenses. There are several types of active attack, for example:
System access attempts, where the attacker aims to exploit security loopholes to gain access and control over a client or server system.
Spoofing, where the attacker masquerades as a trusted system to try to persuade you to send him secret information.
Cryptographic attacks, where the attacker attempts to break 0your passwords or decrypt some of your data.
Denial of Service Attacks In this case the attacker is not so much trying to learn your secrets as to prevent your operation, by re-directing traffic or bombarding you with junk.
Internet security : Http Methods
When a client sends an HTTP request it includes a methods specification which tells the server what the client wants it to do. So, for example, a request to retrieve a document will have a method type of GET. When we start to restrict access to files on the server, we will need to specify which method(s) are permitted.
In the IBM Internet Connection Secure Sever the methods are specified by Mask specifications, which are part of the Protection directives. The following is a list of the methods that the servers support and a description of how the server would respond to a client request containing the method. The description assumes the method is enabled.
- GetMask – The server returns whatever data is defined by the URL. If the URL refers to an executable program, the server returns the output of the program. Briefly you can receive and display all the GTML pages, but you cannot submit a form.
- PostMask – The request contains data and a URL. The server creates a new object with the data portion of the request. The server links the new object to the URL sent on the request. The server gives the new object a URL. The server sends the URL of the new object back to the client. The new object is subordinate to the URL contained on the request (the same way a file is subordinate to a directory or a news article is subordinate to a news group.) POST creates new documents; use PUT to replace existing data.
- PutMask - The request contains data and a URL. The URL must already exist on the server. The server deletes the current data defined by the URL and replaces it with the new data contained in the request. PUT replaces existing data; use POST to create new documents. Because PUT lets clients replace information on your server, it’s extremely important you use protection rules to define who you want to be able to use this method.
- Mask – Mask provides the protection definition for the directives that you have not explicitly coded..
In the IBM Internet Connection Secure Sever the methods are specified by Mask specifications, which are part of the Protection directives. The following is a list of the methods that the servers support and a description of how the server would respond to a client request containing the method. The description assumes the method is enabled.
- GetMask – The server returns whatever data is defined by the URL. If the URL refers to an executable program, the server returns the output of the program. Briefly you can receive and display all the GTML pages, but you cannot submit a form.
- PostMask – The request contains data and a URL. The server creates a new object with the data portion of the request. The server links the new object to the URL sent on the request. The server gives the new object a URL. The server sends the URL of the new object back to the client. The new object is subordinate to the URL contained on the request (the same way a file is subordinate to a directory or a news article is subordinate to a news group.) POST creates new documents; use PUT to replace existing data.
- PutMask - The request contains data and a URL. The URL must already exist on the server. The server deletes the current data defined by the URL and replaces it with the new data contained in the request. PUT replaces existing data; use POST to create new documents. Because PUT lets clients replace information on your server, it’s extremely important you use protection rules to define who you want to be able to use this method.
- Mask – Mask provides the protection definition for the directives that you have not explicitly coded..
Thursday, August 23, 2007
Motherboards an explanation
A motherboard is also known as a main board, system board and logic board. A common abbreviation is "mobo" they can be found in all computers, it is the central circuit board of your computer. All other components and peripherals plug into it, and the job of the motherboard is to relay information between them all.
A motherboard houses the BIOS (Basic Input/Output System), which is the simple software run by a computer when initially turned on. Other components attach directly to it, such as the memory, CPU (Central Processing Unit), graphics card, sound card, hard-drive, disk drives, along with various external ports and peripherals.
There are a lot of motherboards on the market to choose from. The big question is, how do you go about choosing which one is right for you? different motherboards support different components, and so it is vital you make a number of decisions concerning general system specifications before you can pick the right motherboard, what type of Computer do you want to build, an Intel based or AMD based "the two most common".
If you purchase your case before the rest of the components, the first factor to think about concerning motherboards is the size, or form factor, a form factor is a standardized motherboard size, if you think about fitting a motherboard in a case, there are a number of mounting holes, slot locations and PSU connectors - 20 pin and mostly now 24 pin. The most popular motherboard form factor today is ATX, which evolved from it's predecessor, the Baby AT, a smaller version of the AT (Advanced Technology) form factor. Nowadays a standard computer will have an ATX form factor motherboard: only special cases require different form factors
Windows XP Keyboard Shortcuts
CTRL+C(Copy)
CTRL+X (Cut)
CTRL+Z (Undo)
DELETE (Delete)
SHIFT+DELETE (Delete the selected item permanently without placing the item in the Recycle Bin)
CTRL while dragging an item (Copy the selected item)
CTRL+SHIFT while dragging an item (Create a shortcut to the selected item)
F2 key (Rename the selected item)
CTRL+RIGHT ARROW (Move the insertion point to the beginning of the next word)
CTRL+LEFT ARROW (Move the insertion point to the beginning of the previous word)
CTRL+DOWN ARROW (Move the insertion point to the beginning of the next paragraph)
CTRL+SHIFT with any of the arrow keys (Highlight a block of text)
CTRL+UP ARROW (Move the insertion point to the beginning of the previous paragraph)
SHIFT with any of the arrow keys (Select more than one item in a window or on the desktop, or select text in a document)
CTRL+A (Select all)
F3 key (Search for a file or a folder)
ALT+ENTER (View the properties for the selected item)
ALT+F4 (Close the active item, or quit the active program)
ALT+ENTER (Display the properties of the selected object)
ALT+SPACEBAR (Open the shortcut menu for the active window)
CTRL+F4 (Close the active document in programs that enable you to have multiple documents open simultaneously)
ALT+TAB (Switch between the open items)
ALT+ESC (Cycle through items in the order that they had been opened)
F6 key (Cycle through the screen elements in a window or on the desktop)
F4 key (Display the Address bar list in My Computer or Windows Explorer)
SHIFT+F10 (Display the shortcut menu for the selected item)
ALT+SPACEBAR (Display the System menu for the active window)
CTRL+ESC (Display the Start menu)
ALT+Underlined letter in a menu name (Display the corresponding menu)
Underlined letter in a command name on an open menu (Perform the corresponding command)
F10 key (Activate the menu bar in the active program)
RIGHT ARROW (Open the next menu to the right, or open a submenu)
LEFT ARROW (Open the next menu to the left, or close a submenu)
F5 key (Update the active window)
BACKSPACE (View the folder one level up in My Computer or Windows Explorer)
ESC (Cancel the current task)
SHIFT when you insert a CD-ROM into the CD-ROM drive (Prevent the CD-ROM from automatically playing)
CTRL+SHIFT+ESC (Open Task Manager)
CTRL+X (Cut)
CTRL+Z (Undo)
DELETE (Delete)
SHIFT+DELETE (Delete the selected item permanently without placing the item in the Recycle Bin)
CTRL while dragging an item (Copy the selected item)
CTRL+SHIFT while dragging an item (Create a shortcut to the selected item)
F2 key (Rename the selected item)
CTRL+RIGHT ARROW (Move the insertion point to the beginning of the next word)
CTRL+LEFT ARROW (Move the insertion point to the beginning of the previous word)
CTRL+DOWN ARROW (Move the insertion point to the beginning of the next paragraph)
CTRL+SHIFT with any of the arrow keys (Highlight a block of text)
CTRL+UP ARROW (Move the insertion point to the beginning of the previous paragraph)
SHIFT with any of the arrow keys (Select more than one item in a window or on the desktop, or select text in a document)
CTRL+A (Select all)
F3 key (Search for a file or a folder)
ALT+ENTER (View the properties for the selected item)
ALT+F4 (Close the active item, or quit the active program)
ALT+ENTER (Display the properties of the selected object)
ALT+SPACEBAR (Open the shortcut menu for the active window)
CTRL+F4 (Close the active document in programs that enable you to have multiple documents open simultaneously)
ALT+TAB (Switch between the open items)
ALT+ESC (Cycle through items in the order that they had been opened)
F6 key (Cycle through the screen elements in a window or on the desktop)
F4 key (Display the Address bar list in My Computer or Windows Explorer)
SHIFT+F10 (Display the shortcut menu for the selected item)
ALT+SPACEBAR (Display the System menu for the active window)
CTRL+ESC (Display the Start menu)
ALT+Underlined letter in a menu name (Display the corresponding menu)
Underlined letter in a command name on an open menu (Perform the corresponding command)
F10 key (Activate the menu bar in the active program)
RIGHT ARROW (Open the next menu to the right, or open a submenu)
LEFT ARROW (Open the next menu to the left, or close a submenu)
F5 key (Update the active window)
BACKSPACE (View the folder one level up in My Computer or Windows Explorer)
ESC (Cancel the current task)
SHIFT when you insert a CD-ROM into the CD-ROM drive (Prevent the CD-ROM from automatically playing)
CTRL+SHIFT+ESC (Open Task Manager)
Windows XP Run Commands / Short Cuts :1
How To - Click Start, Click Run and enter the command Click OK
Run commands
Calc - Calculator
Cfgwiz32 - ISDN Configuration Wizard
Charmap - Character Map
Chkdisk - Repair damaged files
Cleanmgr - Cleans up hard drives
Clipbrd - Windows Clipboard viewer
Cmd - Opens a new Command Window (cmd.exe)
Control - Displays Control Panel
Dcomcnfg - DCOM user security
Debug - Assembly language programming tool
Defrag - Defragmentation tool
Drwatson - Records programs crash & snapshots
Dxdiag - DirectX Diagnostic Utility
Explorer - Windows Explorer
Fontview - Graphical font viewer
Ftp - ftp.exe program
Hostname - Returns Computer's name
Ipconfig - Displays IP configuration for all network adapters
Jview - Microsoft Command-line Loader for Java classes
MMC - Microsoft Management Console
Msconfig - Configuration to edit startup files
Msinfo32 - Microsoft System Information Utility
Nbtstat - Displays stats and current connections using NetBios over TCP/IP
Netstat - Displays all active network connections
Nslookup- Returns your local DNS server
Ping - Sends data to a specified host/IP
Regedit - egistry Editor
Regsvr32 - egister/de-register DLL/OCX/ActiveX
Regwiz - Reistration wizard
Sfc /scannow - Sytem File Checker
Sndrec32 - Sound Recorder
Sndvol32 - Volume control for soundcard
Sysedit - Edit system startup files (config.sys, autoexec.bat, win.ini, etc.)
Taskmgr - Task manager
Telnet - Telnet program
Tracert - Traces and displays all paths required to reach an internet host
Winipcfg - Displays IP configuration
Run commands
Calc - Calculator
Cfgwiz32 - ISDN Configuration Wizard
Charmap - Character Map
Chkdisk - Repair damaged files
Cleanmgr - Cleans up hard drives
Clipbrd - Windows Clipboard viewer
Cmd - Opens a new Command Window (cmd.exe)
Control - Displays Control Panel
Dcomcnfg - DCOM user security
Debug - Assembly language programming tool
Defrag - Defragmentation tool
Drwatson - Records programs crash & snapshots
Dxdiag - DirectX Diagnostic Utility
Explorer - Windows Explorer
Fontview - Graphical font viewer
Ftp - ftp.exe program
Hostname - Returns Computer's name
Ipconfig - Displays IP configuration for all network adapters
Jview - Microsoft Command-line Loader for Java classes
MMC - Microsoft Management Console
Msconfig - Configuration to edit startup files
Msinfo32 - Microsoft System Information Utility
Nbtstat - Displays stats and current connections using NetBios over TCP/IP
Netstat - Displays all active network connections
Nslookup- Returns your local DNS server
Ping - Sends data to a specified host/IP
Regedit - egistry Editor
Regsvr32 - egister/de-register DLL/OCX/ActiveX
Regwiz - Reistration wizard
Sfc /scannow - Sytem File Checker
Sndrec32 - Sound Recorder
Sndvol32 - Volume control for soundcard
Sysedit - Edit system startup files (config.sys, autoexec.bat, win.ini, etc.)
Taskmgr - Task manager
Telnet - Telnet program
Tracert - Traces and displays all paths required to reach an internet host
Winipcfg - Displays IP configuration
Sunday, July 1, 2007
A heap alternative to BroadBand
Are you a dial-up user looking for a faster connection, but don't like Broadband prices? If so, you should take a look at a new service called OnSpeed, which has received rave reviews in Internet technology publications.
What OnSpeed does is to re-route web pages and email via its own servers, compressing the data on the fly prior to sending it onwards to your PC. A small program then decompresses the data, so that you can view it in the normal way via your browser or email client.
Some file types like MP3 also cannot yet be compressed. The company is working on these issues however and expects to find solutions soon.
For further details click here.
What OnSpeed does is to re-route web pages and email via its own servers, compressing the data on the fly prior to sending it onwards to your PC. A small program then decompresses the data, so that you can view it in the normal way via your browser or email client.
Some file types like MP3 also cannot yet be compressed. The company is working on these issues however and expects to find solutions soon.
For further details click here.
Saturday, May 26, 2007
What is Serial ATA (SATA)
In computer hardware, Serial ATA (SATA, [ˈseɪ.tə] or IPA: [ˈsæ.tə]) is a computer bus technology primarily designed for transfer of data to and from hard disks and optical drives. It was designed as a successor to the legacy Advanced Technology Attachment standard (ATA), and is expected to eventually replace the older technology (retroactively renamed Parallel ATA or PATA). Serial ATA adapters and devices communicate over a high-speed serial link.
Architecture
At the physical layer of the Serial ATA architecture, the data-connection is formed by two pairs of (unidirectional) signal wires. Over these wires, SATA uses Low Voltage Differential Signaling (LVDS), enabling much higher (per-wire) signalling rates (1.5 Gbit/s and up) than traditional parallel ATA. Byte data is encoded and transmitted using 8B/10B encoding, which is also used in Ethernet, Fibre Channel, PCI Express, etc. This encoding scheme has an efficiency of 80%, but the 8B/10B encoding embeds the information necessary to distinguish bit and character boundaries, eliminating the need for a separate clock signal. The switch from a parallel to serial electrical scheme facilitates future upgrades to performance, and lowers costs (compared to a comparably fast parallel-interface.) Above the SATA physical level are the link level and transport level. These higher levels convert configuration and data-operations into discrete ordered packets, for transmission over the SATA link. At the application level, SATA inherits ATA's operational model, with the 'task register file' (for generating read/write PIO and DMA requests) a mandatory part of all SATA host implementations. Vendor implementations may include additional functionality (such as simulated RAID) above and beyond the SATA specification, but require device-specific drivers to exploit. The final major difference between SATA and PATA, from a user standpoint, is the point-to-point link between host and drive. Each SATA/device has a link to a SATA host-port, with no sharing of cable or bandwidth between devices.
Many vendors have implemented SATA in conjunction with SAS (Serial Attached SCSI). Since the connectors are universal between the protocols, it allows them to create an entry level product which connects to SATA storage while providing an upgrade path for users to move to the higher end SAS technology.
[edit] SATA 1.5 Gbit/s
First-generation SATA interfaces, also known as SATA/150 or (erroneously) as SATA 1, communicate at a rate of 1.5 gigabits per second (Gbit/s). Taking into account 8b10b coding overhead, the actual uncoded transfer-rate is 1.2 Gbit/s, or 150 megabytes per second (MB/s). In actual operation, SATA/150 and PATA/133 are comparable in terms of their theoretical burst-throughput. However, newer SATA devices offer enhancements (such as native command queuing) to SATA's performance in a multitask environment.
During the initial period after SATA/150's finalization, both adapter and drive manufacturers used a "bridge chip" to convert existing designs with the PATA-interface to the SATA-interface. Bridged drives have a SATA connector, may include either or both kinds of power connectors, and generally perform identically to native drives. They generally lack support for some SATA-specific features (such as NCQ). Bridged products gradually gave way to native SATA products.
[edit] SATA 3.0 Gbit/s
Soon after SATA/150's introduction, a number of shortcomings in the original SATA were observed. First and foremost, at the application-level, SATA's operational model emulated PATA in that the interface could only handle 1 pending transaction at a time. SCSI disks have long benefited from the SCSI-interface's support for multiple outstanding requests, allowing the drive targets to re-order the requests to optimize response-time. Native command queuing (NCQ) adds this capability to SATA. NCQ is an optional feature, and may be used in both SATA 1.5 Gbit/s or SATA 3.0 Gbit/s devices.
First-generation SATA devices were scarcely faster than legacy parallel ATA/133 devices. So a 3 Gbit/s signaling rate was added to the Physical layer (PHY layer), effectively doubling data throughput from 150 MB/s to 300 MB/s. SATA/300's transfer rate is expected to satisfy drive throughput requirements for some time, as the fastest desktop hard disks barely saturate a SATA/150 link. This is why a SATA data cable rated for 1.5Gbps will currently handle second generation, SATA 3.0Gbps sustained and burst data transfers without any loss of performance.
Backward compatibility between SATA 1.5 Gbit/s controllers and SATA 3.0 Gbit/s devices was important, so SATA/300's autonegotiation sequence is designed to fallback to SATA/150 speed (1.5 Gbit/s rate) when in communication with such devices. In practice, some older SATA controllers do not properly implement SATA speed negotiation. Affected systems require user-intervention to manually set the SATA 3.0 Gbit/s peripherals to 1.5 Gbit/s mode, generally through the use of a jumper. [1] Known faulty chipsets include the VIA VT8237 and VT8237R south bridges, and the VIA VT6420 and VT6421L standalone SATA controllers. [2] SiS's 760 and 964 chipsets also initially exhibited this problem, though it can be rectified with an updated SATA controller ROM.[citation needed]
The 3.0 Gbit/s specification has been very widely referred to as “Serial ATA II” (“SATA II”), contrary to the wishes of the Serial ATA standards organization that authored it. The official website notes that SATA II was in fact that organization's name at the time, the SATA 3.0 Gbit/s specification being only one of many that the former SATA II defined, and suggests that “SATA 3.0 Gbit/s” be used instead. (The Serial ATA standards organization has since changed names, and is now “The Serial ATA International Organization”, abbreviated SATA-IO.) Most SATA drive and controller manufacturers also do not use the term “SATA II”.
SATA 3.0 Gbit/s is sometimes also referred to as SATA 3.0 or SATA/300, continuing the line of ATA/100, ATA/133 and SATA/150.
[edit] Future design: SATA 6.0 Gbit/s
SATA's roadmap includes plans for a 6.0 Gbit/s standard. In current PCs, SATA 3.0 Gbit/s already greatly exceeds the sustainable (non-burst) transfer-rate of even the best hard-disks. The 6.0 Gbit/s standard will however be useful in combination with port multipliers, which allow multiple drives to be connected to a single Serial ATA port, thus sharing the port's bandwidth with multiple drives. Solid-state drives such as RAM disks may also one day exploit the faster transfer-rate. Since the theoretical burst speeds marketed by drive manufacturers are rarely achieved, a smaller power and interface cable plus the ability to hot-plug are the most practical SATA benefits to everyday computing.
[edit] Serial ATA innovations
SATA uses only 4 signal-lines, allowing for much more compact (and less-expensive) cables compared to PATA. SATA also offers new features such as hot-swapping and native command queuing.
SATA drives may be plugged into Serial Attached SCSI (SAS) controllers and communicate on the same physical cable as native SAS disks. SAS disks, however, may not be plugged into a SATA controller.
[edit] Cables and connectors
A 7-pin Serial ATA data cable.
A 7-pin Serial ATA data cable.
The SATA power and data cables are the most noticeable change from Parallel ATA.
The SATA standard defines a data cable using seven conductors (of which 4 are active data lines) and 8 mm wide wafer connectors on each end. SATA cables can be up to 1 m (39 in) long. PATA ribbon cables, in comparison, carry either 40- or 80-conductor wires and are limited to 46 cm (18 in) in length. Thus, SATA connectors and cables are easier to fit in closed spaces and reduce obstructions to air cooling. However, they are more susceptible to accidental unplugging.
Cables and connectors
A 7-pin Serial ATA data cable.
A 7-pin Serial ATA data cable.
The SATA power and data cables are the most noticeable change from Parallel ATA.
The SATA standard defines a data cable using seven conductors (of which 4 are active data lines) and 8 mm wide wafer connectors on each end. SATA cables can be up to 1 m (39 in) long. PATA ribbon cables, in comparison, carry either 40- or 80-conductor wires and are limited to 46 cm (18 in) in length. Thus, SATA connectors and cables are easier to fit in closed spaces and reduce obstructions to air cooling. However, they are more susceptible to accidental unplugging.
Pin # Function
1 Ground
2 A+
3 A-
4 Ground
5 B-
6 B+
7 Ground
A 15-pin Serial ATA power connector.
A 15-pin Serial ATA power connector.
The SATA standard also specifies a new power connector. Like the data cable, it is wafer-based, but its wider 15-pin shape prevents accidental misidentifcation and forced insertion of the wrong connector type. Native SATA devices favor the SATA power-connector over the old four-pin Molex connector (found on all PATA equipment), although some SATA drives retain older 4-pin Molex. The SATA/power connector has been criticized for its poor robustness -- the thin plastic tops of the connectors (see power connector picture at right) can break due to shearing force when the user pulls the plug at a non-orthogonal angle. The seemingly large number of pins are used to supply three different voltages: 3.3 V, 5 V, and 12 V. Each voltage is supplied by three pins ganged together, 5 of the remaining pins are for ground. The last pin, pin 11, is used in newer drives for staggered spinup. The supply pins are ganged together because the small pins by themselves cannot supply sufficient current for some devices. One pin from each of the three voltages is also used for hotplugging. The same physical connections are used on 3.5-in (90 mm) and 2.5-in (70 mm) (notebook) hard disks.
Pin # Function
1-3 3.3V
4-6 Ground
7-9 5V
10-12 Ground
13-15 12V
Adaptors are available to convert a 4-pin Molex connector to SATA power connector. However, because the 4-pin Molex connectors do not provide 3.3 V power, these adapters provide only 5 V and 12 V power and leave the 3.3 V lines disconnected. This precludes the use of such adapters with drives that require 3.3 V power. Understanding this, drive manufacturers have largely left the 3.3 V power lines unused. However, without 3.3 V power, the SATA device may not be able to implement hotplugging as mentioned in the previous paragraph.
[edit] External SATA
The official eSATA logo
Standardized in mid-2004, eSATA defined separate cables, connectors, and revised electrical requirements for external applications:
* Minimum transmit potential increased: Range is 500–600 mV instead of 400–600 mV.
* Minimum receive potential decreased: Range is 240–600 mV instead of 325–600 mV.
* Identical protocol and logical signaling (link/transport-layer and above), allowing native SATA devices to be deployed in external enclosures with minimal modification
* Maximum cable length of 2 m (USB and FireWire allow longer distances.)
Aimed at the consumer market, eSATA enters an external storage market already served by the USB and FireWire interfaces. Most external hard disk drive cases with FireWire or USB interfaces use either PATA or SATA drives and "bridges" to translate between the drives' interfaces and the enclosures' external ports, and this bridging incurs some inefficiency. In the case of USB 2.0, protocol overhead limits the maximum effective bandwidth to a fraction of USB's physical signalling rate. With modern hard disk drives, USB's transfer rate is a bottleneck. FireWire, with its isochronous transfer mode, is more efficient, such that even in its slower variant, FireWire 400 (IEEE 1394a), the effective transfer rate is significantly faster than that of USB 2.0, but this can still be a bottleneck for fast drives or RAIDs. Some single disks can transfer well over 70 MB/s during real use, well in excess of USB 2.0's or the older FireWire 400's abilities. Finally, some low-level drive features, such as S.M.A.R.T., are not usable through USB or FireWire bridging. eSATA does not suffer from these issues.
eSATA will likely co-exist alongside USB 2.0 and FireWire storage for several reasons. The ubiquity of USB ports on all mass-market computers, and FireWire ports on many consumer electronic appliances, guarantee a large market for USB and FireWire storage. For small form-factor devices (such as external 2.5" disks), a PC-hosted USB or FireWire link supplies sufficient power to operate the device. Where a PC-hosted port is concerned, eSATA connectors cannot supply power, and would therefore be more cumbersome to use.
As of 2007, few computer motherboards have eSATA connectors. An eSATA external drive enclosure will typically ship with a passive eSATA-to-SATA bracket/cable-adapter to install on desktops. Desktops can also be upgraded with the installation of an eSATA host bus adapter (HBA), while notebooks can be upgraded with Cardbus or ExpressCard versions of an eSATA HBA. With passive-adapters, the maximum cable length is reduced to 1 meter, due to the absence of compliant eSATA signal levels. Full SATA speed for external disks (115 MB/s) have been measured with external RAID enclosures.
eSATA is likely to be ignored by the enterprise and server market, which has already standardized on the separately-developed Serial Attached SCSI (SAS) interface, which has extra features for remote management, link redundancy, and link monitoring.
Note: Prior to the final eSATA specification, there were a number of products designed for external connections of SATA drives. Some of these use the internal SATA connector or even connectors designed for other interface specifications, such as FireWire. These products are not eSATA compliant. The final eSATA specification features a specific connector designed for rough manipulation. It's similar to the regular SATA connector, but with reinforcements in both the male and female sides, inspired by the USB connector. It's harder to unplug and can withstand a cable being yanked or wiggled. On a SATA connector, this kind of action will break the male side of the connection (the hard drive or host adapter), rendering the device unusable. With an eSATA connector, considerably more force is needed to damage the connector, and even in this situation, only the female side (the cable itself) will break, possibly leaving the male usable.[citation needed]
[edit] eSATA compared to other buses
eSATA SATA 300 PATA 133 FireWire 800 FireWire 400 USB 2.0 Ultra-320 SCSI
Speed (Mbit/s) 2400 2400 1064 786 393 480 (burst) 2560
Max. cable length (m) 2 1 0.46 4.5 (16 cables can be
daisy chained up to 72 m) 4.5 (16 cables can be
daisy chained up to 72 m) 5 (USB hubs can be
daisy chained up to 25 m) 12
Power provided No No No Yes (12-25 V, 15 W) Yes (12-25 V, 15 W) Yes (5 V, 2.5 W) No
Devices per Channel 1 (15 with port multiplier) 1 per line 2 63 63 127 16
Unlike PATA, both SATA and eSATA are designed to support hot-plugging. However, this feature requires proper support at the host, device (drive), and operating-system level. In general, all SATA/devices (drives) support hot-plugging (due to the requirements on the device-side), but requisite support is less common on SATA host adapters.
USB allows hot-plugging; this is supported by virtually every current operating system. However, USB-based storage hardware can infrequently sustain data loss when disconnected. This problem exists with media players and digital cameras using flash memory as well as mobile 2.5-inch USB hard drives. Firmware damage and data loss can occasionally result from unclean spin-downs and power loss when the drive or device is removed from the USB port without first initiating a device shutdown via the computer's operating system.[citation needed]
SCSI devices with SCA-2 connectors are designed for hot plugging. Many server and RAID systems provide hardware support for transparent hot-plugging. The SCSI standard prior to SCA-2 connectors was not designed for hot-plugging, but, in practice, most RAID implementations support hot-swapping of hard disks.
Serial Attached SCSI (SAS) is designed for hot-plugging.
[edit] Backward and forward compatibility
[edit] SATA and PATA
At the device level, SATA and PATA devices are completely incompatible -- they cannot be interconnected. At the application level, SATA devices are specified to look and act like PATA devices. In early motherboard implementations of SATA, backward compatibility allowed SATA drives to be used as drop-in replacements for PATA drives, even without native (driver-level) support at the operating system level.
The common heritage of the ATA command set has enabled the proliferation of low-cost PATA<->SATA bridge-chips. Bridge chips were widely used on PATA drives (before the completion of native SATA drives) as well as standalone ‘dongles’. When attached to a PATA drive, a device-side dongle allows the PATA drive to function as a SATA drive. Host-side dongles allow a motherboard PATA port to function as a SATA host port.
Powered enclosures are available for both PATA and SATA drives, which interface to the PC through USB or Firewire, with the restrictions noted above. PCI cards with a SATA connector exist that allow SATA drives to connect to legacy systems without SATA connectors.
[edit] SATA-150 and SATA-300
SATA is designed to be backwards and forwards compatible with future revisions of the SATA standard [3]. Unfortunately, there are already documented incompatibilities between particular first-generation SATA/150 controllers and later-generation drives.
To address interoperability problems, some drive manufacturers have added a user-accessible jumper-switch, to select between SATA-150 and SATA/300 operation [4]. Users with a SATA-150 motherboard should either buy an ordinary SATA-150 hard disk, or buy a SATA-300 hard disk with the user-accessible jumper.
[edit] SATA vs SCSI
SCSI currently offers transfer rates higher than SATA, but is a more complex bus usually resulting in higher manufacturing cost. Some drive manufacturers offer longer warranties for SCSI devices, however, indicating a possibly higher manufacturing quality control of SCSI devices compared to PATA/SATA devices. SCSI buses also allow connection of several drives (using multiple channels, 7 or 15 on each channel) whereas SATA only allows one per channel.
SATA 3.0 Gbit/s offers a maximum bandwidth of 300 MB/s per device compared to SCSI with a maximum of 320 MB/s. Also, SCSI drives provide greater sustained throughput than SATA drives because of disconnect-reconnect and aggregating performance. SATA devices are generally compatible with SAS enclosures and adapters, while SCSI devices cannot be directly connected to a SATA bus.
SCSI hardware is used in enterprises for server purposes, partially due to higher cost of drives and adapters, and partially due to market reasons. The MTBF of SATA drives is usually about 150,000 hours, while SCSI drives are rated for upwards of 1,500,000 hours.
Architecture
At the physical layer of the Serial ATA architecture, the data-connection is formed by two pairs of (unidirectional) signal wires. Over these wires, SATA uses Low Voltage Differential Signaling (LVDS), enabling much higher (per-wire) signalling rates (1.5 Gbit/s and up) than traditional parallel ATA. Byte data is encoded and transmitted using 8B/10B encoding, which is also used in Ethernet, Fibre Channel, PCI Express, etc. This encoding scheme has an efficiency of 80%, but the 8B/10B encoding embeds the information necessary to distinguish bit and character boundaries, eliminating the need for a separate clock signal. The switch from a parallel to serial electrical scheme facilitates future upgrades to performance, and lowers costs (compared to a comparably fast parallel-interface.) Above the SATA physical level are the link level and transport level. These higher levels convert configuration and data-operations into discrete ordered packets, for transmission over the SATA link. At the application level, SATA inherits ATA's operational model, with the 'task register file' (for generating read/write PIO and DMA requests) a mandatory part of all SATA host implementations. Vendor implementations may include additional functionality (such as simulated RAID) above and beyond the SATA specification, but require device-specific drivers to exploit. The final major difference between SATA and PATA, from a user standpoint, is the point-to-point link between host and drive. Each SATA/device has a link to a SATA host-port, with no sharing of cable or bandwidth between devices.
Many vendors have implemented SATA in conjunction with SAS (Serial Attached SCSI). Since the connectors are universal between the protocols, it allows them to create an entry level product which connects to SATA storage while providing an upgrade path for users to move to the higher end SAS technology.
[edit] SATA 1.5 Gbit/s
First-generation SATA interfaces, also known as SATA/150 or (erroneously) as SATA 1, communicate at a rate of 1.5 gigabits per second (Gbit/s). Taking into account 8b10b coding overhead, the actual uncoded transfer-rate is 1.2 Gbit/s, or 150 megabytes per second (MB/s). In actual operation, SATA/150 and PATA/133 are comparable in terms of their theoretical burst-throughput. However, newer SATA devices offer enhancements (such as native command queuing) to SATA's performance in a multitask environment.
During the initial period after SATA/150's finalization, both adapter and drive manufacturers used a "bridge chip" to convert existing designs with the PATA-interface to the SATA-interface. Bridged drives have a SATA connector, may include either or both kinds of power connectors, and generally perform identically to native drives. They generally lack support for some SATA-specific features (such as NCQ). Bridged products gradually gave way to native SATA products.
[edit] SATA 3.0 Gbit/s
Soon after SATA/150's introduction, a number of shortcomings in the original SATA were observed. First and foremost, at the application-level, SATA's operational model emulated PATA in that the interface could only handle 1 pending transaction at a time. SCSI disks have long benefited from the SCSI-interface's support for multiple outstanding requests, allowing the drive targets to re-order the requests to optimize response-time. Native command queuing (NCQ) adds this capability to SATA. NCQ is an optional feature, and may be used in both SATA 1.5 Gbit/s or SATA 3.0 Gbit/s devices.
First-generation SATA devices were scarcely faster than legacy parallel ATA/133 devices. So a 3 Gbit/s signaling rate was added to the Physical layer (PHY layer), effectively doubling data throughput from 150 MB/s to 300 MB/s. SATA/300's transfer rate is expected to satisfy drive throughput requirements for some time, as the fastest desktop hard disks barely saturate a SATA/150 link. This is why a SATA data cable rated for 1.5Gbps will currently handle second generation, SATA 3.0Gbps sustained and burst data transfers without any loss of performance.
Backward compatibility between SATA 1.5 Gbit/s controllers and SATA 3.0 Gbit/s devices was important, so SATA/300's autonegotiation sequence is designed to fallback to SATA/150 speed (1.5 Gbit/s rate) when in communication with such devices. In practice, some older SATA controllers do not properly implement SATA speed negotiation. Affected systems require user-intervention to manually set the SATA 3.0 Gbit/s peripherals to 1.5 Gbit/s mode, generally through the use of a jumper. [1] Known faulty chipsets include the VIA VT8237 and VT8237R south bridges, and the VIA VT6420 and VT6421L standalone SATA controllers. [2] SiS's 760 and 964 chipsets also initially exhibited this problem, though it can be rectified with an updated SATA controller ROM.[citation needed]
The 3.0 Gbit/s specification has been very widely referred to as “Serial ATA II” (“SATA II”), contrary to the wishes of the Serial ATA standards organization that authored it. The official website notes that SATA II was in fact that organization's name at the time, the SATA 3.0 Gbit/s specification being only one of many that the former SATA II defined, and suggests that “SATA 3.0 Gbit/s” be used instead. (The Serial ATA standards organization has since changed names, and is now “The Serial ATA International Organization”, abbreviated SATA-IO.) Most SATA drive and controller manufacturers also do not use the term “SATA II”.
SATA 3.0 Gbit/s is sometimes also referred to as SATA 3.0 or SATA/300, continuing the line of ATA/100, ATA/133 and SATA/150.
[edit] Future design: SATA 6.0 Gbit/s
SATA's roadmap includes plans for a 6.0 Gbit/s standard. In current PCs, SATA 3.0 Gbit/s already greatly exceeds the sustainable (non-burst) transfer-rate of even the best hard-disks. The 6.0 Gbit/s standard will however be useful in combination with port multipliers, which allow multiple drives to be connected to a single Serial ATA port, thus sharing the port's bandwidth with multiple drives. Solid-state drives such as RAM disks may also one day exploit the faster transfer-rate. Since the theoretical burst speeds marketed by drive manufacturers are rarely achieved, a smaller power and interface cable plus the ability to hot-plug are the most practical SATA benefits to everyday computing.
[edit] Serial ATA innovations
SATA uses only 4 signal-lines, allowing for much more compact (and less-expensive) cables compared to PATA. SATA also offers new features such as hot-swapping and native command queuing.
SATA drives may be plugged into Serial Attached SCSI (SAS) controllers and communicate on the same physical cable as native SAS disks. SAS disks, however, may not be plugged into a SATA controller.
[edit] Cables and connectors
A 7-pin Serial ATA data cable.
A 7-pin Serial ATA data cable.
The SATA power and data cables are the most noticeable change from Parallel ATA.
The SATA standard defines a data cable using seven conductors (of which 4 are active data lines) and 8 mm wide wafer connectors on each end. SATA cables can be up to 1 m (39 in) long. PATA ribbon cables, in comparison, carry either 40- or 80-conductor wires and are limited to 46 cm (18 in) in length. Thus, SATA connectors and cables are easier to fit in closed spaces and reduce obstructions to air cooling. However, they are more susceptible to accidental unplugging.
Cables and connectors
A 7-pin Serial ATA data cable.
A 7-pin Serial ATA data cable.
The SATA power and data cables are the most noticeable change from Parallel ATA.
The SATA standard defines a data cable using seven conductors (of which 4 are active data lines) and 8 mm wide wafer connectors on each end. SATA cables can be up to 1 m (39 in) long. PATA ribbon cables, in comparison, carry either 40- or 80-conductor wires and are limited to 46 cm (18 in) in length. Thus, SATA connectors and cables are easier to fit in closed spaces and reduce obstructions to air cooling. However, they are more susceptible to accidental unplugging.
Pin # Function
1 Ground
2 A+
3 A-
4 Ground
5 B-
6 B+
7 Ground
A 15-pin Serial ATA power connector.
A 15-pin Serial ATA power connector.
The SATA standard also specifies a new power connector. Like the data cable, it is wafer-based, but its wider 15-pin shape prevents accidental misidentifcation and forced insertion of the wrong connector type. Native SATA devices favor the SATA power-connector over the old four-pin Molex connector (found on all PATA equipment), although some SATA drives retain older 4-pin Molex. The SATA/power connector has been criticized for its poor robustness -- the thin plastic tops of the connectors (see power connector picture at right) can break due to shearing force when the user pulls the plug at a non-orthogonal angle. The seemingly large number of pins are used to supply three different voltages: 3.3 V, 5 V, and 12 V. Each voltage is supplied by three pins ganged together, 5 of the remaining pins are for ground. The last pin, pin 11, is used in newer drives for staggered spinup. The supply pins are ganged together because the small pins by themselves cannot supply sufficient current for some devices. One pin from each of the three voltages is also used for hotplugging. The same physical connections are used on 3.5-in (90 mm) and 2.5-in (70 mm) (notebook) hard disks.
Pin # Function
1-3 3.3V
4-6 Ground
7-9 5V
10-12 Ground
13-15 12V
Adaptors are available to convert a 4-pin Molex connector to SATA power connector. However, because the 4-pin Molex connectors do not provide 3.3 V power, these adapters provide only 5 V and 12 V power and leave the 3.3 V lines disconnected. This precludes the use of such adapters with drives that require 3.3 V power. Understanding this, drive manufacturers have largely left the 3.3 V power lines unused. However, without 3.3 V power, the SATA device may not be able to implement hotplugging as mentioned in the previous paragraph.
[edit] External SATA
The official eSATA logo
Standardized in mid-2004, eSATA defined separate cables, connectors, and revised electrical requirements for external applications:
* Minimum transmit potential increased: Range is 500–600 mV instead of 400–600 mV.
* Minimum receive potential decreased: Range is 240–600 mV instead of 325–600 mV.
* Identical protocol and logical signaling (link/transport-layer and above), allowing native SATA devices to be deployed in external enclosures with minimal modification
* Maximum cable length of 2 m (USB and FireWire allow longer distances.)
Aimed at the consumer market, eSATA enters an external storage market already served by the USB and FireWire interfaces. Most external hard disk drive cases with FireWire or USB interfaces use either PATA or SATA drives and "bridges" to translate between the drives' interfaces and the enclosures' external ports, and this bridging incurs some inefficiency. In the case of USB 2.0, protocol overhead limits the maximum effective bandwidth to a fraction of USB's physical signalling rate. With modern hard disk drives, USB's transfer rate is a bottleneck. FireWire, with its isochronous transfer mode, is more efficient, such that even in its slower variant, FireWire 400 (IEEE 1394a), the effective transfer rate is significantly faster than that of USB 2.0, but this can still be a bottleneck for fast drives or RAIDs. Some single disks can transfer well over 70 MB/s during real use, well in excess of USB 2.0's or the older FireWire 400's abilities. Finally, some low-level drive features, such as S.M.A.R.T., are not usable through USB or FireWire bridging. eSATA does not suffer from these issues.
eSATA will likely co-exist alongside USB 2.0 and FireWire storage for several reasons. The ubiquity of USB ports on all mass-market computers, and FireWire ports on many consumer electronic appliances, guarantee a large market for USB and FireWire storage. For small form-factor devices (such as external 2.5" disks), a PC-hosted USB or FireWire link supplies sufficient power to operate the device. Where a PC-hosted port is concerned, eSATA connectors cannot supply power, and would therefore be more cumbersome to use.
As of 2007, few computer motherboards have eSATA connectors. An eSATA external drive enclosure will typically ship with a passive eSATA-to-SATA bracket/cable-adapter to install on desktops. Desktops can also be upgraded with the installation of an eSATA host bus adapter (HBA), while notebooks can be upgraded with Cardbus or ExpressCard versions of an eSATA HBA. With passive-adapters, the maximum cable length is reduced to 1 meter, due to the absence of compliant eSATA signal levels. Full SATA speed for external disks (115 MB/s) have been measured with external RAID enclosures.
eSATA is likely to be ignored by the enterprise and server market, which has already standardized on the separately-developed Serial Attached SCSI (SAS) interface, which has extra features for remote management, link redundancy, and link monitoring.
Note: Prior to the final eSATA specification, there were a number of products designed for external connections of SATA drives. Some of these use the internal SATA connector or even connectors designed for other interface specifications, such as FireWire. These products are not eSATA compliant. The final eSATA specification features a specific connector designed for rough manipulation. It's similar to the regular SATA connector, but with reinforcements in both the male and female sides, inspired by the USB connector. It's harder to unplug and can withstand a cable being yanked or wiggled. On a SATA connector, this kind of action will break the male side of the connection (the hard drive or host adapter), rendering the device unusable. With an eSATA connector, considerably more force is needed to damage the connector, and even in this situation, only the female side (the cable itself) will break, possibly leaving the male usable.[citation needed]
[edit] eSATA compared to other buses
eSATA SATA 300 PATA 133 FireWire 800 FireWire 400 USB 2.0 Ultra-320 SCSI
Speed (Mbit/s) 2400 2400 1064 786 393 480 (burst) 2560
Max. cable length (m) 2 1 0.46 4.5 (16 cables can be
daisy chained up to 72 m) 4.5 (16 cables can be
daisy chained up to 72 m) 5 (USB hubs can be
daisy chained up to 25 m) 12
Power provided No No No Yes (12-25 V, 15 W) Yes (12-25 V, 15 W) Yes (5 V, 2.5 W) No
Devices per Channel 1 (15 with port multiplier) 1 per line 2 63 63 127 16
Unlike PATA, both SATA and eSATA are designed to support hot-plugging. However, this feature requires proper support at the host, device (drive), and operating-system level. In general, all SATA/devices (drives) support hot-plugging (due to the requirements on the device-side), but requisite support is less common on SATA host adapters.
USB allows hot-plugging; this is supported by virtually every current operating system. However, USB-based storage hardware can infrequently sustain data loss when disconnected. This problem exists with media players and digital cameras using flash memory as well as mobile 2.5-inch USB hard drives. Firmware damage and data loss can occasionally result from unclean spin-downs and power loss when the drive or device is removed from the USB port without first initiating a device shutdown via the computer's operating system.[citation needed]
SCSI devices with SCA-2 connectors are designed for hot plugging. Many server and RAID systems provide hardware support for transparent hot-plugging. The SCSI standard prior to SCA-2 connectors was not designed for hot-plugging, but, in practice, most RAID implementations support hot-swapping of hard disks.
Serial Attached SCSI (SAS) is designed for hot-plugging.
[edit] Backward and forward compatibility
[edit] SATA and PATA
At the device level, SATA and PATA devices are completely incompatible -- they cannot be interconnected. At the application level, SATA devices are specified to look and act like PATA devices. In early motherboard implementations of SATA, backward compatibility allowed SATA drives to be used as drop-in replacements for PATA drives, even without native (driver-level) support at the operating system level.
The common heritage of the ATA command set has enabled the proliferation of low-cost PATA<->SATA bridge-chips. Bridge chips were widely used on PATA drives (before the completion of native SATA drives) as well as standalone ‘dongles’. When attached to a PATA drive, a device-side dongle allows the PATA drive to function as a SATA drive. Host-side dongles allow a motherboard PATA port to function as a SATA host port.
Powered enclosures are available for both PATA and SATA drives, which interface to the PC through USB or Firewire, with the restrictions noted above. PCI cards with a SATA connector exist that allow SATA drives to connect to legacy systems without SATA connectors.
[edit] SATA-150 and SATA-300
SATA is designed to be backwards and forwards compatible with future revisions of the SATA standard [3]. Unfortunately, there are already documented incompatibilities between particular first-generation SATA/150 controllers and later-generation drives.
To address interoperability problems, some drive manufacturers have added a user-accessible jumper-switch, to select between SATA-150 and SATA/300 operation [4]. Users with a SATA-150 motherboard should either buy an ordinary SATA-150 hard disk, or buy a SATA-300 hard disk with the user-accessible jumper.
[edit] SATA vs SCSI
SCSI currently offers transfer rates higher than SATA, but is a more complex bus usually resulting in higher manufacturing cost. Some drive manufacturers offer longer warranties for SCSI devices, however, indicating a possibly higher manufacturing quality control of SCSI devices compared to PATA/SATA devices. SCSI buses also allow connection of several drives (using multiple channels, 7 or 15 on each channel) whereas SATA only allows one per channel.
SATA 3.0 Gbit/s offers a maximum bandwidth of 300 MB/s per device compared to SCSI with a maximum of 320 MB/s. Also, SCSI drives provide greater sustained throughput than SATA drives because of disconnect-reconnect and aggregating performance. SATA devices are generally compatible with SAS enclosures and adapters, while SCSI devices cannot be directly connected to a SATA bus.
SCSI hardware is used in enterprises for server purposes, partially due to higher cost of drives and adapters, and partially due to market reasons. The MTBF of SATA drives is usually about 150,000 hours, while SCSI drives are rated for upwards of 1,500,000 hours.
What is USB Flash Drive?
USB flash drives (also known as USB drives, key drives, pen drives or thumb drives) are NAND-type flash memory data storage devices integrated with a USB (universal serial bus) interface. They are typically small, lightweight, removable and rewritable. As of April 2007, memory capacities for USB Flash Drives currently are sold from 32 megabytes up to 64 gigabytes [1]. Capacity is limited only by current flash memory densities, although cost per megabyte may increase rapidly at higher capacities due to the expensive components. (USB Memory card readers are also available, whereby rather than being built-in, the memory is a removable Flash memory card housed in what is otherwise a regular USB flash drive, as described below.)
USB flash drives offer potential advantages over other portable storage devices, particularly the floppy disk. They are more compact, generally faster, hold more data, and are more reliable (due to both their lack of moving parts, and their more durable design) than floppy disks. These types of drives use the USB mass storage standard, supported natively by modern operating systems such as Linux, Mac OS X, Unix, and Windows.
A flash drive consists of a small printed circuit board encased in a plastic or metal casing, making the drive sturdy enough to be carried about in a pocket, as a key fob, or on a lanyard. Only the USB connector protrudes from this protection, and is usually covered by a removable cap. Most flash drives use a standard type-A USB connection allowing them to be connected directly to a port on a personal computer.
To access the data stored in a flash drive, the drive must be connected to a computer, either by plugging it into a USB host controller built into the computer, or into a USB hub. Flash drives are active only when plugged into a USB connection and draw all necessary power from the supply provided by that connection. However, some flash drives, especially high-speed drives utilizing the USB 2.0 standard, may require more power than the limited amount provided by a bus-powered USB hub, such as those built into some computer keyboards or monitors. These drives will not work unless plugged directly into a host controller (i.e., the ports found on the computer itself) or a self-powered hub.
Wednesday, April 25, 2007
Web conferencing software
Web conferencing software
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Main Features of Megameeting
1. Megameeting is a browser based system that requires no downloads or complicated installations.
2. MegaMeeting runs on all operating systems and with all browsers.
3. Video Conferencing with MegaMeeting allows up to 16 simultaneous video windows. This is a video-centric conferencing system.
4. MegaMeeting is easy to use and extremely powerful, delivering a service that can be used by thousands of small, medium and large organizations and businesses.
5. It has low start-up prices allowing even individuals and the smallest organizations to use it.
6. High-end users can have a "private label" version and offer the service without the MegaMeeting.com logo or identification.
Web and Video Conferencing Services
Through its variety of services, MegaMeeting provides full-featured and flexible web conferencing software and webinar software. Participants can communicate by voice, instant messaging chat and see each other by video/videoconference. With Professional and Enterprise versions of its web conferencing software, MegaMeeting includes multipoint, desktop video conferencing software that allows up to 16 individuals to be seen at the same time, and an unlimited number of additional web conferencing attendees to see those 16. Participants can talk and hear
one another by using standard microphones and headsets thanks to Voice over Internet Protocol (VoIP). As an alternative, if you wish, you can choose to use free, integrated teleconferencing for the handling of audio in your webinars.
Purchase Video Conferencing Equipment
Participants can share applications and open and examine common documents while online. Hosts of the conference can show a PowerPoint presentation that will be visible to all attendees. And some versions even allow an operator to remotely control the computer of another participant.
Host Webinars With Easy to use, yet Powerful Webinar Software
The uses of MegaMeeting's web and desktop video conferencing systems are limited only by your imagination. Companies are presently using MegaMeeting services to hold meetings online (videoconferencing), demonstrate their products and services to potential clients, conduct staff training sessions and even perform after-sales servicing of their products and software (by using remote desktop control software). Educational, social and religious organizations are using MegaMeeting to connect with students and members at a distance. Many organizations are using the webinar hosting features to conduct virtual, web based
meetings and seminars.
An Affordable Conferencing System
Online conferencing will not break your budget! In fact, when you add up the travel costs that you will save when you hold meetings online, the costs of this service become negligible.
MegaMeeting is available in four versions, suited to individuals, small companies, large organizations and companies that wish a "private branded version." MegaMeeting offers superior Web and Video Conferencing solutions at a fraction of the cost. Try one of our online
demos now and find out how this service can help bring your organization together, boost morale, raise efficiency, improve team work and lower your travel costs. If you have any questions, just call or e-mail us and we will be happy to help you out. Give MegaMeeting a try and see why more and more organizations are turning to our solutions for videoconferences, web conferencing and other online meeting needs.
Use Online Meetings to Reduce Travel Related Costs & Headaches, Extend Your Marketing Reach & Make Geography Inconsequential. Holding meetings online is about to become commonplace. Now, anyone with a broadband Internet connection and a browser can log onto the Internet and take part in or host a web conference, a web and video conference or a webinar. Previously it was necessary to download and install complicated software and buy expensive equipment in order to enjoy the convenience of online meetings and webinars. MegaMeeting has taken web and video conferencing services a step further with new, 100%
desktop, browser based web conferencing services and webinar software that does not require any special installation on your computer. Meeting online has never been this easy!
Do you want to keep in touch with employees, business contacts or clients? MegaMeeting's video and web conferencing services make it possible for anyone, anywhere in the world to log on and participate in your online meeting. The service works on any operating system, Mac,
Windows or Linux, and users can take part even if their computers are protected by a firewall.
Main Features of Megameeting
1. Megameeting is a browser based system that requires no downloads or complicated installations.
2. MegaMeeting runs on all operating systems and with all browsers.
3. Video Conferencing with MegaMeeting allows up to 16 simultaneous video windows. This is a video-centric conferencing system.
4. MegaMeeting is easy to use and extremely powerful, delivering a service that can be used by thousands of small, medium and large organizations and businesses.
5. It has low start-up prices allowing even individuals and the smallest organizations to use it.
6. High-end users can have a "private label" version and offer the service without the MegaMeeting.com logo or identification.
Web and Video Conferencing Services
Through its variety of services, MegaMeeting provides full-featured and flexible web conferencing software and webinar software. Participants can communicate by voice, instant messaging chat and see each other by video/videoconference. With Professional and Enterprise versions of its web conferencing software, MegaMeeting includes multipoint, desktop video conferencing software that allows up to 16 individuals to be seen at the same time, and an unlimited number of additional web conferencing attendees to see those 16. Participants can talk and hear
one another by using standard microphones and headsets thanks to Voice over Internet Protocol (VoIP). As an alternative, if you wish, you can choose to use free, integrated teleconferencing for the handling of audio in your webinars.
Purchase Video Conferencing Equipment
Participants can share applications and open and examine common documents while online. Hosts of the conference can show a PowerPoint presentation that will be visible to all attendees. And some versions even allow an operator to remotely control the computer of another participant.
Host Webinars With Easy to use, yet Powerful Webinar Software
The uses of MegaMeeting's web and desktop video conferencing systems are limited only by your imagination. Companies are presently using MegaMeeting services to hold meetings online (videoconferencing), demonstrate their products and services to potential clients, conduct staff training sessions and even perform after-sales servicing of their products and software (by using remote desktop control software). Educational, social and religious organizations are using MegaMeeting to connect with students and members at a distance. Many organizations are using the webinar hosting features to conduct virtual, web based
meetings and seminars.
An Affordable Conferencing System
Online conferencing will not break your budget! In fact, when you add up the travel costs that you will save when you hold meetings online, the costs of this service become negligible.
MegaMeeting is available in four versions, suited to individuals, small companies, large organizations and companies that wish a "private branded version." MegaMeeting offers superior Web and Video Conferencing solutions at a fraction of the cost. Try one of our online
demos now and find out how this service can help bring your organization together, boost morale, raise efficiency, improve team work and lower your travel costs. If you have any questions, just call or e-mail us and we will be happy to help you out. Give MegaMeeting a try and see why more and more organizations are turning to our solutions for videoconferences, web conferencing and other online meeting needs.
Saturday, April 14, 2007
Check your Windows systems Memory with this tool
Check the health of your system's memory.
If your system crashes often and you're getting blue screens loaded with error messages, your problem may be bad system memory. Use this diagnostic tool for a quick checkup. Click here to download the diagnostic tool.
If your system crashes often and you're getting blue screens loaded with error messages, your problem may be bad system memory. Use this diagnostic tool for a quick checkup. Click here to download the diagnostic tool.
Backups using Windows's own Tools
Any PC user who hasn't been hiding under a rock knows the importance of making backup copies of critical system and data files. But many people may not realize that Windows XP and 2000 have several built-in backup options. These tips will help you devise a perfect Windows backup strategy.
Option #1: Last Good Configuration: Every time you shut down your system, Windows makes a backup of certain Registry and driver settings (specifically, those in HKEY_LOCAL_MACHINE\System\CurrentControlSet). If things go awry and you can't start Windows (or you merely have second thoughts about a new graphics driver you've just installed), you can restore your machine to its previous state by pressing just before Windows starts. Use the arrow keys to select Last Known Good Configuration, and press . (If you have already restarted Windows with hardware settings you don't want, this technique won't work because the system stored the info from those drivers in its backup when you most recently exited Windows.)
Option #2: Device Driver Rollback: Windows XP automatically backs up your old device drivers when you update them. You can restore a device to the way it was in happier times by reverting to this backup when a new driver causes problems. Choose Start, Run, type devmgmt.msc, and press to open Device Manager. Double-click the device whose driver you want to restore to open its Properties dialog box. Click the Driver tab and select Roll Back Driver (see Figure 1).
Option #3: System Restore: A good way to back up system settings, drivers, and critical system files in XP is by using System Restore, which can back up your configuration automatically on a defined schedule if you allocate sufficient storage to it. Use it to make backups (which it refers to as "restore points") prior to making any system change (Windows creates a new restore point automatically whenever you install new software.) Choose Start, Programs (or All Programs), Accessories, System Tools, System Restore. Then select Create a restore point and follow the prompts. System Restore doesn't affect your data, nor does it work every time, so don't count on it as your only protection.
Option #4: Hardware Profiles: You might find these useful when testing new hardware or device drivers. Choose Start, Run, type sysdm.cpl, and press. Click the Hardware tab and then the Hardware Profiles button. Select your current profile---or the profile that you want to back up---from the list, and click Copy. Name it something like Test Profile and press . Choose the startup settings you prefer under 'Hardware profiles selection', and click OK. When you restart your PC, choose Test Profile (or whatever you named the profile). If your experiments make Windows unusable, choose your original profile at the startup prompt; you may need to change your hardware back, too. If you like the new configuration, return to the Hardware Profiles dialog box and either delete the old default profile or make the new one your default.
Option #5: Windows' Backup Utility: To back up your files manually in XP and 2000, choose Start, Programs (or All Programs), Accessories, System Tools, Backup. Users of XP Home Edition can install the program from the Windows CD: Look for it in the valueadd\msft\ntbackup folder, right-click the Ntbackup file, and choose Install. Be forewarned, however, that the utility's Automated System Recovery feature doesn't work in XP Home.
Option #1: Last Good Configuration: Every time you shut down your system, Windows makes a backup of certain Registry and driver settings (specifically, those in HKEY_LOCAL_MACHINE\System\CurrentControlSet). If things go awry and you can't start Windows (or you merely have second thoughts about a new graphics driver you've just installed), you can restore your machine to its previous state by pressing
Option #2: Device Driver Rollback: Windows XP automatically backs up your old device drivers when you update them. You can restore a device to the way it was in happier times by reverting to this backup when a new driver causes problems. Choose Start, Run, type devmgmt.msc, and press
Option #3: System Restore: A good way to back up system settings, drivers, and critical system files in XP is by using System Restore, which can back up your configuration automatically on a defined schedule if you allocate sufficient storage to it. Use it to make backups (which it refers to as "restore points") prior to making any system change (Windows creates a new restore point automatically whenever you install new software.) Choose Start, Programs (or All Programs), Accessories, System Tools, System Restore. Then select Create a restore point and follow the prompts. System Restore doesn't affect your data, nor does it work every time, so don't count on it as your only protection.
Option #4: Hardware Profiles: You might find these useful when testing new hardware or device drivers. Choose Start, Run, type sysdm.cpl, and press
Option #5: Windows' Backup Utility: To back up your files manually in XP and 2000, choose Start, Programs (or All Programs), Accessories, System Tools, Backup. Users of XP Home Edition can install the program from the Windows CD: Look for it in the valueadd\msft\ntbackup folder, right-click the Ntbackup file, and choose Install. Be forewarned, however, that the utility's Automated System Recovery feature doesn't work in XP Home.
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