WHILE the film industry has forced 321 Studios, a Missouri company, to stop selling software that can copy Hollywood movies sold on DVD's, its success may be limited. Purveyors of software tools that can do the same thing, sometimes better, are flourishing on the Internet - and the wares are often free.

The availability and apparently widespread use of such tools is fostering debate about the legality and the ethical implications of such copying by individual consumers - including people who copy DVD's onto a computer to avoid carrying a disc while they travel, or to keep children from damaging the originals - who do not distribute copies of the DVD as pirates do.

The free copying tools are available through Internet sites that are not directly subject to American law, often because the nations that those sites call home permit individuals to copy material for their own use.

People seeking such tools need only pose the question in an Internet search engine to find dozens of sites devoted to the subject, including the Afonic DVD Guides site (www .dvd-guides.com), run by Joseph Chatzimichail, a 20-year-old electrical and computer engineering student in Salonika, Greece.

The site draws about 100,000 visitors each month, Mr. Chatzimichail said, most of them looking for advice on what tools to use, where to get them - the site does not carry such tools - and how to use them. He and the others who help manage the message boards on the site have no tolerance for pirates, he said.

"Many people ask how to copy rented DVD's or how to convert downloaded movies to DVD, and of course they are informed that it is illegal and the thread is closed," Mr. Chatzimichail said. "Personally I believe that a user should be able to back up a DVD he owns. I don't understand why movies should be different than other media, like audio CD's; it is obviously the same thing."

Photocopying a magazine article or recording a television broadcast on a VCR is generally considered legal under the fair-use provision of American copyright law. In the electronic realm, however, it may be illegal for individuals in the United States to circumvent any antipiracy measures that might be used to prevent copying material on something like a DVD.

Film studios have successfully argued that three programs sold by 321 Studios violated the Digital Millennium Copyright Act of 1998, which forbids the distribution or use of any program that cracks digital copyright-protection systems, whether or not the ultimate purpose is illegal. This year a series of legal rulings forced 321 Studios to remove the copying software from the market.

The Federal District Court judge in one case, Susan Illston of San Francisco, was unswayed by arguments that users of the company's products did not routinely engage in piracy or otherwise damage the market for DVD movies. "It is the technology itself at issue, not the uses to which the copyrighted material may be put," she wrote in her opinion.

Before the software from 321 Studios was withdrawn from the market, a million people had paid for its DVD-copying programs, according to the company.

The programs had become popular partly because making a copy of a DVD with the free tools available on the Internet was until recently a demanding task. The 321 programs automated the process, making it easy for even nontechnical users; some of the free tools available on the Internet do likewise, automatically synchronizing the audio track with the images, for example. While copying tools are also available commercially, the quality, power and flexibility of the free tools on the Internet put those products to shame.

It typically takes four to eight hours to copy a DVD movie onto a hard drive. The copied data can take up a great deal of space, from two to eight gigabytes, though many tools can compress the raw data into a gigabyte or so as a way of saving space at the cost of a slightly degraded picture or sound. By way of comparison, the typical hard drive in a laptop computer today averages 60 gigabytes.

Once copied onto a hard drive, the material can be also copied onto a recordable DVD or even squeezed onto a recordable CD by using compression technologies, a task popular with parents concerned that curious hands will damage the original disc. Laptop users also copy a movie onto a hard drive to eliminate the need to power the machine's DVD drive, thereby preserving battery life.

One user of the 321 software, George Works, spends part of the year working as an electronic engineer for a company in McLean, Va. The rest of the year, when hurricanes are not a danger in the Caribbean, he and his wife spend their time on a sailboat, which has a DVD player.

"We have a big DVD collection, and we've invested a lot of money in them," he said. Rather than lug a large collection of movies between the places they call home twice a year and risk damage or theft, they started copying the discs and keeping the copies on the boat. Mr. Works says he doesn't think he's doing anybody any harm with this practice. "Obviously, we're only watching one at a time," he said.

Still, the film industry argues that software for duplicating encrypted DVD's should be outlawed. "If everybody was a good citizen and used it for benign purposes, you'd have no problem," said Jack Valenti, president of the Motion Picture Association of America. "But if you let one person circumvent the encryption, you have to let everyone. What about the person who is not so benign?"

The association argues that the only way to prevent people from using such tools in an illegal way is to make the tools themselves illegal.

Representative Rick Boucher, a Virginia Democrat, rejects that premise as "hogwash." He has introduced legislation intended to promote the availability of DVD-copying tools designed primarily for legitimate consumer use, and to extend fair-use provisions of copyright law to consumers who break anti-copying protection.

"Because a hammer can be used to break a window, and a burglar can use a hammer, outlaw the hammer, that's the philosophy," he said of Hollywood's position. "But historically we have never outlawed technology that was capable of legitimate use. If the technology has bad uses, then punish the people who use it wrongfully. Don't outlaw the technology."

From The New York Times