Updated

Western Digital Corp. is offering free software to about 1 million consumers to resolve a class-action lawsuit alleging that its computer hard drives stored less material than promised — a discrepancy stemming from the high-tech industry's differing standards for sizing up digital data.

Under the settlement announced Tuesday, Western Digital (WDC) will give away software designed to back up and recover computer files to anyone who bought one of the company's disk drives from March 22, 2001, through Feb. 15 of this year.

To get the software, the 1 million eligible consumers must register their claims before July 16 at http://www.wdc.com/settlement.

The settlement, approved earlier this month by U.S. Magistrate Judge Bernard Zimmerman in San Francisco, pegs the software's retail value at $30 per copy. Consumers paid an average of $150 for the hard drives covered in the suit.

Besides buying the software for consumers, Western Digital has agreed to pay $500,000 in fees and expenses to San Francisco lawyers Adam Gutride and Seth Safier, who filed the suit last year. The proposed legal fees still require court approval.

Lake Forest, Calif.-based Western Digital believes the suit's allegations are unfounded, but decided to settle to avoid a potentially expensive legal battle, said company spokesman Steve Shattuck.

A similar lawsuit, filed in San Francisco Superior Court by the same lawyers, is still pending against another top disk drive maker, Seagate Technology (STX).

The dispute over hard-drive capacity illuminates the contradictory methods for measuring the bits and bytes that devour a computer's memory.

Microsoft Corp. (MSFT) and Apple Computer Inc. (AAPL), which make the operating systems for most personal computers, use a binary system to measure kilobytes, megabytes and gigabytes while most disk drive manufacturers like Western Digital derive their calculations from the more-familiar decimal system.

That means Microsoft's Windows systems interprets a gigabyte as 1.07 billion bytes — more than the 1 billion bytes adopted by Western Digital and many other hard drive makers.

The difference can add up to a substantial gap between what's promised on a hard drive's packaging and what gets stored on a personal computer.

The lawsuit against Western Digital alleged the company's 80-gigabyte hard drive had an actual capacity of 74.4 gigabytes. If not for that 7 percent shortfall, the buyer could have stored an additional 80 hours of digital music or 5,600 digital pictures, the suit claimed.

Most hard drive makers warn that the storage capacity listed on the package might not be fully accessible. The Western Digital settlement requires the company to include a similar disclaimer within six months after the agreement becomes final.