“It’s more difficult now, because there are software and hardware issues,” said Collender, managing director of Qorvis Communications LLC in Washington. “But it will vary by facility to facility -- depending on their information technology and particular security approaches.”

Agencies that continued to collect large amounts of data measured in tera- or petabytes should reboot systems to ensure the networks are operating properly after a period of lax monitoring, said Carmelo McCutcheon, “chief evangelist” at Hitachi Data Systems Federal Corp., a private-cloud storage contractor based in Reston, Virginia.

‘Fewer People’

About two petabytes of data are housed in all academic research libraries in the U.S.

These systems will take an average of four to eight hours to bring back online, and if there are glitches, the process could take 16 hours or more, McCutcheon said. More significant delays will occur when analysts have to sift through data that accumulated over the past three weeks. The chance of errors will increase, he said.

“What happens if something gets missed because you have to look at three times the amount of data with fewer people?” McCutcheon said.

At the same time, the impact of the shutdown was mitigated by decisions at some agencies to recall some furloughed workers. That included a move by the Pentagon to bring back about 90 percent of its 350,000 civilian defense employees and the Federal Aviation Administration to recall 800 furloughed workers who aid with inspections.

Application Backlogs

“The entities that are affected are much more targeted than in previous shutdowns,” Alan Balutis, director of the Internet Business Solutions Group for Cisco Systems Inc., based in San Jose, California, said in an interview. “I don’t see a big effect.”

Balutis, who headed the management and budget office for the Commerce Department during the 1990s shutdown, said nonetheless that some effects of this month’s halt in federal operations may linger for weeks. Returning workers will grapple with backlogs in applications for everything from veterans’ health benefits to visas for foreigners, he said.