IBM said that it added 2,500 iSeries customers last year, increasing the total base to 245,000 users. Most of the new customers were small to midsize companies.

The new operating system version improves iSeries integration with IBM's xSeries line, which runs Windows and Linux by replacing proprietary IBM interfaces with Internet SCSI technology.

The i5/OS upgrade also offers improved security and auditing capabilities, including automatic detection of denial-of-service attacks, said IBM.

Beverly Russell, IT director at E.D. Smith & Sons Ltd., a food products manufacturer in Winona, Ontario, and a beta tester of the new operating system, said she is pleased with the new storage capabilities and its ability to write to disk instead of tape. The new features can speed backup operations and open the door to the possibility of electronically sending backups to the company's disaster recovery site, she said.

Russell, who is also president of the Chicago-based iSeries user group Common, said that IBM has "definitely done a lot to energize the i5 and attract new [independent software vendors] and customers."