Are the missing White House emails lost without a trace or not?

Jason Leopold writes:

The White House’s chief information officer said the Bush administration should not be compelled to search for millions of e-mails on individual computers and hard drives that may have been lost between 2003 and 2005 because it would be too expensive and require hundreds of hours of work, according to a filing the White House made with a federal court. More on the story.

Here was what the Internet security consultant in April 2007 in the NYT:

Mr. Smith, the Internet security consultant, said e-mail ordinarily is initially stored in at least four places: in the “sent” file of the computer used to send the message; on the computer server of the sender’s Internet service provider; on the computer server of the recipient’s provider; and on the recipient’s computer.
Even if the message is deleted, it may be recoverable from a computer’s hard drive. Eventually, however, the deleted file may be overwritten and lost, Mr. Smith said.

“If you keep sending e-mails, it will probably get overwritten pretty quickly, and then it’s really gone,” he said. More from the NY Times.