Scores of students checking their e-mail on Tuesday found messages from mid to late October that spent at least nine days lost in Harvard's computer network.

Franklin M. Steen, director of the Faculty of Arts and Sciences (FAS) Computer Services, said that on at least two occasions last month, both the main FAS mail server and a secondary backup server went down, forcing student mail into a third, defective system.

"The mail was shunted into the third server, but it was not then sending the mail it had received back to the main server, and we didn't notice that until Tuesday," Steen said.

All lost mail found on the third server was sent out through the FAS system soon after it was discovered, he said. About 50 students sent mail during the time the system was routed to the third server, he said.

"When it affected people, though, it usually affected them a lot, because if someone sat down and wrote five or six e-mails during a time when the first two servers were down, all of those ended up in the third system," he said.

Rachel W. Podolsky '00 said she received a message from the Civil Liberties Union of Harvard more than a week after it was sent.

"It was kind of funny, because it was just a short message, saying 'Don't forget the meeting tomorrow.' That didn't make sense to me because our meetings are always on Mondays," Podolsky said. "Then I saw it had been sent Sunday, November 27th."

Steen said the primary server was down in October for improvements designed to accommodate the system's expanding workload, already twice as high as last year's peak.

"We have to keep tuning an old server. At some points we have 1,200 to 1,300 people logged on at one time, and [the system] begins to slow down around those spikes," he said.

At the beginning of the term, the system slowed down when 800 or 900 people were logged on at the same time, but system upgrades have alleviated the problem somewhat, he said.

"For a while there, it was pretty bad. People had to wait a long time to open their mail," Steen said.

But he said the third backup system is now set to empty itself every hour, making another rash of lost messages theoretically impossible.

To avoid delays in the future, Steen said Harvard is looking to companies like Microsoft and Netscape that are developing e-mail programs that only make brief connections to the system.

"Since these are still in development, I don't know exactly when we'll have them," he said. "We hope to have a new program by the fall and be able to test it out in the spring. For the time being, we have to continue to tune our old system.