Disruptions from the weekend attack on the Internet are shaking popular perceptions that vital national services, including banking operations and 911 centers, are largely immune to such attacks. Damage in some of these areas was worse than many experts had believed possible. The nation’s largest residential mortgage firm, Countrywide Financial Corp., told customers who called Monday that its systems were still suffering. Its Web site, where customers can make payments and check their loans, was closed most of the day. Countrywide predicted it would be early Tuesday before all its computers were fully repaired and its systems validated for security, spokesman Rick Simon said. Full Story