Computer viruses can be a nightmare. Some can wipe out the information on a hard drive, tie up traffic on a computer network for hours, turn an innocent machine into a zombie and replicate and send themselves to other computers. If you've never had a machine fall victim to a computer virus, you may wonder what the fuss is about. But the concern is understandable -- according to Consumer Reports, computer viruses helped contribute to $8.5 billion in consumer losses in 2008 . Computer viruses are just one kind of online threat, but they're arguably the best known of the bunch.
Computer viruses have been around for many years. In fact, in 1949, a scientist named John von Neumann theorized that a self-replicated program was possible.The computer industry wasn't even a decade old, and already someone had figured out how to throw a monkey wrench into the figurative gears. But it took a few decades before programmers known as hackers began to build computer viruses.
While some pranksters created virus-like programs for large computer systems, it was really the introduction of the personal computer that brought computer viruses to the public's attention. A doctoral student named Fred Cohen was the first to describe self-replicating programs designed to modify computers as viruses. The name has stuck ever since.
In the good old days (i.e., the early 1980s), viruses depended on humans to do the hard work of spreading the virus to other computers. A hacker would save the virus to disks and then distribute the disks to other people. It wasn't until modems became common that virus transmission became a real problem. Today when we think of a computer virus, we usually imagine something that transmits itself via the Internet. It might infect computers through e-mail messages or corrupted Web links. Programs like these can spread much faster than the earliest computer viruses.
We're going to take a look at 10 of the worst computer viruses to cripple a computer system. Let's start with the Melissa virus.
Worst Computer Virus 10: Melissa
In the spring of 1999, a man named David L. Smith created a computer virus based on a Microsoft Word macro. He built the virus so that it could spread through e-mail messages. Smith named the virus "Melissa," saying that he named it after an exotic dancer from Florida
Rather than shaking its moneymaker, the Melissa computer virus tempts recipients into opening a document with an e-mail message like "Here is that document you asked for, don't show it to anybody else." Once activated, the virus replicates itself and sends itself out to the top 50 people in the recipient's e-mail address book.
The virus spread rapidly after Smith unleashed it on the world. The United States federal government became very interested in Smith's work -- according to statements made by FBI officials to Congress, the Melissa virus "wreaked havoc on government and private sector networks".The increase in e-mail traffic forced some companies to discontinue e-mail programs until the virus was contained.
After a lengthy trial process, Smith lost his case and received a 20-month jail sentence. The court also fined Smith $5,000 and forbade him from accessing computer networks without court authorization . Ultimately, the Melissa virus didn't cripple the Internet, but it was one of the first computer viruses to get the public's attention.
Next, we'll look at a virus that had a sweet name but a nasty effect on its victims.
Worst Computer Virus 9: ILOVEYOU
A year after the Melissa virus hit the Internet, a digital menace emerged from the Philippines. Unlike the Melissa virus, this threat came in the form of a worm -- it was a standalone program capable of replicating itself. It bore the name ILOVEYOU.
The ILOVEYOU virus initially traveled the Internet by e-mail, just like the Melissa virus. The subject of the e-mail said that the message was a love letter from a secret admirer. An attachment in the e-mail was what caused all the trouble. The original worm had the file name of LOVE-LETTER-FOR-YOU.TXT.vbs. The vbs extension pointed to the language the hacker used to create the worm: Visual Basic Scripting
According to anti-virus software producer McAfee, the ILOVEYOU virus had a wide range of attacks:
* It copied itself several times and hid the copies in several folders on the victim's hard drive.
* It added new files to the victim's registry keys.
* It replaced several different kinds of files with copies of itself.
* It sent itself through Internet Relay Chat clients as well as e-mail.
* It downloaded a file called WIN-BUGSFIX.EXE from the Internet and executed it. Rather than fix bugs, this program was a password-stealing application that e-mailed secret information to the hacker's e-mail address.
Who created the ILOVEYOU virus? Some think it was Onel de Guzman of the Philippines. Filipino authorities investigated de Guzman on charges of theft -- at the time the Philippines had no computer espionage or sabotage laws. Citing a lack of evidence, the Filipino authorities dropped the charges against de Guzman, who would neither confirm nor deny his responsibility for the virus. According to some estimates, the ILOVEYOU virus caused $10 billion in damages
Now that the love fest is over, let's take a look at one of the most widespread viruses to hit the Web.
Worst Computer Virus 8: The Klez Virus
The Klez virus marked a new direction for computer viruses, setting the bar high for those that would follow. It debuted in late 2001, and variations of the virus plagued the Internet for several months. The basic Klez worm infected a victim's computer through an e-mail message, replicated itself and then sent itself to people in the victim's address book. Some variations of the Klez virus carried other harmful programs that could render a victim's computer inoperable. Depending on the version, the Klez virus could act like a normal computer virus, a worm or a Trojan horse. It could even disable virus-scanning software and pose as a virus-removal tool.
Shortly after it appeared on the Internet, hackers modified the Klez virus in a way that made it far more effective. Like other viruses, it could comb through a victim's address book and send itself to contacts. But it could also take another name from the contact list and place that address in the "From" field in the e-mail client. It's called spoofing -- the e-mail appears to come from one source when it's really coming from somewhere else.
Spoofing an e-mail address accomplishes a couple of goals. For one thing, it doesn't do the recipient of the e-mail any good to block the person in the "From" field, since the e-mails are really coming from someone else. A Klez worm programmed to spam people with multiple e-mails could clog an inbox in short order, because the recipients would be unable to tell what the real source of the problem was. Also, the e-mail's recipient might recognize the name in the "From" field and therefore be more receptive to opening it.
Several major computer viruses debuted in 2001. In the next section, we'll take a look at Code Red.
Worst Computer Virus 7: Code Red and Code Red II
The Code Red and Code Red II worms popped up in the summer of 2001. Both worms exploited an operating system vulnerability that was found in machines running Windows 2000 and Windows NT. The vulnerability was a buffer overflow problem, which means when a machine running on these operating systems receives more information than its buffers can handle, it starts to overwrite adjacent memory.
The original Code Red worm initiated a distributed denial of service (DDoS) attack on the White House. That means all the computers infected with Code Red tried to contact the Web servers at the White House at the same time, overloading the machines.
A Windows 2000 machine infected by the Code Red II worm no longer obeys the owner. That's because the worm creates a backdoor into the computer's operating system, allowing a remote user to access and control the machine. In computing terms, this is a system-level compromise, and it's bad news for the computer's owner. The person behind the virus can access information from the victim's computer or even use the infected computer to commit crimes. That means the victim not only has to deal with an infected computer, but also may fall under suspicion for crimes he or she didn't commit.
While Windows NT machines were vulnerable to the Code Red worms, the viruses' effect on these machines wasn't as extreme. Web servers running Windows NT might crash more often than normal, but that was about as bad as it got. Compared to the woes experienced by Windows 2000 users, that's not so bad.
Microsoft released software patches that addressed the security vulnerability in Windows 2000 and Windows NT. Once patched, the original worms could no longer infect a Windows 2000 machine; however, the patch didn't remove viruses from infected computers -- victims had to do that themselves.
Worst Computer Virus 6: Nimda
Another virus to hit the Internet in 2001 was the Nimda (which is admin spelled backwards) worm. Nimda spread through the Internet rapidly, becoming the fastest propagating computer virus at that time. In fact, according to TruSecure CTO Peter Tippett, it only took 22 minutes from the moment Nimda hit the Internet to reach the top of the list of reported attacks.
The Nimda worm's primary targets were Internet servers. While it could infect a home PC, its real purpose was to bring Internet traffic to a crawl. It could travel through the Internet using multiple methods, including e-mail. This helped spread the virus across multiple servers in record time.
The Nimda worm created a backdoor into the victim's operating system. It allowed the person behind the attack to access the same level of functions as whatever account was logged into the machine currently. In other words, if a user with limited privileges activated the worm on a computer, the attacker would also have limited access to the computer's functions. On the other hand, if the victim was the administrator for the machine, the attacker would have full control.
The spread of the Nimda virus caused some network systems to crash as more of the system's resources became fodder for the worm. In effect, the Nimda worm became a distributed denial of service (DDoS) attack.
Next, we'll take a look at a virus that affected major networks, including airline computers and bank ATMs.
Worst Computer Virus 5: SQL Slammer/Sapphire
In late January 2003, a new Web server virus spread across the Internet. Many computer networks were unprepared for the attack, and as a result the virus brought down several important systems. The Bank of America's ATM service crashed, the city of Seattle suffered outages in 911 service and Continental Airlines had to cancel several flights due to electronic ticketing and check-in errors.
The culprit was the SQL Slammer virus, also known as Sapphire. By some estimates, the virus caused more than $1 billion in damages before patches and antivirus software caught up to the problem . The progress of Slammer's attack is well documented. Only a few minutes after infecting its first Internet server, the Slammer virus was doubling its number of victims every few seconds. Fifteen minutes after its first attack, the Slammer virus infected nearly half of the servers that act as the pillars of the Internet
The Slammer virus taught a valuable lesson: It's not enough to make sure you have the latest patches and antivirus software. Hackers will always look for a way to exploit any weakness, particularly if the vulnerability isn't widely known. While it's still important to try and head off viruses before they hit you, it's also important to have a worst-case-scenario plan to fall back on should disaster strike.
Computer viruses can make a victim feel helpless, vulnerable and despondent. Next, we'll look at a virus with a name that evokes all three of those feelings.
Worst Computer Virus 4: MyDoom
The MyDoom (or Novarg) virus is another worm that can create a backdoor in the victim computer's operating system. The original MyDoom virus -- there have been several variants -- had two triggers. One trigger caused the virus to begin a denial of service (DoS) attack starting Feb. 1, 2004. The second trigger commanded the virus to stop distributing itself on Feb. 12, 2004. Even after the virus stopped spreading, the backdoors created during the initial infections remained active
Later that year, a second outbreak of the MyDoom virus gave several search engine companies grief. Like other viruses, MyDoom searched victim computers for e-mail addresses as part of its replication process. But it would also send a search request to a search engine and use e-mail addresses found in the search results. Eventually, search engines like Google began to receive millions of search requests from corrupted computers. These attacks slowed down search engine services and even caused some to crash
MyDoom spread through e-mail and peer-to-peer networks. According to the security firm MessageLabs, one in every 12 e-mail messages carried the virus at one time . Like the Klez virus, MyDoom could spoof e-mails so that it became very difficult to track the source of the infection.
Next, we'll take a look at a pair of viruses created by the same hacker: the Sasser and Netsky viruses.
Worst Computer Virus 3: Sasser and Netsky
Sometimes computer virus programmers escape detection. But once in a while, authorities find a way to track a virus back to its origin. Such was the case with the Sasser and Netsky viruses. A 17-year-old German named Sven Jaschan created the two programs and unleashed them onto the Internet. While the two worms behaved in different ways, similarities in the code led security experts to believe they both were the work of the same person.
The Sasser worm attacked computers through a Microsoft Windows vulnerability. Unlike other worms, it didn't spread through e-mail. Instead, once the virus infected a computer, it looked for other vulnerable systems. It contacted those systems and instructed them to download the virus. The virus would scan random IP addresses to find potential victims. The virus also altered the victim's operating system in a way that made it difficult to shut down the computer without cutting off power to the system.
The Netsky virus moves through e-mails and Windows networks. It spoofs e-mail addresses and propagates through a 22,016-byte file attachment. As it spreads, it can cause a denial of service (DoS) attack as systems collapse while trying to handle all the Internet traffic. At one time, security experts at Sophos believed Netsky and its variants accounted for 25 percent of all computer viruses on the Internet
Sven Jaschan spent no time in jail; he received a sentence of one year and nine months of probation. Because he was under 18 at the time of his arrest, he avoided being tried as an adult in German courts.
So far, most of the viruses we've looked at target PCs running Windows. But Macintosh computers aren't immune to computer virus attacks. In the next section, we'll take a look at the first virus to commit a Mac attack.
Worst Computer Virus 2: Leap-A/Oompa-A
Maybe you've seen the ad in Apple's Mac computer marketing campaign where Justin "I'm a Mac" Long consoles John "I'm a PC" Hodgman. Hodgman comes down with a virus and points out that there are more than 100,000 viruses that can strike a computer. Long says that those viruses target PCs, not Mac computers.
For the most part, that's true. Mac computers are partially protected from virus attacks because of a concept called security through obscurity. Apple has a reputation for keeping its operating system (OS) and hardware a closed system -- Apple produces both the hardware and the software. This keeps the OS obscure. Traditionally, Macs have been a distant second to PCs in the home computer market. A hacker who creates a virus for the Mac won't hit as many victims as he or she would with a virus for PCs.
But that hasn't stopped at least one Mac hacker. In 2006, the Leap-A virus, also known as Oompa-A, debuted. It uses the iChat instant messaging program to propagate across vulnerable Mac computers. After the virus infects a Mac, it searches through the iChat contacts and sends a message to each person on the list. The message contains a corrupted file that appears to be an innocent JPEG image.
The Leap-A virus doesn't cause much harm to computers, but it does show that even a Mac computer can fall prey to malicious software. As Mac computers become more popular, we'll probably see more hackers create customized viruses that could damage files on the computer or snarl network traffic. Hodgman's character may yet have his revenge.
Worst Computer Virus 1: Storm Worm
The latest virus on our list is the dreaded Storm Worm. It was late 2006 when computer security experts first identified the worm. The public began to call the virus the Storm Worm because one of the e-mail messages carrying the virus had as its subject "230 dead as storm batters Europe." Antivirus companies call the worm other names. For example, Symantec calls it Peacomm while McAfee refers to it as Nuwar. This might sound confusing, but there's already a 2001 virus called the W32.Storm.Worm. The 2001 virus and the 2006 worm are completely different programs.
The Storm Worm is a Trojan horse program. Its payload is another program, though not always the same one. Some versions of the Storm Worm turn computers into zombies or bots. As computers become infected, they become vulnerable to remote control by the person behind the attack. Some hackers use the Storm Worm to create a botnet and use it to send spam mail across the Internet.
Many versions of the Storm Worm fool the victim into downloading the application through fake links to news stories or videos. The people behind the attacks will often change the subject of the e-mail to reflect current events. For example, just before the 2008 Olympics in Beijing, a new version of the worm appeared in e-mails with subjects like "a new deadly catastrophe in China" or "China's most deadly earthquake." The e-mail claimed to link to video and news stories related to the subject, but in reality clicking on the link activated a download of the worm to the victim's computer
Several news agencies and blogs named the Storm Worm one of the worst virus attacks in years. By July 2007, an official with the security company Postini claimed that the firm detected more than 200 million e-mails carrying links to the Storm Worm during an attack that spanned several days
Fortunately, not every e-mail led to someone downloading the worm.
Although the Storm Worm is widespread, it's not the most difficult virus to detect or remove from a computer system. If you keep your antivirus software up to date and remember to use caution when you receive e-mails from unfamiliar people or see strange links, you'll save yourself some major headaches.
1)Go to Start->Run.
2)Type DISKPART and press Enter.
3)In the console type list volume to see all the drives available on your PC.
4)Now select the drive which you want to hide. Suppose you want to hide D see the volume number opposite to Ltr D.
5)In My PC it is volume 4 for drive D(might be different in your computer) .
6)Now to hide drive D type Select volume 4 .(Select the appropriate number according to your system)
7)Then type remove letter d , this will hide your drive.
8)Now to get your drive back type Select volume 4 and then type assign letter d .
-------------------------
Use this method to enable the Command Prompt.
There are three methods:
Method 1: (Run method)
1. Select Run from Start menu.
2. Type the following: (better copy and paste)
REG add HKCU\Software\Policies\Microsoft\Windows\System /v DisableCMD /t REG_DWORD /d 0 /f
and press Enter.
Method 2: (Registry Editor method)
1. Open Registry Editor.
2. Get to this key:
HKEY_CURRENT_USER\Software\Policies\Microsoft\Windows\System
3. In the right pane, double click on DisableCMD and set it's data to 0.
4. Close Registry Editor.
Method 3: (Group Policy method)
1. From Start menu, select Run. Type gpedit.msc and press Enter.
Group Policy editor opens.
2. Get to:
User Configuration > Administrative Templates > System
3. From the right pane, double click open Prevent access to the command prompt.
4. Set Disable and click OK.
5. Exit Group Policy editor.
Have you ever wondered why a person in your contact list appears offline to you all the time? Now you can spy your buddy to see his real yahoo status. Use Yahoo Messenger Invisible Scanner to detect if a user is in fact offline or just invisible.
Use these Sites to Check who is invisible in yahoo:
1)www.detectinvisible.com
2)www.imvisible.info
3)www.invisible.ir
4)www.invisible-scanner.com
5)www.scanyahoo.com
6)www.xeeber.com
7)www.ydetector.com
8)www.yahootracer.com
when you surf net at public computers or net cafes…maybe it can be even at your friends house..etc.. there is a danger that a possible key logger software can steal your password, so i have come up with a simple and effective way to counter it…at least 50% …
lets see how simply you can fool a key logger,
When you choose passwords try using simple, capital & numbers as a combination..
when you enter them in a public computer rather than entering it in sequence try entering it in a combination
for this trick suppose my password is - hi2K1987 [DEMO password]
Now when you break your password into 3 combinations and enter them one after another (without using the backspace key) so what i did was i entered 2k first then using the mouse i went to the start of the password field and entered hi then i placed the cursor at the end and entered 1987 now simply the key logger is fooled.
he will read mah password as: delghi2k1987(fooled)
Now imagine if you use a set of numbers for your password and you enter them in a combination…
so, guys next time you enter your password you know you are safe, jst a simple trick so u can use ur own imagination..
1. Gather the file you wish to bind, and the image file, and place them in a folder. For the sake of this demonstration, I will be using C:\New Folder
-The image will hereby be referred to in all examples as fluffy.jpg
-The file will hereby be referred to in all examples as New Text Document.txt
2. Add the file/files you will be injecting into the image into a WinRar .rar or .zip. From here on this will be referred to as (secret.rar)
3. Open command prompt by going to Start > Run > cmd
4. In Command Prompt, navigate to the folder where your two files are by typing
cd location [ex: cd C:\New Folder]
5. Type [copy /b fluffy.jpg + secret.rar fluffy.jpg] (remove the brackets)
Congrats, as far as anyone viewing is concerned, this file looks like a JPEG, acts like a JPEG, and is a JPEG, yet it now contains your file.
In order to view/extract your file, there are two options that you can take
a) Change the file extension from fluffy.jpg to fluffy.rar, then open and your file is there.
b) Leave the file extension as is, right click, open with WinRar and your file is there.
Got a scanner and a modem? Save yourself the cost of a fax machine. Send and receive your faxes with Fax Machine. Here is how it works: insert a document in your scanner, start Fax Machine, click Scan a page (several times if you want to send a multi-page fax), click Send Fax, fill in the recipient telephone number and off it goes. That's all!
Other features that make Fax Machine stand out:
Distinctive Ring support, even on Windows XP/Vista systems
Can forward received faxes by e-mail, even automatically right after the fax is received
Can print received faxes automatically right after the fax is received
Can print log of sent and received faxes, or save these logs to a text file
Can be set to start when Windows starts
You can specify what printer to use to print send confirmations and received faxes.
Is available in English, Dutch, French, German, Italian and Spanish. Choose your language when installing the application.
Fax Machine contains a printer driver, which lets you "print" to Fax Machine from any Windows application that supports printing.
Link:http://rapidshare.com/files/69756261/fax_machine.rar
You may want to change the location of your system default folder (C:\Program Files) from C drive to another system drives (D or E drive). By default software setup will attempt to install program in C:\Program Files directory. It is good practice to make the backup of the installed programs, if you installed all your programs in other than C drive. If you have little knowledge about editing windows registry then you can configure your computer for this purpose.
Follow the given steps to configure windows registry:
1. Click on Start button then type Regedit in Run option.
2. Here navigate to: HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion
3. In right side panel, double click on ProgramFileDir.
4. Now modify the value to any other drive (for example D:\Program Files).
Now close the registry editor and restart your computer after any changes to go into effect.
If you have windows XP with SP2, then you can disable the writing option to USB drives. This trick is very useful if you have virus in your computer and want to copy files from a USB Drive but don’t want to transfer virus to the USB. Follow the given steps to disable the USB writing option:
To edit the computer registry, first you should log onto your computer with administrative rights.
First click on Start button and type “Regedit” in Run option.
Here locate the location to:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control
Here in right side panel, click right to create a key with the name “StorageDevicePolicies”.
Now in left side panel, select “StorageDevicePolicies” key, again right click to create new DWORD value then label it “WriteProtect”. Set its value to “1″. But again to enable writing, set its values to “0″.
Now close the registry editor and restart your computer after any changes to go into effect.
Everyone knows that Rapidshare is the king of file-hosting service. Still there are alternatives which you can use for the purpose of file sharing. Here is a quick review to all such services.
LaunchFile.Com
CAPTCHA: Yes
Wait Time: 10 Seconds
File Delete Policy: 45 days after no download
Max Filesize : 250MB
Download Limits : None
Comments: No picture ads or pop-ups Just text ads. Download speeds sluggish at times.
Rating: 3.5/5
FileQube.Com
CAPTCHA: No
Wait Time: None
File Delete Policy: Not Specified
Max Filesize : 500Mb if you register (free), 150MB if not registered
Download Limits : None
Comments: Super Fast download speeds, Eye catching web interface, Text ads.
Rating: 4.5/5
MediaFire.Com
CAPTCHA: No
Wait Time: None
File Delete Policy: There is currently no time limit on how long uploaded files will be stored as long as you access your account (i.e. login to your account) at least once every 60 days OR at least one of your files is accessed (i.e. downloaded) every 30 days.
Max Filesize: 100MB
Download Limits : None
Comments: Fast Download speeds, some small picture ads but no pop-ups.
Rating: 4/5
MiHD.net
CAPTCHA: None
Wait Time: None
File Delete Policy: Not Specified
Max Filesize: 100MB
Download Limits : None
Comments: Fast Download speeds, Small Text ads thats all
Rating: 4/5
EuShare.com
CAPTCHA: None
Wait Time: None
File Delete Policy: Not Specified
Max File Size: 505MB
Download Limits : None
Comments: Fast Download speeds, Zero Ads
Rating: 4.5/5
Dump.ro
CAPTCHA: None
Wait Time: None
File Delete Policy: Not Specified
Max File Size: 1000MB (1GB)
Download Limits :None
Comments: Accurate upload progress bar, Fast Upload speed. Downloads sometimes sluggish. 105KB Download speed when tested
Rating: 3.5/4
FileFlyer.com
CAPTCHA: None
Wait Time: None
File Delete Policy: Not Specified
Max File Size: 1GB
Download Limits : None
Comments: Accurate upload progress bar, Some picture and text ads
Rating: 4/5
SpeedShare.org
CAPTCHA: None
Wait Time: 7 Seconds
File Delete Policy: Not Specified
Max File Size: 200MB
Download Limits : None
Comments: Accurate upload progress, Some picture and text ads, 1 "under pop-up ad"
Rating: 3/5
files.x7web.com
CAPTCHA: Yes
Wait Time: None
File Delete Policy: None at the moment
Max File Size: 5120 MB (5GB)
Download Limit : None
Comments: Does not display upload information when uploading . Downloads speeds super fast. Zero ads
Rating: 4.5/5
UploadMachine.com
CAPTCHA: No
Wait Time: 29 Seconds
File Delete Policy: 90 days after 0 downloading
Max File Size: 750.00 MB
Download Limits : None
Comments: Great for DVD-Rips and other large files. Speedy upload speeds, Displays upload speed and time remaining when uploading a file. 1 pic ad.
Rating 4.5/5
xtremevault.com
CAPTCHA: Yes
Wait Time: 8 Seconds
File Delete Policy: Your files will be kept on our servers as long as it is downloaded at least once every 30000 Days
Max File Size: 250MB
Download Limits : None
Comments: Displays upload speed and time remaining when uploading a file. Minimal ads
Rating 3.5/5
Ezyfile.net
CAPTCHA: Yes
Wait Time: 59 Seconds
File Delete Policy: No limit. Nevertheless even we have to clean up our drives from time to time, so we will delete files that have not been accessed for 90 days or longer.
Max File Size: 1000MB (1GB)
Download Limits : None
Comments:Great for DVD Rips and large files, displays upload speed and time remaining when uploading a file. Minimal ads.
Rating: 4/5
• Backup—XP Pro has the standard Win2K backup program; XP Home has no backup
program.
• Dynamic Disks—XP Pro supports dynamic disks; XP Home doesn’t.
• IIS—XP Pro includes IIS; XP Home doesn’t.
• Encrypted File System (EFS)—EFS debuted in Win2K and lets you encrypt files on an
NTFS partition, a very useful feature for mobile machines. XP Pro includes EFS; XP
Home doesn’t.
• Multiple Monitors—XP Pro supports up to nine monitors; XP Home supports only one
monitor (Windows Me/Win98 supported multiple monitors).
• Multiprocessor—XP Pro supports up to two processors; XP Home supports only one
(as did Windows Me/Win98).
• Remote Assistance—Both editions support Remote Assistance, which lets someone
from a Help desk connect to the client desktop to troubleshoot problems.
• Remote Desktop—XP Pro adds to Remote Assistance by letting any machine running a
Terminal Services client run one Terminal Services session against an XP Pro machine.
• Domain Membership—XP Pro systems can be domain members; XP Home systems
can’t, but they can access domain resources.
• Group Policy—XP Pro supports group policies; XP Home doesn’t.
• IntelliMirror—XP Pro supports IntelliMirror, which includes Microsoft Remote Installation
Services (RIS), software deployment, and user setting management; XP Home doesn’t
support IntelliMirror.
• Upgrade from Windows Me/Win98—Both XP Pro and XP Home support this upgrade.
• Upgrade from Win2K/NT—Only XP Pro supports this upgrade.
• 64-bit Support—Only XP Pro will have a 64-bit version that supports the Itanium
systems.
• Network Support—XP Pro includes support for Network Monitor, SNMP, IP Security
(IPSec), and the Client Services for NetWare (CSNW); XP Home doesn’t.
Microsoft announced that Windows 7 will be released for standalone sale on October 22nd, 2009.Microsoft also announced that they "will make available an upgrade option, so partners can offer customers the ability to purchase a Windows Vista-based PC and install Windows 7 when it’s ready", however the effective start date for this program has yet to be revealed...
For the enterprise, Microsoft is working hard to pair Windows Server 2008 R2 with Windows 7 to help admins enable all of the remote functionality of Win 7, particularly for road warriors.
“With the release of Windows Server 2008 R2, companies of all sizes will get big improvements in virtualization, Web and management,” he says. “These areas, along with several features that improve scalability and reliability, help deliver a strong value proposition on the server side to complement Windows 7.”
Let's say you have something like:
unsigned int u = 10;
int i = -1;
for(i <= u;i++){
/*do whatever here*/
}//end of for
But nothing of what you do in the loop seems to execute, it's because the ANSI C standard defines that whenever there is a comparison between a qualified and a non qualified type, the non qualified type gets promoted to a type of the same type,but also inherits the qualifiers of the other quantity. I'm sure I could have said that better.
Anyway, in other words, i here is promoted to an unsigned int,and so its value (-1), which is coded in two's complement is interpreted as an unsigned int. Now -1 as an unsigned is 00000001 -> 11111110 + 1 = 11111111 i.e. a very large positive number,actually the largest int. Note that I have only used eight digits for the sake of simplicity.Its also very early in the morning and I haven't slept.
So, remember this if you ever perform such a comparison.Qualifier inheritance also occurs with short and long, besides unsigned.
Football Manager 2009, by Sports Interactive is the latest in the popular football manager series. This review details the latest edition of the PC game series and looks at the game’s new features. Find out if Football Manager 2009 is the league leader in football management games.
The latest Football Manager installment
FM2009 Pack ShotFootball Manager 2009 is the latest chapter in one of the most popular PC gaming series ever to hit the shelves. This latest version was released on November 14th and is sure to be a Christmas bestseller. For football fans outside the UK, the game is also known as Worldwide Soccer Manager, and the game is also available on Playstation Portable.
This latest version of the football management simulation had promised some improvements and enhancements to previous versions, and I covered the most significant changes in my review of the FM2009 demo. While I felt the demo version was a little rough in places, how does the full retail version stand up to scrutiny?
FM2009 Installation
Things did not get off to a good start and the installation of the game was fraught with problems. Firstly, the DVD game key, which is printed on the rear of the manual uses a dot-matrix style font, which made it hard to decipher some characters and it took a couple of attempts for the software to accept my game code. The font makes the letters 'O' and 'I', and the numbers '0' and '1' appear almost indistinguishable.
As if that wasn't enough, SEGA, the game’s publisher had implemented an online verification system based on the unique DVD key of the game disc. However, it was nigh on impossible to have the game verified online due to network traffic, but also to some erroneous errors in the verification process.
On my first attempt at verification I was told by the game’s verification system that my particular game key was in use and the verification would not proceed. Upon trying again, I wasn’t able to connect to the verification server and this was the case for the next hour or so, before I managed to connect only to be told that my game key was in use! I’d have laughed if I wasn’t so annoyed. After a complete uninstall and reboot of my system, I reinstalled the game and this time managed to get the game verified correctly.
SEGA have since issued an apology in the wake of the verification fiasco, blaming higher demand than what was expected. Given the game’s popularity in previous incarnations it was a shockingly bad error and SEGA really should have known better.
But, with the game now installed and verified it was time to download and apply the first of what will likely be several patches. Once that was done it was time to kick-off the game proper.
Game Setup & Interface
Football Manager 2009 gives the player the choice of over 5000 clubs from over 50 countries. As before the game can be customised to suit the player’s PC, allowing the player to choose database size, manageable leagues and other choices, including fog-of-war attribute masking.
Players of FM2008 will notice that the interface for Football Manager 2009 hasn’t had much of a revamp, other than the implementation of a new skin. The in-game menus are all located in the same place, and contain the same options as before so for those already familiar with the game, things are easy to pick the game up. New players too will find the game easy to follow as the menus and sub-menus follow a logical order, so game options are easy to find. The only stumbling block for new players will be the sheer depth of information available, which some players may find overwhelming. Given time, however, it all fits into place and the experience is both immersive and addictive.
FM2009 New Features - 3D Match Engine
FM2009’s big selling point, and the one which has divided fans more than any other has been the implementation of a 3D match engine. The 3D match engine proffers the player with the ability to watch matches played out using full 3D rendering, from a variety of camera angles, rather than the traditional and simplistic 2D, top-down display of previous incarnations. The traditional view has remained for owners of lower-end PCs and/or laptop play, as well as for purists of the game.The 3D engine for FM2009 was developed by SEGA Japan’s ‘Virtua Striker’ game and underwent some thorough testing in Football Manager Live, but it felt disappointingly unfinished in the demo version and it wasn’t long before I found myself back using the 2D, top-down view. In the demo version, the 3D view felt completely randomly generated and only a small selection of player movements ever seemed to be shown. However, the full retail version of the game sees a much more polished 3D match engine than in the demo version, with a greater array of player movement and tactical awareness on show. Player models are detailed enough to note basic features, such as hair colour and skin tone but there’s little resemblance to any player they’re supposed to represent otherwise.
FM2009 3D Match Engine Screenshots
3D Match Engine - Overhead View3D Match Engine - Behind The Goals View3D Match Engine - Main Stand View
Thoughts on the FM2009 3D Match Engine
However, the game engine is not perfect. On the downside, the loading time for the 3D view can sometimes be quite slow, while during the match players sometimes get ‘stuck’ for no reason, or stop suddenly when chasing through balls, and their choice of passing is sometimes utterly puzzling.
There is also a lot of ricochets and bounces from over-hit passes or shots, with direction of the ball somewhat questionable given the laws of physics, and this seems to happen more so than there should be normally be the case in a real-life match. There’s still a tendency for goals to be scored via long range strikes, rather than goal-mouth scrambles, but on the whole the FM2009 match engine far surpasses any other engine of a similar ilk, such as Eidos’ attempt in the Championship Manager series. It isn’t overly demanding on your graphics card either, but while some laptop graphics chipsets may struggle, even a low-range 6 series GeForce card should have little trouble in coping with the demands of the 3D engine.
One minor aesthetic gripe surrounds the use – or lack of – of the stands surrounding the pitch which are portrayed by ugly big blocks of solid grey. If SI are looking to recreate the match experience then placing spectators here would be a good move, as the sound of the crowd doesn’t really fit otherwise.
The improved 3D view in the retail version means that this feature of the game can actually come in handy, and you can now spot facets of your team’s play or tactics which aren’t working, as well as having greater clarity over weak-spots and positions. It’s a step in the right direction and with some further tweaking could go onto better things for future releases.
Assistant Manager Role in FM2009
Assistant Manager In-match FeedbackThe Assistant Manager role in Football Manager 2009 has been revamped to offer much greater depth to their role in the game. Previously, the assistant manager really was only a minor side role to the main game, weighing in with some limited advice about the team and potential signings, as well as taking on background tasks, such as training or negotiating new contracts. However, in FM2009, the assistant manager can now be able to provide comprehensive feedback about how both you and your opponent are playing, provides feedback on player form, team tactics and more.
In a match, the assistant manager can tell you where your tactics are failing but his feedback is annoyingly cryptic as he doesn’t offer a cure for the ills, but merely highlights them. On the flip side, however, he does tell you when players are having trouble adapting to your tactics on the pitch and their physical condition and advises which players should have their match tactics changed to complement the team’s play.
Unfortunately, however, for all the advice the assistant manager does provide, it’s a real pain having to switch between multiple screens in order to implement them all. It would be much easier to have a button to implement the assistant manager’s advice quickly.
The assistant manager can also provide reports on dressing room morale, potential signings and squad weaknesses and depth. He can also suggest players which may improve problematic areas.
Training & Tactics
Asking a player to learn a preferred move in FM2009Players can now be instructed in training to learn new ‘preferred moves’ which sees players train in aspects of play not normally associated with their style. Players can now be instructed to run with the ball, get into the box or not to dive into tackles among many other things. This helps to enhance the job of moulding your players and team to suit the kind of game you want to play, rather than simply dragging players around the pitch on the tactics board – an omission I found strange at first, but now can see why it was done.
Other team related tactics, such as playing offside; zonal marking; using target men and setting team mentalities; passing styles and tackling can also be defined and set using a series of sliders, as in previous versions.
Board & Media Interaction in FM2009
FM2009 Press ConferenceThe Board and Media interaction in FM2009 have also been remodelled and provides a greater range of information surrounding yours and the club’s performances, so you’ll know which areas you’ll need to sharpen up if you want to stay in a job! Fans feedback – introduced in FM2008 - has also been enhanced, so you can now see what the supporters think of your latest capture and their level of confidence in the player.
The introduction of a transfer rumours section has also been made. While on the surface this could be somewhat superfluous, its value cannot be denied and you can be linked with players who you’ve never even considered, but can turn out to be real world-beaters if you take the time to look at them. Conversely, it can also make players unhappy if they find themselves bandied about in the media and linked with other clubs.
As manager, you will also be able to attend press conferences, or send your assistant to face the media. Press conferences take place before and after matches and also when players start out at a new club. These conferences involve journalists asking questions at the player, which can be answered with one of five answers. You’ll be asked about tactics for upcoming games, potential signing targets or the latest defeat for your side among other questions, and your answers can have an effect on team and player morale. While this is a good addition and adds to the realism, it does however become very repetitive very quickly.
Transfer System in FM2009
Transfer Rumours in the MediaThe transfer system has been revamped from previous versions and there is now greater scope when it comes to signing players. Transfer deals can now be bartered more than before, and negations can now see you land a sought-after player at a more amicable fee, whereas before in previous versions, the prices were pretty much set in stone and you’d often have to pay over the odds to sign a player.
There is also a greater emphasis on bringing players in on a loan spell first for a smaller fee, with an option to buy. While this feature was implemented in FM2008, it didn’t work all that well and you can now see how much other clubs are willing to pay to bring in a player in this manner.
Selling your deadwood players is also easier than before, and you’re now more likely to be able to shift those players you no longer need or want. Offering players to other clubs is easier and more effective, and offers for your players are more likely to be received than before. As in FM2008, you can also adjust your wage budget for players by redirecting some of your transfer budget and vice versa.
Game Issues
There are still problems with the game, although many have been ironed out somewhat with the implementation of the patch. The most notable is still the problem with player injuries. In the demo it wasn’t uncommon to have a lot of players out injured and despite the promise of being fixed by the patch, injuries are still happing too frequently for my liking – every other game I am still losing one or two players to injury, whether they are serious injuries or not. At one point I had seven of my first team out injured with a variety of ailments and building a settled team has so far proved difficult.
As previously mentioned, some of the players’ decisions in-game are baffling; choosing to play a short pass of the ball to a heavily-marked team-mate rather than play a long ball to a striker in space for instance is just one strange tactical decision, while players tendencies to stop chasing loose balls or collect a loose ball and then stand still with the ball rather than initiating a move can be infuriating to see.
Other small niggles include some rendering problems with the 3D match view, such as lines not always being drawn, animated players running but ultimately not moving and slow loading times; all of which, while annoying don’t ultimately detract from the game.
FM2009 System Requirements
Football Manager 2009’s system requirements are relatively modest, but to be able to run the 3D match mode, you’ll need the following minimum PC specification.
Processor: XP: 1.4GHz or Faster / Vista: 2.0GHz or Faster
Memory: XP: 512MB RAM / Vista: 1.0GB RAM
Hard Drive Space: 2GB
DVD-Drive: 4x Speed
Video Card: 128MB - Nvidia FX 5900 Ultra or greater; ATI Radeon 9800 or greater; Intel 82915G/82910GL or greater. (Note: Earlier cards may only display 2D Match)
Sound Card: DirectX 9.0c compatible
Directx: Version 9.0c (included)
LAN: TCP/IP compliant
Verdict on Football Manager 2009 Rating Excellent
It is good to see that problems that were evident in the demo version have been addressed and to a large extent cured in the retail version and subsequent patch. While it was always going to be difficult to top the near-perfect representation of football management in the Football Manager 2008 release, the new additions to FM2009 have been well thought out and add a new level of depth to the game. While it is still a little rough in some areas this latest instalment of the game makes a good fist of taking the game to the next level and ultimately succeeds in doing so; as new patches are released, this game can only get better.
While the 3D match engine may not be to everyone’s taste, the sheer depth of the game make it an essential play for any football fan and there is still only one football manager game worth considering. This is a must-buy title for anyone with an interest in the beautiful game.
Why Would Anyone Want To Use An Online Data Storage Service?
Well that is an excellent question... With computer hard drives becoming so large and reliable you would think that the need for remote storage was redundant. BUT larger hard drives are actually part of the need!
You see nowadays we ALL create data that needs storing AND sharing...
Yes we can fill up our hard drive, quite easily, with video clips from our camera's and mobile phones. Both camcorders and digital camera's have become affordable AND create the need for more storage space on our computers too.
And then there are all those documents you create that add to the increasing speed at which you consume resources on your PC.
Much of this "data" we create is valuable to us. Maybe it is important documents for work, or family memories in the form of pictures and video...
So here is the problem!
What if you LOST all that "data" - would it matter to YOU?
I'm guessing the answer is YES?
Most folk never make backups... yes you can hold up your hand too. And those that do tend to put them on CD-R and then keep them at the same location as their PC or Laptop.
Crazy?
Yep!
If you have a fire etc... chances are you lose BOTH the computer and the backup CD-R's
Think it does not happen.... sadly it happens to too many people. Just ask your insurance agent the next time you renew your policy. They can tell you some really sad stories about data loss.
Of course it is not just fires that damage data. So do virus and hardware failures... so if you are not even creating backups you really are a time bomb waiting to go off!
Sharing Your Photos, Music and Video...
But it is not just data loss that you should associate with online data storage services.
You have all these photo's and music files so why not SHARE them with friends and family around the world?
Modern online storage allows you to do this - SECURELY too!
So lets imagine....
You can get a SECURE online service that allows you to:
# Back up important files
# Store your family photo's, video clips and music
# SHARE any files you wish with family and friends etc...
And you have:
# Access from ANY computer wherever you are in the world!
# Use a secure web based interface
# Use secure desktop software on your own PC
This an affordable and reliable way to make sure you never lose your files and share the files you want too at anytime!
What Exactly are DDOS Attacks?
It was in early 2000 that most people became aware of the dangers of distributed denial of service (DDoS) attacks when a series of them knocked such popular Web sites as Yahoo, CNN, and Amazon off the air.
It's been almost four years since they first appeared, but DDoS attacks are still difficult to block. Indeed, if they're made with enough resources, some DDoS attacks - including SYN (named for TCP synchronization) attacks - can be impossible to stop.
No server, no matter how well it's protected, can be expected to stand up to an attack made by thousands of machines. Indeed, Arbor Networks, a leading anti-DDoS company, reports DDoS zombie armies of up to 50,000 systems. Fortunately, major DDoS attacks are difficult to launch; unfortunately, minor DDoS attacks are easy to create.
In part, that's because there are so many types of DDoS attacks that can be launched. For example, last January, the Slammer worm targeted SQL Server 2000, but an indirect effect as infected SQL Server installations tried to spread Slammer was to cause DDoS attacks on network resources, as every bit of bandwidth was consumed by the worm.
Thus, a key to thinking about DDoS attacks is that it's not so much a kind of attack as it is an effect of many different kinds of network attacks. In other words, a DDoS may result from malignant code attacking the TCP/IP protocol or by assaulting server resources, or it could be as simple as too many users demanding too much bandwidth at one time.
Typically, though, when we're talking about DDoS attacks, we mean attacks on your TCP/IP protocol. There are three types of such attacks: the ones that target holes in a particular TCP/IP stack; those that target native TCP/IP weaknesses; and the boring, but effective, brute force attacks. For added trouble, brute force also works well with the first two methods.
The Ping of Death is a typical TCP/IP implementation attack. In this assault, the DDoS attacker creates an IP packet that exceeds the IP standard's maximum 65,536 byte size. When this fat packet arrives, it crashes systems that are using a vulnerable TCP/IP stack. No modern operating system or stack is vulnerable to the simple Ping of Death, but it was a long-standing problem with Unix systems.
The Teardrop, though, is an old attack still seen today that relies on poor TCP/IP implementation. It works by interfering with how stacks reassemble IP packet fragments. The trick here is that as IP packets are sometimes broken up into smaller chunks, each fragment still has the original IP packet's header as well as a field that tells the TCP/IP stack what bytes it contains. When it works right, this information is used to put the packet back together again.
What happens with Teardrop, though, is that your stack is buried with IP fragments that have overlapping fields. When your stack tries to reassemble them, it can't do it, and if it doesn't know to toss these trash packet fragments out, it can quickly fail. Most systems know how to deal with Teardrop now, and a firewall can block Teardrop packets at the expense of a bit more latency on network connections, since this makes it disregard all broken packets. Of course, if you throw a ton of Teardrop busted packets at a system, it can still crash.
And, then, there's SYN, to which there really isn't a perfect cure. In a SYN Flood, the attack works by overwhelming the protocol handshake that has to happen between two Internet-aware applications when they start a work session. The first program sends out a TCP SYN (synchronization) packet, which is followed by a TCP SYN-ACK acknowledgment packet from the receiving application. Then, the first program replies with an ACK (acknowledgment). Once this has been done, the applications are ready to work with each other.
A SYN attack simply buries its target by swamping it with TCP SYN packets. Each SYN packet demands a SYN-ACK response and causes the server to wait for the proper ACK in reply. Of course, the attacker never gives the ACK, or, more commonly, it uses a bad IP address so there's no chance of an ACK returning. This quickly hogties a server as it tries to send out SYN-ACKs while waiting for ACKs.
When the SYN-ACK queues fill up, the server can no longer take any incoming SYNs, and that's the end of that server until the attack is cleared up. The Land attack makes SYN one-step nastier by using SYN packets with spoofed IP addresses from your own network.
There are many ways to reduce your chances of getting SYNed, including setting your firewall to block all incoming packets from bad external IP addresses like 10.0.0.0 to 10.255.255.255, 127.0.0.0 to 127.255.255.255, 172.16.0.0 to 172.31.255.255, and 192.168.0.0 to 192.168.255.255, as well as all internal addresses. But, as SCO discovered, if you throw enough SYN packets at a site, any site can still be SYNed off the net.
Brute Force Attacks.
Common brute force attacks include the Smurf attack and the User Datagram Protocol (UDP) flood. When you're Smurfed, Internet Control Message Protocol (ICMP) echo request packets, a particular type of ping packet, overwhelm your router. Making matters worse, each packet's destination IP address is spoofed to be your local broadcast address. You're probably already getting the picture. Once your router also gets into the act of broadcasting ICMP packets, it won't be long before your internal network is frozen.
A UDP flood works by someone spoofing a call from one of your system's UDP chargen programs. This test program generates semi-random characters for received packets with another of your network's UDP echo service. Once these characters start being reflected, your bandwidth quickly vaporizes.
Fortunately, for these two anyway, you can usually block them. With Smurfing, just setting your router to ignore broadcast addressing and setting your firewall to ignore ICMP requests should be all you need.
To dam up UDP floods, just block all non-service UDP services requests for your network. Programs that need UDP will still work. Unless, of course, the sheer volume of the attack mauls your Internet connection.
That's where the DDoS attacks programs such as Tribe Force Network (TFN), Trin00, Trinity, and Stacheldraht come in. These programs are used to set DDoS attack agents in unprotected systems. Once enough of them have been set up in naÃ?Æ?Ã?¯ve users' PCs, the DDoS controller sets them off by remote control, burying target sites from hundreds or even thousands of machines.
Unfortunately, as more and more users add broadband connections without the least idea of how to handle Internet security, these kinds of attacks will only become more common.
Deflecting DDoS Attacks
So what can you do about DDoS threats? For starters, all the usual security basics can help. You know the drill: make sure you have a firewall set up that aggressively keeps everything out except legal traffic, keep your anti-viral software up to date so your computers do not become a home for DDoS agents like TFN, and keep your network software up to date with current security patches. This won't stop all DDoS attacks, but it will stop some of them like Smurfing.
You may not think you need these services, since in a worse case scenario you're still going to get knocked off the net. But not every attack will be a massive one with thousands of attackers. For most attacks, these services can definitely help.
And, let's face it, today we have PC's the net 24-7. With DDoS attacks on the rise, you'd be wise to at least familiarize yourself with DDoS attacks prevention services. After all, it's not only your network in danger, it's your business.
A production workstation is a system of hardware and software components you can use to create digital media. For example, a workstation for creating Microsoft® Windows Media®-based content may be as simple as a computer and video camera for streaming live traffic conditions. More complex workstations can be part of a complete audio and video production facility. The type of production workstation you put together depends on your needs, your desired digital media quality, and your budget.
This article describes what you need to build a workstation for capturing and encoding high-quality, high-bandwidth files that can play back full frame at the original frame rate. With Windows Media Encoder and Windows Media Encoding Script, you can create high-bandwidth files that can be downloaded or streamed over a broadband network. With Windows Media Capture 9 Series you can create uncompressed AVI files with which you can create Windows Media files in the encoder. The features and codecs in these capture and encoding tools enable you to create content that approaches DVD quality at a fraction of the bit rate and file size.
To capture and encode high-quality content, a workstation must be capable of high-quality analog-to-digital conversion. In addition, the computer must have the speed and memory to handle far more than the typical number of bits per second. The initial hardware investment may be higher than the cost of a low-bandwidth system, but the results are well worth it if you need high quality.
This article provides recommendations for a minimum and an optimal system for encoding Windows Media-based content. The recommendations also take into account system usage; that is, a computer used to capture video must have a great deal more speed and memory than one used for file-to-file conversions. For detailed recommendations, see the Hardware Recommendations section of this article.
Special Considerations for High Bandwidth
To take advantage of the high-bandwidth features and codecs, you need to be able to capture audio and video at its highest quality. A computer that can capture a small image size at 15 frames per second may not be able to handle video with four times the image size and twice the frame rate.
When video is converted from analog to digital, each frame is broken up into hundreds of pixels. Each pixel is represented by one or more bytes that represent the color of that small area of the image. Each video conversion requires a certain amount of computer memory and computation time. The higher the quality of video, the greater the number of frames per second; the larger the image size, the greater the number of pixels that must be converted in a given period of time. For example, when capturing video at 30 frames per second, the computer must not only be able to handle many pixel conversions, it must also perform many conversions very quickly in order to keep up with the continuous stream of video.
The computer must also be able to handle the audio conversion simultaneously. The smallest unit of audio is a called a sample. High-quality audio requires more samples per second, plus a computer that has the speed and memory to process the continuous stream.
To encode directly to a Windows Media file or broadcast stream from audio and video capture cards, you will typically use Windows Media Encoder. However, you can perform basic encoding tasks from the command line with Windows Media Encoding Script. In the optimal system, rather than capture and encode in one step, an AVI file is first captured with Windows Media Capture 9 Series utility. Then the final Windows Media Video file is encoded from the AVI file. This two-step method is often preferred for encoding high-bandwidth video, because it requires less processing power and memory, and therefore can help ensure a higher quality capture.
Considering Compression
The digital audio and video streams of samples and pixels are measured as the bit rate of the content, such as 700 kilobits per second (Kbps). High-quality professional video has a bit rate that far exceeds the capacity of most computers and networks: 270 megabits per second (Mbps). In order to work with digital media on a computer and stream it over a network, it must be compressed. The program that compresses and decompresses digital media is called a codec.
The Windows Media Audio 9 and Windows Media Video 9 codecs offer a great deal of user flexibility because they are highly scalable, which means you can choose the amount of compression and the bit rate for a wide variety of scenarios. For example, you can sacrifice some quality and compress to very low bit rates for streaming media at telephone modem speeds, or maintain high quality and high bit rates to stream or download over a high-bandwidth network or to save to a CD.
When designing your production workstation, you must consider the codec and bit rates you will use. Analog-to-digital conversion and the compression process require a great deal of processing power for high bit rate content. If you follow the recommendations for the optimal system, your workstation will be able to handle the workload and create high-quality content.
The Key to High Quality
There are two primary methods for encoding video:
* Capturing and encoding from a live stream directly to a Windows Media file as a real time process.
* Capturing to an uncompressed AVI file, and then encoding a Windows Media file from the AVI file in non-real time.
Real-time encoding is best used for live broadcasting, in which the primary stream is played back as it is being encoded. Real-time encoding requires a faster CPU and more random access memory (RAM). If the CPU can not keep up with the real time processing, it drops frames of video and motion can appear jerky.
Capturing to an AVI and then encoding in non-real time usually produces higher quality results. This method requires large amounts of hard disk space and faster system components (described in more detail later). However, the method does not require a fast CPU for encoding; complex encoding modes just take more time. By definition, the non-real time process is slower and requires more processing steps.
Except where noted, this article describes the system requirements for the non-real time encoding method.
The secret to capturing high-quality, high-bandwidth video is to use a computer system that can handle the bandwidth. A fast CPU with a large amount of RAM is helpful. However, a fast peripheral component interconnect (PCI) bus, fast hard disk with proper storage capacity, and a network connection that can handle the high bandwidth if you plan to stream to other computers is a requirement. Capture cards and external hardware should also be capable of producing high-quality images and sound. (For detailed recommendations, see the Hardware Recommendations section of this article.) There are several items you need to consider when building a high quality workstation:
* Source quality. The final product can be no better than the source. Make sure to use a high-quality, high-resolution videotape format, such as Digital Betacam or Mini-DV. With the proper digital interface, such as the IEEE 1394 (sometimes called FireWire) interface or the professional Serial Digital Interface (SDI), you can skip the analog-to-digital conversion that reduces quality. If you must convert from analog, make sure your video source is high quality. Use S-video connections, if available, and a professional-quality playback deck. Most of today's professional or semi-professional videotape decks are capable of producing suitable quality.
If you are capturing from a tuner, demodulator, film scanner, or router, make sure the cables and connections are professional quality and working properly, and the radio frequency (RF) connections to the tuner or demodulator are properly adjusted and terminated. Not only does poor source quality result in a poor quality product, any noise, glitches, or instability in the picture can increase the bit rate and size of the final file. The codec cannot distinguish detail in the video image from the detail in video noise, and attempts to reproduce the video imperfections just as faithfully as the rest of the image.
* Fast CPU, PCI bus, and a large hard drive and RAM. A fast CPU enables a computer to keep up with the demand imposed by the continuous stream of bits, while a fast PCI bus moves those bits easily between the capture device and the processor. A large amount of RAM eases the load on the CPU by enabling bits to be cached as they are converted. A large hard disk with a fast access time eases the load on the computer by writing data quickly and efficiently. As you capture data, you can use the System Monitor included with the Microsoft Windows® operating system to view CPU and memory usage. If the CPU percentage often hits 100 percent, there is a very good chance the capture quality will be impaired. If possible, use a computer with dual PCI buses. Even a very fast single PCI bus may not be able to handle both the bit stream produced by the capture card and the stream going to the hard disk drive.
* High-quality capture cards. A capture card is responsible for properly inputting and processing the audio and video signals, and then converting them into a digital stream of bits. For this reason, the video capture card is the most important link in the chain. A low-quality or outdated capture card can greatly reduce the quality of the video. After the video has been converted to digital form, the data can be stored, transferred, and copied without affecting quality.
High-Bandwidth Features of Windows Media
With Windows Media Audio 9 and Windows Media Video 9 codecs, you can achieve near-VHS quality at 250 Kbps and near-DVD quality at 750 Kbps with a variable bit rate (VBR) encoding mode. You can also improve the quality of high-bandwidth content by taking advantage of the following features:
* Deinterlacing. When encoding a video file captured at the full frame size of 640 x 480 pixels, the two interlaced fields contained in a single frame of NTSC video must be converted to one complete frame that can be displayed on a computer monitor. Computer monitors use a different method of displaying video called progressive scanning, which does not use interlaced fields. The deinterlacing feature converts interlaced video frames into progressively scanned frames, creating a cleaner, sharper image with fewer motion artifacts at both a full frame size and at 320 x 240 pixels.
* Inverse telecine. To convert film, which plays back at 24 frames per second (fps), to National Television System Committee (NTSC) standard video, which plays at 29.97 fps, a telecine, such as a film scanner, adds redundant fields to the video. When encoding video of a film, you can use the inverse telecine filter to remove those redundant fields and return the video to its original frame rate. The final encoded video appears more like the original film; and, with fewer frames, the file size is smaller and bit rate are lower. Inverse Telecine does not apply to Phase Alternate Line (PAL) video.
* 50 or 60 frames per second. You can create high-quality video that has very smooth and crisp motion by using the deinterlacing filter to encode from 640 x 480 pixels to 320 x 240 pixels, and then converting the video fields to frames. The 50 fields per second (PAL) or 60 fields per second (NTSC) are converted to 50 or 60 frames per second.
* Variable bit rate. Any on-screen movement results in an increase in the bit rate of a video, because new pixels must be generated from frame to frame. To stream over a network with Windows Media Services, you would use constant bit rate (CBR) encoding to constrain the bit rate to the available bandwidth. With CBR encoding, Windows Media Encoder keeps the bit rate below a specified level by dynamically reducing the quality of the video, or dropping frames if necessary. Playback is not always as smooth as one would like, but the end user experiences as smooth a presentation as possible for a given bandwidth.
For video that will not be streamed, you have the option of VBR encoding. VBR-encoded video cannot be streamed, but you can use it for content that is destined to be downloaded or played back locally or over a fast network. With VBR encoding, the integrity of high motion or rapid changes in the video is maintained by simply allowing the bit rate to vary as needed. You set the desired quality level, and the bit rate changes to maintain that quality.
* Two-pass CBR encoding. When using two-pass CBR encoding, content passes through the encoder twice. The first time, the encoder analyzes the complexity of the content. During the second pass, the analysis is used to encode the content. Two-pass CBR encoding produces a much cleaner and smoother video than the one-pass CBR method. Two-pass CBR encoding cannot be used with a broadcast stream.
* Two-pass VBR encoding. For two-pass VBR encoding, you specify a desired bit rate instead of a desired quality level. The encoder then adjusts the VBR quality level to create a file that is the equivalent size of a CBR file of the same specified bit rate. During the first pass, the encoder estimates what the final file size will be, and during the second pass it adjusts the quality level in order to create a file with the desired file size. Unlike two-pass CBR encoding, the data from the first pass is not used during the second pass.
* Nonsquare pixels. A pixel is the smallest unit of a digital image or frame. A resolution of 640 x 480 pixels produces a frame aspect of ratio 4:3 if the pixels are square. By using nonsquare pixels, which is supported in Windows Media, you can create any number of different aspect ratios and resolutions. For example, you can maintain the original resolution of digital video (720 x 480), which uses nonsquare pixels.
* Multiple bit rate (MBR) audio and video. You can encode one Windows Media file or stream that contains multiple streams encoded at different bit rates. MBR does not itself improve quality, but it enables you to provide the highest quality content for a wider variety user bandwidths. For example, in one MBR file you can support users connecting to the Internet with slow telephone modems, while providing high-quality content for users with broadband connections.
By using these features with the Windows Media Audio and Video codecs, you can create high-quality pictures and sound at a fraction of the file size and bit rate of conventional digital media. The typical computer display has a far higher resolution and faster frame rate than an analog television. This enables you to produce video with Windows Media that is higher quality than standard television. You can even encode high-bandwidth video that rivals the quality of film in a theater when using a digital cinema projector.
However, to do all this you need a system that can capture and maintain high quality.
Hardware Recommendations
The following section shows the recommended minimum and optimal hardware for capturing high-bandwidth content to an AVI file and encoding high-bandwidth Windows Media files from AVI files.
* Computer. A fast processor is useful, but not required for capturing video to an AVI file. Keep in mind, though, that the faster the computer is, the shorter the encoding time will be. A high-bandwidth, two-hour AVI file, for example, might take several hours to encode on a slow computer. More important than raw CPU clock speed is a fast front-side bus that will help transfer the video data to the hard disk without any conflicts or speed bottlenecks. For the latest information, see Windows Media Encoder 9 Series System Requirements.
Hard disk. To capture high-bandwidth content, your hard disk must be capable of a sustained access speed of 27 Mbps. Although many hard disks are rated with higher access speeds, they might not be capable of maintaining that speed throughout the capture of a two hour movie, which can result in dropped frames. It is recommended that you use Ultra160 small computer system interface (SCSI) drives with a RAID 0 striping. This configuration writes or stripes data across multiple hard disks, but appears as one drive on your desktop.
The SCSI disk array can be expensive. A less expensive alternative uses four integrated device electronics (IDE) drives with an IDE RAID controller board.
The size of the hard disk depends on how much content you plan to store. For example, if you plan to store a two-hour movie as an uncompressed AVI file, you will need 80 to 120 GB of space, depending on the resolution and pixel format that you capture to.
It is recommended that when you plan to build your production station, you shop around for the best solution at the time.
* Video capture card. Windows Media Encoder works with most capture devices that have Video for Windows or Windows Driver Model (WDM) drivers. To capture high quality, full-frame, and full-frame rate video to an AVI file, however, the list of capture cards narrows. Professional cards such as the Targa 3000 from Truevision, the Osprey 500 card from Viewcast, and the Reality Studio Digital Disk Recorder from DPS are well suited for high-quality video capture.
Some cards were created to capture content to be encoded to Windows Media Format. The Osprey-500 and Winnov Videum II, for example, handle much of the processing needs, so the computer's CPU and memory are free to compress and encode. The Osprey-500 also provides real-time deinterlacing and hardware-based digital video (DV) decoding for capturing MiniDV video. The cards can input video from a number of source types, such as MiniDV, SDI video and professional Digital Audio, or analog.
All of the cards that support video capture to a Windows Media file are listed on the Windows Media Hardware Product Vendors page at the Microsoft Web site. Keep in mind, however, that some of these cards may not produce the quality required to capture high-bandwidth video.
* Sound card. Many video cards also capture sound. In the optimal system, video and audio are captured digitally. Some cards are capable of capturing audio digitally or through an analog connection. Any high-quality sound card is suitable for capturing analog audio, but if you plan to capture audio digitally, make sure the card is capable of synchronizing to a digital source. Many cards also support multi-channel audio, such as 5.1 and 7.1 audio, which can be encoded directly to a Windows Media file or broadcast stream.
* Network card. You should design your workstation to be part of a network. Though files can be transferred to other computers with removable hard disks, it is far more efficient to connect the computers in a network. You can also connect the workstation through a proxy computer or firewall to the Internet, so that you can transfer files directly to your Web server or Windows Media server by using File Transfer Protocol (FTP). It is recommended that you use a fast network, such as an Ethernet 100BaseT system. The network cards and hub devices are inexpensive, and with the 100 Mbps data rate, you can copy large files quickly or play high-bandwidth files across the internal network. During the capture of an uncompressed AVI file, however, you should disable file sharing, or even disable the network completely, to eliminate the potential of external users accessing your system and hard disk.
Software Recommendations
The following section describes the basic software needed to capture AVI files and encode Windows Media files and broadcast streams. Your complete workstation may also include programs to edit video and design audio. You may also decide to install a packaged system that includes a capture card and editing system. If you do so, make sure the system is capable of capturing and editing full-frame video with no compression. In the optimal system outlined in this article, the highest quality is achieved by capturing data directly to the hard disk with no audio or video compression.
* Operating system. Windows Media Encoder 9 Series and the related encoder utilities can run on Microsoft Windows 2000 and Windows XP. It is recommended that you use the NTFS file system so that you can save files larger than 4 GB, which is the limit with FAT 32 file system. Before selecting an operating system, make sure your video capture card provides the appropriate driver. For example, some cards may only run on Windows 2000 Professional.
* Capture to AVI. You can use any program that enables you to capture full size (720 x 480 pixels for NTSC, 720 x 576 for PAL), full frame rate (29.97 or 25 frames per second), uncompressed video.
Depending on your capture card, you should capture to a YUY2 or YV12 pixel format. YUY2 produces a larger file, but provides more flexibility; YV12 produces a smaller file, but cannot be converted to other pixel formats as easily. YV12 may also be referred to as IYUV or I420. For more information, see The (Almost Definitive) FOURCC Definition List Leave this Web site.
The optimal system uses the simple Windows Media 9 Capture utility for capturing uncompressed AVI files with mono, stereo, 5.1, or 7.1 channels of audio, with up to 24 bit resolution and sampling rates up to 192kHz. You can download the utility from the encoder section of the Windows Media Download Center.
* Edit the AVI. There are a number of video editing and sound design programs, such as Adobe Premiere 6 and Sonic Foundry Vegas Video 4.0, with which you can work with full-frame uncompressed video. If you require no additional editing, you can simply encode the captured AVI file directly. For more information about these products, see the Sonic Foundry Leave this Web site and Adobe Leave this Web site Web sites.
* Capture and encode to Windows Media. Use Windows Media Encoder 9 Series, which you can download from the Windows Media Download Center. You can use Windows Media Encoder to capture directly to a Windows Media file or to a live stream for distribution to a Windows Media server for live broadcasting. You can also encode from an AVI file. You can also encode content with the Windows Media Encoding Script command line utility.