In a conference call, company executives said the changes were made to accelerate growth at Novell, which has had disappointing financial results, particularly in its Linux business.
"The board's decision is based purely on an evaluation of who is best suited to lead the company at this stage," Thomas Plaskett, the newly elected chairman of the board, said.
Hovsepian, 45, had been named chief operating officer last fall and was the heir apparent to Messman, 66, who had served on Novell's board since its founding.
Hovsepian immediately took on the new position of CEO. Messman, who had previously also been chairman, will remain on as a board director until the end of October.
Hovsepian, who has also been elected to the board of directors as part of his new role, joined Novell in June 2003 as its North America president. Before that, he worked in management and executive positions at IBM for 17 years.
Dana Rusell, the current vice president of finance and corporate controller, will serve as the interim CFO, replacing ousted CFO Joseph Tibbetts.
Novell, once a powerhouse in the PC software industry, in the past three years has developed an open-source software strategy. Its sells support for Linux-based software and also has a line of closed-source identity management and security tools.
But Novell's transtion to open source has not been fully successful, leading some financial analysts to call for Messman's departure.
Hovsepian said he intends to narrow the company's focus on its existing strategy and improve execution.
"As CEO, my top priority is to acclerate the speed and urgency behind our strategy," Hovsepian said, adding that the company faces significant challenges.
Plaskett said the management shakeup had nothing to do with financial improprieties.
