There were winners and losers. Datacenter continuity, backup, and recovery services did their jobs in most cases. By contrast, landline and cellular networks suffered long outages. To fill the communications void, emergency e-mail services kicked in.

Preparedness made all the difference between success and failure in maintaining continuity of IT operations. “We have a customer right now who didn’t plan ahead,” said Belinda Wilson, Hewlett-Packard’s executive director of Business Continuity and Availability Services. “It’s a consumer goods retailer in New Orleans that is completely underwater. No backup. They called us in desperation.”

The businesses that did carry on despite the disaster were well prepared and had help. HP, IBM, SunGard Data Systems, and others served scores of clients with hosted continuity services in mobile datacenters as well as centers located throughout the country.

The collapsed cellular communications network left many enterprises disabled. Service recovery has been slow. By Sept. 3, T-Mobile had opened a cell site in downtown New Orleans.

Last week, Verizon Wireless and Cingular Wireless said limited coverage was available in New Orleans.

Emergency e-mail systems proved to be a bright spot in the communications breakdown. Companies such as Electric Mail, HP, MessageOne, and USA.Net, provided emergency e-mail services for companies crippled by the failed phone networks.

MessageOne’s Emergency Mail System (EMS) served about 50 businesses following the hurricane, including Adams & Reese, one of New Orleans’ largest law firms, said Mike Rosenfelt, MessageOne’s executive vice president.

“Think of EMS as a life support for e-mail,” Rosenfelt said. If a company’s e-mail goes down, EMS is a standby backup that can be activated within 30 seconds by phone or Internet, he said.

Temporary rebuilding of communications systems is under way. Last week, Intel joined Cisco Systems, Dell, SBC Communications, and others to work with the Red Cross to build voice and data communications at hundreds of evacuation shelters and link them together.

By midweek, Microsoft Chairman and Chief Software Architect Bill Gates summed up the feelings of many. “It’s a terrible disaster of large proportions,” he said at a Microsoft event. “It’s great to see that technology can help in terms of re-establishing communications and hopefully helping businesses get going and get back on a strong basis.”

Paul Krill and Nancy Gohring, IDG New Service, contributed to this article